• Journal of Biosystems Engineering
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• v.12 no.2
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• pp.16-27
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• 1987

Greenhouse farming was introduced to the Korean farmers in the middle of 1950's and its area has been increased annually. The plastic greenhouse, which is covered with polyethylene or polyvinyl chloride film, has been rapidly spread in greenhouse farming since 1970. The greenhouse farming greatly contributed to the increase of farm household income and the improvement of crop productivity per unit area. Since the greenhouse farming is generally practiced during winter, from November to March, the thermal environment in the plastic greenhouse should be controlled in order to maintain favorable condition for plant growing. Main factors that influence the thermal environment in the plastic greenhouse are solar radiation, convective and radiative heat transfer among the thermal component of the greenhouse, and the use of heat source. The objective of this study was to develop a simulation model for thermal environment of the plastic greenhouse in order to determine the characteristics of heat flow and effects of various ambient environmental conditions upon thermal environments within the plastic greenhouse. The results obtained are summarized as follows: 1. Simulation model for thermal environment of the plastic greenhouse was developed, resulting in a good agreement between the experimental and predicted data. 2. Solar radiation being absorbed in the plant and soil during the daytime was 75 percent of the total solar radiation and the remainder was absorbed in the plastic cover. 3. About 83 percent of the total heat loss was due to convective and radiative heat transfer through the plastic cover. Air ventilation heat loss was 5 to 6 percent of total heat loss during the daytime and 16 to 17 percent during the night. 4. The effectiveness of thermal curtain for the plastic greenhouse at night was significantly increased by the increase of the inside air temperature of the greenhouse due to the supplementary heat. 5. When the temperature difference between the inside and outside of the greenhouse was small, the variation of ambient wind velocity did not greatly affect on the inside air temperature. 6. The more solar radiation in the plastic greenhouse was, the higher the inside air temperature. Because of low heat storage capacity of the plant and soil inside the greenhouse and a relatively high convective heat loss through the plastic cover, the increase of solar radiation during the daytime could not reduce the supplymentary heat requirement for the greenhouse during the night.

• Journal of Bio-Environment Control
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• v.6 no.1
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• pp.15-25
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• 1997

Plug seedlings of bell pepper(Capsicum annuum L.) were grown for 50 days in controlled environment chambers under 12 hrs per day photoperiodic condition with sixteen different day and night temperature regimes to investigate the possibility of height control. The seedlings were then transplanted to greenhouse to investigate the growth, flowering, and yield afterward. Plant height and stem length of seedlings were mainly affected by day temperature rather than night temperature. Internode elongation was suppressed by a negative DIF and was enhanced by a positive DIF even with the same average daily temperature (ADT). Leaf unfolding rate was influenced more by ADT than by DIF. Fresh and dry weights increased as ADT increased. Leaf area and stem diameter increased until temperature increased up to 24$^{\circ}C$ day and night temperature and decreased above 24$^{\circ}C$, The position at which the first flower was initiated was lowered as ADT increased. The first flower degeneration was not obvious up to 24$^{\circ}C$ ADT but increased rapidly above 24$^{\circ}C$ ADT. Seedling compactness(Dry weight per plant height :mg.mm$^{-1}$ ) was greater under -DIF than +DIF condition. In conclusion, DIF treatment was an applicable technique to control stem elongation and growth rate such as leaf unfolding rate and position at which first flower was initiated could be controlled by ADT.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.6
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• pp.1025-1033
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• 2016

It is important to compare and analyze digital camouflage from different countries to promote the continuous development of a camouflage combat uniform. This effort should lead to developing a camouflage pattern suitable for the domestic environment and expand its performance of night camouflage. This study investigates digital camouflage by comparing camouflage fabrics sampled from Korea and eight other countries (USA, UK, Singapore, Croatia, Colombia, and Mongolia) in terms of textile, near-infrared reflectivity of colors, and color distribution. First, the fabric construction of camouflage from Korea, UK, US, Singapore, Span, and Croatia were all characterized by derivative plain weaves, while derivative twill weaves were generally used in Croatia and Mongolia. It is assumed that derivative plain weaves are adopted to improve the tearing strength of fine yarns. However, twill weaves enhance the flexibility of coarse yarn fabrics. Next, reflectivity change was analyzed based on camouflage color. The reflectivity of a combat uniform in Korea, Colombia, Croatia, and UK increased before 780nm in the visible light range, but remained consistent from 800nm which falls under the near-infrared range. In contrast, camouflage samples in Mongolia, Span, Singapore and USA showed a gradual increase of reflectivity in the near-infrared range. Finally, the color distribution analysis of digital camouflage found that camouflage of countries with desert or woodland combat settings dominantly contained brown colors. It indicates the color pattern consideration of different geographic regions is important to determine camouflage performance. This research involves basic study that will have implications for developing patterns and colors suitable for the South Korean environment and expand its use as night camouflage that helps achieve continuous improved camouflage performance.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.176-177
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• 2008

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.04a
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• pp.267-268
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• 2006

• Journal of Bio-Environment Control
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• v.19 no.3
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• pp.140-146
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• 2010

This experiment was conducted to find the day and night temperature combination and the light-emitting diodes (LEDs) on the most effective globe coloration and growth of Chamecereus silvestrii f. variegata 'Hee-Mang'. The $L^*$value, $a^*$value and $b^*$value were all significant difference in the yellow globe color expression in the day and night temperature combination. Especially, the bright yellow color and visual value were the highest in the temperature combination, the day temperature of $20^{\circ}C$ and night temperature of $20^{\circ}C$. Globe color quality was lowered from the day temperature of $25^{\circ}C$ and night temperatures of $5^{\circ}C$ and $10^{\circ}C$ combination. In light-emitting diodes (LEDs) treatments, $a^*$value and $b^*$value are significant difference. A unique beautiful yellow coloration and globe quality were maintained the $a^*$value of +5.23, $b^*$value of +39.9 in a red LED. The optimum temperature range and light-emitting diodes (LEDs) on the globe color expression were the most effective the day temperature of 200e and night temperature of $20^{\circ}C$ and a red LED. In addition, the outer globe color quality of Chamecereus silvestrii f. variegata cultivation, rather than the light environment improvement is better in a proper temperature environment to keep. Especially, a unique globe color expression of yellow lines was most effective in a red LED.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.04a
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• pp.75-78
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• 1999

토마토의 육묘시에 화아분화에 미치는 제요인의 영향에 대한 정확한 정보는 미흡하다. 흔히 육묘 중인 토마토의 생식생장을 촉진하기 위해서는 질소비료의 공급량을 줄이고 야간기온을 낮추어 야냉육묘해야 한다고 알려져 있다. 그러나 공정육묘기술의 도입으로 인하여 다품목 소량생산을 위주로 하는 국내의 채소 육묘농가들이 다양한 종류의 묘를 하나의 온실에서 생산해야 하는 한계성을 가지고 있다. (중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2004.03a
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• pp.228-232
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• 2004

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1995.10a
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• pp.58-60
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• 1995

1995년 현재 전국의 육묘장 수는 대략 25개소에 이른다. 1992년부터 도입되기 시작한 플러그육묘 방식은 급속도로 늘어나 매년 5-7개소가 신설되고 있다. 이와 같이 양적팽창에도 불구하고 품질, 수량, 납기 및 경영상의 문제점을 드러내고 있어 상당수의 육묘장은 경영적 어려움에 처해 있다. 이와 같은 문제점 중에서도 가장 심각한 것은 기술수준의 낙후로 인한 품질의 저하이다. 플러그는 작은 셀내에서 육모되기 때문에 밀도가 높아 도장의 우려가 크다. (중략)

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.1
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• pp.69-76
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• 1995

Water content and strong acidity are estimated for ambient particles measured between Fall, 1991 and Summer, 1992 in Seoul using a gas/aerosol equilibrium model, called SCAPE. Particle water content and formation of solid species are closely related to ambient relative humidity and ionic concentrations. Generally, water content of particles is high during the night and summer. Estimated particle strong acidity level of Seoul is similar to that of Los Angeles, U.S.A. Acidity of wet and dry depositions in Seoul is discussed.