• Journal of Bio-Environment Control
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• v.7 no.1
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• pp.15-24
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• 1998

The greenhouse temperature controls in general have been managed by the above-ground part environment, But the temperature of root zone was known very important factor for the 9rofth and the yield of vegetables in greenhouse. The purpose of this study is to develop a good method for cultivation using solar energy which can apply warming soil and to develop the greenhouse soil temperature automatic control system. Followings are summary of this study：1 When the greenhouse inner temperature changes were about 24$^{\circ}C$ during a day in October, the temperature of non-warmed soil was differenced 6$^{\circ}C$ in the depth 10cm and 3$^{\circ}C$ in the depth 20cm. 2. When water supply temperature was kept at 40, 50 and 6$0^{\circ}C$, the lowest soil temperature in the depth of 10cm is 2$0^{\circ}C$ and that of 20cm was 23$^{\circ}C$. and when the water supply temperature was over 4$0^{\circ}C$, the space heating temperature did not affect the temperature variation of soil. 3. In comparison with conditions of the warmed and non-warmed soil, when the water supply temperature is 28$^{\circ}C$, soil temperatures had the high temperature of 4$0^{\circ}C$~7$^{\circ}C$ in the depth of 10cm to 20 cm. 4. The line of boundary area was appeared in the depth of 15~20cm, 13~19cm and 12~17cm. when the water supply temperature was 4$0^{\circ}C$, 5$0^{\circ}C$ and 6$0^{\circ}C$. 5. When th inner greenhouse air temperature is maintained over 11$^{\circ}C$ and the water supply temperature is supported 28$^{\circ}C$, the lowest temperature is kept up over 2$0^{\circ}C$.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.05a
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• pp.59-62
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• 2000

In cope with insufficient agricultural labor and requirement of high quality product Hydroponics is a really good method. It makes the high density agriculture possible and all the growing environments controllable. So its research is so much progressing to maximize the quantity and quality of farm products. Furthermore, the big progress, in the research of a future agriculture, is systematically conducted for the automatic controlled system. In this paper, a new approach to the automation of the cultivation in a green house is suggested and a practical automatic control cultivation system is implemented. To automatically control and optimize the very nonlinear and time-varying growth of farm products, a hybrid strategy(FECA; Fuzzy Expertized Control Algorithm) is proposed which serially combines a fuzzy expert system with the fuzzy logic control. The fuzzy expert system(FMES; Fuzzy Model-based Expert System) is intended to overcome the non-linearity of the growth of farm products. The part of fuzzy controller is incorporated to solve the time-variance of the growth of farm products. Finally, the efficiency and the effectiveness of the implemented agricultural automation system is presented through the cultiviation results.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.242-249
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• 1997

Environmental control operations have been considerably contributed to the reduction of labor cost in both plastic film and glass greenhouses since government supported projects were begun. However, some problems are still remaining on the optimal environmental control and excessive operation due to an inflexible software regulating ventilation gear - reducers. The unadjustable software caused the damage of ventilation system, resulting in heat stresses of crops. This study was performed to develop a ventilation software controlling the vent opening level, opening sequence, based on the wind direction, and control interval according to the difference between ambient and set- up temperatures. The software included a beeper system alarming urgent cases, while a manager was remote from the greenhouse. A compatible hardware with the software was also developed by using a low-cost diffused DSP controller.

• Journal of Bio-Environment Control
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• v.9 no.4
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• pp.212-222
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• 2000

This study was performed to investigate the performance of heat recovery device attached to exhaust gas flue connected to combustion chamber of greenhouse heating system. The experimental heat recovery system is mainly consisted of LPG combustion chamber and two heat recovery units; unit-A is attached directly to the exhaust gas flue, and unit-B is connected with unit-A. Heat recovery performance was evaluated by estimating total energy amounts by using enthalpy difference between two measurement points together with mass flow rate of gas and/or air passing through each heat recovery unit depending on 5 different flow rates controlled by voltage meter. The results of this experimental study, such as heat exchange behavior of supply air tubes and exhaust air passages crossing the tubes, pressure drop between inlet and outlet, heat recovery performance of exchange unit, etc., will be used as fundamental data for designing optimum heat recovery device to be used for fuel saving purpose by reducing heat loss amounts mostly wasted outside of greenhouse through flue.

• Journal of Bio-Environment Control
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• v.5 no.1
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• pp.57-64
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• 1996

To use effectively the solar energy in greenhouse heating, a high performance solar collector should be developed. And then the size of the solar collector and thermal storage tank should be determined through the calculation of heating load. The solar collector must be set in the optimum tilt angle and direction to take daily solar radiation maximally, and the flow rate of heat transfer fluid through the solar collector should be kept in the optimum range. In this research, the performance tests of a capillary tube solar collector were performed to determine the optimum water flow rate and the results summarized as follows. 1. The regressive equations for efficiency estimations of the capillary tube solar collector in the open loop were modeled in the water flow rate of 700-l,000 $\ell$/hr. 2. The optimum water flow rate of the solar collector was estimated by the second order polynomial regression and the maximum efficiency was 80% at the water flow rate of 850 $\ell$/hr. 3. The solar thermal storage system consisted of a capillary tube solar collector and a water storage tank was tested at the water flow rate of 850 $\ell$/hr in the closed loop, and obtained the solar thermal storage efficiency of 55.2%. 4. As the capillary tube solar collector engaged in this experiment was made of non-corrosive polyolefin tubes, its weight was as light as 1/30 of the flat plate solar collector made of copper tubes. Therefore it was considered to be suitable for the greenhouse heating system.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.271-277
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• 2021

In this study, experiments of local heating on crown and supplying warm nutrient for energy saving and improving growth of 'Seolhyang' strawberry were conducted. The temperature of inside and crown in greenhouses which were control (space heating 8℃) and test (space heating 5℃+crown heating) was measured. In the control greenhouse, the average of temperature and humidity in December was 7.1℃, 87.2%, respectively. In the test greenhouse, the average of temperature and humidity in December was 5.7℃, 88.7%. The temperature of crown and inside the bed were 7.9℃, 10.8℃ in control, 9.3℃, 12.7℃ in test. During the test period, the total 16,847×10³ kcal of energy was consumed in control greenhouse including space heating. In test greenhouse including space heating, crown heating and warm water supplying, total 9,475.7×10³ kcal of energy was consumed. So, energy consumption in test was 43.8% less than in the control. The total yields of strawberry during test period were 412.7g/plant for test greenhouse and 393.3g/plant for control greenhouse respectively.

• Journal of Bio-Environment Control
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• v.7 no.4
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• pp.283-289
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• 1998

The adaptability of an evaporative cooling system to hot summer climate in greenhouses was comprehensively judged by fuzzy theory, based on the 20 years(1975~1994) weather data of nine representative regions in Korea. As uses the evaporative cooling system for greenhouses during summer in Korea, the inside air temperature of most regions except the southwest coastal areas, the south coastal areas, and Cheju island can be basically controlled below 32.5$^{\circ}C$, and ventilating air can be cooled 5$^{\circ}C$ and more. The analyzed results in this paper are on the basis of good ventilation system. When the evaporative cooling system is applied, the ventilation system which has good air flow organization is needed. Although the summer climate in Korea is high temperature and humidity, evaporative cooling systems are suitable for farm buildings in most regions. This facts better meet the needs of cooling for greenhouse in summer and provides a scientific basis for spreading the evaporative cooling system It is proposed that the further research is needed about the application of evaporative cooling system to greenhouses.

• The Journal of Korean Association of Computer Education
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• v.7 no.1
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• pp.67-77
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• 2004

In this paper, a new approach to the automation of the cultivation in a green house is suggested and a practical automatic control cultivation system is implemented. To automatically control and optimize the very nonlinear and time-varying growth of farm products, a hybrid strategy(FECA, Fuzzy Expertized Control Algorithm) is proposed which serially combines a fuzzy expert system with the fuzzy logic control. The fuzzy expert system(FMES, Fuzzy Model-based Expert System is intended to overcome the non-linearity of the growth of farm products. The part of fuzzy controller(FLC, Fuzzy Logic Controller) is incorporated to solve the time-variance of the growth of farm products. Finally, the efficiency and the effectiveness of the implemented agricultural automation system is presented through the cultivation results.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.1
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• pp.77-83
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• 2011

This paper proposes a remote monitoring system, which manages crops' growth environment on a real-time basis by applying to greenhouses Green U-IT technology connecting environment control equipment such as temperature sensors, soil sensors, and moisture censors with computers. Information on greenhouses' environment is stored in a database, and by utilizing linear regression analysis and differential item functioning (DIF) analysis, optimal information on growth and environment is extracted from stored information in the form of items desired by users, and compared, analyzed, and monitored. By linking greenhouse environment control system with web environment and remotely controlling the system, users do not need to visit farmland and can remotely control greenhouses' environment on a real-time basis. Therefore farmhouses' production efficiency may be enhanced by continuously providing optimal growth environment for plants.

• Journal of Bio-Environment Control
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• v.24 no.1
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• pp.34-38
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• 2015

This research was conducted to establish efficient methods to overcome high temperature and low humidity with light selective shading agent and two-fluid fogging system in greenhouses in hot season. There were four experimental treatments; not treated (Non), fogging by two-fluid fogging system (Fog), spraying onto the greenhouse surface with shading coating agent (Coat), and using fogging and coating together (F&C). The amount of solar radiation entered into the greenhouses was higher in Non, and then Fog, Coat, and F&C in descending order. Fog was more efficient to lower the air temperature and also raise relative humidity than Coat treatment. The crop temperature was about $6^{\circ}C$ higher in Control than the other treatments. F&C revealed as the most efficient method to control the environment inside the greenhouse, but fogging system seemed to be more economic. In stand-alone greenhouses spraying coating agent may be the appropriate choice because of their structural limitations, mainly eave height.