• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.153-160
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• 2015

The objectives of this study were to determine optimal length of off-time between irrigation cycles to improve irrigation efficiency using a frequency domain reflectometry (FDR) sensor-automated irrigation (FAI) system for tomato (Solanum lycopersicum L.) cultivation aimed at minimizing effluent from coir substrate hydroponics. For treatments, the 5-minute off-time length between 3-minute run-times (defined as 3R5F), 10-minute off-time length between 3-minute run-times (defined as 3R10F), or 15-minute off-time length between 5-minute run-times (defined as 5R15F) were set. During the 3-minute or 5-minute run-time, a 60mL or 80mL of nutrient solution was irrigated to each plant, respectively. Until 62 days after transplant (DAT) during the autumn to winter cultivation, daily irrigation volume was in the order of 3R5F (858mL) > 5R15F (409mL) > 3R10F (306mL) treatment, and daily drainage ratio was in the order of 3R5F (44%) > 5R15F (23%) > 3R10F (14%). Between 63 and 102 DAT, daily irrigated volume was in the order of 5R15F (888mL) > 3R5F (695mL) > 3R10F (524mL) with the highest drainage ratio, 19% (${\pm}2.6$), at the 5R15F treatment. During the spring to summer cultivation, daily irrigation volume and drainage ratio per plant was higher in the 3R5F treatment than that of the 3R10F treatment. For both cultivations, a higher water use efficiency (WUE) was observed under the 3R10F treatment. Integrated all the data suggest that the optimal off-time length is 10 minutes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.285-289
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• 2012

In this paper, the farm information system was designed by ubiquitous computing. The irrigation system was set up for growing forest products. Also, the integrated sensing system with the radar sensors would be constructed for sensing the temperature, the humidity and the direction of the wind, ect. And the monitoring programs for workers in the fields were provided for the control and the monitoring the growing conditions of the forest products. Finally the database was constructed for the total monitoring and management system, so the data from sensor system was stored in the database sever for analysing growing environment.

• Journal of Bio-Environment Control
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• v.9 no.1
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• pp.66-72
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• 2000

Effects of irrigation control by time and integrated solar radiation on musknelon quality in perlite culture were investigated. Sugar content of melon flesh was high in the irrigation treatment at the following times 6：00, 8：00, 10：00, 11：00, 12：00, 12：30, 13：00, 13：30, 14：00, 14：30, 15：00, 16：00, and 17：00(T-2), compared to the irrigation treatment at every hour from 6：00 to 18：00(T-1) within the irrigation experiment controlled by time. Within the irrigation experiment controlled by integrated solar radiation, sugar content was as high as 15.7(Brix$^{\circ}$) in the 240Wh.m$^{-2}$ , compared to the 180, the 200, and the 220Wh.m$^{-2}$ . Fruit firmness was low in T-2 within the Irrigation experiment by time and in the 220Wh.m$^{-2}$ within the irrigation experiment by integrated solar radiation. Fruit size was smaller in the treatment controlled by integrated solar radiation than by the time treatment. Fruit weight was the heaviest in T-1. The weight of the shoot except for the fruit was lower in treatment of irrigation by integrated solar radiation than by time. In conclusion it is suggested that the appropriate integrated solar radiation pet each irrigation cycle should be 180~20Wh.m$^{-2}$ in the early growing stage, and then gradually increased to 240Wh.m$^{-2}$ from net formation to harvest time.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.401-408
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• 2022

As research on a controlled environment system based on crop growth environment sensing for sustainable production of horticultural crops and its industrial use has been important, research on how to properly utilize soil moisture sensors for outdoor cultivation is being actively conducted. This experiment was conducted to suggest the proper method of utilizing the TEROS 12, an FDR (frequency domain reflectometry) sensor, which is frequently used in industry and research fields, for each orchard soil in three regions in Korea. We collected soils from each orchard where fruit trees were grown, investigated the soil characteristics and soil water retention curve, and compared TEROS 12 sensor calibration equations to correlate the sensor output to the corresponding soil volumetric water content through linear and cubic regressions for each soil sample. The estimated value from the calibration equation provided by the manufacturer was also compared. The soil collected from all three orchards showed different soil characteristics and volumetric water content values by each soil water retention level across the soil samples. In addition, the cubic calibration equation for TEROS 12 sensor showed the highest coefficient of determination higher than 0.95, and the lowest RMSE for all soil samples. When estimating volumetric water contents from TEROS 12 sensor output using the calibration equation provided by the manufacturer, their calculated volumetric water contents were lower than the actual volumetric water contents, with the difference up to 0.09-0.17 m³·m^-3 depending on the soil samples, indicating an appropriate calibration for each soil should be preceded before FDR sensor utilization. Also, there was a difference in the range of soil volumetric water content corresponding to the soil water retention levels across the soil samples, suggesting that the soil water retention information should be required to properly interpret the volumetric water content value of the soil. Moreover, soil with a high content of sand had a relatively narrow range of volumetric water contents for irrigation, thus reducing the accuracy of an FDR sensor measurement. In conclusion, analyzing soil water retention characteristics of the target soil and the soil-specific calibration would be necessary to properly quantify the soil water status and determine their adequate irrigation point using an FDR sensor.

• Journal of Biosystems Engineering
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• v.28 no.6
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• pp.517-524
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• 2003

There have been worldwide research and development efforts to automate various processes of bio-production and those efforts will be expanded with priority given to tasks which require high intensive labor or produce high value-added product and tasks under hostile environment. In the field of bio-production capabilities of the versatility and robustness of automated system have been major bottlenecks along with economical efficiency. This paper introduces a new concept of automation based on tole-operation, which can provide solutions to overcome inherent difficulties in automating bio-production processes. Operator(farmer), computer, and automatic machinery share their roles utilizing their maximum merits to accomplish given tasks successfully. Among processes of greenhouse watermelon cultivation tasks such as pruning, watering, pesticide application, and harvest with loading were chosen based on the required labor intensiveness and functional similarities to realize the proposed concept. The developed system was composed of 5 major hardware modules such as wireless remote monitoring and task control module, wireless remote image acquisition and data transmission module, gantry system equipped with 4 d.o.f. Cartesian type robotic manipulator, exchangeable modular type end-effectors, and guided watermelon loading and storage module. The system was operated through the graphic user interface using touch screen monitor and wireless data communication among operator, computer, and machine. The proposed system showed practical and feasible way of automation in the field of volatile bio-production process.

• Smart Media Journal
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• v.12 no.10
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• pp.47-54
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• 2023

As understanding sudden climate change and agricultural productivity becomes increasingly important due to global warming, soil moisture prediction is emerging as a key topic in agriculture. Soil moisture has a significant impact on crop growth and health, and proper management and accurate prediction are key factors in improving agricultural productivity and resource management. For this reason, soil moisture prediction is receiving great attention in agricultural and environmental fields. In this paper, we collected and analyzed open field environmental data using a pilot field through random forest, a machine learning algorithm, obtained the correlation between data characteristics and soil moisture, and compared the actual and predicted values of soil moisture. As a result of the comparison, the prediction rate was about 92%. It was confirmed that the accuracy was . If soil moisture prediction is carried out by adding crop growth data variables through future research, key information such as crop growth speed and appropriate irrigation timing according to soil moisture can be accurately controlled to increase crop quality and improve productivity and water management efficiency. It is expected that this will have a positive impact on resource efficiency.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.1
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• pp.75-84
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• 2015

This study was conducted to investigate the effects of high temperature and drought on growth performance, photosynthetic parameters and photosynthetic pigment contents of Liriodendron tulipifera L. seedlings. The seedlings were grown in controlled-environment growth chambers with combinations of four temperature ($-3^{\circ}C$, $0^{\circ}C$, $+3^{\circ}C$, $+6^{\circ}C$; based on the monthly average for 30 years in Korea) and two water status (control, drought). Temperature rise increased growth, total dry weight and leaf area in all water status. Also photosynthetic rate, dark respiration, stomatal conductance and transpiration rate increased with increasing temperature. In contrast, growth and photosynthetic parameters of L. tulipifera seedlings were lower in $-3^{\circ}C$ than $0^{\circ}C$. But temperature rise decreased water use efficiency in all water status. Temperature rise increased photosynthetic pigment contents of leaf. Also chlorophyll a/b ratio increased with increasing temperature. In conclusion, the elevated temperature lead to causes growth increase through the increase of energy production by higher photosynthetic rate during a growth period of L. tulipifera seedlings.

• Journal of Bio-Environment Control
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• v.30 no.1
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• pp.46-55
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• 2021

This experiment was conducted to investigate the effect on chlorophyll fluorescence, stem sap flux relative rate (SFRR) and leaf temperature of cucumber when irrigation is controlled using a soil moisture tensiometer. Cucumber (Cucumis sativus L.) 'Chungchun' was irrigated of 10-10-20 kPa and 20-10-10 kPa by soil starting point of irrigation at each growth stage. At the 66 days after treatment (DAT) of 736 to 854 W·m-2 and above 32℃, chlorophyll fluorescence variables (Fo, Fm, Fv/Fm) values showed significantly different between treatments. The Fo and Fv/Fm value in the daytime (10:30 am to 6:00 pm) at 66 DAT was higher in 20-10-10 kPa treatment than in 10-10-20 kPa treatment. The Fv/Fm value decreased when the leaf temperature was increased. There was no difference in leaf growth (length, width and area) at 28 and 66 DAT, but the chlorophyll content (SPAD value) was significantly higher in 20-10-10kPa treatment. SFRR and leaf temperature increased with light intensity and temperature increased. In both treatments, the SFRR started to increase sharply between 8 am and 9 am when the solar radiation is 170 W·m-2 or higher. The soil temperature of the treatments decreased after irrigation, that showed 31.0℃ at 10-10-20kPa and 28.5℃ at 20-10-10kPa on July 5 (820W·m-2 at 1 pm). However, there was no difference in SFRR, leaf temperature, temperature difference (leaf temperature - air temperature) and VPD between treatments. SFRR was significantly positive correlate with the leaf temperature (p < 0.01, r = 0.770). The SFRR and leaf temperature showed positive significant correlation with solar radiation, temperature, soil temperature, soil moisture content and VPD. There was a negative significant correlation with relative humidity and temperature difference.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.5
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• pp.358-364
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• 2001

To obtain information for the proper fertilization management of cut-flower roses, the amount of macro and micro elements absorbed by cut-flower roses from soil for a year was investigated. Three cut-flower rose cultivars which are called 'Grandgara', 'Nobless', and 'Centina' were transplanted to a sandy loam soil, N-P-K standard fertilization was applied to the soil, and drip irrigation was done at the level of 10 kPa soil moisture tension. There was not significantly different in the harvest amount of cut-flower rose between 'Grandgara' and 'Nobless', but the harvest yield of 'Centina' was about 63% level when compared to that of 'Grandgara'. Considering seasonal changes in the content of nutrients in plant, parts, the uptake of untrients was higher in winter season than that in spring and summer seasons. Except for 'Centina', the nutrient amount removed from plant parts of 'Grandgara' and 'Nobless' increased with the sequence of floral part < stem < leaf, indicating that it is more dependent on biomass yield than on the content of nutrients in each plant part. The ratio of N/K amount absorbed by 'Nobless' and 'Centina' was 1.13 and 1.28. respectively, lower than 1.68 of 'Grandgara', showing that the requirement for K is greater in 'Nobless' and 'Centina' than in 'Grandgara'. The use efficiency of nutrients by cut-flower roses ranged from 39 to 64% in nitrogen, 5 to 9% in phosphorus, and 37 to 67% in potassium. It suggests that the requirement for P in cut-flower roses is very low.

• Journal of Biosystems Engineering
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• v.28 no.6
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• pp.511-516
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• 2003

Computer vision technology has been utilized as one of the most powerful tools to automate various agricultural operations. Though it has demonstrated successful results in various applications, the current status of technology is still for behind the human's capability typically for the unstructured and variable task environment. In this paper, a man-machine interactive hybrid decision-making system which utilized a concept of tole-operation was proposed to overcome limitations of computer image processing and cognitive capability. Tasks of greenhouse watermelon cultivation such as pruning, watering, pesticide application, and harvest require identification of target object. Identifying water-melons including position data from the field image is very difficult because of the ambiguity among stems, leaves, shades. and fruits, especially when watermelon is covered partly by leaves or stems. Watermelon identification from the cultivation field image transmitted by wireless was selected to realize the proposed concept. The system was designed such that operator(farmer), computer, and machinery share their roles utilizing their maximum merits to accomplish given tasks successfully. And the developed system was composed of the image monitoring and task control module, wireless remote image acquisition and data transmission module, and man-machine interface module. Once task was selected from the task control and monitoring module, the analog signal of the color image of the field was captured and transmitted to the host computer using R.F. module by wireless. Operator communicated with computer through touch screen interface. And then a sequence of algorithms to identify the location and size of the watermelon was performed based on the local image processing. And the system showed practical and feasible way of automation for the volatile bio-production process.