• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.188-193
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• 2022

The Korean mint (Agastache rugosa Kuntze) is used as a leaf vegetable. Therefore, it is important to improve the quality and quantity of leaves by maintaining vegetative growth. When the development of a plant is switched from vegetative to reproductive growth, leaf development may be lowered, leading to a decrease in marketability. Therefore, this study was conducted to investigate the effect of the photoperiod on the flowering characteristics and inflorescence development of the Korean mint to select an appropriate photoperiod for leaf production. The seeds were sown in 105-cell trays on 29 November 2021, and planted in each pot on 27 December 2021, when four main leaves appeared. After planting, the light/dark period was adjusted to 10/14hrs, 12/12hrs, 14/10hrs, 16/8hrs. After 19 days of planting, the first flowering occurred in 10/14hrs, which had a short photoperiod, and the 12/12hrs had 20 days for flowering, and other treatments had 21 days. In addition, it was confirmed that the Korean mint has the characteristics of facultative quantitative short-day plant, through the increase in the development of inflorescences as the light period is shorter than the dark period. As for the growth of Korean mint, the longer the photoperiod, the higher values were shown with leaf length, number of leaves, fresh weight, dry weight, and leaf area of the shoot. Therefore, it is considered that 14 h or more light period is suitable for increasing the productivity of Korean mint as a leafy vegetable.

• Journal of Internet of Things and Convergence
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• v.3 no.1
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• pp.1-8
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• 2017

Information and time are very important for a modem life, and researches about the personal secretary system that provides specific information for each individual are being studied. In this research, we developed the personal secretary system called Genie which provides the user with desired informations such as weather, news, and traffic information with time. It is expected that the Genie system will provide information on news, weather, traffic information including bus arrival times, and memos with time so that users can find their own leisure time and live a comfortable life.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.5
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• pp.141-152
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• 2011

Cuttings based on water media are relatively low-cost and easy to manage compared to those based on soil media. Nevertheless, species that root out in water media are very few. Water-medium rooted cuttings are not widely used. In water media, the survival rate of cuttings is high, but in many cases, they only form callus while not rooting. If cuttings with callus formed in a water medium were to root and survive after being transplanted in soil, water-medium cuttings could be used as an important means of propagating landscape tree species. In this study, cuttings of Ternstroemia japonica having various reactions to water media were soaked in different types of water media. Their callus formation and rooting conditions were analyzed. The water-medium cutting swere then transplanted in soil, and conditions for their survival were examined. The study concluded: 1. Cuttings that only formed callus in water media were able to root and survive after being transplanted. 2. Cuttings with satisfactory callus formation showed more satisfactory survival conditions than those with unsatisfactory callus formation. 3. Cuttings rooted in water media showed a high survival rate of 96.6% after being transplanted. 4. Water-medium cutting of Ternstroemia japonica proved to be more effective in Late July or August than in late June. 5. Cuttings pre-treated in 50ppm-IBA for 24 hours showed better survival conditions than those that were not pre-treated inIBA. 6. Cuttings pre-treated in 50ppm-IBA for 24 hours and soaked in water media with 0.02% atonic, 0.02% polyoxin, and 0.01% polyoxin showed a rooting and survival rate of 80 to 85%. Regardless their low rooting rate, water-medium cuttings can show a high survival rate when these factors are considered: proper cutting time, plant hormone treatment, and types of water media. Accordingly, water-medium cuttings will emerge as major means of propagating landscape tree species that require small volumes of multi-species.

• Journal of Navigation and Port Research
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• v.43 no.4
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• pp.231-236
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• 2019

As ships become bigger, faster, and diverse, transportation has increased the usage of marine vehicles. However, ship accidents are increasing. Ship accidents cause loss of life and property as well as environmental disasters. The occurrence of ship accidents causes enormous economic and environmental impacts. Notably, in the case of passenger ships, methods for preventing ship accidents are being discussed to avoid losing numerous human lives. The purpose of this study is to provide essential data for evacuation before reaching the dangerous time by predicting the time to reach the risk of capsizing based on the heeling angle of the passenger ship. Based on sinking accidents between 2012 and 2016, we set up specific scenarios and simulated the PRR1 data using commercial software MOSES V20. In the case of the linear equation, the simulation results showed a low error rate because the simulation data showed the linear graph. In the case of the quadratic equation, the error rate was low at the beginning but showed a high error rate at the subsequent angle.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.04a
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• pp.87-91
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• 1999

봄철 하우스 수박 무가온 조숙재배에 알맞는 보온방법을 개발하고자 아취형 단동하우스에 PE필름터널, 유공필름＋축열물주머니, 유공필름터널＋부직포터널구를 처리하고, 삼복꿀수박을 '98년 3월 23일 정식하여 4월 27일까지 36일간 터널피복재의 보온성을 검토한 결과는 다음과 같다. (1) 보온재 피복 재배 기간중 터널내 최저온도는 PE터널구 10.9$^{\circ}C$에 비하여 유공필름터널에 축열물주머니구와 부직포터널구는 각각 0.9, 2.1$^{\circ}C$ 높았다. (2) 3월하순 활착기의 하우스내 일사량은 실외 175.2w/$m^2$ 비하여 124.2w/$m^2$로 51w/$m^2$ 낮았다. (3) 터널피복재 환기작업에 따른 소요 노동력은 PE터널구 25.2시간/10a/36일에 비하여 유공필름터널＋부직포터널구는 32.4시간으로 7.2시간/10a/36일 증가하였으나, 유공필름터널＋축열물주머니는 개폐작업으로 인한 투하 노동력이 없었다. (4) 터널재배 기간중 유공필름터널＋부직포터널구가 초기생육이 촉진되었으며, 생육후기에 발생한 흰가루병 이병엽율은 2.8%로 현저히 감소하였다. (5) 수박의 수확기는 PE필름터널구 6월 22일에 비하여 유공필름터널＋축열물주머니와 부직포터널구는 6월 12, 15일로 7, 10일 앞당겼으며, 수량은 PE터널구 2,385kg/10a에 비하여 20, 32% 각각 증수하였다.

• Journal of the Korean Magnetics Society
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• v.8 no.3
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• pp.161-168
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• 1998

In this paper, a algorithm is proposed, which is applicable to the transient analysis of diffusion equations by combined use of the Laplace transform and the finite element method. The proposed method removes the time terms using the Laplace transform and then solves the associated equation with the finite element method. The solution which is solved at frequency domain is transformed into time domain by use of the Laplace inversion. To verify the proposed algorithm, a heat conduction problem is analysed. And the solution showed a good agreement with analytic solution. Because the time-step method is not needed, the proposed method is very useful in solving various kinds of diffusion equations.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.54-63
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• 2018

Red and blue lights are effective wavelengths for photosynthesis in plants. In this study, we determined the effects of various combined ratios of red to blue LEDs on the quality of cherry tomato seedlings prior to transplantation, and their subsequent effects on the yield and quality of tomato fruits after transplanting. Two-week-old cherry tomato seedlings (Solanum lycopersicum cv. 'Cuty') were cultivated under various combined ratios of red (R; peak wavelength 655 nm) to blue (B; 456 nm) LEDs [red:blue = 41:59 (59B), 53:47 (47B), 65:35 (35B), 74:26 (26B), 87:13 (13B), or 100:0 (0B)] and fluorescent lamps and raised for 27 days. The cherry tomato seedlings were subsequently transplanted into a venlo-type greenhouse and cultivated for 75 days. At the seedling stage, the shoot fresh weight of seedlings in all RB combined treatments, except 0B and 59B, was higher than that of the control after 27 days of LED treatment. Shoot dry weight and leaf area also showed trends similar to that of shoot fresh weight. The stem length was significantly higher in 13B, 26B, and 35B treatments compared with the control and other treatments. In particular, the stem length of 26B plants was approximately 3.2 times longer than that of 59B plants. At 37 days after transplanting, the number of nodes was significantly higher in 26B and 47B plants, and the plant height of 26B plants was significantly higher than that of control and 59B plants. Total fruit yield in 26B plants, which was the highest, was approximately 1.6 and 1.8 times higher than that in control and 59B plants, respectively. Thus, the results of this study indicate that various combined ratios of red to blue LEDs directly affected to the growth of cherry tomato seedlings and may also affect parameters of reproductive growth such as fruit yield after transplantation.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.69-78
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• 2017

This study was conducted to investigate the effects of waterlogging on the net photosynthetic rate, root activity and fruit yield of hot pepper. Plants were grown in two greenhouses: extractor fans and side ventilators began to operate when the inside temperature reached $25^{\circ}C$ in one greenhouse and $35^{\circ}C$ in the other. Waterlogging treatments were performed 54 days after transplanting (when fruit setting at the second flower truss was complete). The plot in each greenhouse was divided into five sections, and each section was watered for 0, 12, 24, 48 or 72 h using drip irrigation. Plants under $25^{\circ}C$ and non - waterlogging treatment exhibited in the greatest growth among treatments. Plant growth generally decreased as the waterlogging period increased. The net photosynthetic rate was highest under non - waterlogging and $25^{\circ}C$ treatment and lowest under 72 h waterlogging and $25^{\circ}C$ treatment. The root activity decreased as the waterlogging period increased, except for plants under 72 h waterlogging treatment at $35^{\circ}C$. The number and weight of red pepper fruits per plant were highest under non - waterlogging treatment at $35^{\circ}C$. The greatest fruit yield was also observed under non - waterlogging treatment at $35^{\circ}C$, with production reaching 3,697 kg / 10a. At the appropriate temperature for hot pepper ($25^{\circ}C$), yields were reduced by 25 - 30% under 12, 24 and 48 h waterlogging treatment compared to non - waterlogging treatment. These results indicate that longer waterlogging periods reduce the growth, net photosynthetic rate, root activity and yields of hot pepper. However, the net photosynthetic rate and stomatal conductance of hot pepper plants grown under 72 h waterlogging treatment recovered nine days after growth under normal growth conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3822-3826
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• 2012

We have studied the effect of temperature and exposure time on the UV curing rate of Urethane Acrylate. UV dose has been modulated by changing the electric power, and temperature has been controled by coating rate and water temperature of the coating roll. Curing rate was evaluated by measuring gel fraction of the cured film. It has been found that effect of coating velocity on the gel fraction of the final film is predominant, but role of temperature of the UV chamber is negligible. These observations imply that exposure time of UV light is critical to have a fully cured film. To better understand the effect of design and operating condition of UV coater on the behavior of UV curing of Urethane Acrylate, we have also conducted heat-flux analysis of UV chamber.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.101-105
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• 2003

This experiment was conducted to find out the effect of day length on the production of high quality plug seedlings in onion (Allium cepa L.). Two cultivars, ‘Changnyongdaego’ and‘Wolryun’, were grown to seedlings in 200-cell plug trays under 11.5, 12.5, 13.5 hours and natural day length. These seedlings were transplanted to the pot (16 cm In diameter) and grown under 16 hours day length. Number of leaves and neck diameter showed better growth in the longer than shorter day length treatments, but plant height old sheath length were retarded in the longer day length treatments. Growth such as no. of leaves, neck diameter, plant height and sheath length increased with the passage of day, but plant height and neck diameter decreased by treatment over 20 days with 13.5 hours day length. Bulbing and bulb size of onion after transplanting were enhanced in the seedlings cultured under longer day lengths. From the above results, treatment of long day length during seedling culture in plug tray can control the overgrowth and produce high quality plug seedlings.