• Horticultural Science & Technology
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• v.31 no.1
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• pp.56-64
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• 2013

Recent unusual weather due to global warming causes shortage of daily sunlight and constitutes one of the primary reasons for agricultural damages. LED light sources are frequently utilized to compensate for the shortage of sunlight in greenhouse agriculture. The present study is aimed at evaluating formations of phytochemicals as well as growth characteristics of mature strawberry fruits ('Daewang' cultivar) during cultivation in a closed growth chamber equipped with artificial LED light as a sole light source. Each LED light of blue (448 nm), red (634 and 661 nm) or mixed blue plus red (blue:red = 3:7) was separately supplied and the intensity of each light was adjusted to $200{\pm}1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at plant level with a photoperiod consisted of 16 hours light and 8 hours darkness. Strawberries grown under mixed LED light of blue and red wavelengths showed a higher production of fruits than those grown under other LED treatments. Fructose, one of the free sugars, increased in mixed LED light-grown fruits. Anthocyanin contents were elevated remarkably in the mixed LED light-grown fruits compared with those in other LED treatments. Contrastingly, contents of total phenolics and flavonoids were not of much different from one another among the fruits treated with various LED lights. On the other hand, ripening of strawberry fruits was found to be faster when grown under blue LED light compared with other LED treatments. Moreover, antioxidant activities of blue or red LED light-grown fruits, respectively, were significantly higher than those of mixed LED light-grown fruits. We suggest that when daylight is in shortage during cultivation in a greenhouse, supplementation of sunlight with LED light, which is composed of blue and red wavelengths, could be useful for the enhancement of productivity as well as of free sugar content in strawberry fruits. In addition, for the strawberry culture in the plant factory, selective adoption of LED light wavelength would be required to accomplish the purpose of controlling fruit maturation time as well as of enhancing contents of sugars and antioxidants of fruits.

• Journal of agriculture & life science
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• v.46 no.6
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• pp.25-31
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• 2012

This study aimed to investigate the effect of night temperature on the productivity, growth, and fruit characteristics of tomatoes and set the optimal night air temperature. Tomatoes (Solanum lycopersicum Mill. cv. Superdoterang and cv. Rapito) were grown at 5, 10, 15, and $20^{\circ}C$ during night time and ventilation temperature point during day time set $27^{\circ}C$. Depending on night air temperature, plant height, leaf area, fresh and dry weight of each organ, leaf, stem, and root were changed. Condition of high night temperature resulted in promotion of tomatoes growth with high dry weight and fresh weight. However, the dry weight under night temperature $20^{\circ}C$ decreased, especially, in 'Superdoterang'. On changes of yield, 'Rapito' showed higher productivity than 'Superdoterang' and the highest productivity point for nigh temperature is $13.32^{\circ}C$ for 'Superdoterang' and $14.25^{\circ}C$ for 'Rapito'. Although the total yield decreased from the point, the daily productivity increased with increasing night temperature, the highest point for nigh temperature is $14.45^{\circ}C$ for 'Superdoterang' and $16.46^{\circ}C$ for 'Rapito'. High temperature deceased the fruit weight and increased total soluble solid content in fruits. It is concluded that the night air temperature changes productivity of tomato and the temperatures between productivity and growth velocity have differences depending on different cultivars. scores than the other beef jerky samples (p<0.05).

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.447-453
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• 2019

In this study, the effect of supplying volume and frequency of a nutrient solution consisted with $NO_3-N$ 4.6, $NH_4-N$ 3.4, $PO_4-P$ 3, K 3, Ca 4.6 and Mg $2.2mmol{\cdot}L^{-1}$ on growth and fruit quality of 'Duke' blueberry was investigated. Three years old 'Duke' blueberry bushes cultivated in containers ($60{\times}80{\times}40cm$) filled with 130L peat moss and 40L pearlite (v/v) were selected for the experiment. The growth containers were mulched with sawdust. Two different volumes (4L and 8L) of nutrient solution was tested at three different supplying frequencies (one time, two times, and three times) per week and the drainage quality of nutrient solution and fruit quality of 'Duke' blueberry was evaluated. The optimal drainage rate for the vegetable cultivation is known to be 20-30%. The results revealed that the average drainage rates of 27% and 29% for the nutrient solution supplied in 'Duke' blueberry growth medium at 4L, 2 times/7 days and 4L, 3 times/7days, respectively. The highest shoot diameter (4.2mm) and shoot length (31cm) of 'Duke' blueberry was recorded with the 8L of nutrient solution supplied at 3 times per 7 days. According to the analysis of inorganic components in the drainage of nutrient solution, there was a tendency of absorbing nitrogen at the early stage of growth. The supplying volume and frequency of nutrient solution was not significantly affected on 'Duke' blueberry fruit weight, soluble solids content, and titratable acidity. The highest yield per bush (2.7kg) was recorded for the nutrient solution supplied with 4L at three times per 7 days, while the 4L nutrient solution supplied at one time per 7 days resulted the lowest yield of 1.4kg per bush. Consequently, the tested nutrient solution can be applied for the 'Duke' blueberry bushes with the volume of 4L at three times per week for the better crop growth.

• Korean Journal of Organic Agriculture
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• v.27 no.1
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• pp.33-44
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• 2019

This study was initiated to find possibility of substitute of gibberellin acid and to prevent negative girdling effect such as slow growth of 'Niitaka' (Pyrus pyrifolia Nakai) trees, a major pear cultivar, at harvest and at 60-, 90-, and 120-d after storage. Seasonal wiring with 3.0-mm-diameter were applied on the main branch at 70, 80, 90, 110, and 130 days after full bloom (DAF) to compare the fruit quality and storability. Fruit weight and sugar contents were the greatly increased by the wiring treatment at 110 DAF, with the lowest values observed for the wiring at 70 DAF. All the wiring treatments reduced fruit acidity but did not affect fruit firmness. a-value on fruit skin was the highest for wiring at 110 DAF and 130 DAF, advancing fruit ripening. The lowest fruit weight loss was occurred at wiring at 110 DAF. a-value on fruit skin was the highest for wiring at 90 DAF and 110 DAF. Wiring at 80 DAF the most increased floral bud diameter, resulting in the lowest L:D ratio of 1.74 observed. As for the mineral nutrients concentrations of floral buds, the concentration of K (0.63%) and Mg (0.31%) were the highest after 80 DAF wiring treatment, whereas Ca and P concentrations did not differ among treatment plots. The leaf K concentrations was the highest in the 130-day wiring treatment (0.76%) and in the control plot (0.78%), whereas there was no significant difference in the concentrations of either Ca or P among treatment plots. Short periods of wiring increased foliar Mg concentrations. In floral buds, carbohydrates showed a tendency for accumulating at a lower concentrations (7.75%) after 70 DAF wiring treatment, which was a relatively short treatment period. On the other hand, the carbohydrate concentrations in leaves showed a tendency for accumulating at lower concentrations after 130 DAF wiring treatment (2.51%), which is a long treatment period, and in the control plot (2.43%). Wiring increased the size and sugar content of fruits, and influenced fruit storability. For the wiring treatment period was delayed, the carbohydrate concentration in flower buds showed curvilinear correlation and the negative correlation with the carbohydrate in leaf tissue.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.548-556
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• 2022

In this study, basic data were obtained to determine the optimal cultivation method to achieve stable fruiting and yield increase in "Cheonhwang" jujube trees. Accordingly, thefructification, fruit characteristics, and yield according to tree age were analyzed. The mean (and range of) tree height, crown area, stem diameter near the root, clear stem length, number of main branches, and distance between main branches were 235.6 (217.4-253.8) cm, 3.5 (3.1-4.1) m², 5.5 (4.0-7.1) cm, 70.6 (66.2-72.7) cm, 9.7 (8.6-10.5), and 10.4 (7.9-14.2) cm, respectively. Correlationanalysis results indicated that tree age was positively correlated with crown area, stem diameter near the root, and clear stem length but not with the number of main branches. The mean number (and range) of fruit per fruit-bearing mother shoot and tree were 18.3 (16.7-18.3) and 170.7 (157.9-178.3), respectively. Tree age was not significantlycorrelated with fruiting characteristics (i.e., the numbers of fruit-bearing mother shoots per main branch, fruit-bearing shoots per fruit-bearing mother shoot, fruit per fruit-bearing shoot, and fruit per tree). Given that the shape of jujube trees is constantly managed according to the growing area and greenhouse type, the tree growth characteristics were more affected by tree management techniques than by tree age. The mean (and range of) fruit weight, fruit hardness, and soluble solid content were 28.6 (27.7-30.3) g, 29.4 (28.5-30.4) N, and 20.4 (19.3-21.0) °brix, respectively, and these fruit characteristics were not significantly correlated with tree age.The average yield per tree of the 'Cheonhwang' jujube cultivar was 4.9 (4.8-5.0) kg, which was not significantly correlated with tree age.

• Food Science and Preservation
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• v.17 no.3
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• pp.370-375
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• 2010

Cherries (Prunus avium L) were selected at the light red (LR) and dark red (DR) stages of maturation. Soluble solid content and the physicochemical properties of fresh 'Bing' cherries were analyzed to identify an instrumental nondestructive attribute reflecting changes in sweetness. Soluble solid content was significantly correlated with various physicochemical properties (firmness, color, and acid level) in LR-stage cherries. In DR-stage cherries, only firmness was positively correlated with soluble solid content. A positive correlation was found between soluble solid content and firmness of 200 randomly selected cherries. Thus, flesh firmness may be a useful quality factor indicating potential consumer acceptance of 'Bing' cherries.

• Journal of the Korean Society of Industry Convergence
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• v.10 no.3
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• pp.137-141
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• 2007

The sugar content of persimmon fruits was decreased when food-waste compost was used. Dungsi was brighter with yellow color than that of control. The Gabjubaekmok was darker than that of control with red color. It was suggested that taste of astringent was reduced because total phenol and soluble tannin contents were reduced by that compost. The vitamin C content of persimmon fruits during storage was higher than that of control. Stability of persimmon fruits by that compost and usual compost was about the same at room temperature. At low temperature, hardness of persimmon fruits was maintained for 20days. Hardness and reducing sugar contents of persimmon fruits were increased by food-waste compost. The result was shown that there was no effect on composition of persimmon fruits by food-waste compost and maintaining hardness at room temperature, but at low temperature, the composition of persimmon fruits was changed.

• Korean Journal of Organic Agriculture
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• v.18 no.1
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• pp.55-62
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• 2010

The study was conducted to investigate effects of different organic fertilizers on 'Niitaka' pear tree performances in a controlled greenhouse. The four 'Niitaka' pear seedling trees per treatment were grown in a greenhouse for 6 months. Each pot was filled with control, rice bran (RB), coffee bran compost (CBC), and the mixture (RCC) of RB + CBC + chitin incubated compost (CIC). Each pot was filled with 1:1:1 (v/v/v) of soil : sand : fertilizer, and control, RB, CBC, CIC, and RCC were applied as treatments. Root fresh weights and root activities were increased by all the organic fertilizers, especially by RCC. RCC treated trees had the highest tree height and thickest tree trunk, and all organic fertilized trees showed increased tree growth compared to the control. The more diseased and damaged degrees on the leaf by spider mites increased leaf falling rates on all the treatments. The reduced diseased and healthy leaves were found on RCC treated trees that had better tree performance. Also, all the organic fertilized trees seemed to prevent the occurrence of disease in the leaf. Therefore, the organic fertilizer applications could be a good strategy to obtain better tree performance and maintain healthy seedlings in the nursery market or young organic pear orchard.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.503-510
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• 2013

This study aims to propose safety culture design to ease to find out and control behavior characteristics of Korean seafarers. By empirical research of 377 Korean seafarers, the result revealed that significant characteristic of Korean seafarers was "affection to others" and custom of Confucianism affected Korean maritime society prevalently. But there were no significant differences between groups, such as rank, age, gender and sailing route with vessel type except educational background. Furthermore, this study concluded that positive reinforcement was more useful than negative reinforcement to promote safety operation of vessels. Regarding the vessel's safety management, the fact that means for vessel's safety management are linked only to the levels of educational background suggests that the efficiency of vessel's safety operation would be achieved by introducing suitable safety management system depending on the level of educational background.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.84-95
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• 2018

A mathematical model of responsibility-sensitive safety (RSS) has been proposed as a way to determine whether an autonomous driving accident has occurred. Autonomous vehicles related industry and academia have shown great interest in this model. However, this mathematical model lacks a comprehensive review on whether the model can be used to clarify responsibilities of autonomous vehicles in the event of a traffic accident. In this study, we analyzed the issues that need to be solved in order to apply the RSS model. In conclusion, there is a limit in the equation and the social acceptability of the RSS model. To use the RSS model practically, it is necessary to define the response time of the autonomous vehicle and to measure and control the reaction time value according to the appropriate technology level for each autonomous vehicle.