• Korean Journal of Agricultural Science
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• v.4 no.2
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• pp.344-390
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• 1977

The purpose of this paper was to schedule optimum cutting strategy which could maximize the total yield under certain restrictions on periodic timber removals and harvest areas from an industrial forest, based on a linear programming technique. Sensitivity of the regulation model to variations in restrictions has also been analyzed to get information on the changes of total yield in the planning period. The regulation procedure has been made on the experimental forest of the Agricultural College of Seoul National University. The forest is composed of 219 cutting units, and characterized by younger age group which is very common in Korea. The planning period is devided into 10 cutting periods of five years each, and cutting is permissible only on the stands of age groups 5-9. It is also assumed in the study that the subsequent forests are established immediately after cutting existing forests, non-stocked forest lands are planted in first cutting period, and established forests are fully stocked until next harvest. All feasible cutting regimes have been defined to each unit depending on their age groups. Total yield (Vi, k) of each regime expected in the planning period has been projected using stand yield tables and forest inventory data, and the regime which gives highest Vi, k has been selected as a optimum cutting regime. After calculating periodic yields and cutting areas, and total yield from the optimum regimes selected without any restrictions, the upper and lower limits of periodic yields(Vj-max, Vj-min) and those of periodic cutting areas (Aj-max, Aj-min) have been decided. The optimum regimes under such restrictions have been selected by linear programming. The results of the study may be summarized as follows:- 1. The fluctuations of periodic harvest yields and areas under cutting regimes selected without restrictions were very great, because of irregular composition of age classes and growing stocks of existing stands. About 68.8 percent of total yield is expected in period 10, while none of yield in periods 6 and 7. 2. After inspection of the above solution, restricted optimum cutting regimes were obtained under the restrictions of Amin=150 ha, Amax=400ha, $Vmin=5,000m^3$ and $Vmax=50,000m^3$, using LP regulation model. As a result, about $50,000m^3$ of stable harvest yield per period and a relatively balanced age group distribution is expected from period 5. In this case, the loss in total yield was about 29 percent of that of unrestricted regimes. 3. Thinning schedule could be easily treated by the model presented in the study, and the thinnings made it possible to select optimum regimes which might be effective for smoothing the wood flows, not to speak of increasing total yield in the planning period. 4. It was known that the stronger the restrictions becomes in the optimum solution the earlier the period comes in which balanced harvest yields and age group distribution can be formed. There was also a tendency in this particular case that the periodic yields were strongly affected by constraints, and the fluctuations of harvest areas depended upon the amount of periodic yields. 5. Because the total yield was decreased at the increasing rate with imposing stronger restrictions, the Joss would be very great where strict sustained yield and normal age group distribution are required in the earlier periods. 6. Total yield under the same restrictions in a period was increased by lowering the felling age and extending the range of cutting age groups. Therefore, it seemed to be advantageous for producing maximum timber yield to adopt wider range of cutting age groups with the lower limit at which the smallest utilization size of timber could be produced. 7. The LP regulation model presented in the study seemed to be useful in the Korean situation from the following point of view: (1) The model can provide forest managers with the solution of where, when, and how much to cut in order to best fulfill the owners objective. (2) Planning is visualized as a continuous process where new strateges are automatically evolved as changes in the forest environment are recognized. (3) The cost (measured as decrease in total yield) of imposing restrictions can be easily evaluated. (4) Thinning schedule can be treated without difficulty. (5) The model can be applied to irregular forests. (6) Traditional regulation methods can be rainforced by the model.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.286-290
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• 2018

This study was carried on comparison of forage yields and growth of cropping system as forage (winter & summer) in Cheonan 2015~2016. The species of forage crop used were Barley (cv. Youngyang), Sorghum (cv. SX17), Proso millet (domestic) and Japanese millet (cv. Jeju). Plant height is the lowest when harvested in lough stage than in the harvests of all summer crops. The dry matter yield of lough stage was 1,343 kg/10a in barley. Looking at the dry matter according to cropping systems, the sorghum was higher at 10,018 kg when harvested at the lough stage than at the harvest. Dry matter of Proso millet and Japanese millet also had higher at the lough stage than at other harvest times. ADF content of sorghum was lower than that of harvesting, but Proso millet and Japanese millet showed higher ADF content in lough stage. The NDF content of the three crops was higher than that of the harvests, and crude protein content was higher in harvest than that of at lough stage. Total production of crude protein against dry matter yield was about 761 kg when sorghum was harvested at lough stage. There was no difference in the content of TDN among three crops according to harvesting time.

• Korean Journal of Food Science and Technology
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• v.51 no.3
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• pp.214-220
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• 2019

Four rice varieties (Boseogchal for waxy, Baegjinju for medium-waxy, and Seolgaeng and Haiami for non-waxy) were milled to 2% degree of milling (DOM), and physicochemical and sensory properties of 2% milled rice (2% MR) were compared to those of brown rice (BR). No significant differences in the approximate compositions of BR and 2% MR were observed, whereas the grain color of 2% MR was slightly brighter than that of BR. For all varieties, water absorption ratio of BR was significantly increased by milling. The pasting properties of rice varied significantly depending on the variety, but there was no significant difference in peak and through viscosities between BR and 2% MR. Analysis of the texture of cooked rice showed that milling to 2% DOM caused a significant decrease in hardness, but an increase in adhesiveness and stickiness. Cooked Seolgaeng 2% MR scored significantly higher in the sensory evaluation than the corresponding BR. These results suggest that 2% DOM would be useful for improving the sensory properties of cooked non-waxy rice.

• Proceedings of the Korean Society of Crop Science Conference
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• 2020.06a
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• pp.121-121
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• 2020

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.405-414
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• 2021

This study predicted waxy corn harvest date in South Korea using 30-year (1991-2020) hindcasts (1-6 month lead) produced by the Pusan National University Coupled General Circulation Model (PNU CGCM)-Weather Research and Forecasting (WRF) chain. To estimate corn harvest date, the cumulative temperature is used, which accumulated the daily observed and predicted temperatures from the seeding date (5 April) to the reference temperature (1,650~2,200℃) for harvest. In terms of the mean air temperature, the hindcasts with a bias correction (20.2℃) tends to have a cold bias of about 0.1℃ for the 6 months (April to September) compared to the observation (20.3℃). The harvest date derived from bias-corrected hindcasts (DOY 187~210) well simulates one from observation (DOY 188~211), despite a slight margin of 1.1~1.3 days. The study shows the possibility of obtaining the gridded (5 km) daily temperature and corn harvest date information based on the cumulative temperature in advance for all regions of South Korea.

• Journal of agriculture & life science
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• v.50 no.5
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• pp.61-68
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• 2016

This study was focused to examine the effects of pre- or post-harvest Ca-chitosan treatment on the shelf-life of 'Daesung' hardy kiwifruit. In the preharvest treatment, Ca-chitosan at 200 mg/L was intensively sprayed to the fruit three times on August 20, 25, and 28 in an order whereas harvested fruits were dipped for 10 sec. at the same concentration of chitosan as the postharvest treatment. Fruits were stored at 17℃ for 9 days and 1℃ for 40 days, respectively. Soluble solid contents, titratable acidity, firmness, respiration rate, and weight loss were examined to configure the qualities of fruits during storage. The changes of fruit quality parameters occurred more rapidly in calcium-chitosan treatment compared to untreated control when fruit were stored at 17℃. Both pre- or post-harvest Ca-chitosan treatment, however, effectively decreases the weight and firmness of fruit stored at 1℃. Fruit respiration rate was also reduced, indicating the increase of shelf-life throughout ripening of the fruit.

• Science of Emotion and Sensibility
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• v.16 no.1
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• pp.85-94
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• 2013

Recently, researches of piezoelectric energy harvesting were tried and in this study, a piezoelectric energy harvesting clothes was developed. First, piezoelectric energy harvesting zone on the extremities were drawn by 3D motion capturing and as a result, the hip, the elbow, and the knee were determined. A new structure of piezoelectric harvester was developed for appling to clothes. Because it needed to be flexible and sensitive for human body, the 2 layer stacked structure was proposed. A prototype of seamless garment was designed for a harvesting clothes because it needed to be body-tight and not to restrict the movement. High peak-to-peak voltages were acquired from the energy harvesting clothes.

• The Korean Journal of Food And Nutrition
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• v.32 no.5
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• pp.511-521
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• 2019

The purpose of this study was to investigate the inhibitory effect of enzyme activity and anti-proliferation of human cancer cell lines (HCT 116, NCI-H460 and MCF-7) of peanut skin depending on cultivars (Arachis hypogaea L. cv. K-Ol, cv. Sinpalkwang, cv. Daan, cv. Heuksaeng) and extraction solvent. Peanut skin was extracted with 80% ethanol, 80% methanol, 80% acetone, and distilled water, followed by analysis of the enzyme inhibitory activity and anticancer activity. Methanol extract of Daan cultivar most effectively inhibited ${\alpha}$-gluosidase (65.08%, 0.025 mg/mL), tyrosinase (82.49%, 2 mg/mL) and ACE (73.61%, 10 mg/mL). The inhibitory effect of peanut skin extracts on colon cancer cell (HCT-116), lung cancer cell (NCI-H460) and breast cancer cell (MCF-7) growth were investigate using MTT assay. The highest anti-proliferation of cancer cell line of peanut skin extracts was observed in the methanol extract of Daan cultivar. The cell viability on HCT 116, NCI-H460 and MCF-7 cell lines of methanol extracts from peanut skin of Daan cultivar was 48.13%, 41.03%, and 36.02% at $200{\mu}g/mL$, respectively. These results suggest that peanut skin extracts may mediate physiological activity, and provide valuable information for the use of peanut byproduct as a functional food material.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.644-650
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• 2022

Aralia elata (Miq.) SEEM is a deciduous shrub that has attracted attention as a high-income forest product. To improve the efficiency of cultivation and increase income, productivity according to the pruning period and annual pruning after harvesting Aralia elata shoots was analyzed. The optimal time was determined by pruning five times at 2-week intervals from 6 days after shoot harvesting. To investigate the pruning effect, pruning was performed at 30 cm from the ground in the first year after planting. From the second year after planting, branches grown for 1 year were pruned to 10 cm, and the annual shoots and branches were compared. Thenumber of first pruned branches after 6 days was 1.3-2.1 times higher after shoot harvesting than at other times, and the shoot characteristics were 1.2-1.7 times better than those at other periods. The faster the pruning, the better the quality of the harvested shoots. Annual pruning produced high-quality shoots (approximately 1.5 cm in diameter and 16 cm in length) from the second year after planting, and it was possible to increase productivity by inducing generation of branches capable of harvesting shoots. Annual pruning also made it possible to maintain easy shoot harvesting at approximately150 cm. These results showed that it was efficient to perform Aralia elatapruning as early as approximately 6 days after shoot harvesting. Pruning enabled production ofuniform-quality shoots every year and increasedthe yield of the trees.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.95-101
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• 2012

This study was conducted to investigate the effect of climate conditions during cultivation and harvesting on the quality and storability of fresh bulb cabbage (Brassica oleracea L. var. capitata). Plug seedlings of six cabbage cultivars were transplanted to Gangneung-Wonju University high elevation research station in Gangwon province (780 m above sea level, lat. $37.5^{\circ}N$.) and harvested with four different harvest times like August 3 ($1^{st}$), August 13 ($2^{nd}$), August 23 ($3^{rd}$), and September 10 ($4^{th}$), respectively from 50 days after transplanting. Weight loss, Hunter color factors, firmness, and soluble solids content (SSC) of the cabbage bulbs were investigated during storage at $3^{\circ}C$ (85% RH) and $25^{\circ}C$ (60% RH). Decreased bulb weight and poor quality cabbages were apparent at the late transplanting (July 14) and harvest (September 10) respectively. Quality index such as firmness and SSC at August 23 ($3^{rd}$) harvested cabbage was better than August 3 ($1^{st}$) and August 13 ($2^{nd}$) cabbages due to the good weather condition just before harvesting. The cv. 'Speed king' and 'Minix 40' showed good qualities among the cultivars, especially when the bulbs were harvested during sunny day conditions from one week before harvesting. Also SSC was influenced by weather condition before harvesting rather than transplanting date, while firmness was influenced by transplanting and harvest date. However, the differences among the cultivars were not significant. The potential of storage as maintaining the quality was different, depending on weather conditions at harvest time. Generally the storage periods of six cultivars were around 3~5 days and 9~10 days at room and low temperature, respectively. However, the August 3 ($1^{st}$) harvested cabbage lost their marketable quality very fast because of rainy and cloudy weather condition before harvesting and also storability of bulbs was 2 days and 4 days at room temperature and $3^{\circ}C$, respectively. Quality index was also not significant difference among cultivars.