• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.4
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• pp.386-393
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• 2016

It is essential to provide good environment for juvenile fish to grow and spawn in order to keep reproduction mechanism of fisheries resources. However, harvesting juvenile fish deprives adult fish of the opportunity to reproduce, thereby changing self-regulating renewable resources into non-renewable ones and preventing sustainable harvesting as well as reducing fishers' income. We reviewed the catch status of Korea on juvenile mackerel and analyzed how reducing the catch ratio of juvenile mackerel may affect the spawning stock and Korean fishermen's revenue. In addition, we analyzed the problem of caching juvenile mackerel in Korean fisheries and current efforts to protect and reduce the catch ratio of juvenile mackerel in Korea. Furthermore, we suggested future efforts to protect juvenile mackerel. The result of the study showed that reducing the catch ratio of juvenile mackerel from 44.4% to 30.0% would increase fishers' revenue by 60.6 billion KRW. We suggest the changing of purse seine fishery's catching methods from night operation to day operation, relocation of fishing vessels to move to other fishing grounds when fishing vessels meet high density of juvenile mackerel, and consumers' clever choice of consuming adult mackerel in order to accelerate the move toward protecting juvenile mackerel in Korea.

• Journal of Biosystems Engineering
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• v.26 no.4
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• pp.337-354
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• 2001

This study was conducted in order to develop a Chinese cabbage harvester attachable to tractors. For designing Chinese cabbage harvester in which laboratory and field tests were conducted with to determine feasible values design factors. To adopt the various sizer of C-cabbages, U-type soft rubber band was attached to the chain conveyor with an angle. Required torque of the conveyor axle was about 206-210kgf$.$cm. And the required peripheral speed of the disk cutter was 6.54m/s or more to have a clean session in root cutting. Three different harvest method were tested. The best harvesting method with minimum pulling force and damage was disk cutting flying just above the soil surface were the cut chinese cabbages are transferring to the holding conveyor attached soft rubber lug in prompt. Theoretical speed ratio of the tractor travel and feed of a chain conveyor was 1:1.2 with the attaching angle of 30 degree and 1:1.1 with the angle of 20 degree. Actual field experiment showed the speed ratio of 1:1.5 was the best because of the slip effect.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.35-41
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• 2006

This study was conducted to establish the post-harvest management system in rice. Harvested hulled rice was gathered into large-scale bag and combine bag, in which the rice quality and the influence on quality change were investigated on various storage periods and moisture contents. Moisture content of hulled rice ranged from 23.7% to 28.8% on different harvest times, which grew lower as harvesting time was delayed. When desiccation was retarded hulled rice in large scale bag was changed in color and emitted an of offensive odor in 3 days and that in combine bag showed similar symptom in 4 days. Inner temperature in large scale bag was changed a lot when the storage period was prolonged and also the moisture content was higher while that in combine bag increased regularly corresponding to the moisture content at the time of harvest. Moisture content of hulled rice stored in large-scale bag increased 2 days after harvest and the more moisture content showed the more increased tendency, while in the case of combine bag the moisture content was not changed much whether the hulled rice contained low or high moisture content in harvesting. As desiccation was delayed fatty acid increased much more in large-scale bag than in combine bag even though protein and amylose contentwere not changed. As desiccation was delayed more and hulled rice contained moisture more in harvesting head rice ratio of brown rice decreased and green-kerneled rice and damaged grain ratio increased and quality of milled rice also became deteriorated. As a result, desiccation day to minimize the deterioration of rice quality was estimated 1-2 days in large scale bag and 2-3 days in combine bag after harvesting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.436-441
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• 1992

This study was carried out to discuss the influences of the different fertilizer levels and plant densities on the flowering and balling in cotton in Mokpo Branch Station, Crop Experiment Station in 1991. The cotton flowered 67% before Aug. 25 which is the limit date of picked-cotton harvest, and the ratio of flowering for stalk-cut cotton was 30%. The 1.5 times fertilizer levels and the 70cm row density had more flower buds, flowers and bolls per m$^2$ than any other treatment plot. The crop growing was bad in dense planting due to the nutrient deficiency. The flowering ratio to flower bud was about 70%, and the balling ratio to flower numbers was about 48%. The bolling ratio was lower in the case of more flower number. The shedding ratio of flower buds was about 30% in average and showed increasing tendency by dense planting. It was observed that the higher ratio of bud shedding tended to accompany with shedding the lower ratio of boll shedding.

• Journal of Mushroom
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• v.15 no.1
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• pp.21-24
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• 2017

In this study, the effect of different substrates of agricultural by-products on the mycelial growth rate and density of Trametes versicolor (Turkeytail mushroom) was analyzed. We found that pepper stem and rice bran with a mixing ratio of 9:1(v/v) produced the best mycelial growth of 101 mm in 10 days, while a mixing ratio of 8:2 resulted in mycelial growth of 83 mm in 10 days. The control group treated with a 9:1 mixing ratio of oak sawdust and rice bran (v/v) produced mycelial growth of 74 mm in 10 days. The following results are in the order of beanstalk, sesame stem, and perilla stem. After the harvest of the mushrooms, the mycelial growth rate and the density of T. versicolor in each substrate were as follows the group with waste substrate of Pleurotus eryngii and rice bran with a mixing ratio of 9:1(v/v) produced the best result of 76 mm in days, while a mixing ratio of 8:2 produced of 61 mm in 10 days. The control group with a 9:1 ratio of oak sawdust and rice bran produced mycelia of 74 mm in 10 days, while a mixing ratio of 8:2 resulted in mycelia of 59 mm in10 days.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.4
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• pp.397-404
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• 1994

This experiment was conducted to determine best harvesting time and observe paeoniflorin and some chemical component concentrations of 4-year-old paeonia radix in Euisung and Milyang varieties. Concentrations of paeoniflorin and some chemical components were investigated at 8 periods from Feb. to Oct. Yield of paeonia radix was investigated in Aug. 19, Sep. 18 and Oct. 17. Paeoniflorin and some chemical components were changed seriously at May as flowering time and stabilized after June. The lowest dry matter ratio was 23% and the maximum shrinkage ratio was 47% in May during all the growing stages. Especially, the difference of paeoniflorin concentrations between Euisung and Milyang was about 2%, and paeoniflorin concentrations in Milyang were higher than in Euisung variety during all the stages. Serious infection of disease in October, stem length, stem number per stock and healthful stem ratio in October were more reduced than in August. Yield of paeonia radix was not different from August to September, but that of October harvest was obviously reduced by root-decay-disease. Reasonable harvesting time in 4-year-old paeonia radix was late August to mid-September. When infected shoot rate by disease were severely high, early harvest was more stable in the yield and quality aspects.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.2
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• pp.150-155
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• 2018

In Korea, the mechanization ratio of field farming is about 58.3%. Especially, mechanization ratio of harvest operation is 10% or less. So, it is required to improve the mechanization ratio of harvest operation to analyze the power requirement analysis of agricultural tractor. The purpose of this study is to analyze power requirement of the underground crop harvester attached on agricultural tractor for traction operation. First, a power measurement system was developed and installed in 45 kW agricultural tractor. Second, field experiments were conducted at two driving speed levels (1.41, 2.17 km/h), and axle torque and rotation speed were analyzed. At 1.41km/h driving speed, the average power requirement of driving axle is 3.13 kW, respectively, at 2.17km/h driving speed, the average power requirement of driving axle is each 4.20 kW. In addition, the field tests show that as the driving speed increases by 53%, the power requirement of the underground crop harvester attached on agricultural tractor increases by 34%. Therefore, it indicated that the power requirement of agricultural tractor was affected by the driving speed.

• Journal of the Korean Society of Tobacco Science
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• v.9 no.1
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• pp.11-17
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• 1987

KA 101 and Xanthi-Basma were cultivated in Korea and Greece to compare the respective responses to environment and cultivation method on their growth characteristics and some properties of harvested leaves during 1984 and 1985. The contents of clay, calcium, organic matter and pH were higher in the soil of greece than that of Korea. Sunshine hours and precipitation in Greece during harvest and curing season were 8.6 hours per day and 53.3mm compared to that of 3.8 hours per day and 320mm in Korea, respectively. The plant height, leaf size and yield decreased, and days to flower was shorter 8-11 days in greek grown plants. The dehydration and curing process in Greece was linear and rapid due to the constant daily change of temperature and relative humidity with dry weather during curing season during curing season. But those process in Korea was variable and tardy due to rainy weather. Cured leaf ratio increased with upper stalk leaves in Greece but it was rather lower at top stalk position in Korea. The harvested green leaf cultivated in Greece showed higher contents of petroleum ether extract, total nitrogen and nicotine, but lower contents of reducing sugar and lower ratio of protein nitrogen to total nitrogen than in Korea.

• Journal of the Korean Society of Tobacco Science
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• v.9 no.2
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• pp.59-68
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• 1987

This study was conducted to investigate the change of starch, total sugar, nicotine, and total nitrogen contents in green leaves at various stages of maturity(50-106 days after transplanting), and to relate between chemical constituents for flue-cured tobacco (Cv NC82 and BY 4). For the two cultivars and all stalk positions, starch contents increased with maturation, but decreased with senescence. Nicotine contents increased, while total nitrogen contents decreased with delay of harvest. Total sugar contents had a tendency of decrease. For the two cultivars , starch correlated negatively with total nitrogen, and positively with nicotine. Total nitrogen correlated negatively with nicotine. A delay of 5 to 7 days than conventional harvesting time would reach to the better ratio of the reducing sugar to nicotine ratio.

• Journal of Satellite, Information and Communications
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• v.10 no.4
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• pp.71-76
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• 2015

In this paper, we propose a system model which effectively transmits the data and conducts RF energy harvesting in a wireless communication network of LTE and 5G. Through time switching and power splitting schemes, we find a time & power ratio to show the good performance according to the standard that we set up for transmitting a signal and conducting RF energy harvesting. So selecting optimal time & power ratio, we can efficiently transfer data to other drones and harvest the amount of harvested power simultaneously we desire. Also, according to conducting the performance analysis, we can compare an ideal receiver with the proposed system model. And, we suggest a future direction of research.