• Journal of Drive and Control
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• v.20 no.3
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• pp.35-41
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• 2023

Radish and Chinese cabbage are the most produced and consumed vegetables in Korea. The mechanization of harvesting operations is necessary to minimize the need for manual labor. This study to develop and evaluate the performance of a multi-purpose driving platform that can apply modular Radish and Chinese cabbage harvesting devices. The multi-purpose driving platform consisted of driving, device control, engine, hydraulic, harvesting, conveying, and loading part. Radish and Chinese cabbage harvesting conducted using the multi-purpose driving platform each harvesting module. The performance of the multi-purpose driving platform was evaluated the field efficiency and loss rate. The total Radish harvesting operation time 34.3 min., including 28.8 min., of harvesting time, 1.9 min., of turning time, and 3.6 min., of replacement time of bulk bag. During Radish harvesting, the field efficiency and average loss rate of the multi-purpose driving platform were 2.0 hr/10a and 3.1 %. Chinese cabbage harvesting operation 49.3 min., including 26.6 min., of harvesting time, 4.6 min., of turning time, and 18.1 min., of replacement time of bulk bag. During Chinese cabbage harvesting, the field efficiency and average loss rate of the multi-purpose driving platform 2.1 hr/10a and 0.1 %. Performance evaluation of the multi-purpose driving platform that harvesting work was possible by installing Radish and Chinese cabbage harvest modules. Performance analysis through harvest performance evaluation in various Radish and Chinese cabbage cultivation environments is necessary.

• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.215-223
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• 2015

Energy harvesting technique is an energy charging technique for communication device in energy-constrained environment. Recently, energy harvesting technique that harvests energy from wireless radio frequency signal is proposed. Representatively, there are time switching technique and power splitting technique. This paper proposes an optimal harvesting time allocation scheme in a wireless cognitive relay network when secondary user relay uses energy harvesting technique to transmit information. Secondary user relay receives information and energy simultaneously from the secondary user source's signal via time switching technique. We aim to maximize the instantaneous throughput by optimizing harvesting time of the secondary user relay. Simulation results show that using optimized harvesting time gets larger instantaneous throughput compared to using constant harvesting time.

• Biomedical Science Letters
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• v.26 no.4
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• pp.376-382
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• 2020

This study was the change of compound and bioactivity were analyzed by different harvesting time (May, August, and November) of Suaeda japonica Makino. The total polyphenol and flavonoid contents of S. japonica were the highest at about 22.81 mg GAE/g and 4.56 mg QE/g, respectively, in the S. japonica harvested in Nov. Also, the contents of quercetin, showed the highest content in Nov harvested S. japonica. In addition, the antioxidative activity of each extract from S. japonica changed depending on harvesting time. For S. japonica harvested in Nov showed the highest DPPH and ABTS radical scavenging activity. From the NO inhibition assay, the S. japonica harvested in Nov had shown the highest anti-inflammatory effects. Therefore, consideration of the optimal harvesting time for S. japonica could be an important factor attributing to its natural antioxidant and anti-inflammatory properties and the optimal harvesting time was confirmed especially to be in Nov.

• The Journal of Korea Robotics Society
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• v.15 no.2
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• pp.91-99
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• 2020

Fruit and vegetable harvesting robots have been widely studied and developed in recent years to reduce the cost of harvesting tasks such as labor and time. However, harvesting robots have many challenges due to the difficulty and uncertainty of task. In this paper, we characterize the crop environment related to the harvesting robot and analyzes state-of-the-art of the harvesting robot especially, in the viewpoint of robotic end-effector. The end-effector, an one of most important element of the harvesting robot, was classified into gripper and harvesting module, which were reviewed in more detail. Performance measures for the evaluation of harvesting robot such as test, detachment success, harvest success, and cycle time were also introduced. Furthermore, we discuss the current limitations of the harvesting robot and challenges and directions for future research.

• Kyungpook Mathematical Journal
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• v.47 no.1
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• pp.31-56
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• 2007

In this paper, we consider a delay differential equation model of two competing species with harvesting of the mature and immature members of each species. The time delay in the model represents the time from birth to maturity of that species, which appears in the adults recruitment terms. We study the dynamics of our model analytically and we present results on positivity and boundedness of the solution, conditions for the existence and globally asymptotically stable of equilibria, a threshold of harvesting, and the optimal harvesting of the mature populations of each species.

• Korean Journal of Medicinal Crop Science
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• v.5 no.3
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• pp.232-236
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• 1997

This experiment was conducted to determinate the optimum harvesting time of Carthami Flos and grain in safflower. In dry Carthami Flos yields harvested at different days after flowering, threre was no significant difference between 2 days and 4 days, however, yield harvested at 6 days was decreased significantly compared with 2 days after flowering. As the harvesting time were delayed, lightness (L') and redness (a') of dry Carthami Flos were decreased but yellowness (b') of that was increased. Color differences (${\Delta}E'ab$) of dry Carthami Flos between harvesting days after flowering were not visible between 4 days and 6 days but between those (4 days and 6 days) and 2 days were visible. As the result, the optimum harvesting time of Carthami Flos was 4 days after flowering. Grain yields and its components were affected by not harvesting Carthami Flos but grain harvesting time. Threre was no significant difference in number of grain per flower head, percentage of ripened grain between grain harvesting time. However, weight of 1000 grains and grain yields increased until 20 days after flowering. As a conclusion, the optimum harvesting time was 4 days after flowering for Carthami Flos and 20 days for grain regardless Carthami Flos harvesting time.

• 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.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.329-329
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• 2017

The study was conducted to investigate the effects of different harvesting time on pasting properties of starch in three colored rices. Seven major parameters of starch pasting properties, peak viscosity (PKV), hot pasting viscosity (HPV), cool pasting viscosity (CPV), setback (CPV minus PKV), breakdown (PKV minus HPV), peak time, and pasting time were determined by Rapid Visco Analyzer. The peak viscosity, hot viscosity, cool viscosity and peak time were influenced by different harvesting times. Pasting time was delayed slightly with prolonged harvesting time in all rice cultivars. Pasting temperature in each rice cultivar differed from each harvesting time, and pasting temperature of the two rice cultivars, Hongjinju and Joseongheugchal, showed the highest at the 40 days after heading and then it decreased at the final harvesting time. With the delay of the harvesting time, peak viscosity, hot viscosity, cool viscosity, setback value and pasting temperature did not exhibit a regular trend depending on their genetic characteristics. Branch chain length distribution of amylopectin was demonstrated a distinct difference among these colored rices. In changes of amylopectin branch chain-length distribution, the amylopectin structure of Hongjinju rice cultivar as affected by different harvesting time, the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant increase in A chains with $DP{\geq}12$ and remarked decrease in long chains $37{\leq}DP$ compared to that of 30, 40, and 50 days after heading. In particular, when harvesting time is delayed the distribution percentage of short chain (A chains with $DP{\geq}12$) was increased except for the rice which harvested 20 days after heading. The similar results were also observed in Sintoheugmi rice cultivar like that of Hongjinju rice cultivar. Otherwise, distribution percentage of the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant decrease in A chains with $DP{\geq}12$ and remarked increase in B chains $13{\leq}DP{\geq}24$ compared to that of 30, 40, and 50 days after heading.

• Korean Journal of Medicinal Crop Science
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• v.4 no.4
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• pp.329-332
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• 1996

This experiment was carried out to investigate the growth characteristics and root yield with different harvesting times in Astragalus membranaceus. The growth of stem diameter. number of nodes. number of branches and dry weight of top plant were not affected in late harvesting time compare to early harvesting time. but stem height was increased by harvesting time. Otherwise root growth were effected by harvesting time in one and two years old plant. So, root length, weight of dry root and dry root yield were the most excellent until reached up to harvesting of 10th November. The content of methanol extract was not different between one and two years old plant, but that of different harvesting time was the most by harvesting time in mid November. It was suggested that the optimal harvesting time seems to be in mid November rather than in mid or late October.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.153-162
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• 2018

The importance of energy harvesting technique is increasing due to the elevated level of demand for sustainable power sources for wearable device applications. In this study, we developed an Energy Harvesting wearable Platform(EH-P) architecture which is used in the design of a multi-energy source based on TENG. The proposed switching circuit produces power with higher current at lower voltage from energy harvesting sources with lower current at higher voltage. This can powers microcontrollers for a short period of time by using PV and TENG complementarily placed under hard conditions for the sources such as indoors. As a result, the whole interface circuit is completely self-powered with this makes it possible to run of sensing on a Wearable device platform. It was possible to increase the wearable device life time by supplying more than 29% of the power consumption to wearable devices. The results presented in this paper show the potential of multi-energy harvesting platform for use in wearable harvesting applications, provide a means of choosing the energy harvesting source.