• 한국약용작물학회:학술대회논문집
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• 2012.05a
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• pp.155-156
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• 2012

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.1
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• pp.58-63
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• 2008

Variation of chalkiness expression in milled waxy rice with the moisture contents of grains was investigated using instrument and naked eye evaluation methods. To find out any effects of varieties and harvesting times on the chalkiness development, rice grains of seven waxy varieties harvested at early, optimal and late times were tested after being sun-dried to have three different moisture contents of about $13.0{\sim}14.5%$, $14.5{\sim}16.0%$ and above 16.0%. The moisture contents of rice grains were distributed in the ranges of about 13.0% to 17.5% with the drying intensity right after harvesting. Although there were some genetical variations in whiteness and degree of transparency of milled rice grains among varieties at the same condition, chalkiness was most significantly affected by the changes of moisture content in all waxy varieties and harvesting times. At the moisture content less than 13.5%, all varieties exhibited waxy unique chalkiness, and at the moisture ranges between 13.5% and 14.0% the chalkiness was more or less affected by harvesting time and varieties. At the moisture content ranges between 14.0% and 16.0%, chalkiness gradually disappeared as with the increase of moisture content. However the degrees of chalkiness loses were strongly depended on individual kernels by showing as if the number of non-waxy rice kernels would be increasing in waxy rice grains with the moisture content increase. At the moisture content above about 16.0%, all waxy kernels lost their unique chalkiness, and showed non-waxy rice appearance.

• Journal of the Korea Society of Computer and Information
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• v.27 no.12
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• pp.17-27
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• 2022

In this paper, ED-H algorithm, an optimal real-time scheduling algorithm dealing with the characteristics of the integrated energy harvester system with a capacitor, is extended to satisfy the time constraint under the blackout state which is a deliberate power-off state by an intelligent power management unit adopted in the system. If the power supply system does not have enough energy, it temporarily shuts off the power supply to protect the circuit and capacitor and resumes the supply again when the capacitor is fully charged, which may delay the task execution during these blackout states by calculating the time according to the occurrence of the events. To mitigate the problem, even if task execution is delayed by the original ED-H algorithm, the remaining time of the subsequent time units no longer can afford to delay the execution of the task is predicted in the extended algorithm and the task is forced to be scheduled to meet the time deadline. According to the simulation results, it is confirmed that the algorithm proposed in this paper has a high scheduling performance increase of 0.4% to 7.7% depending on the characteristics of the set of tasks compared to the ED-H.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1A
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• pp.27-33
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• 2010

This study addresses a methodology to use small wind turbines for dual purposes, improving aerodynamic performance of flexible bridges and wind energy harvesting. A way to proper placement of small wind turbines on flexible bridges were proposed according on the analogy of conventional aerodynamic appendages. From the wind tunnel tests, it was found that the wind turbine attached like fairing was effective to reduce the vortex-induced vibration of bridge and the optimal spanwise interval of the wind turbine was 3-4.5 time of turbine diameter. Moreover the aerodynamic coefficients of the bridge were improved after installation of the wind turbines. Present results showed the general availability of wind turbine for improvement of aerodynamic performance and energy supply of flexible bridges although the capacity of wind power generation was strongly dependent on wind characteristics of the bridge site.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.2
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• pp.135-142
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• 2010

This study was carried out to establish the optimum pre-wilting time for the high-quality silage production of whole crop oat. Plants were harvested for three time at intervals of 10 days after heading (DAH) and silage production was conducted after the pre-wilting treatment of 0, 4, 8 and 32 hours, respectively. Results showed to attain a proper moisture content for profitable silage production, which was an optimal content for making silage, by pre-wilting oat for 4 hours after harvest at either 20 days after heading or harvesting 30 DAH(days after heading). As the feed value of silage, the processing of proper moisture contents showed that crude protein contents were high and the entire feed value showed higher than others. High content of lactic acid and the low content of acetic and butyric acid showed on 60~65% the moisture conditions of silage. There was desired that whole crop oat was pre-wilting on 4 hours and harvested at about 20~30 DAH and after that, even if harvesting at once, it was judged that it could produce good quality silage.

• Preventive Nutrition and Food Science
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• v.21 no.2
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• pp.97-103
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• 2016

In our previous study, an early-maturing variety of rice (Oryza sativa L.), Jinbu can have feature with unique green color, various phytochemicals as well as nutritive components by the optimal early harvesting, called Green Rice$^{(R)}$ (GR). The aims of the present field experiments were to evaluate the changes in the weight of 1,000 kernels, yield, and contents of proximate and bioactive compounds in Chuchung, a mid-late maturing variety, during the pre-harvest maturation of rough rice and to research the appropriate harvest time and potent bioactivity of Chuchung GR. The weights of 1,000 kernels of Chuchung GR dramatically increased until 27 days after heading (DAH). The yields of Chuchung GR declined after 27 DAH and significantly declined to 0.0% after 45 DAH. The caloric value and total mineral contents were higher in the GR than in the full ripe stage, the brown rice (BR). In the GR, the contents of bioactive compounds, such as ${\gamma}$-aminobutyric acid, ${\gamma}$-oryzanol, and ${\alpha}$-tocopherol, were much higher (P<0.05) than those in the BR, specifically during 24~27 DAH. Therefore, bioactive Chuchung GR can be produced with a reasonable yield at 24~27 DAH and it could be useful for applications in various nutritive and functional food products.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.344-347
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• 2007

Optimal date to cover plastic film tunnel for hastening the harvest and increasing the yield in asparagus was studied using 2-year-old 'Green tower' cultivar in Jeju. Plastic film tunnel was covered on January 10 and 21, and February 10 and 25 in 2004. The asparagus spear sprouted on March 3 in the control. They emerged earlier by about 2 to 3 weeks in the plots covered on January 10 and 25 than the control. First harvesting was hastened by 3 weeks in the plots covered on February 10 and two weeks in the plots covered on January 25 and February 10 compared to the control. Yield per plant was the highest in plastic film tunnel covered on January 10 and 25. Early harvesting in february in plastic film tunnel covered on January 10 and 25 were 325 and 333 kg/10a respectively with no significant difference between two treatments whereas yield was low significantly in plastic film tunnel covered on February 10 and 25.

• Journal of Sensor Science and Technology
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• v.33 no.1
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• pp.34-39
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• 2024

Energy harvesting technology that converts the wasted energy resources into electrical energy is emerging as a semipermanent power source for self-powered electronics and wireless low-power sensor systems. Among the various energy conversion techniques, flexible piezoelectric energy harvesters (f-PEHs), using materials with piezoelectric effects, have attracted significant interest because they can harvest a small mechanical energy into electrical signals without constraints of time and space in various environments. In this study, we used a flexible piezoelectric composite film fabricated by dispersing BaHf_xTi_(1-x)O₃ (x = 0, 0.01, 0.05, 0.1) piezoelectric powders inside a polymeric matrix to facilitate f-PEHs. The fabricated f-PEH with optimal Hf contents (x = 0.05) generated a maximum output voltage of 0.95 V and current signal of 130 nA with stable electrical/mechanical disabilities under periodically bending deformations. In addition, we demonstrated a cantilever-type f-PEH and investigated its potential as a sensor by characterizing the output performance under mechanical vibrations at various frequencies. This study provides the breakthrough for realizing self-powered energy harvesting and sensing systems by adopting the lead-free piezoelectric composites under vibrational environments.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.25-25
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• 2023

As the demand for processing potatoes increases, imports of raw potatoes and potato products are increasing, so it is necessary to expand potato production as raw materials for processing in Korea. Potato varieties for processing that can be grown in fall have been developed, but research on cultivation technology and processing quality management technology to improve chip processing quality is very insufficient. Therefore, this study was conducted to investigate the optimal harvest time by investigating the quantity and chipping characteristics of potato chips during autumn cultivation. As the test varieties, the chip processing varieties "Saebong", "Eunsun", and "Geumnaru" were used, and the potato cultivation site was the Seocheon-gun Test field (214 Gaeya-ri) of the Chungcheongnam-do. The test treatment was at harvest time after spring cultivation, and the potatoes were harvested at 70, 80, 90, and 100 days after sowing based on the sowing time. The investigation items were potato productivity (total yield, yield of standard processing, and number of tubers) and chip-processing characteristics (chip color, dry matter content, glucose content, etc.). As a result of examining the yield characteristics according to the harvest time, statistical significance was not found according to the treatment. The total yield (ton/ha) was 27.5 to 30.5, and there was no significant difference depending on the time of 70 to 100 days after harvest. The standard quantity for processing (yield of 81-250g potatoes per unit) also showed a similar trend. In chipping characteristics according to harvest time, statistical significance was high in specific gravity and glucose content. The specific gravity was highest at 1.077 at 70 days after harvest, and the glucose (mg/dL) content was the lowest at 37.5 at 80 days after harvest. Statistical significance was not recognized, but chip color (L value) was the highest at 64.4 at 70 days after harvest. Therefore, it is judged that the optimal harvesting time for chip processing is 70 to 80 days after sowing.

• ETRI Journal
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• v.39 no.6
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• pp.794-802
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• 2017

In this paper, a wireless powered communication network (WPCN) consisting of a hybrid access point (H-AP) and multiple user equipment (UE), all of which operate in full-duplex (FD), is described. We first propose a transceiver structure that enables FD operation of each UE to simultaneously receive energy in the downlink (DL) and transmit information in the uplink (UL). We then provide an energy usage model in the proposed UE transceiver that accounts for the energy leakage from the transmit chain to the receive chain. It is shown that the throughput of an FD WPCN using the proposed FD UE (FD-WPCN-FD) can be maximized by optimal allocation of the UL transmission time to the UE by solving a convex optimization problem. Simulation results reveal that the use of the proposed FD UE efficiently improves the throughput of a WPCN with a practical self-interference cancellation capability at the H-AP. Compared to the WPCN with FD H-AP and half-duplex (HD) UE, FD-WPCN-FD achieved an 18% throughput gain. In addition, the throughput of FD-WPCN-FD was shown to be 25% greater than that of WPCN in which an H-AP and UE operated in HD.