• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1213-1223
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• 2018

This study was carried out to investigate extraction efficiency by microwave for extraction of pesticide residues and the bioconversion of ginsenosides of ginseng leaf by using various lactic acid bacteria in order to promote the utilization of ginseng leaf. The hexane extraction by microwave of tolclofos-methyl and azoxystrobin in ginseng leaf was efficient. The optimal condition for extraction of tolclofos-methyl and azoxystrobin in ginseng leaf by microwave was 50 to 95 watts of power supply, 3 minutes of extraction.The gisenosides Rg1 and Rb1 contents have decreased, while the Rh1, Rg3, Rk1 and Rh2 have increased due to fermentation. The ginsenosides Rg3 of the fermented ginseng leaf has increased and the contents were $70.62{\sim}77.61{\mu}g/g$(control $2.77{\mu}g/g$). The total phenolic acid content and electron donating ability of the ginseng leaf have totally decreased after 7 days of fermentation. The total phenolic acid contents of the fermented ginseng leaf with various lactic acid bacteria did not show any tendency as different strains.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.529-535
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• 2018

The range extender vehicle runs on a mechanism that allows the small power generation engine to start in the most efficient specific operating range to charge the battery and extend the mileage. In this study, we developed a step motor type intake air supply system that replaces existing throttle body system to develop a simple low cost control logic system. The system was applied to the existing base engine, and in order to improve the performance by increasing the amount of intake air, the effect of changing the length of the intake and exhaust manifold was experimentally examined. As a result, the Type B intake air control actuator operated by one step motor showed higher performance than the Type A in all the operation region, but the performance was lower than that of the base engine due to the increase of flow resistance. To improve this, it was confirmed that the engine performance was improved at both speeds of 2200rpm and 4300rpm when the 140mm adapter was installed in the intake manifold and when the newly designed 70mm exhaust manifold was applied. Through this process, high - precision operation control was realized by connecting the generator load to the optimized engine for the range extender electric vehicle. Experimental results showed that the speed change rate was within ${\pm}2.5%$ at 2200rpm in 1st stage and 4300rpm in 2nd stage and the speed follow-up result of 610 rpm/s was obtained when the speed was increased from 2200rpm to 4300rpm.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.525-530
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• 2019

The performance and stability of solid oxide fuel cells (SOFCs) depend on the microstructure of the electrode and electrolyte. In anode, porosity and pore distribution affect the active site and fuel gas transfer. In an electrolyte, density and thickness determine the ohmic resistance. To optimizing these conditions, using costly method cannot be a suitable research plan for aiming at commercialization. To solve these drawbacks, we made high performance unit cells with low cost and highly efficient ceramic processes. We selected the NiO-YSZ cermet that is a commercial anode material and used facile methods like die pressing and dip coating process. The porosity of anode was controlled by the amount of carbon black (CB) pore former from 10 wt% to 20 wt% and final sintering temperature from $1350^{\circ}C$ to $1450^{\circ}C$. To achieve a dense thin film electrolyte, the thickness and microstructure of electrolyte were controlled by changing the YSZ loading (vol%) of the slurry from 1 vol% to 5 vol. From results, we achieved the 40% porosity that is well known as an optimum value in Ni-YSZ anode, by adding 15wt% of CB and sintering at $1350^{\circ}C$. YSZ electrolyte thickness was controllable from $2{\mu}m$ to $28{\mu}m$ and dense microstructure is formed at 3vol% of YSZ loading via dip coating process. Finally, a unit cell composed of Ni-YSZ anode with 40% porosity, YSZ electrolyte with a $22{\mu}m$ thickness and LSM-YSZ cathode had a maximum power density of $1.426Wcm^{-2}$ at $800^{\circ}C$.

• Journal of Environmental Impact Assessment
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• v.28 no.3
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• pp.332-345
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• 2019

The purpose of the study is to evaluate the treatability of contaminated groundwater with TPH and (or) $Cr^{6+}$. Laboratory scale tests were performed for oil/water separation, dissolved air flotation (DAF), coagulation and precipitation, and filtration with sand and activated carbon respectively. Two times of oil/water separation tests for total 40 minutes of separation or separating time shows 90.2 % of TPH removal rate. In case of DAF test for high TPH sample, the TPH removal rates were not varied significantly by the variation of microbubble size. However, tests for low TPH samples show that TPH removal rate increases as microbubbles are smaller. When coagulant was added to sample for DAF test, TPH removal rate was increased 12.3 %. SS removal rate by DAF was 97.9 % at $16-40{\mu}m$ and it was increased as the size of microbubble is reduced. Tests for coagulation and precipitation were performed to evaluate the removal of $Cr^{6+}$ in groundwater. The increase of $FeSO_4$ dosage increased $Cr^{6+}$ removal rate in the coagulation and precipitation process. As the amount of activated carbon in the filter media increased TPH removal rate in the filtration process. SS removal rate by the filtration was 96.7 % similar to the results of DAF process tests. The filtration process treats TPH and SS. Best design parameters are determined as the size of sand is $425-850{\mu}m$ and the ratio of activated carbon and sand is 50:50.

• Korean Journal of Construction Engineering and Management
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• v.20 no.1
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• pp.52-61
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• 2019

On 30 June, 2017, the Ministry of Land, Infrastructure, and Transport announced the minimum size of parking section will be expanded in parking lots. The expansion of parking section could lead to increase in apartment prices because of increase in total area of the parking lots. It is necessary to adjust the column spacing and number in the parking lots and to apply the 8-Bay long-span parking module with good parking efficiency. According to the study, the construction cost of the 6-Bay module and 8-Bay module was almost the same. But The 8-Bay module was more economical than the 6-Bay module because of the reduction in total area of 8-Bay multi-moduel. The Result of construction cost of 8-Bay modules, Removal Deck-plate RC system was most economical. While the construction cost of PC system was higher due to increase in volume of the member, it would ensure sufficient economy by reducing the girder height to apply a pre-stress method. Also, the construction cost of hollow slab system was the highest. But it could be used as the underground parking lots for apartment, because it had the lowest cost per square meter. This Study has a academic significance by proving the applicability of the 8-Bay Module to underground parking lot of apartment. And it is expected that this study will be used as basic data to derive optimal construction method that applies 8-Bay Module.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.401-408
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• 2018

EQPS (Effluent Quality Prediction System, Dynamita, France) was applied to analyze the appropriateness of the design of a bioreactor in A sewage treatment plant. A sewage treatment plant was designed by setting the design concentration of the secondary clarifier effluent to total nitrogen and total phosphorus, 10 mg/L and 1.8 mg/L, respectively, in order to comply with the target water quality at the level of the hydrophilic water. The retention time of the 4-stage BNR reactor was 9.6 hours, which was 0.5 for the pre-anoxic tank, 1.0 for the anaerobic tank, 2.9 for the anoxic tank, and 5.2 hours for the aerobic tank. As a result of the modeling of the winter season, the retention time of the anaerobic tank was increased by 0.2 hours in order to satisfy the target water quality of the hydrophilic water level. The default coefficients of the one step nitrification denitrification model proposed by the software manufacturer were used to exclude distortion of the modeling results. Since the process modeling generally presents optimal conditions, the retention time of the 4-stage BNR should be increased to 9.8 hours considering the bioreactor margin. The accurate use of process modeling in the design stage of the sewage treatment plant is a way to ensure the stability of the treatment performance and efficiency after construction of the sewage treatment plant.

• Science of Emotion and Sensibility
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• v.22 no.1
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• pp.89-100
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• 2019

Sleep apnea, a medical condition associated with a variety of complications, is generally monitored by standard sleep polysomnography, which is expensive and uncomfortable. To overcome these limitations, this study proposes an unconstrained wearable monitoring system with stretch-fiber sensors that integrate with the wearer's clothing. The system allows patients to undergo examinations in a familiar environment while minimizing the occurrence of skin allergies caused by adhesive tools. As smart clothing for adult males with sleep apnea, long-sleeved T-shirts embedding fibrous sensors were developed, enabling real-time monitoring of the patients' breathing rate, oxygen saturation, and airflow as sleep apnea diagnostic indicators. The gauge factor was measured as 20.3 in sample 4. The maximum breathing intake, measured during three large breaths, was 2048 ml. the oxygen saturation was measured before and during breath-holding. The oxygen saturation change was 69.45%, showing a minimum measurable oxygen saturation of 70%. After washing the garment, the gauge factor reduced only to 18.0, confirming the durability of the proposed system. The wearable sleep apnea monitoring smart clothes are readily available in the home and can measure three indicators of sleep apnea: respiration rate, breathing flow and oxygen saturation.

• Science of Emotion and Sensibility
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• v.22 no.1
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• pp.77-88
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• 2019

As the social interest of the Baby Boomer generation is increasing, this study derives implications for lifelong education policy through identification of the need and support for lifelong education among baby boomers lifelong learning, taking into account such aspects of quality of life as emotional psychology-based self-development and self-realization. To optimally explore support for lifelong learning for the baby-boomer generation, first-tier (top-level), sixth-tier (bottom-level), and five-other evaluation criteria were available. For the first layer, we examined whether potentiality or realizability was more desirable, and for the second layer, detailed criteria for realizability were set up, dividing them into financial, legal, and administrative feasibility. A study conducted by experts on the policy priority analysis of Baby Boomers showed that their support for lifelong learning places a greater priority on its feasibility (the more feasible alternative) than desire (the more desirable option). Among the six criteria, lifestyle activities had high priority, and the relative importance of the five assessment alternatives for lifetime learning activities was shown to be higher for employment skills education (0.377), civil participation education (0.181), lifestyle activities (0.200), and 'lifetime activities' (06.11). These results are meaningful: they can help shape and refine the needs of lifelong education, assess their relative importance, and prepare basic data for lifelong learning policies for baby boomers who are about to enter their old age.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.595-598
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• 2014

In order to provide the Mobile Stations operating in IEEE 802.11 Wireless LAN network with seamless handover, a comprehensive study on the functions of handover considering various networking environments and characteristics of Mobile Stations is required. Note that the channel scan process finding a new AP takes the major portion of handover time, and this is the most significant issue with seamless handover for real-time multimedia service in WLAN environment. In this paper the functions required to provide seamless handover in IEEE 802.11 WLAN network are identified, and a new scanning technique is proposed with which the Mobile Stations can selectively scan the channels to reduce the channel scan time in various network environments. Here each Mobile Station awares of the channels the neighbor APs are using by scanning them in advance according to the proposed technique. Afterwards, when handover is actually required, the optimal AP is decided quickly by scanning only the predetemined group of channels and order of scan without unnecessary scan of all the channels. In addition, proposes to enter the Scan Trigger Value and Handover Threshold Value in mobile phones in order to prevent the phenomenon can not handover.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.79-81
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• 2014

Recently, It is built various information systems evolve IT skills. But When you build the information system, Difficult to determine whether the appropriate scale and problems that rely heavily on SI companies and professionals. To solve this problem, Korea Information Security Agency, etc., based on the primary objective was to develop H/W Capacity Equation formally to each system type. But the problems are to present H/W capacity equation by discussion of the expert group of suppliers and relatively long that it is difficult to formally apply in the situation now so it is no longer the limit. In this study, we proposes proper capacity planning techniques, which can guarantee the best performance compared to the budget invested. For this purpose, we derived the proper H/W capacity equation by regression analysis to gather performance metrics and cost of various cases by simulation of a virtual environment in the cloud. Through this study, when capacity planning, It is possible to reduce costs that It is possible to build an information system based on the digitized data and build information system in an environment that does not rely on the SI business or professional.