• Journal of the Korea Society of Computer and Information
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• v.26 no.4
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• pp.133-142
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• 2021

The purpose of this study was to examine the most suitable exercise for the elderly women by comparing the changes in body composition and physical function fitness after modern dance, aquarobic and combined exercise programs for the elderly women. The subjects of this study were 47 elderly women in J-do, chosen as MDG(n=13), AEG(n=11), CEG(n=11) and CG(n=12) for participated for 60 minutes/day and three times/wk for 12 weeks. The results of grip strength, chair stand, arm curl, 2 minute step, 244cm up and go was significantly than in the control group. Back scratch was decreased significantly after exercise only in the modern dance group and combined exercise group but there was no change in chair sit and reach. These results suggest that various exercises were found to play a positive role in maintaining and improving fitness for the elderly women. In addition, additional exercise programs are needed to improve flexibility and mobility of joints for the elderly. It is thought that it is important to voluntarily participate in a movement that suits your interests to make it sustainable.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.203-210
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• 2021

In many metropolitan cities around the world, ground and underground transportation networks are saturated due to urbanization. In addition, regulations on carbon emissions to prevent global warming are becoming stricter, and eVTOL, which will be operating in complex cities, is gaining popularity as the next generation of eco-friendly transportation. In this study, the hover lift efficiency and disc loading of eVTOLs for each type were calculated by classifying eVTOLs into following types: multicopter, lift+cruise, and vectored thrust. In addition, using the aerodynamic analysis programs OpenVSP, Fluent and Javaprop, the specific battery energy required for the smooth operation of eVTOL, which will be realized in the near future, was calculated and analyzed base on reports published by Uber and airworthiness authorities of each country.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.7
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• pp.593-599
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• 2021

The demand for e-VTOL aircraft is expected to be increased rapidly in the future as a means of urban transportation due to operating cost reduction, eco-friendliness and convenience of vertical take-off and landing using pilot-aids automation system. However, there are many technical hurdles to be solved in securing safety and certification which are essential for commercialization and urban operation. So far, there is no e-VTOL aircraft that has received type certificate and standard airworthiness certificate due to the technical problems and safety requirement differences with conventional aircraft. The e-VTOL aircraft certification should also meet the equivalent level of safety required by the current airworthiness standards, but there are existing problems in securing safety and meeting current standards. In this study, the e-VTOL's certification problems and technical limitations in satisfying the current standards are presented.

• Journal of Microbiology and Biotechnology
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• v.32 no.9
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• pp.1134-1145
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• 2022

SCO6993 (606 amino acids) in Streptomyces coelicolor belongs to the large ATP-binding regulators of the LuxR family regulators having one DNA-binding motif. Our previous findings predicted that SCO6993 may suppress the production of pigmented antibiotics, actinorhodin, and undecylprodigiosin, in S. coelicolor, resulting in the characterization of its properties at the molecular level. SCO6993-disruptant, S. coelicolor ΔSCO6993 produced excess pigments in R2YE plates as early as the third day of culture and showed 9.0-fold and 1.8-fold increased production of actinorhodin and undecylprodigiosin in R2YE broth, respectively, compared with that by the wild strain and S. coelicolor ΔSCO6993/SCO6993⁺. Real-time polymerase chain reaction analysis showed that the transcription of actA and actII-ORF4 in the actinorhodin biosynthetic gene cluster and that of redD and redQ in the undecylprodigiosin biosynthetic gene cluster were significantly increased by SCO6993-disruptant. Electrophoretic mobility shift assay and DNase footprinting analysis confirmed that SCO6993 protein could bind only to the promoters of pathway-specific transcriptional activator genes, actII-ORF4 and redD, and a specific palindromic sequence is essential for SCO6993 binding. Moreover, SCO6993 bound to two palindromic sequences on its promoter region. These results indicate that SCO6993 suppresses the expression of other biosynthetic genes in the cluster by repressing the transcription of actII-ORF4 and redD and consequently negatively regulating antibiotic production.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.12
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• pp.819-828
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• 2022

Sensitivity of aircraft sizing depending on battery performance was studied for a generic quad tilt rotor type electric vertical takeoff and landing vehicle. The mission requirements proposed by Uber Elevate and NASA were used for initial sizing, and the calculated gross weight is ranged between 5,000lb and 11,000lb for battery specific energy range of 200-400Wh/kg in pack level and continuous discharge rate range of 4-5C. For the assumed gross weight of 7,000lb, the required battery performance was calculated with two different criteria: available power and energy, and the effects of battery specific energy and discharge rate are analyzed. The maximum discharge rate is also recommended considering failure cases such as one battery pack inoperative and one prop rotor inoperative.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.419-431
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• 1999

InP, III-V binary compound semiconductor, single crystal was grown by VGF (vertical gradient freeze) method using quartz ampoule and its electrical optical properties were investigated. Phosphorous powders were put in the bottom of quartz ampoule and Indium metal changed in conical quartz crucible hat was attached at the upper side position inside the quartz ampoule. It was vacuous under the pressure of 10-5 Torr and sealed up. In metal in the quartz crucible was melted at 1070$^{\circ}C$ and phophorous sublimated at 450$^{\circ}C$, there after it was diffused in In melt and so InP composition was formed. By cooling the InP composition melt (2$^{\circ}C$∼5$^{\circ}C$/hr of cooling rate) in range of 1070$^{\circ}C$∼900$^{\circ}C$, InP crystal was grown. the grown InP single crystals were investigated by X-ray analysis and polarized optical microscopy. Electrical properties of them were measured by Van der Pauw method. At the cooling rate of 2$^{\circ}C$/hr, its direction was (111), quality of the ingot ws better upper side of the ingot than lower. It was found that the InP crystals were n-type semiconductor and the carrier concentration, electron mobility and relative resistivity were 1015∼1016/㎤, 2x103∼3x104$\textrm{cm}^2$/Vsec and 2x10-1∼2x10-3Ωcm in the range of 150K∼300K, respectively.

• Journal of Powder Materials
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• v.30 no.1
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• pp.22-28
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• 2023

The global demand for raw lithium materials is rapidly increasing, accompanied by the demand for lithiumion batteries for next-generation mobility. The batch-type method, which selectively separates and concentrates lithium from seawater rich in reserves, could be an alternative to mining, which is limited owing to low extraction rates. Therefore, research on selectively separating and concentrating lithium using an electrodialysis technique, which is reported to have a recovery rate 100 times faster than the conventional methods, is actively being conducted. In this study, a lithium ion selective membrane is prepared using lithium lanthanum titanate, an oxide-based solid electrolyte material, to extract lithium from seawater, and a large-area membrane manufacturing process is conducted to extract a large amount of lithium per unit time. Through the developed manufacturing process, a large-area membrane with a diameter of approximately 20 mm and relative density of 96% or more is manufactured. The lithium extraction behavior from seawater is predicted by measuring the ionic conductivity of the membrane through electrochemical analysis.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.4
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• pp.97-113
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• 2023

Swift and appropriate responses in emergency situations like objects falling on the road can bring convenience to road users and effectively reduces secondary traffic accidents. In Korea, current intelligent transportation system (ITS)-based detection systems for emergency road situations mainly rely on loop detectors and CCTV cameras, which only capture road data within detection range of the equipment. Therefore, a new detection method is needed to identify emergency situations in spatially shaded areas that existing ITS detection systems cannot reach. In this study, we propose a ResNet-based algorithm that detects and classifies emergency situations from vehicle camera footage. We collected front-view driving videos recorded on Korean highways, labeling each video by defining the type of emergency, and training the proposed algorithm with the data.

• Journal of the Korean Applied Science and Technology
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• v.40 no.3
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• pp.579-588
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• 2023

This study attempted to reveal the causal relationship (SEM) focusing on communication style on the impact of lapo formation between personal trainers and customers on motor performance. Accordingly, the following results were derived through the mobile program "Survey Monkey" for 187 PT customers according to the sample plan from October 1 to April 28, 2022. First, it was found that communication style had an effect (+) on lapo formation. Second, communication style partially affects (+) mobility performance, and the control type has no influence relationship. Third, lapo formation was found to have an effect on motor performance. Therefore, since PT is a human service, not a general service, its importance should be emphasized more. In addition, the dominance in the fierce PT market is expected to have both athletic performance and management performance if the verbal and non-verbal aspects of expression methods that customers can respond to are properly reflected.

• Restorative Dentistry and Endodontics
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• v.47 no.3
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• pp.34.1-34.12
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• 2022

Objectives: This study aimed to evaluate the success rate of endodontic treatments performed by undergraduate students and the factors associated with the outcome. Materials and Methods: A follow-up of 3 to 8 years after root canal filling was carried out in 91 patients. At the follow-up visits, medical and dental history questionnaires were applied along with clinical and radiographic examinations. Data collected in the clinical exam included: the presence of pain, swelling, sinus tract, mobility, tenderness to palpation and percussion, periodontal probing profile, and type/quality of coronal restoration. Postoperative and follow-up radiographs were digitalized and analyzed by 2 trained and calibrated examiners to assess periapical healing. The treatment outcome was based on strict clinical and radiographic criteria and classified as success (absence of any clinical and radiographic sign of apical periodontitis) or failure (other combination). Logistic regression was used to investigate the impact of clinical and radiographic variables on endodontic treatment outcomes at a 5% significance level. Results: The success rate of endodontic treatments was 60.7%. The only risk factor significantly associated with failure was the presence of a periapical lesion on the postoperative radiograph (odds ratio, 3.35; 95% confidence interval, 1.17-9.54). Conclusions: The success rate of endodontic treatments performed by undergraduate students was low and was jeopardized by the presence of a periapical lesion on the postoperative radiograph.