• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1641-1648
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• 2017

Many researchers had examined the validity of using the high-to-low ratio between two fixed frequency band amplitudes (H/L-FFB) from the surface electromyography of a face and body as the first spectral index to assess muscle fatigue. Despite these studies, the disadvantage of this index is the lack of a criterion for choosing the optimal border frequency. We tested the potential of using the high-to-low ratio between two signal spectral moments (H/L-SSM), without fixed border frequencies, to evaluate muscle fatigue and predict endurance time ($T_{end}$), which was determined when the subject was exhausted and could no longer follow the fixed contraction cycle. Ten healthy participants performed five sets of voluntary isotonic contractions until they could only produce 10% and 20% of their maximum voluntary contraction (MVC). The $T_{end}$ values for all participants were $138{\pm}35s$ at 10% MVC and $69{\pm}20s$ at 20% MVC. Changes in conventional spectral indices, such as the mean power frequency (MPF), Dimitrov spectral index (DSI), H/L-FFB, and H/L-SSM, were extracted from surface EMG signals and were monitored using the initial slope computed every 10% of $T_{end}$ as a statistical indicator and compared as a predictor of $T_{end}$. Significant correlations were found between $T_{end}$ and the initial H/L-SSM slope as computed over 30% of $T_{end}$. In conclusion, initial H/L-SSM slope can be used to describe changes in the spectral content of surface EMG signals and can be employed as a good predictor of $T_{end}$ compared to that of conventional spectral indices.

• 융합정보논문지
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• 제11권7호
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• pp.288-297
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• 2021

본 연구는 호스피스팀원을 대상으로 임종돌봄 수행의 중요도와 수행도 간의 차이를 조사하여 임종돌봄 프로그램 개발의 기초자료를 제공하고자 시도되었다. 2020년 12월 1일부터 2021년 2월 15일까지 총 6개 기관의 대학병원, 종합병원, 호스피스의료기관의 호스피스팀을 대상으로 127부의 자료를 분석하였고, 서술적 통계, 임상돌봄 수행 중요도와 수행도의 상호차이(Gap)는 paired t-test를 사용하였으며, 임상돌봄 수행 중요도와 수행도의 상호차이 결과분석은 IPA Matrix를 사용하였다. IPA Matrix로 분석한 결과 '신체간호'과 '심리간호'는 지속적으로 유지 강화해야하는 제1사분면 영역에 속하였고, '영적간호'는 장기적인 개선이 요구되는 제3사분면 영역으로 나타났다. 집중개선이 필요한 제2사분면에 속하는 것은 없는 것으로 나타났다. 본 연구결과를 토대로 호스피스팀의 임종돌봄 수행 교육프로그램 구성 시, 신체 및 심리간호는 계속적으로 유지 강화할 수 있는 전략과 영적간호에 대한 장기적인 개선전략 수립이 필요하다.

• Corrosion Science and Technology
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• 제10권4호
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• pp.136-142
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• 2011

Al alloys have been used widely for commercial and military ships in most ocean countries since mid-1950s, and the value as light metal with high mechanical strength has been proven. As the safety and fuel efficiency of Al ships have improved, she can carry more freight, sail faster and travel longer distances. Furthermore, in the shipbuilding industry, Al alloys are applied as structural materials for ships to various areas including the deck of luxurious cruises, battleships and leisure ships. In addition, Al alloys are being spotlighted as environmental-friendly material as they can be recycled even after end of lifespan. However, Al alloys for ships must be carefully selected after considering corrosion resistance, endurance, strength, and weldability in sea water environment. Al alloys to satisfy these conditions are used widely include 5000 series Al-Mg alloy and 6000 series Al-Mg-Si alloy. Thus, this study selected and evaluated the cavitation characteristics of the 5000 series Al alloys that are used in hulls that directly contact seawater and the 6000 Al alloys that are used in the upper structures of ships. Results of cavitation test with time, weightloss and cavitation rate of 5456-H116 showed the smallest damage among 5052-O, 5456-H116 and 6061-T6.