• 대한의용생체공학회:의공학회지
• /
• 제43권1호
• /
• pp.1-10
• /
• 2022

Non-alcoholic fatty liver disease(NAFLD) is excessive hepatic lipid accumulation mainly caused by obesity. This study aimed to evaluate whether micro-current stimulation(MCS) could modulate lipid metabolism regarding the Sirt1/AMPK pathway, fatty acid β-oxidation pathway, and lipolysis and lipogenesis-related factors in FL83B cells. For the NAFLD cell model, FL83B cells were treated with oleic acid for lipid accumulation. MCS were stimulated for 1 hr and used frequency 10 Hz, duty cycle 50%, and biphasic rectangular current pulse. The intensity of MCS was divided into 50, 100, 200, and 400 ㎂. Through the results of Oil red O staining, it was confirmed that MCSs with the intensity of 200 ㎂ and 400 ㎂ significantly reduced the degree of lipid droplet formation. Thus, these MCS intensities were applied to western blot analysis. Western blot analysis was performed to analyze the effects of MCS on lipid metabolism. MCS with the intensity of 400 ㎂ showed that significantly activated the Sirt1/AMPK pathway, a key pathway for regulating lipid metabolism in hepatocytes, and fatty acid β-oxidation-related transcription factors. Moreover, it activated the lipolysis pathway and suppressed lipogenesis-related transcription factors such as SREBP-1c, FAS, and PPARγ. In the case of MCS with the intensity of 200 ㎂, only PGC1α and SREBP-1c showed significant differences compared to cells treated only with oleic acid. Taken together, these results suggested that MCS with the intensity of 400 ㎂ could alleviate hepatic lipid accumulation by modulating lipid metabolism in hepatocytes.

• Korean Journal of Acupuncture
• /
• 제38권4호
• /
• pp.222-234
• /
• 2021

Objectives : The purpose of this study is to examine the efficacy of fire needling and warm needling for De Quervain Syndrome by reviewing clinical studies for recent 10 years. Methods : Randomized controlled trials, non-randomized controlled trials, and case series containing more than 20 cases about fire needling and warm needling for De Quervain Syndrome published since 2011 were searched through four foreign online databases (CNKI, Pubmed, EMBASE, Cochrane Library) and five Korean online databases (OASIS, Science ON, DBPIA, KISS, RISS). The number and characteristics of participants, treatment points and main treatment methods involving other combination treatments, treatment cycle or total periods of treatments, evaluation indices, efficacy, and adverse events were analyzed. Risk of bias of included randomized clinical trials was assessed using a revised tool for assessing risk of bias in randomized trials (RoB 2). Results : A total of 6 randomized clinical trials and 2 case series involving 471 participants were included. Tender point or 'Ashi point' was the most commonly used treatment point, followed by LU4. Treatment frequency ranged from once a day to once a week. One to three outcome measures were used to evaluate the results of the studies, with the efficacy rate the most frequently used, followed by visual analogue scale. Overall risk of bias of all included randomized clinical trials was judged to have some concerns. Conclusions : All selected studies showed that fire needling and warm needling treatments for De Quervain syndrome were more effective than other clinical methods or acupuncture treatments. However, as the number of clinical studies is still too small and the risk of bias of the studies is not low, it is believed that more systematic and objective studies should be conducted.

• 한국치위생학회지
• /
• 제21권6호
• /
• pp.721-729
• /
• 2021

Objectives: This study aimed to examine the actual use of interdental care products (ICPs), such as dental floss (DF) and interdental brushes (IDB), among Korean youth, confirm their relevance to periodontal health, and determine the factors that influence the use of each product. Methods: This study included 15,912 young adults aged 19-39 years and data from the Korea National Health and Nutrition Examination Survey (KNHANES) (2007-2018). The usage rate of ICPs according to the characteristics of the subjects for each cycle of KNHANES was presented. Multivariable logistic regression analysis was performed to identify factors affecting the use of ICP. Results: The use rates of DF and IDB gradually increased until the 7th period, reaching 34.8% and 26.8%, respectively. The rate of using more than one ICP also showed a tendency to gradually increase from 25.2% in the 4th period to 50.0% in the 7th period. The use of interdental care products is related to gingivitis and periodontitis. Factors related to the use of ICP were gender, age, education level, frequency of brushing, and dental examination experience. Conclusions: The use of dental floss or interdental toothbrushes was related to periodontal health, but only half of the adults aged 19-39 years used ICP. Therefore, oral health experts should actively encourage the use of DF and IDB in young adults.

• 센서학회지
• /
• 제31권1호
• /
• pp.51-56
• /
• 2022

In this study an efficient method for detecting and monitoring engine misfiring, focusing on minute speed changes in the crankshaft is proposed., Its validity is verified using various misfiring cases. Typically, the crankshaft speed fluctuates around the normal value depending on the engine misfiring status. Even a minute speed change in the crankshaft can be estimated by measuring the rotation time of each tooth of the 118-tooth flywheel attached to the crankshaft with a 2-MHz timer. Therefore, a speed pattern for an in-line six-cylinder engine consists of 236 tooth rotation speeds corresponding to the two rotations of the crankshaft, in which all the cylinders complete four-stroke cycle. FFT analysis can reduce the number of components of a speed pattern from 236 to just four major components: - fundamental frequency_(f), 2f, 3f, 6f., - This makes the comparison of the misfiring cases simpler and faster. In the experiment, five engine status cases (one normal firing and, four misfiring cases) were simulated. While the 6f component was the largest for the normal case, the f component increased as misfiring occurred one, two apart, and two consecutive times. The 3D FFT pattern comprising the ratio of f, 2f, and 3f, 6f showed that the distance between the misfiring and normal states was larger

• 융합정보논문지
• /
• 제11권5호
• /
• pp.50-56
• /
• 2021

본 연구는 임부의 사회적 지지, 임신 스트레스 그리고 불안이 삶의 질에 영향을 미치는 영향요인을 파악하기 위해 시도 되었다. 본 연구는 2개 지역 D 와 S 지역에 거주하는 임부 117명을 대상으로 한 서술적 조사연구이다. 설문 전 연구의 취지와, 목적, 절차에 대하여 설명을 하고 진행하였다. 자료는 SPSS 21.0 을 이용하였고, 빈도분석, 분산분석, t검증, 상관분석, 희귀분석으로 실시하였다. 자료 수집은 2020년 1월부터 2월까지 하였다. 본 연구결과는 일반적 특성에 따른 임부의 삶의 질 차이는 수면시간, 경제수준, 건강상태, 활동량, 임신주기에서 유의미한 차이를 보였다. 삶의 질에 영향을 미치는 변수는 사회적 지지(β= .432, p= .000), 임신 스트레스(β=- .407, p= .000), 불안(β=- .182, p= .010) 순으로 확인되었다. 임부는 임신 스트레스와 불안 등을 경험하는 삶의 질 저하문제로 이어질 수 있어 임부에 대한 건강증진 프로그램 개발을 해야 할 것이며 삶의 질 증진을 위한 적극적인 간호중재 제공에 대한 필요성이 제기된다.

• 한국융합학회논문지
• /
• 제12권11호
• /
• pp.391-401
• /
• 2021

본 연구는 코로나19 시기 인터넷 중독이 2030세대의 자아존중감에 미치는 영향에서 스트레스 대처방식의 조절효과를 검증하는 데 목적이 있다. 온라인 설문조사를 통하여 최종 762명의 유효 표본을 선정하고 수집된 자료는 SPSS WIN26.0 프로그램을 활용하여 빈도분석, 상관분석, 위계적 회귀분석을 실시하였다. 분석결과, 인터넷 중독은 자아존중감에 부정적인 영향을 미쳤고, 스트레스 대처방식의 조절효과는 사회적지지 추구 대처방식만이 조절변수로서 작용하였다. 즉 인터넷중독이 높을수록 자아존중감은 낮아지며, 인터넷중독이 자아존중감에 미치는 영향은 사회적 지지 추구 대처 수준에 따라 변화됨을 알 수 있었다. 연구결과에 따른 제언으로 연구대상의 확장과 학제 간 융합연구, 스트레스 대처관리 프로그램 제공, 지역사회 차원에서의 커뮤니티 구축, 2030세대의 역할과 과업달성에 중요한 영향을 미치는 자아존중감의 부정적 역할을 상쇄시키는 변수 발굴 등을 제시하였다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
• /
• pp.961-965
• /
• 1998

The rapid development of small-scale (1-10 MJ) Superconducting Magnetic Energy Storage Systems (SMES) can be explained by real perspective of practical implementation of these devices in electro power nets. However the serious problem of all high mechanically stressed superconducting coils-problem of training and degradation (decreasing) of operating current still exists. Moreover for SMES systems this problems is more dangerous because of pulsed origin of mechanical stresses-one of the major sources of local heat disturbances in superconducting coils. We investigated acoustic emission (AE) phenomenon on model and 0.5 MJ SMES coils taking into account close correlation of AE and local heat disturbances. Two-coils 0.5 MJ SMES system was developed, manufactured and tested at Russian Research Center in the frames of cooperation with Korean Electrical Engineering Company (KEPCO) [1]. The two-coil SMES operates with the stored energy transmitted between coils in the course of a single cycle with 2 seconds energy transfer time. Maximum operating current 1.55 kA corresponds to 0.5 MF in each coil. The Nb-Ti-based conductor was designed and used for SMES manufacturing. It represents transposed cable made of Nb-Ti strands in copper matrix, several cooper strands and several stainless steel strands. The coils are wound onto fiberglass cylindrical bobbins. To make AE event information more useful a real time instrumentation system was used. Two main measured and computer processed AE parameters were considered: the energy of AE events (E) and the accumulated energy of AE events (E ). Influence of current value in 0.5 MJ coils on E and E was studied. The sensors were installed onto the bobbin and the external surface of magnets. Three levels of initial current were examined: 600A, 1000A, 2450 A. An extraordinary strong dependence of the current level on E and E was observed. The specific features of AE from model coils, operated in sinusoidal vibration current changing mode were investigated. Three current frequency modes were examined: 0.012 Hz, 0.03 Hz and 0.12 Hz. In all modes maximum amplitude 1200 A was realized.

• 산업융합연구
• /
• 제21권1호
• /
• pp.193-200
• /
• 2023

본 연구의 목적은 연령에 따른 지각된 건강상태, 주관적 체형인식 및 체중변화와의 상관관계를 알아보고자 하였다. 본 연구에서는 질병관리본부 제7차 국민건강영양조사(KNHANES VIII-3, 2016-2018) 자료를 활용한 2차 자료 분석 연구이다. 수집된 자료는 IBM SPSS 21.0 프로그램을 이용하여 빈도분석 및 카이제곱 검정을 실시하였다. 유의수준은 p <.01로 설정하였다. 분석결과, 주관적 신체인식과 건강상태 지각은 통계적으로 유의한 양의 관계가 있었다(r=0.256, p<.01). 1년 동안 지각된 건강상태와 체중 변화 사이에는 통계적으로 유의한 양의 관계가 있었다(r=0.303, p<.01). 그러므로, 중장년층을 위한 주관적 건강상태와 다양한 변인들을 알아봄으로써 더 나은 건강, 삶의 질, 그리고 웰빙을 위한 대책들을 찾기 위한 기초자료로 활용되기를 기대한다.

• Human Ecology Research
• /
• 제60권4호
• /
• pp.625-643
• /
• 2022

The purpose of this study was to explore the trends and core keywords of the secondary school home economics teacher selection test using content analysis and text network analysis. The sample comprised texts of the secondary school home economics teacher 1st selection test for the 2017-2022 school years. Determination of frequency of occurrence, generation of word clouds, centrality analysis, and topic modeling were performed using NetMiner 4.4. The key results were as follows. First, content analysis revealed that the number of questions and scores for each subject (field) has remained constant since 2020, unlike before 2020. In terms of subjects, most questions focused on 'theory of home economics education', and among the evaluation content elements, the highest percentage of questions asked was for 'home economics teaching·learning methods and practice'. Second, the network of the secondary school home economics teacher selection test covering the 2017-2022 school years has an extremely weak density. For the 2017-2019 school years, 'learning', 'evaluation', 'instruction', and 'method' appeared as important keywords, and 7 topics were extracted. For the 2020-2022 school years, 'evaluation', 'class', 'learning', 'cycle', and 'model' were influential keywords, and five topics were extracted. This study is meaningful in that it attempted a new research method combining content analysis and text network analysis and prepared basic data for the revision of the evaluation area and evaluation content elements of the secondary school home economics teacher selection test.

• 한국전자통신학회논문지
• /
• 제18권3호
• /
• pp.483-494
• /
• 2023

최근 가스터빈 발전기는 전력계통의 주파수 조절용으로 널리 사용되고 있다. 가스터빈의 입구온도는 기기의 성능과 수명에 관련된 핵심요소이지만 터빈구조 및 운전환경 등의 이유로 입구온도를 직접 측정하지 않고 가스터빈 배기가스 온도 측정값을 이용하여 입구온도의 추정 값을 구해 이를 연소제어에 사용하고 있다. 특히 재열 가스터빈의 입구온도는 안정적 운전관리에 있어서 매우 중요하지만 제작사가 산출 식에 대한 정보를 제공하지 않고 있어 현장 실무자들은 많은 어려움을 겪고 있다. 이에 본 연구에서는 폴리트로픽 과정식의 기반 위에 머신러닝 기반의 선형회귀 분석기법을 사용하여 가스터빈의 입구온도를 추정할 수 있는 방법을 제시하고자 한다. 또한 선형회귀분석을 통해 얻어진 입구온도 산출 모델식의 유용성 분석과 검증을 통해 입구온도 산출 알고리즘을 제안함으로서 재열 가스터빈 연소튜닝 기술수준 향상에 도움이 되고자 한다.