• 한국자원식물학회지
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• 제24권6호
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• pp.659-665
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• 2011

The aim of this study was to determine total phenolics (TP) content, total flavonoids (TF) level, and antioxidant activity of methanol extracts from leaf parts of 15 Vietnamese wild plants. TP content showed the highest amount in methanol extracts from Altenanthera sessilis ($409.7{\pm}1.4$ ppm), and followed by Eclipta prostrata ($183.6{\pm}3.8$ ppm) and Cassia tora ($159.3{\pm}5.7$ ppm). The highest TF level also was found in A. sessilis ($156.3{\pm}1.7$ ppm), followed by E. prostrata, and C. tora, showing similar tendency to TP. Methanol extracts of A. sessilis, E. prostrate and C. tora at 1000 ppm exhibited the highest DPPH radical scavenging activity by 94.5, 92.6 and 92.7%, respectively. The methanol extracts from A. sessilis showed the highest ABTS and nitrite scavenging activities by 97% and 92%, respectively. The highest correlation coefficient ($r^2$) was 0.9522 between TP and TF, and followed by 0.8919 between DPPH and ABTS activities. However, polyphenols and antioxidant activities showed low correlation coefficients, ranging from $r^2=0.4114$ to 0.4826. It was concluded that Vietnamese wild plants contain polyphenol compounds with antioxidant activities depending on plant species.

• 대한전자공학회논문지SP
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• 제46권5호
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• pp.162-166
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• 2009

본 논문은 적응 반향 제거기인 parametric wiener filter (PWF)의 반향신호 제거 파라미터를 구간 조건에 따라 차등적으로 적용시키는 새로운 음향학적 반향제거 (Acoustic Echo Suppression, AES) 알고리즘을 제안한다. PWF는 반향 신호 추정의 부정확성을 보상하고자 반향신호 제거 파라미터를 사용한다. 기존의 방법은 단일통화 구간과 동시통화 구간에 관계없이 동일한 반향신호 제거파라미터 값을 적용하여 동시통화 환경에서 근단 신호의 왜곡을 발생 시킨다. 본 논문에서는 상관계수 (Correlation Coefficient)를 이용한 동시통화(Double-Talk) 검출 알고리즘과 음성구간검출기 (Voice Activity Detector, VAD)의 결과로부터, 원단 화자만 있는 구간과 동시통화 구간을 구분하고 각각의 경우에 반향제거 파라미터를 달리 적용하여 동일한 반향신호 제거 파라미터를 사용함에 따른 동시통화 구간내의 근단 화자신호의 음질 저하 없이 반향신호를 보다 효과적으로 제거하는 방법을 제안한다. 제안된 방법의 결과는 객관적인 실험을 통해 비교 평가한 결과 우수한 성능을 보였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.366-366
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• 2002

Cloud-to ground lightning and total precipitation over Korean peninsula during the summer monsoon season are studied extensively with a special emphasis on the characteristics of convective precipitation. Ten years (1988-1997) lightning and rainfall data and a temporal and spatial scale of one month and 10$^2$ km$^2$ respectively are used to calculate the monthly number of CG lightning flash count. Monsoonal convective activity is higher over the west coast with maxima at two different regions, one in the northern part which increases nortwestward and the other is at the middle west coast of Korea increasing towards the west coast. East coast represents the minimum value of monsoonal convective activity. In the east coast of Korean peninsula, particularly in the region east of Tae-back mountain, the value of Rain yield, (which is defined as the ratio of total precipitation to CG flash count over a common area), is maximum with an average value of 3$\times$10$^{8}$ kg fl$^{-1}$, while the minimum value of rain yield is occurred in the west of Tae-back mountain, with an average value of 0.8$\times$10$^{8}$ kg fl$^{-1}$. Results show in the west coast stations, nearly 82% of the total rainfall is convective in nature, at the middle of the peninsula 53% of the total rain is convective while in the east coast stations 46% contribution from the convective rain is seen. Kanghwa receives the maximum convective rain while at Ulsan the convective rain is minimum. Correlation coefficient between the total precipitation and CG lightning during the summer monsoon season is 0.54.

• 대한금속재료학회지
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• 제48권8호
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• pp.765-774
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• 2010

Oxygen equilibrium and the solubility of MgO have been measured in the $CaO-Fe_tO-MgO-SiO_2({\leq}5mass%)-{\Sigma}M_xO_y$ slag in equilibrium with liquid iron in the temperature range of 1550 to $1700^{\circ}C$. The effect of oxides on the MgO solubility, and a method for calculating the solubility of MgO using slag composition and temperature,were discussed. The solubility of MgO is increased with increasing temperature and $Fe_tO$ content, and with decreasing basicity (C/S). The effect of ${\Sigma}M_xO_y$ on the solubility of MgO is a dilution effect due to the increase in slag volume. The activity and activity coefficient of $Fe_tO$ decreased with increasing basicity (B). The effect of temperature on the activity was negligible. The value of ${\rho}=Fe^{3+}/Fe^{2+}$ increased with the increase of the slag basicity (B") and the decrease of the $Fe_tO$ content in the slag.

• 임상간호연구
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• 제17권2호
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• pp.204-214
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• 2011

Purpose: This study was aimed to provide information on the awareness of patient safety culture and safety care activities among operating room (OR) nurses and to analyze the factors influencing the safety care activities. Methods: For this descriptive research, self-reported questionnaires were administered to 168 OR nurses who were working at the university-affiliated and general hospitals. The collected data were analyzed using descriptive statistics, t-test, ANOVA, $Scheff{\grave{e}}$ test, Pearson's correlation coefficient and Stepwise multiple regression with SPSS/WIN 17.0. Results: The mean score of the awareness on patient safety culture was 3.27 out of 5 points and that of safety care activity was 4.31 out of 5. The statistically significant difference was found between experience of safety education and the awareness on patient safety culture. Also, the scores of safety care activities were significantly different according to OR nurses' position, education levels, and experience of safety education. There was a positive correlation between the awareness of patient safety culture and safety care activity. Their explanatory power on safety care activity was 8.8%, which includes working environment in operating room 3.3% and nursing position 5.5%. Conclusion: Compared to the level of patient safety activities, the OR nurses' awareness on patient safety culture was low. Given the specific characteristics and conditions in each hospital, it needs to increase the OR nurses' awareness on patient safety culture and activities related to patient safety.

• Journal of Korean Biological Nursing Science
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• 제23권4호
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• pp.287-297
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• 2021

Purpose: This study aimed to evaluate the correlation and agreement of physical activity (PA) between data obtained from wearable Actigraph devices and self-reporting questionnaires, and to investigate the relationship between psychological state (depression, anxiety, and fatigue) and PA. Methods: A descriptive study was conducted using physical measurements and surveys. PA was measured through both the International Physical Activity Questionnaire (IPAQ) and the Actigraph GT3X+ device. The demographic characteristics of the subjects, as well as their depression, anxiety, and fatigue scores, were collected with structured questionnaires. The Spearman's rank correlation coefficient and the Bland-Altman plot method were employed. Results: Data from 36 healthy adults were analyzed. The overall levels of PA measured using the IPAQ and the Actigraph were 1,891.69 MET min/week and 669.96 MET/day, respectively. Total levels of PA did not show a significant correlation between the two measurement methodologies. However, the moderate-intensity PA resulting from the IPAQ scores showed a significant positive correlation with the light-intensity PA recorded by the Actigraph. The Bland-Altman plot analysis demonstrated that the levels of PA as measured by the two different methods did not match. In addition, PA measured using the Actigraph showed a significant negative correlation with depression and anxiety whereas PA measured using the IPAQ showed a significant positive correlation with fatigue. Conclusion: The conclusion of this study is that the data obtained from the subjective self-reporting questionnaire and the wearable Actigraph do not correlate or match in healthy adults. Future research should investigate the relationship between depression and PA intensity through the Actigraph, or other wearable devices equipped with smartphone apps.

• 운동영양학회지
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• 제24권1호
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• pp.9-13
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• 2020

[Purpose] This preliminary study aimed to develop a regression model to estimate the resting metabolic rate (RMR) of young and middle-aged Koreans using various easy-to-measure dependent variables. [Methods] The RMR and the dependent variables for its estimation (e.g. age, height, body mass index, fat-free mass; FFM, fat mass, % body fat, systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse pressure, and resting heart rate) were measured in 53 young (male n = 18, female n = 16) and middle-aged (male n = 5, female n = 14) healthy adults. Statistical analysis was performed to develop an RMR estimation regression model using the stepwise regression method. [Results] We confirmed that FFM and age were important variables in both the regression models based on the regression coefficients. Mean explanatory power of RMR₁ regression models estimated only by FFM was 66.7% (R²) and 66.0% (adjusted R²), while mean standard errors of estimates (SEE) was 219.85 kcal/day. Additionally, mean explanatory power of RMR₂ regression models developed by FFM and age were 70.0% (R²) and 68.8% (adjusted R²), while the mean SEE was 210.64 kcal/day. There was no significant difference between the measured RMR by the canopy method using a metabolic gas analyzer and the predicted RMR by RMR₁ and RMR₂ equations. [Conclusion] This preliminary study developed a regression model to estimate the RMR of young and middle-age healthy Koreans. The regression model was as follows: RMR₁ = 24.383 × FFM + 634.310, RMR₂ = 23.691 × FFM - 5.745 × age + 852.341.

• 근관절건강학회지
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• 제29권3호
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• pp.218-227
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• 2022

Purpose: This study aimed to describe the current level of physical activity (PA) and to explore the relationships between self-efficacy for PA, perceived health status (PHS), attitudes toward aging, ego-integrity and PA in community-dwelling older Koreans. Methods: A total of 164 participants were recruited from community centers, churches, and senior welfare centers in Korea. With questionnaires, a survey was conducted from June 3rd to 22th, 2016. Data were analyzed with descriptive statistics, independent t-test, one-way ANOVA and Pearson's correlation coefficient using SPSS/WIN 22.0 program. Results: The mean amount of total PA was 5,295.33±6,272.38 MET/min/week. The number of subjects engaged in vigorous, moderate, and low-intensity activities were 87 (53.0%), 45 (27.4%), and 32 (19.5%), respectively. Overall, physical activities were different according to the presence of spouse (t=-2.79, p=.006) and the presence of housemate (t=2.03, p=.044). The mean scores of self-efficacy for PA, PHS, attitudes towards aging, and ego-integrity were 17.16±4.45, 9.00±2.41, 68.12±9.28 and 51.62±7.59, respectively. There were significant positive correlations between overall PA and self-efficacy for PA (r=.34, p<.001), PHS (r=.23, p=.003), attitudes towards aging (r=.26, p=.001). Conclusion: Specific programs to promote physical activities in addition to continuous education for improving self-efficacy for PA, PHS, and attitudes towards aging in community-dwelling older adults are needed.

• 대한통합의학회지
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• 제10권3호
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• pp.53-62
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• 2022

Purpose : This research is a descriptive study that aimed to identify the levels of health promotion behaviors, fatigue, and depression of nursing students and confirm the effect of health promotion behaviors on fatigue and depression. Methods : Data were collected from September 27 to October 15, 2021 through survey questionnaires on 178 nursing students of 2 universities in G-do who voluntarily agreed to participate. The collected data were analyzed using SPSS 23.0, the general characteristics of nursing students were analyzed by frequency and percentage, and the levels of their health promotion behaviors, fatigue, and depression of nursing students was analyzed by mean and standard deviation. The relationship among the health promotion behaviors, fatigue, and depression was analyzed by Pearson's Correlation Coefficient. Multiple regression analysis was performed for the effects of health promotion behaviors on fatigue and depression of nursing students. Results : The nursing students' health promotion behaviors averaged 2.25±.43 points out of 5, and for each sub-factor, interpersonal relationship was the highest at 2.66±.49 points and physical activity was the lowest at 2.01±.60 points. Fatigue was 4.89±1.02 points out of 7 and depression was 10.52±9.10 points out of 63. A statistically significant correlation was found among health promotion behaviors, fatigue, and depression. Health promotion behaviors that significantly affected fatigue were stress management (𝛽=-.263, p=.004) and physical activity (𝛽=-.208, p=.026), which showed 35 % explanatory power on fatigue. Health promotion behaviors that significantly affected depression were spiritual growth (𝛽=-.342, p=.002), and physical activity (𝛽=-.231, p=.016), which showed 31 % explanatory power for depression. Conclusion : This study is meaningful in that it provided basic data to develop an effective health promotion behavior program to prevent and manage nursing students' fatigue and depression, by identifying and analyzing the sub-factors of health promotion behaviors affecting their fatigue and depression.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.257-264
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• 2020

Objective: To investigate test-retest reliability and responsiveness of Equivital Lifemonitor and photoplethysmography based wristwatch tools in assessing physiological parameters during a simulated fatigue task. Methods: Ten university students (Mean age, 30.6 ± 1.7 years) participated in this pilot study. Participants were asked to perform a 30-minute of a simulated fatigue task in an experimental setup in a lab. The physiological parameters (e.g., heart rate, heart rate variability, respiratory rate, electrodermal activity, and skin temperature) were measured at baseline and immediately after the fatigue task. An intraclass correlation coefficient (ICC2,1) was used to evaluate the test-retest reliability of each tool in assessing physiological measures. In addition, the responsiveness of each tool to measure changes from baseline to posttest was calculated using a standardized response mean. Results: The Equivital Lifemonitor has shown good to excellent test-retest reliability for the assessment of heart rate (ICC, 0.97), heart rate variability (ICC, 0.86), respiratory rate (ICC, 0.77), and local skin temperature (ICC, 0.76). However, photoplethysmography based wristwatch showed moderate to good test-retest reliability for the assessment of heart rate (ICC, 0.71), heart rate variability (ICC, 0.73), electrodermal activity (ICC, 0.80), and skin temperature (ICC, 0.72). A large standardized response mean (>0.8) indicates that both tools can capture the changes in heart rate, heart rate variability, respiratory rate, skin temperature, and electrodermal activity after a 30-minute of fatigue task. Conclusions: The Equivital Lifemonitor and photoplethysmography based wristwatch devices are reliable in measuring physiological parameters after the fatigue task. Additionally, both devices can capture the fatigue response after a simulated construction task. Future field studies with a larger sample should investigate the sensitivity and validity of these tools in measuring physiological parameters for fatigue assessment at construction sites.