• Journal of Korean Critical Care Nursing
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• v.17 no.2
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• pp.25-41
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• 2024

Purpose : This study aimed to investigate changes in critical nursing activities from 2009 to 2020 and explore the relationship between nurse staffing and such activities in intensive care units. Methods : A total of 446,445 adult patients admitted to intensive care units in tertiary and general hospitals from 2009 to 2020 were identified using the National Health Insurance claims database. The Critical Nursing Activities Index was calculated based on the following critical nursing activities: ventilator, extracorporeal membrane oxygenation (ECMO), and continuous renal replacement therapy (CRRT). Trend analysis was performed to analyze changes in critical nursing activities over 12 years and to assess linear trends across different staffing levels. Results : The annual utilization days for ventilators, ECMO, and CRRT, as well as the Critical Nursing Activities Index significantly increased over the study period (p-for-trend<.001) in tertiary and general hospitals, except for ventilator use in general hospitals. Ventilator, ECMO, and CRRT utilization exhibited a significant upward trend with higher nurse staffing levels (Bonferroni adjusted p-for-trend<.001). The Critical Nursing Activities Index was significantly higher in hospitals with higher staffing levels compared to those with lower staffing levels (Bonferroni adjusted p <.05). Conclusion : The findings underscore the need for improved nurse staffing levels in intensive care units. Government policies should ensure that staffing levels align with critical nursing activities among critically ill patients to uphold the quality of care.

• Journal of Korean Home Economics Education Association
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• v.35 no.1
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• pp.1-14
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• 2023

The objective of the study was to examine the associations of dietary carbohydrate and fat intake with the prevalence of metabolic syndrome in Korean women. A cross-sectional study was employed based on data from the Korea National Health and Nutrition Examination (2007-2016). A total of 22,850 women aged 19 to 69 years were studied after excluding responses from pregnant or lactating women and those with missing metabolic values. Dietary intake data were collected with a 24-hour recall method. Dietary carbohydrate and fat intakes were divided into quintiles. After controlling for confounding variables, a multivariable logistic regression and general linear model were used. The findings indicated that HDL cholesterol levels were lower (p for trend<0.01), while triglyceride levels (p for trend=0.04), waist circumference (p for trend<0.01), and systolic blood pressure (p for trend<0.01) were higher among participants in the highest quintile of carbohydrate intake compared to those in the lowest quintile. Participants in the highest quintile of fat intake had lower waist circumference (p for trend=0.02), triglyceride level (p for trend<0.01), and systolic blood pressure (p for trend<0.01), while higher HDL cholesterol level (p for trend<0.01) compared to those in the lowest fat intake quintile. Metabolic syndrome was more likely to be present in the highest quintile of carbohydrates intake than in the lowest quintile (5^th quintile vs. 1^st quintile, OR: 1.32; 95% CI: 1.11 to 1.57). However, metabolic syndrome was less likely to be present in the highest quintile of fat intake than in the lowest quintile (5^th quintile vs. 1^st quintile, OR: 0.73; 95% CI: 0.61 to 0.86). This study revealed that high dietary carbohydrate intake and low dietary fat intake were associated with metabolic syndrome in Korean women.

• Ocean and Polar Research
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• v.39 no.3
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• pp.181-194
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• 2017

The long-term linear trend of global sea-to-air dimethyl sulfide (DMS) flux was analyzed over a 16-year time span (2000~2015), based on satellite observation data. The emission rates of DMS (i.e. DMS flux) in the global ocean were estimated from sea surface DMS concentrations, which were constructed with chlorophyll a (Chl-a) concentrations and mixed layer depths (MLD), and transfer velocity from sea to air, which was parameterized with sea surface wind (SSW) and sea surface temperature (SST). In general, the DMS flux in the global ocean exhibited a gradual decreasing pattern from 2000 (a total of 12.1 Tg/yr) to 2015 (10.7 Tg/yr). For the latitude band ($10^{\circ}$ interval between $0^{\circ}$ and $60^{\circ}$), the DMS flux at the low latitude of the Northern (NH) and Southern hemisphere (SH) was significantly higher than that at the middle latitude. The seasonal mean DMS flux was highest in winter followed by in summer in both hemispheres. From the long-term analysis with the Mann-Kendall (MK) statistical test, a clear downward trend of DMS flux was predicted to be broad over the global ocean during the study period (NH: $-0.001{\sim}-0.036{\mu}mol/m^2/day\;per\;year$, SH: $-0.011{\sim}-0.051{\mu}mol/m^2/day\;per\;year$). These trend values were statistically significant (p < 0.05) for most of the latitude bands. The magnitude of the downward trend of DMS flux at the low latitude in the NH was somewhat higher than that at the middle latitude during most seasons, and vice versa for the SH. The spatio-temporal characteristics of DMS flux and its long-term trend were likely to be primarily affected not only by the SSW (high positive correlation of r = 0.687) but also in part by the SST (r = 0.685).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.117-133
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• 2014

In this study, we analysed impacts of the recent increasing trend of exceedance rainfall thresholds for separation of data set and different research periods using Quantile Regression (QR) approach. And also we performed significant test for time series data using linear regression, Mann-Kendall test and Sen test over the Korean major 8-city. Spring and summer precipitation was tend to significant increase, fall and winter precipitation was tend to decrease, and heavy rainy days in last 30 years have increased from 3.1 to 15 percent average. In addition, according to the annual ranking of rainfall occurs Top $10^{th}$ percentile of precipitation for 3IQR (inter quartile range) of the increasing trend, most of the precipitation at the point of increasing trend was confirmed. Quantile 90% percentile of the average rainfall 43.5mm, the increasing trend 0.1412mm/yr, Quantile 99% percentile of the average rainfall 68.0mm, the increasing trend in the 0.1314mm/yr were analyzed. The results can be used to analyze the recent increasing trend for the annual maximum value series information and the threshold extreme hydrologic information. And also can be used as a basis data for hydraulic structures design on reflect recent changes in climate characteristics.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1409-1420
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• 2014

In this work, we have carried out a sensitivity analysis of hydrogeologic parameters such as reaction factor and drainable pore space in groundwater table fluctuation model and have found characteristics of parameter distribution according to the altitude. We found that drainable pore space which is hydrogeologic parameter of aquifer didn't show any trend with altitude while reaction factor which is groundwater flow characteristic showed clear trend with altitude. To find a sensitivity of parameters, we compared RMSE of estimated groundwater recharges by using the mean value and linear relationship of parameters. As results, the linear equation derived for entire watersheds could be applied to estimate parameters for ungauged watershed. Furthermore, the features of parameter distribution can be used to predict hydrogeologic parameter in ungauged watersheds and it is expected that those features could be used for a basic data for groundwater modeling.

• Journal of Environmental Health Sciences
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• v.42 no.4
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• pp.280-292
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• 2016

Objectives: The objective of this study was to build COD regression models for the Han River and evaluate water quality. Methods: Water quality data sets for the dry season (as of January) during a four-year period (2012-2015) were collected from the database of the Han River automatic water quality monitoring stations. Statistical techniques, including combined genetic algorithm-multiple linear regression (GA-MLR) were used to build five-descriptor COD models. Multivariate statistical techniques such as principal component analysis (PCA) and cluster analysis (CA) are useful tools for extracting meaningful information. Results: The $r^2$ of the best COD models provided significant high values (> 0.8) between 2012 and 2015. Total organic carbon (TOC) was a surrogate indicator for COD (as COD/TOC) with high reliability ($r^2=0.63$ in 2012, $r^2=0.75$ for 2013, $r^2=0.79$ for 2014 and $r^2=0.85$ for 2015). The ratios of COD/TOC were calculated as 2.08 in 2012, 1.79 in 2013, 1.52 and 1.45 in 2015, indicating that biodegradability in the water body of the Han River was being sustained, thereby further improving water quality. The BOD/COD ratio supported these findings. The cluster analysis revealed higher annual levels of microorganisms and phosphorous at stations along the Hangang-Seoul and Hantangang areas. Nevertheless, the overall water quality over the last four years showed an observable trend toward continuous improvement. These findings also suggest that non-point pollution control strategies should consider the influence of upstreams and downstreams to protect water quality in the Han River. Conclusion: This data analysis procedure provided an efficient and comprehensive tool to interpret complex water quality data matrices. Results from a trend analysis provided much important information about sources and parameters for Han River water quality management.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.3
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• pp.194-206
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• 2008

This study standardized catch per unit effort(CPUE) of the Korean longline fishery, which has been used to assess the status of stock as an index of abundance, for bigeye and yellowfin tunas in the Indian Ocean. The Generalized Linear Model(GLM) was used to analyze the fishery data, which were catch in number and effort data collected each month from 1971 to 2007 by $5\;{\times}\;5$ degree of latitude and longitude. Explanatory variables for the GLM analysis were year, month, fishing area, number of hooks between floats(HBF), and environment factors. The HBF was divided into three classes while the area was divided into eight subareas. Although sea surface temperature(SST) and southern oscillation index(SOI) were considered as environmental factors, only SST was used to build a model based on statistical significance. Standardized CPUE for yellowfin tuna showed a declining trend, while nominal CPUE for the species showed an increasing trend.

• Journal of Preventive Medicine and Public Health
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• v.43 no.2
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• pp.125-130
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• 2010

Objectives: The current study was performed to assess the distribution of intraocular pressure (IOP) and its association with metabolic syndrome (MS) in a community. Methods: We measured IOP and MS components from 446 adults, age 20 or more years old, who reside in a community in Kyunggi Province, South Korea. We compared the level of IOP according to the number of metabolic abnormalities and between normal and abnormal metabolic components. Linear regression analyses were used to determine the relationship between IOP and metabolic components. Results: No significant difference in IOP (mean${\pm}$SE) was found between men ($12.24{\pm}2.42$) and women ($12.55{\pm}2.41$ mmHg, p > 0.1), while IOP of men tended to decrease as age increased (p for trend < 0.01). After adjusting for age, IOP of subjects with abdominal obesity in men and high blood pressure in women were significantly higher than those without abdominal obesity or high blood pressure (p < 0.05). Female subjects with MS showed significantly higher IOP than those without MS. Participants with more metabolic disturbances tended to have a greater IOP elevation with a linear trend after adjusting for age and sex. In the univariate regression analysis, age and waist circumference were significantly associated with IOP in men, but systolic and diastolic blood pressure were associated with IOP in women. In final multiple regression model, age, systolic blood pressure, and triglyceride were associated with IOP in women, and age in men. Conclusions: These findings suggest that MS and its components may be important determinants of elevated IOP.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.1
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• pp.1-11
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• 2003

In this study, TOPMODEL(TOPography based hydrologic MODEL) was tested linked with Muskingum river routing technique for $581.7km^2$ Anseong-cheon watershed. Linear trend surface interpolation was used to give flow direction for flat areas located in downstream watershed. MDF (multiple flow direction) algorithm was adopted to derive the distribution of ln(a/$tan{\beta}$) values of the model. Because the coarser DEM resolution, the greater information loss, the watershed was divided into subwaterhseds to keep DEM resolution, and the simulation result of the upstream watershed was transferred to downstream watershed by Muskingum techniques. Relative error of the simulated result by 500 m DEM resolution showed 27.2 %. On the other hand, the relative error of the simulated result of 300 m DEM resolution by linked 2 subwatersheds with Muskingum method showed 15.8 %.

• Journal of the Ergonomics Society of Korea
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• v.30 no.6
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• pp.689-694
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• 2011

Objective: The aim of this study is to evaluate the fluctuation of signal amplitude during repetitive dynamic contraction based on surface electromyography(EMG). Background: The most previous studies were considered isometric muscle contraction and they were difference to smoothing window length by moving average filter. In practical, the human movement is dynamic state. Dynamic EMG signal which indicated as the nonstationary pattern should be analyzed differently compared with the static EMG signal. Method: Ten male subjects participated in this experiment, and EMG signal was recorded by biceps brachii, anterior/posterior deltoid, and upper/lower trapezius muscles. The subject was performed to repetitive right horizontal lifting task during ten cycles. This study was considered three independent variables(muscle, amplitude processing technique, and smoothing window length) as the within-subject experimental design. This study was estimated muscular activation by means of the linear envelope technique(LE). The dependent variable was set coefficient of variation(CV) of LE for each cycle. Results: The ANOVA results showed that the main and interaction effects between the amplitude processing technique and smoothing window length were significant difference. The CV value of peak LE was higher than mean LE. According to increase the smoothing window length, this study shows that the CV trend of peak LE was decreased. However, the CV of mean LE was analyzed constant fluctuation trend regardless of the smoothing window length. Conclusion: Based on these results, we expected that using the mean LE and 300ms window length increased reproducibility and signal noise ratio during repetitive dynamic muscle contraction. Application: These results can be used to provide fundamental information for repetitive dynamic EMG signal processing.