• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5B
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• pp.449-457
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• 2011

Recently, increasing heavy rainfalls due to climate change and/or variability result in hydro-climatic disasters being accelerated. To cope with the extreme rainfall events in the future, hydrologic frequency analysis is usually used to estimate design rainfalls in a design target year. The rainfall data series applied to the hydrologic frequency analysis is assumed to be stationary. However, recent observations indicate that the data series might not preserve the statistical properties of rainfall in the future. This study incorporated the residual analysis and the hydrologic frequency analysis to estimate design rainfalls in a design target year considering the non-stationarity of rainfall. The residual time series were generated using a linear regression line constructed from the observations. After finding the proper probability density function for the residuals, considering the increasing or decreasing trend, rainfalls quantiles were estimated corresponding to specific design return periods in a design target year. The results from applying the method to 14 gauging stations indicate that the proposed method provides appropriate design rainfalls and reduces the prediction errors compared with the conventional rainfall frequency analysis which assumes that the rainfall data are stationary.

• Journal of Preventive Medicine and Public Health
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• v.52 no.6
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• pp.393-404
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• 2019

Objectives: The purpose of this study was to determine the associations between blood hemoglobin (Hgb) levels and the risk of death by specific causes. Methods: Using the National Health Insurance Services-National Health Screening Cohort (n=487 643), we classified serum Hgb levels into 6 sex-specific groups. Cox regression analysis was used to analyze the associations between Hgb levels and the risk of cause-specific death. Results: Hgb levels in male population showed a U-shaped, J-shaped, or inverse J-shaped association with the risk of death from ischemic heart disease, acute myocardial infarction, liver cancer, cirrhosis and chronic obstructive pulmonary disease (COPD) (all non-linear p<0.05; hazard ratio [HR]; 95% confidence interval [CI]) for the lowest and the highest Hgb levels for the risk of each cause of death in male population: HR, 1.14; 95% CI, 0.98 to 1.34; HR, 2.87; 95% CI, 1.48 to 5.57; HR, 1.16; 95% CI, 0.96 to 1.40; HR, 3.05; 95% CI, 1.44 to 6.48; HR, 1.36; 95% CI, 1.18 to 1.56; HR, 2.11; 95% CI, 1.05 to 4.26; HR, 3.64; 95% CI, 2.49 to 5.33; HR, 5.97; 95% CI, 1.44 to 24.82; HR, 1.62; 95% CI, 1.14 to 2.30; HR, 3.84; 95% CI, 1.22 to 12.13, respectively), while in female population, high Hgb levels were associated with a lower risk of death from hypertension and a higher risk of death from COPD (overall p<0.05; HR, 1.86; 95% CI, 1.29 to 2.67 for the lowest Hgb levels for hypertension; overall p<0.01, HR, 6.60; 95% CI, 2.37 to 18.14 for the highest Hgb levels for COPD). For the risk of lung cancer death by Hgb levels, a linear negative association was found in male population (overall p<0.01; the lowest Hgb levels, HR, 1.17; 95% CI, 1.05 to 1.33) but an inverse J-shaped association was found in female population (non-linear p=0.01; HR, 1.25; 95% CI, 0.96 to 1.63; HR, 2.58; 95% CI, 1.21 to 5.50). Conclusions: Both low and high Hgb levels were associated with an increased risk of death from various causes, and some diseases showed different patterns according to sex.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.464-476
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• 2019

Objectives: This study aimed to assess the exposure levels of tollbooth workers to diesel particulate matter using black carbon (BC) and to find the correlations among variables associated with BC using the motor vehicle management act regulated by the Ministry of Land, Infrastructure and Transport. Methods: This study was performed over 14 days at a university in Seoul. BC levels were monitored using an aethalometer and were conducted around the breathing zones of the workers. There were three sampling locations: inside the tollbooth (front gate and rear gate) and an office as a control group. T-test, correlation, and multiple linear regression analysis were performed using SPSS. Results: The geometric mean (GM) of BC_30min concentrations in the exposure group was 2.44 ㎍/㎥, approximately 1.4 times higher than the control group (1.75 ㎍/㎥). The GM of BC_30min concentrations was 2.75 ㎍/㎥ during the heavy traffic time (9-10 am) and 2.30 ㎍/㎥ during non-heavy traffic times (p<0.001). The multiple linear regression analysis shows that the number of all types of vehicles and PM_2.5 concentrations in the atmosphere were factors increasing the GM of BC(ln(BC_30min)) concentrations (adjusted R²=0.42, p<0.001). The workers were constantly exposed to low concentrations (GM of BC_30min=2.44 ㎍/㎥), but they were exposed to peak concentrations instantly (BC_10sec=3545.04 ㎍/㎥). When the GM of BC_30min concentrations was momentarily represented as high, it was identified that a vehicle mainly using diesel fuel or an aging vehicle had passed. Conclusions: A ventilation system should be installed in the closed tollbooth or aging vehicles should be controlled so as not to pass tollbooths.

• Journal of dental hygiene science
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• v.14 no.3
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• pp.411-416
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• 2014

The purpose of this study was to examine the effects of conscious sedation on pain and anxiety of patients in implant surgery. A total of 95 patients who underwent implant surgery were included in the study. In this study, the patient's anxiety and pain to evaluate the pre-operative Visual Analogue Scale (VAS), during-operative Pain Question (PQ), post-operative (Short-form McGill Pain Questionnaire [SF-MPQ], VAS) was used for tools such as questionnaires. The data were analyzed using the chi-squire, independent-samples t-test, multiple linear regression analysis. As a result, the pain reduction was significantly different between the sedative dental treatment and non-sedative dental treatment (p<0.05). The finding of the study multiple linear regression analysis showed that operation time, implant surgery experience, gender, age, operation form and Pain Catastrophizing Scale (PCS) with factors that affect the pain and anxiety (p<0.05). According to the results of the study, considered to be necessary to develop intervention strategies effective using the PCS when managing pain and anxiety of behavior management of this implant patient. Thus, it is advised to provide necessary practical guidelines and dental utilization behaviors on patients with conscious sedation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.109-115
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• 2019

In case of the cracks in concrete, the penetration of deterioration ions such as chloride ions in to cracks is accelerated. According to the penetration of chloride ions, structural and durability problems to RC(Reinforced Concrete) structures are caused. In this study, the accelerated chloride diffusion coefficient which is in steady state is evaluated for 2 year aged normal and high strength FA(Fly Ash) concrete, after a range of crack depths are induced up to 1.0 mm in 56 aged day. Considering crack effect by linear regression analysis, high strength concrete has slightly less increasing ratio of diffusion coefficient by crack than normal strength concrete, and diffusion coefficient increases non-linearly as crack width is increased. Also, In two types of concrete, crack effect decrease as the curing period increase. In the case of quantifying crack and curing effect by using exponential function form, the coefficients of determination are higher than those of linear regression analysis. Under steady state, it is thought that there is not a high correlation between the crack effect and the curing effect, and considering the two independent effects, it is believed that reasonable prediction equation for diffusion of concrete with crack can be proposed.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.222-228
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• 2010

In this paper, we propose a optimization approach for the Electric Locomotive Overhaul Maintenance Facility (ELOMF), which aims at the simulation optimization so as to meet the design specification. In simulation design, we consider the critical path and sensitivity analysis of the critical (dependent) factors and the design (independent) parameters for the parameter selection and reduction of the metamodel. Therefore, we construct the multi-objective non-linear programming. The objective function is normalized for the generalization of design parameter while the constraints are composed of the simulation-based regression metamodel for the critical factors and design factor's domain. Then the effective solution procedure based on the pareto optimal solution set is proposed. This approach provides a comprehensive approach for the optimization of Train Overhaul Maintenance Facility(TOMF)'s design parameters using the simulation and metamoels.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2484-2498
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• 2017

Various types of social media make the people share their personal experience in different ways. In some social networking sites. Some users post their reviews, some users can support these reviews with comments, and some users just rate the reviews as kind of support or not. Unfortunately, there is rare explicit negative comments towards other reviews. This means if there is a link between two users, it must be positive link. Apparently, the negative link is invisible in these social network. Or in other word, the negative links are redundant to positive links. In this work, we first discuss the feature extraction from social media data and propose new method to compute the distance between each pair of comments or reviews on social media. Then we investigate whether we can predict negative links via regression analysis when only positive links are manifested from social media data. In particular, we provide a principled way to mathematically incorporate multi-facet data in a novel framework, Constructing Negative Links, CsNL to predict negative links for discovering the hidden information. Additionally, we investigate the ways of solution to general negative link predication problems with CsNL and its extension. Experiments are performed on real-world data and results show that negative links is predictable with multi-facet of social media data by the proposed framework CsNL. Essentially, high prediction accuracy suggests that negative links are redundant to positive links. Further experiments are performed to evaluate coefficients on different kernels. The results show that user generated content dominates the prediction performance of CsNL.

• Physical Therapy Korea
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• v.24 no.2
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• pp.76-91
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• 2017

Background: Agricultural work is physically demanding and is associated with a high frequency of musculoskeletal disorders. It is challenging to comprehensively understand the present status of work-related diseases and injuries among farmers in underdeveloped countries. Objects: This study aimed to elucidate the current status of work-related musculoskeletal disorders in local farmers in Tigray, Ethiopia, and identify the agricultural factors associated work-related musculoskeletal pain (AFWMP) and healthy living and healthy behavior factors associated work-related musculoskeletal pain (HFWMP). Methods: The Institute for Poverty Alleviation and International Development at Yonsei University conducted a survey of 126 households in Tigray, Ethiopia in 2014. A total of 116 individuals (73 men, 43 women) representing each household answered the questionnaires. Results: 1) Work-related musculoskeletal pain (WMSP) most commonly occurred when performing heavy lifting and most frequently occurred in the lower back. 2) Age, self-perceived labor intensity, and months of farming work were significantly higher in the pain group than those in the non-pain group. 3) Overall work-related musculoskeletal pain intensity (WPI) showed positive and negative correlations with years of farming experience and self-perceived health status, respectively. 4) In binary logistic regression, the occurrence of WMSP showed significant associations with self-perceived labor intensity. 5) On multiple linear regression analysis, age, months of farming work, and self-perceived health status had a significant impact on overall WPI. Conclusion: The WMSP of farmers in Tigray, Ethiopia was related to the characteristics of farm working and health status. Furthermore, HFWMP and AFWMP were the chief factors affecting the occurrence of WMSP in farmers in Tigray. Therefore, both HFWMP and AFWMP should be considered for clinical health assessments of farmers with WMSP in underdeveloped African countries.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.317-326
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• 2017

In this paper, we investigate the effects of performance and non-performance variables attributed to Korean professional baseball pitchers on annual salary by the records about pitchers between 2010 and 2016. We select the variables in reference to previous research related to this topic. The models are then estimated using linear regression model. For pitchers, age, experience in the league, year, eligibility for free agency, the number of wins, WAR, the number of innings pitched, the number of games, the number of saves, the number of games started, and type of baseball team have a statistically significant effect. Among the notable factors, affecting pitchers salaries are largely measure of starting pitchers. Pitcher sabermetrics indexes were poorly reflected on annual salary. The model presented here can be used to remove any unobjective salary differences for Korean professional baseball pitchers.

• The Journal of Korean Academic Society of Nursing Education
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• v.26 no.4
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• pp.337-347
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• 2020

Purpose: The purpose of this study was to figure out the association of nursing activity participation and clinical practice stress with career maturity during clinical practice among nursing college students. Methods: Participants of the study were 201 nursing college students located in nationwide regions. Data collection was performed between July 18 and August 8, 2019. Data analyses were performed through an independent t-test, ANOVA, Pearson's correlation coefficient, and multiple linear regression analysis using SPSS WIN 25.0. Results: The results of this study were as follows. We ran multiple regression analyses to see which critical factors influenced career maturity. The general characteristics significantly associated with career maturity were preference for clinical nursing, admission to nursing college due to belief, time off, and being satisfied with clinical practice. Regarding clinical practice stress, clinic environment, interpersonal relationship conflict, inappropriate role model and conflict with patients were significantly associated with career maturity. Conclusion: This study suggested that, to improve nursing students' career maturity, nursing colleges and training fields should collaboratively make an efforts to reduce students' stress by building educational clinic environments including managing conflicts in interpersonal relationships among patients, caregivers, and medical and non-medical personnel, and improving inappropriate role models in nursing.