• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.1
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• pp.10-20
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• 2022

Objectives: The aim of this study is to evaluate exposure levels of the extremely low frequency magnetic fields(ELF-MF) radiated from various electric facilities in Liquid Crystal Display(LCD) manufacturing processes. Methods: This study measured the exposure levels of personal and local ELF-MF for the electronic facilities installed in two LCD manufacturing companies. Samplers were installed around workers' waist during working hours to identify personal exposure levels, and direct reading equipment were located at 3 cm, 10 cm, and 30 cm away from the surface of the electronic facilities to measure local exposure levels. Average and maximum(ceiling) values were calculated for personal and local exposure levels. Results: Average and maximum of personal exposure levels for each worker were 0.56(mean) ± 0.02(SE) µT and 6.31 ± 0.75 µT, respectively. Statistical analyses of the study found that maximum of the personal exposure levels for engineers was significantly higher than that for operators since engineers spend more time near the electronic facilities for repairing. The range of maximum personal exposure levels was 0.50 ~ 43.50 µT and its highest level was equivalent to 4.35 % of ACGIH(American Conference of Governmental Industrial Hygienists) exposure limit value(1 mT). Maximum of local exposure levels was 8.18 ± 0.52 µT and the electronic facilities with higher exposure levels were roof rail and electric panel, which were not related to direct manufacturing. The range of maximum local exposure levels was 0.60 ~ 287.20 µT and its highest level was equivalent to 28.7 % of the ACGIH exposure limit value. Lastly, the local exposure levels significantly decreased as the measurement distance from the electronic facilities increased. Conclusions: Maximum of personal and local exposure levels did not exceed the exposure limit value of ACGIH. However, it is recommended to keep the workers as far as possible from the sources of ELF-MF.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3B
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• pp.279-289
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• 2006

The reconstruction of low dimension nonlinear behavior from the hydrologic time series has been an active area of research in the last decade. In this study, we present the applications of a powerful state space reconstruction methodology using the method of Support Vector Machines (SVM) to the Great Salt Lake (GSL) volume. SVMs are machine learning systems that use a hypothesis space of linear functions in a Kernel induced higher dimensional feature space. SVMs are optimized by minimizing a bound on a generalized error (risk) measure, rather than just the mean square error over a training set. The utility of this SVM regression approach is demonstrated through applications to the short term forecasts of the biweekly GSL volume. The SVM based reconstruction is used to develop time series forecasts for multiple lead times ranging from the period of two weeks to several months. The reliability of the algorithm in learning and forecasting the dynamics is tested using split sample sensitivity analyses, with a particular interest in forecasting extreme states. Unlike previously reported methodologies, SVMs are able to extract the dynamics using only a few past observed data points (Support Vectors, SV) out of the training examples. Considering statistical measures, the prediction model based on SVM demonstrated encouraging and promising results in a short-term prediction. Thus, the SVM method presented in this study suggests a competitive methodology for the forecast of hydrologic time series.

• Journal of the Korean Society of Food Culture
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• v.22 no.5
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• pp.621-632
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• 2007

The purposes of this study were as follows. First is to compare the importance of operational factors to determine types of school breakfast program, and second is to do the preference analysis of operation-related people depending on the attributes and levels of the operation of school breakfast program. The questionnaires developed for this study were distributed to 134 school dietitians, 114 school foodservice officials at the educational board, 68 staff members of foodservice contractors and 493 parents. Statistical data analyses were performed using SPSS/WIN 12.0 for descriptive statistics and conjoint analysis. The conjoint design was applied to evaluate the hypothetical foodservice types. According to the analysis on the attributes and levels of the school breakfast operation, the relative importance of each attribute was as followsprice (36.30%), menu (29.60%), foodservice staff (22.54%), serving type (11.55%) to school dietitians, price (34.99%), menu (28.15%), foodservice staff (23.52%), serving type (13.35%) to school foodservice officials at the educational board, menu (30.55%), price (30.24%), foodservice staff (28.75%), serving type (10.47%) to staff members of foodservice contractors and price (36.34%), menu (29.73%), foodservice staff (21.01%), serving type (12.92%) to parents. The results of the conjoint analysis indicated that the school dietitians and school foodservice officials at the educational board preferred the school breakfast operation program with 3 traditional menus and 2 convenience menus per 5 day, $1{\sim}3$ foodservice staff, with a price range of $1501{\sim}2000won$, and tray serving. Staff members of foodservice contractors preferred the school breakfast operation program with 3 traditional menus and 2 convenience menus per 5 day, $1{\sim}3$ foodservice staff, with a price range of $2501{\sim}3000won$, and tray serving. Parents preferred the school breakfast operation with 5 traditional menus per 5 day, $6{\sim}7$ foodservice staff, with a price range of $2501{\sim}3000won$, and tray serving. About a half of school dietitians considered that elementary schools were appropriate for the suggested school breakfast operation program. But, 68.2% of school foodservice officials at the educational board, 69.1% of staff members of foodservice contractors, and 38.1% of parents considered high schools to be the suitable model. Therefore, it indicated the need to recognize the different opinions among breakfast operation-related people and take these factors into consideration in developing the school breakfast program.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5B
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• pp.487-495
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• 2010

Soil moisture is a crucial factor in hydrological system which influences runoff, energy balance, evaporation, and atmosphere. United States National Aeronautic and Space Administration (NASA) and Department of Agriculture (USDA) have established Soil Moisture Experiment (SMEX) since 2002 for the global observations. SMEX provides useful data for the hydrological science including soil moisture and hydrometeorological variables. The purpose of this study is to investigate the relationship between remotely sensed soil moisture data from aircraft and satellite and ground based experiment. C-band of Polarimetric Scanning Radiometer (PSR) that observed the brightness temperature provides soil moisture data using a retrieval algorithm. It was compared with the In-situ data for 2-30 cm depth at four sites. The most significant depth is 2-10 cm from the correlation analysis. Most of the sites, two data are similar to the mean of data at 10 cm and the median at 7 cm and 10 cm at the 10% significant level using the Rank Sum test and t-test. In general, soil moisture data using the C-band of the PSR was established to fit the Normal, Log-normal and Gumbel distribution. Soil moisture data using the aircraft and satellites will be used in hydrological science as fundamental data. Especially, the C-band of PSR will be used to prove soil moisture at 7-10 cm depths.

• 한국노년학
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• v.31 no.4
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• pp.1119-1134
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• 2011

The purpose of this study is firstly to understand socio-demographic and health characteristics and economic characteristics of elderly single households aged over 60 and secondly to examine the relations between these factors and level of life satisfaction, especially differentiated relations by income level. We used the data drawn from third KREIS (Korean Retirement and Income Study) surveyed by National Pension Research Institute. The statistical methods used for the analyses were t-test, X², multiple regression analysis. For the whole sample, the results showed that the life satisfaction is positively related to higher income, better physical and emotional health status and having a religion. When we conducted the regression on two groups, the religion and income level were no longer significant factors. On the other hand, being a woman and enjoying good health contributed to life satisfaction for lower-income group while having a job and enjoying good health played a positive role in life satisfaction for higher-income group.

• 한국노년학
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• v.29 no.3
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• pp.1159-1182
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• 2009

The purpose of this study is to examine everyday emotional experience of urban elderly in Korea. Specifically, this study explores gender differences in the effect of place/location of activity and companionship on the daily emotional experience. Data were collected from 148 urban elderly (men=76, women=72) in Seoul, using Experience Sampling Method(ESM). The unit of analysis was the self-report and in total 5,530 self-reports were provided. The statistical methods used for the data analyses were descriptive statistics, t-test, χ² verification, and ANOVA. The major findings are as follows. First, the elderly in Korea spend a quite substantial portion of their time at home, and they spend the largest share of their time in company with their spouse. Second, women report higher intensity of stress and irritation than men in terms of overall emotional experience. Third, the effect of activity location and companionship on emotional experience turned out to be different depending on gender. Emotional experience of daily lives and overall quality of life are shown to be inter-related. Based on these findings, this study provides a significant implication that situational contexts of experience should be considered in order to understand the daily emotional experience of the contemporary Korean elderly.

• 한국노년학
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• v.29 no.2
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• pp.669-682
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• 2009

The purpose of this study was to explore the role of professional identity as mediating variable in the relationship between job- and organization- related factors and job satisfaction. This study surveyed social workers who worked at 24 senior welfare facilities in Daegu·Gyeoungbuk province from Aug. 1. to Aug. 30. 2006. A total of 137 questionnaires were collected using on-site survey (response rate 76.7%). Statistical analyses were performed using SPSS 12.0 for Windows. Descriptive analysis and frequency analysis were performed on overall measurement items and hierarchical regression analysis was conducted to test the mediating effect of professional identity. The reliability of statements was acceptable since the coefficient alphas were > .70. Results of hierarchical regression showed that professional identity was verified as a partial mediator in the relationship between factors related with job and organization and job satisfaction. As the population ages, there will be an increasing need for professional social workers effectively to work with and help care for the elderly. This study highlighted that job- and organization- related factors, namely self-regulations and social supports, are significantly related with job satisfaction of social workers. Especially, such effect was more significantly apparent in high professional identity which is playing a partial mediator. This result implies that there is potential to change work environments of social workers ensuring a delegation of power and responsibility. Therefore, efforts should be made to improve the promotion system and connect social worker as servant with community through diverse service learning programs.

• 한국노년학
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• v.39 no.2
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• pp.231-240
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• 2019

The study aimed to identify risk factors for falls as well as hospitalization status according to disease and demographic characteristics of demented inpatients by investigating the in-depth Injury Patient Surveillance System data collected by Korea Centers for Disease Control and Prevention(KCDC). Older adults over 60 years old who were diagnosed with dementia were included(n=1,732). Their data were analyzed after being assigned to either a fall group or a non-fall group. STATA was used for statistical analyses, such as frequency analysis, chi-square (χ²) test, and logistics regression. It was found that 8.0% of the demented inpatients experienced falls. According to the analysis on category of fall and non-fall group were statistically significant difference in age and Charlson Comorbidity Index(CCI) and bone density deficiency. Based on the logistic regression analysis of factors affecting falls, older adults over 80 are 2.386 times more likely to fall and based on a target with a CCI of 0, the risk of falls is 0.421 times lower, finally based on those without bone density disorder, the fall risk for those with bone density disorder was 3.581 times higher. Therefore, we expect that the important about the factors relating to falls identified in this can not only be found valuable for educating inpatients with dementia and care-givers, but also be used as reference that supports clinical professionals to make decisions on falls management for patients with dementia.

• Korean Journal of Social Welfare Studies
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• v.41 no.3
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• pp.29-56
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• 2010

One of the most popular keywords in 21th century is "Information Society". Information Society improves the overall quality of human life, but increases the negative aspects such as internet addiction and digital divide. The purpose of this study is to understand the vicious cycle between socio-economic disparities and digital divide. This study analyzed the effects of poverty on school maladjustment and academic achievement and mediation effects by using parental monitoring and internet use types as mediators. Data were obtained from the Korea Youth Panel Survey(KYPS). Structural equation modeling was employed for statistical analyses. The result showed that poverty reduced parental monitoring and information-oriented type of internet use. Youth who used less information-oriented type showed more school maladjustment and less academic achievement. However, the relationship between poverty and entertainment-oriented type was non-significant. Thus, parental monitoring and the internet use types were one of the main pathways which can affect school maladjustment and academic achievement among youth in poverty. There was the possible vicious cycle between poverty and digital divide. Based on this study, we strongly suggest improvement of the media competence to solve the problem of digital divide among youth in poverty.

• Journal of Oral Medicine and Pain
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• v.48 no.3
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• pp.87-95
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• 2023

Purpose: To quantify the relationship between perceived pain intensity and psychological variables in a sample of participants with temporomandibular disorder, with or without central sensitization (CS). Methods: A cross-sectional study with nonprobability convenience sampling was conducted from January 1, 2022, to June 30, 2023. Pain intensity (Numeric Pain Rating Scale), anxiety (State-Trait Anxiety Questionnaire, STAI), catastrophizing (Pain Catastrophizing Scale, PCS), perceived stress (Perceived Stress Scale, PSS), and sleep quality (Pittsburgh Sleep Quality Index, PSQI) were assessed. Statistical analysis was performed using IBM SPSS Statistics for Windows, Version 20.0 (IBM Co.), which included descriptive and normality analyses and the calculation of strength of multiple correlational regression. Results: A total of 52 (n=34 female 65.4%; n=18 male 34.6%) subjects with diagnosis of temporomandibular disorders (TMD) were finally included. A total of 26 participants (n=26, 50.0%) were cases suffered from CS (TMD-CS mean=46.62±11.24) while the remaining participants (n=26, 50.0%) were the controls (TMD-nCS mean=26.77, standard deviation [SD]=8.42). The pain intensity was moderate in both groups TMDCS (mean=7.62, SD=0.83) and TMD-nCS (mean=7.05, SD=0.86), anxiety (TMD-CS STAI mean=53.27, SD=11.54; TMD-nCS STAI mean=49, SD=11.55), catastrophizing (TMD-CS PCS mean=46.27, SD=9.75; TMD-nCS PCS mean=26.69, SD=4.97), perceived stress (TMDCS PSS mean=30.35, SD=4.91; TMD-nCS PSS mean=26.12, SD=6.60) and sleep quality (TMD-CS PSQI mean=15.81, SD=3.65; TMD-nCS PSQI mean=12.77, SD=2.76) levels were measured in both groups. In TMD-CS and TMD-nCS, higher anxiety levels were moderately and significantly associated with greater pain intensity β=0.4467 (t=2.477, p=0.021) and β=0.5087 (t=2.672, p=0.014). Nevertheless, catastrophizing, perceived stress and sleep quality were not associated to pain intensity in neither of group. Conclusions: In both TMD-CS and TMD-nCS patients, elevated anxiety levels were moderately and significantly associated with increased pain intensity. However, heightened levels of pain catastrophizing, perceived stress, and poor sleep quality were not significantly associated with increased pain intensity in either of the two analyzed groups.