• Safety and Health at Work
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• v.11 no.2
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• pp.178-186
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• 2020

Background: Cognitive impairment is a public health burden. Our objective was to investigate associations between work hours and cognitive function. Methods: Multi-Ethnic Study of Atherosclerosis (MESA) participants (n = 2,497; 50.7% men; age range 44-84 years) reported hours per week worked in all jobs in Exams 1 (2000-2002), 2 (2002-2004), 3 (2004-2005), and 5 (2010-2011). Cognitive function was assessed (Exam 5) using the Cognitive Abilities Screening Instrument (version 2), a measure of global cognitive functioning; the Digit Symbol Coding, a measure of processing speed; and the Digit Span test, a measure of attention and working memory. We used a prospective approach and linear regression to assess associations for every 10 hours of work. Results: Among all participants, associations of hours worked with cognitive function of any type were not statistically significant. In occupation-stratified analyses (interaction p = 0.051), longer work hours were associated with poorer global cognitive function among Sales/Office and blue-collar workers, after adjustment for age, sex, physical activity, body mass index, race/ethnicity, educational level, annual income, history of heart attack, diabetes, apolipoprotein E-epsilon 4 allele (ApoE4) status, birth-place, number of years in the United States, language spoken at MESA Exam 1, and work hours at Exam 5 (β = -0.55, 95% CI = -0.99, -0.09) and (β = -0.80, -1.51, -0.09), respectively. In occupation-stratified analyses (interaction p = 0.040), we also observed an inverse association with processing speed among blue-collar workers (adjusted β = -0.80, -1.52, -0.07). Sex, race/ethnicity, and ApoE4 did not significantly modify associations between work hours and cognitive function. Conclusion: Weak inverse associations were observed between work hours and cognitive function among Sales/Office and blue-collar workers.

• Journal of Korean Society of Archives and Records Management
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• v.17 no.1
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• pp.31-49
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• 2017

The purpose of this study is to measure the expectation level and perception level of service quality in 25 records centers in local governments based in Seoul. For this, an evaluation index consisting of 5 factors and 31 items is developed through literature research and an investigation of the present condition. The results of this study confirmed that users are not satisfied with the service quality of the records centers in the local governments as the expectation level is higher than the perception level, with a statistically significant difference. This study can be substantial in attempts to analyze the present status of the service quality of the records centers in local governments and in proposing an improvement plan based on the process quality.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.5
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• pp.967-973
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• 2017

Clustering is one of the most well-known unsupervised learning methods that clusters data into homogeneous groups. Clustering has been used in various applications and FCM is one of the representative methods. In Fuzzy C-Means(FCM), however, cluster centers tend leaning to high density areas because the Euclidean distance measure forces high density clusters to make more contribution to clustering result. Previously proposed was density-independent clustering method, where cluster centers were made not to be close each other and relived the center deviation problem. Density-independent clustering method has a limitation that it is difficult to specify the position of the cluster centers. In this paper, an enhanced density-independent clustering method with an additional term that makes cluster centers to be placed around dense region is proposed. The proposed method converges more to real centers compared to FCM and density-independent clustering, which can be verified with experimental results.

• Parasites, Hosts and Diseases
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• v.47 no.2
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• pp.159-165
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• 2009

House-residual spraying and insecticide-treated bed nets have achieved some success in controlling anthropophilic and endophagic vectors. However, these methods have relatively low efficacy in Korea because Anopheles sinensis, the primary malaria vector, is highly zoophilic and exophilic. So, we focused our vector control efforts within livestock enclosures using ultraviolet black light traps as a mechanical control measure. We found that black light traps captured significantly more mosquitoes at 2 and 2.5 m above the ground (P<0.05). We also evaluated the effectiveness of trap spacing within the livestock enclosure. In general, traps spaced between 4 and 7m apart captured mosquitoes more efficiently than those spaced closer together (P>0.05). Based on these findings, we concluded that each black light trap in the livestock enclosures killed 7,586 female mosquitoes per trap per night during the peak mosquito season (July-August). In May-August 2003, additional concurrent field trials were conducted in Ganghwa county. We got 74.9% reduction (P<0.05) of An. sinensis in human dwellings and 61.5% reduction (P>0.05) in the livestock enclosures. The black light trap operation in the livestock enclosures proved to be an effective control method and should be incorporated into existing control strategies in developed countries.

• Journal of Sensor Science and Technology
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• v.6 no.3
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• pp.228-236
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• 1997

Radioactive materials need to control, measure and protect precisely the overflow because they are dangerous. In this paper, GM-counter type radiation detector system, that can precisely measure the quantity of radioactivity using improved counting program is designed and program that can store and transfer the counted data is studied. The manufactured system, counting system of GM-counter type radiation detector, and counter program can be utilized to measure them at various methods in an atomic power plant and research centers.

• Communications for Statistical Applications and Methods
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• v.9 no.2
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• pp.521-531
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• 2002

Various diagnostic techniques for identifying influential observations are mostly based on the deletion of a single observation. While such techniques can satisfactorily identify influential observations in many cases, they will not always be successful because of some mask effect. It is necessary, therefore, to develop techniques that examine the potentially influential effects of a subset of observations. The partial regression plots can be used to examine an influential observation for a single parameter in multiple linear regression. However, it is often desirable to detect influential observations for a subset of regression parameters when interest centers on a selected subset of independent variables. Thus, we propose a diagnostic measure which deals with detecting influential observations on a subset of regression parameters. In this paper, we propose a measure M, which can be effectively used for the detection of influential observations on a subset of regression parameters in multiple linear regression. An illustrated example is given to show how we can use the new measure M to identify influential observations on a subset of regression parameters.

• KDI Journal of Economic Policy
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• v.29 no.3
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• pp.29-73
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• 2007

This paper evaluates the effects of the Basic Subsidy Program provided to families with infants cared for in private day care centers. There has been a discrepancy in the price and quality level between public and private day care centers. Public day care centers which receive government support in their labor costs are able to maintain relatively higher quality at lower price than their private counterparts, while the majority of children are cared for at private day care centers. To reduce the gap of the price and quality of care between public and private day care centers by improving the quality and decreasing the price of private day care centers, the Basic Subsidy Program was introduced in 2006 to the private day care centers. The subsidies mainly aim to improve the quality and the accessibility of child care, and encourage mothers' labor supply. For this purpose, the provision of the Basic Subsidy Program imposed prerequisites to the care providers including minimum wage and four major insurances for teachers, and child-staff ratio. I examine whether the subsidies improve the quality of care, help mothers balancing work and family, and increase satisfaction with child care from mothers' perspective. Since the outcome variables that measure the quality of care are difficult to obtain, I instead use the input variables for quality production. Child-staff ratio, teachers' welfare, and care environment are considered. The relationship between these variables and the introduction of subsidies is examined. The 2004 National Survey of Child Care and Education and the 2004 National Survey of Day Care Centers are used for the base data set. To reflect the outcomes after the Basic Subsidy Program, equivalent data sets for households and care providers are constructed by the KDI Data Analysis Unit. Using these nationally representative data sets, information regarding child care is collected. The findings show that the subsidies contribute to the quality of care improving the input variables of quality production. The welfare of teachers is improved, and the child-staff ratio significantly decreases. As a result, the usage of private day care centers greatly increases even though the price level rarely changes. However, mothers' satisfaction with child care are rarely affected by the subsidies. Although the subsidies with no eligibility criteria enlarge the recipients, the actual effects to increase maternal labor supply or to improve satisfaction is limited. Given this findings, I suggest some modifications of subsidies to raise the effectiveness of the subsidy program.

• Journal of East-West Nursing Research
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• v.20 no.2
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• pp.112-120
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• 2014

Purpose: The purpose of this study was to compare the differences in characteristics, lactation problems, knowledge, and adaptation of breastfeeding between users and non-users of a lactation clinic. Methods: The descriptive study design was utilized using self-report questionnaires. 446 breastfeeding mothers participated in this study. Data were collected from lactation clinics, postpartum care centers, mother's culture centers, public health centers, pediatrics and obstetrics & gynaecology outpatient clinics in Seoul, Gyeonggi province, and Chungcheongnam province from August 20 to September 30, 2011. The questionnaires to measure lactation problems, knowledge and adaptation of breastfeeding were used. Data were analyzed using SPSS ver. 18.0 for Windows. Results: There was statistically significant differences in the breast feeding problems(t=5.71, p<.001) and breastfeeding knowledge(t=2.87, p=.004) between users and non-users of a lactation clinic. Conclusion: The results of this study may provide a foundation to develop nursing intervention for mothers in breastfeeding, and an evidence to expand the role of nurses as breastfeeding specialists.

• Journal of The Korean Association For Science Education
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• v.25 no.6
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• pp.658-670
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• 2005

Eyes to the Future (ETF) is a year-long, multi-age mentoring program that supports middle-school girls as they make the transition to high school and make informed choices about the opportunities available to them in high school and beyond, particularly in the field of science and technology. In this study, we explore the tension between fidelity and adaptiveness of an educational innovation by examining how teachers in several different schools used a common set of materials and technology to create "native" implementations of an innovative after-school program, adapted to their local setting. First, we found that the implementation of the program varied across the nine clubs. For example, some clubs put a heavy emphasis on science while others emphasized technology. Then, we identified four different profiles of the variations in implementation based on how close the implementation was to the original program and how much clubs were able to customize the implementation to meet their needs and interests. The results showed that some clubs could be regarded as successful because they were faithful to the original program and others were successful because they could adapt the program for their own context. This implies that the measure for success can be and should be multi dimensional.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.571-581
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• 2019

Objectives: This study was conducted to measure the knowledge, attitude, and practices on occupational health and the analysis factors influencing them among researchers working at corporate research centers. Methods: A total of 298 researchers working at corporate research centers participated in the study. After eliminating 12 insufficient responses, the responses of 286 participants were used for the final estimate. The questionnaire consisted of questions about general and occupational characteristics as well as knowledge, attitude, and practices on occupational health. Results: Factors influencing occupational health practices were type of business, job position, and attitude toward occupational health. Attitude toward occupational health was found to have the greatest influence. Conclusions: It is necessary to develop educational contents appropriate for each type of industry, implement educational programs for researchers working at corporate research centers, and take actions to prevent health problems among researchers through various health-care activities such as experience-based activities and discussions.