• Restorative Dentistry and Endodontics
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• v.45 no.2
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• pp.22.1-22.10
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• 2020

Objectives: This study investigated the influence of glide path size and operating kinetics on the time to reach the working length and the fracture resistance of Twisted File (TF) and Endostar E3 files. Materials and Methods: A total of 120 mandibular single-rooted premolars were selected. Two methods of kinetic motion (TF adaptive and continuous rotary motion) and file systems (TF and Endostar E3) were employed. The files were used in root canals prepared to apical glide path sizes of 15, 20, and 25. The time taken to reach the working length and the number of canals used before the instrument deformed or fractured were noted. Fractured instruments were examined with scanning electron microscopy. Results: The TF system took significantly more time to reach the working length than the Endostar E3 system. Both systems required significantly more time to reach the working length at the size 15 glide path than at sizes 20 and 25. A greater number of TFs than Endostar E3 files exhibited deformation, and a higher incidence of instrument deformation was observed in adaptive than in continuous rotary motion; more deformation was also observed with the size 15 glide path. One TF was fractured while undergoing adaptive motion. Conclusions: No significant difference was observed between continuous rotary and adaptive motion. The TF system and adaptive motion were associated with a higher incidence of deformation and fracture. Apical glide path sizes of 20 and 25 required significantly less time to reach the working length than size 15.

• Korean Journal of Human Ecology
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• v.10 no.1
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• pp.19-25
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• 2007

The study is attempted to help double-income families use resources efficiently and rationally by analyzing The Time Use each of working women and housewives having preschool children based on the data of The Time Use survey carried out in 2004 and promote understandings on their quality of life, lifestyle and family welfare. To this end, the study analyzes the actual The Time Use of double-income families haying preschool children. The findings of the study are as follows: First, according to the comparison of The Time Use between double-income families and single-income families in 1999 and 2004, there is no significant difference in husbands' participation time in family management or family care between 1999 and 2004. Second, according to the comparison of The Time Use between double-income families and single-income families depending on the presence or non-presence of preschool children, families haying preschool children spent much more hours in family care than families without preschool children. Third, according to the comparison of the weekend schedule between double-income families and single-income families, it is found that working women work much more than housewives not only on weekdays but also on weekends and in particular, it is found that working women having preschool children work 2 hours longer than housewives.

• International Commerce and Information Review
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• v.8 no.4
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• pp.391-411
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• 2006

The present Study investigated on effect of working time and physical work environment on job satisfaction, and is based on a representative survey carried out in the 15 European Union Member States in 2,000 on behalf of the European Foundation for the Improvement of Living and Working Conditions by Infratest Burke Sozialforschung and a consortium of national fieldwork institutes. In the course of the survey, a total of 21,703 people drawn from the economically active populations in the 15 countries were questioned about their working time, overtime, weekend work, physical work environment, social support of supervisor and co-worker and job satisfaction. Regression analysis and subgroup analysis were employed to examine the hypotheses. It was found that weekend work, overtime and physical work environment associate negatively with job satisfaction. Social support of supervisor and co-worker moderated only relation between working time and job satisfaction. The results provide support for prior quantitative studies partly. Based on these significant research findings, theoretical implications were discussed.

• Korean Journal of Construction Engineering and Management
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• v.24 no.6
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• pp.81-90
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• 2023

Climate change has resulted in increased frequency and intensity of heat waves, which poses a significant threat to the health and safety of construction workers, particularly those engaged in labor-intensive and heat-stress vulnerable working environments. To address this challenge, this study aimed to propose an interpretable machine learning approach for forecasting personal heat strain by considering the cumulative effect of heat exposure as a situational variable, which has not been taken into account in the existing approach. As a result, the proposed model, which incorporated the cumulative working time along with environmental and personal variables, was found to have superior forecast performance and explanatory power. Specifically, the proposed Multi-Layer Perceptron (MLP) model achieved a Mean Absolute Error (MAE) of 0.034 (℃) and an R-squared of 99.3% (0.933). Feature importance analysis revealed that the cumulative working time, as a situational variable, had the most significant impact on personal heat strain. These findings highlight the importance of systematic management of personal heat strain at construction sites by comprehensively considering the cumulative working time as a situational variable as well as environmental and personal variables. This study provided a valuable contribution to the construction industry by offering a reliable and accurate heat strain forecasting model, enhancing the health and safety of construction workers.

• Korean Journal of Rural Living Science
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• v.8 no.2
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• pp.111-117
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• 1997

In this study we tried to give a decision on propriety of working conditions, to present ideas on reducing work loads. and to grope for efficiency of agricultural works. For this we examined the actual conditions of working environment, farmer's clothes, working posture, working methods, working time, resting state, fatigue recovery methods during cultivating lettuce in the winter greenhouse. And Ive improved harmful factors that affect farmer's health by considering results of previous study and farmer's subjective sensation. And we measured, compared, and analyzed the farmer's work loads before and after improvement. The results of this study are as follows ; 1. According to examine the actual conditions of cultivating lettuce in the winter greenhouse, farmers have experienced physical and mental chronic fatigue on the basis of the hot and humid crops-centered working environment, the rough ground condition, inconsistent arrangement of working stand and sorter, heavy-weared habits. and unsuitable working posture. 2. When we improved harmful factors that affect farmer's health, conformed the positive effects on important work efficiency index such as heart rate, electromyovolume, body temperature, and microclimate inside clothing and work loads were decreased by improving the hot and humid working environment, eliminating the hillock and obstacles of working path. deliver way, arranging the working stand and sorter consistantly, decreasing the clothing weight, improving the working postures and methods as using assistant appliances, alloting the working time and sequence effectively and presenting the light gymnastic exercises and rest for fatigue restoration.

• Anxiety and mood
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• v.18 no.1
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• pp.32-37
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• 2022

Objective : Impaired working memory has been known to play an important role in the pathophysiology of obsessive-compulsive disorder (OCD) with growing evidence. Delayed matching-to-sample task (DMST) is a working memory task which have an advantage in analyzing several different working memory processes in one task. However, most of the studies have failed to reveal the working memory impairment with the DMST. The aim of this study was to identify whether working memory deficit in OCD can be evaluated with the DMST. Methods : The participants included 20 OCD patients and 20 healthy volunteers. Working memory was evaluated with the DMST with two different working memory loads. Accuracy of response and mean response time were measured. Results : OCD patients showed a significantly longer reaction time and lower accuracy in DMST compared to healthy controls in the task with high working memory loads. Moreover, the difference in accuracy showed interaction with the working memory load. Conclusion : The present results indicate that working memory deficit in patients with OCD can be evaluated with the DMST. The findings also suggest that previous negative behavioral results using the DMST were from low working memory load of the task.

• Journal of Family Resource Management and Policy Review
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• v.15 no.3
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• pp.131-151
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• 2011

This study attempted to estimate the level of perceived lack of time in Korean society, to link it to time management and to identify the possible association that accounts for time shortage. I employed the gender perspective in order to reveal the dynamics and complexity of the perception of a lack of time in the population. The sample for the study was drawn from the 1999 and 2009 Korean time diary data collected by the Korean National Statistical Office. From the original data, I selected a sample of second shift families(men and women who are presently working and raising children) living in metropolitan areas(including Seoul and six major urban areas in Korea). The dependent variable was time pressure measured by a single-item question on a four-point likert scale. The results of the study showed that working mothers perceived a greater time shortage as compared to working fathers. The time use pattern showed change during the periods, indicating that people worked fewer hours in paid labor and enjoyed more leisure hours and personal care hours. However, on average, people seemed to have experienced a greater time lack in 2009 as compared to 1999. The results from the ordered logistic regression model revealed that even though there were similarities in the impact of relevant factors, men's perception of a lack of time was more closely linked with their work role and social status, while for women, this perception was influenced by work and family duties. This indicates that Korean working mothers and fathers are facing a double jeopardy of time shortage in terms of combining their work and family roles. As a result, the level of time pressure by gender is converging toward a "never enough" phase. These findings generated policy implications and detailed suggestions.

• The Journal of the Korea Contents Association
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• v.16 no.7
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• pp.750-759
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• 2016

This study is to demonstrate the effects of working hour on the workers' subjective well-being. Working hour, in this study, means working time per a day and the generosity of weekly holiday. Firstly, the effects of working hour on the worker's well-being will be analyzed. Secondly, it will be investigated if the effects of working hour on the worker's well-being change according to the existence of the family member who needs care. The results of the analysis show that longer working hour and the lower generosity of weekly holiday decrease workers' well being. If workers have family member who needs care, the effects of working hour and the generosity of weekly holiday on the worker's well-being are not significant. It contrasts to the result that women are more satisfactory to their lives than men in cases they don't have family member who needs care. It is supposed that these results are closely related with the enormous gender gap of care time in Korea.

• Safety and Health at Work
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• v.14 no.4
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• pp.483-487
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• 2023

The objectives of the study were to explore the employment factors associated with long working hours, known as a risk factor for various health outcomes. The study relied on the national representative data of the 2013 French working conditions survey and a study sample of 23,378 full-time employees. Long working hours were defined by the threshold of 48 hours a week following the European Working Time Directive. The prevalence of long working hours was higher among men (13.5%) than among women (8.5%). Employees of the private sector, with permanent work contract, in small companies, and men in the services had a higher prevalence of exposure. This prevalence increased with educational and occupational levels. Our findings may help decision-makers to define preventive strategies. More research is needed to improve our knowledge of the employment factors associated with long working hours, as there may be strong differences between countries.

• Korean Journal of Social Welfare
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• v.64 no.2
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• pp.31-54
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• 2012

Along with increasing mothers' employment, work-family reconciliation has been recognised as a key policy agenda in contemporary welfare states. Although various policy instruments have been introduced and expanded in recent years, the problem of time allocation within couples still remains as a fundamental issue, which has been largely underresearched at a micro perspective. In this context, this study aims to identify dominant types of work-family time allocation within married couple, and to apply these types to the Korean case using the fuzzy-set ideal type analysis. Further, a series of multiple regression analyses will be implemented to find factors affecting each ideal type of work-family time allocation. The 1999 and 2009 Korea Time Use Survey datasets will be adopted for the analyses. Married couples are selected as samples only when men work 40 hours or more per week and they have at least one pre-school child. Empirical analyses cover three parts. First of all, four ideal types on work-family time allocation are classified by intersecting two core variables - the ratio of men's (paid) working and family (caring time plus domestic work) time to total working and family time. In this research, the four types will be labelled the traditional male breadwinner model (TM, high working and low family time), the dual burden model (DB, shared working but low family time), the family-friendly male breadwinner model (FM, high working but shared family time), and the adaptive partnership model (AP, shared working and shared family time). By comparing the composition of the four ideal types in 1999 and 2009, it will examine the trend of work-family time allocation in Korea. In addition, multiple regressions will be useful for investigating which characteristics contribute to the different degree of each fuzzy ideal score in the four models. Finally, policy implications and further research agenda will be discussed.