• Safety and Health at Work
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• v.9 no.1
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• pp.109-114
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• 2018

Background: Although work absenteeism is in the focus of occupational health, longitudinal studies on organizational absenteeism records in hospital work are lacking. This longitudinal study tests time pressure and lack of time autonomy to be related to higher sickness absenteeism. Methods: Data was collected for 180 employees (45% nurses) of a Swiss hospital at baseline and at follow-up after 1 year. Absent times (hours per month) were received from the human resources department of the hospital. One-year follow-up of organizational absenteeism records were regressed on self-reported job satisfaction, time pressure, and time autonomy (i.e., control) at baseline. Results: A multivariate regression showed significant prediction of absenteeism by time pressure at baseline and time autonomy, indicating that a stress process is involved in some sickness absenteeism behavior. Job satisfaction and the interaction of time pressure and time autonomy did not predict sickness absenteeism. Conclusion: Results confirmed time pressure and time autonomy as limiting factors in healthcare and a key target in work redesign.

• Communications for Statistical Applications and Methods
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• v.30 no.3
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• pp.291-309
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• 2023

Longitudinal count data has been widely collected in biomedical research, public health, and clinical trials. These repeated measurements over time on the same subjects need to account for an appropriate dependency. The Poisson regression model is the first choice to model the expected count of interest, however, this may not be an appropriate when data exhibit over-dispersion or under-dispersion. Recently, Conway-Maxwell-Poisson (CMP) distribution is popularly used as the distribution offers a flexibility to capture a wide range of dispersion in the data. In this article, we propose a Bayesian CMP regression model to accommodate over and under-dispersion in modeling longitudinal count data. Specifically, we develop a regression model with random intercept and slope to capture subject heterogeneity and estimate covariate effects to be different across subjects. We implement a Bayesian computation via Hamiltonian MCMC (HMCMC) algorithm for posterior sampling. We then compute Bayesian model assessment measures for model comparison. Simulation studies are conducted to assess the accuracy and effectiveness of our methodology. The usefulness of the proposed methodology is demonstrated by a well-known example of epilepsy data.

• Journal of Internet Computing and Services
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• v.13 no.2
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• pp.127-136
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• 2012

IT industry is rapidly changing technologies and trends are leading the field. Website also typical of these areas in the field of IT as a sector, technological advances faster, depending on the nature of the IT industry and the emergence of new services, changes in a variety of platforms, and is rapidly rising. In addition, a website containing information in accordance with the social situation changes and exposure of the agenda and vary greatly. Therefore, these changes in terms of B2C websites that can make a difference in the reliability factor looks. From this perspective, in this study to compare data before and after 10 years on the reliability factor by conducting longitudinal studies, most are not addressed in previous studies due to time differences website users to change the reliability of the analyzed factors.

• Journal of Science Education
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• v.38 no.1
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• pp.57-77
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• 2014

A longitudinal study traced changes in students' understanding of Nature Of science (NOS) through the public secondary science education in Ontario Canada. Although the concepts of NOS are complicated, and students' understandings are not easy to change, not many longitudinal studies have been done across the world. The current study tried to identify the changes of participating students' understandings of NOS for two and half years of public secondary science education in Ontario Canada. Pretest was administered using Views of Nature of Science (VNOS-C) when six participants graduated from a middle school of Toronto. Two and half years of secondary education, the posttest was carried out using the same instrument. After pre and posttest, probing interviews were performed. The analysis of the data was founded on the Standards and the conceptual framework for this study. The findings were that the initial views have little changed. Most examples and explanations the participants provided were from their science classes. Lab activities for confirming the existing laws and theories and observable photos in science textbooks made students regard the knowledge as a truth. Naturally, their knowledge has been expanded for 2 and 1/2 years, but this expansion of scientific knowledge led students toward Universalist views on science. On the other hand, when science was presented with a historical approach or was networked with other concepts, students acknowledged science and scientific knowledge had been induced from inferences as well as observations and experimental results. Based on the findings the authors of this research suggest that educating the knowledge of science should be historical and networked approaches rather than teaching the knowledge as concise and true statements of the nature.

• Human Ecology Research
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• v.56 no.2
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• pp.133-144
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• 2018

The study examined the longitudinal relations of preschool children's peer interaction, linguistic and cognitive abilities, and self-control, while taking into account gender differences. The study was conducted with 671 preschoolers from the $5^{th}$, $6^{th}$, and $7^{th}$ wave of the Korean Children and Youth Panel Study (KCYPS). Data were analyzed by means of basic descriptive statistics, Pearson's correlations, and structural equation modeling analysis. Bootstrapping method was also used to determine the significance of indirect effects. The analysis were conducted to find the longitudinal effects of peer interaction at the age of 4 on their self-control at the age of 6, and the mediating effects of linguistics and cognitive abilities at the age of 5 on its associations. The results indicated gender differences among the variables. According to multi-group analysis, there was a significant influence of 4 years' peer interaction on subsequent 5 years' linguistic and cognitive abilities but also on 6 years' self-control across time for boys; however, no significant direct effect of peer interaction on self-control was found for girls. Based on the findings of this study, it can be implied that it is necessary to apply different methods for boys and girls to promote self-control from the influence of peer interaction and linguistic and cognitive abilities.

• Journal of architectural history
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• v.29 no.1
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• pp.21-37
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• 2020

The purpose of this paper is to reconstruct the original floor plan and wall design of Seokbulsa Grotto in Kyungju; commonly known as 'Seokguram'. The paper presents an array of dimensional studies of the existing Seokguram to examine its architectural form, and infers the original floor plan and wall design of Seokbulsa Grotto. Seokbulsa Grotto is designed as a system of 'coherent modules' and was constructed using the dry stone method, which interlocks large stone modules into a whole that becomes the load-bearing structure itself. The design principles governing Seokbulsa Grotto are the spatial axis of symmetry, modular coordination, and the layout grid of a quarter Tang-Ruler(TR: 唐尺). Dimensional studies were conducted with these governing principles in mind and concludes the following about the original floor plan design. In the main chamber, Ansang-stone's radius is 12 TR, and Flagstone's radius is 12¼ TR. In the front chamber, the width between the two Ansang-stones facing each other is 22 TR and the longitudinal space depth is 12 TR, while the width between the two Flagstones facing each other is 22½ TR and Flagstone's depth is 12 TR. In the passageway, the width between the two Ansang-stones facing each other is 11½ TR and longitudinal space depth is 9 TR, while the width between the two Flagstones facing each other is 12 TR and Flagstone's depth is 7¾ TR. The distance from the center to the entrance line of the main chamber is 10½ TR. Therefore, the total longitudinal length of the Grotto is 43½ TR at the level of the Ansang-stones, and 44 TR at the level of the Flagstones.

• Journal of Preventive Medicine and Public Health
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• v.42 no.1
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• pp.59-66
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• 2009

Objectives : This study was performed using a longitudinal approach to explore the predictors for current smoking among male high school students. Methods : Baseline data was collected in May 2004 through a self-administrated questionnaire completed by 607 male students in a technical high school in Daegu city, Korea. Subsequently, their smoking behaviors were followed one year after. Among the 544 followed participants, data for 439 non-smokers in the first year was used in longitudinal analysis. Current smokers were defined as those respondents who had smoked one or more cigarettes within the 30 days preceding the survey. Several potential predictors for smoking were investigated including smoking history(never, experimental, former smoker), sociodemographic factors, environmental factors, attitudes toward smoking, and behavioral factors. Logistic regression was used to predict smoking with SPSS ver. 12.0. Results : According to multiple logistic regression analysis, those students who were more likely to smoke after one year were former smokers(OR: 2.12, 95% CI=1.01-4.44), current drinkers(OR: 2.55, 95% CI=1.33-4.89), who had four or five smokers among five best friends(OR: 3.43. 95% CI=1.14-10.30). In addition, those who had smokers among family members besides parents or siblings(OR: 1.66, 95% CI=0.92-2.98), exhibited a high level of subjective stress(OR: 1.77, 95% CI=0.96-3.26), or had a very good relationship with friends(OR: 1.93, 95% CI=0.99-3.75) were also more likely to smoke albeit with marginal statistical significance(p<0.1). Conclusions : A smoking prevention program aimed at high school students may be more effective with due consideration of the predictors highlighted in this study. However, further studies with larger sample size and various target populations are necessary to find potential predictors not found in this study but suggested in other longitudinal studies.

• Communications of Mathematical Education
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• v.35 no.1
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• pp.97-118
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• 2021

Since the characteristics of teachers that affect mathematics academic achievement are constantly changing and affecting mathematics achievement, longitudinal studies that can predict and analyze growth are needed. This study used data from middle and high school students from 2013(first year of middle school) to 2017(second year of high school) of the Seoul Education Longitudibal Study(SELS). By classifying the longitudinal changes in mathematics academic achievement into similar subgroups, the direct influence of teachers' characteristics(professionalism, expectations, academic feedback) perceived by students on the longitudinal changes in mathematics academic achievement was examined. As a result of the study, it was found that the characteristics of mathematics teachers(professional performance, expectation, and academic feedback) in group 1(343 students), which included the top 14.5% of students, did not directly affect longitudinal changes in mathematics academic achievement. Students in the middle 2nd group(745, 32.2%) had academic feedback from the mathematics teacher, and the 2nd group(1225 students) in the lower 53%, which included most of the students, showed that the expectations of the mathematics teacher were the longitudinal mathematics achievement. The change has been shown to have a direct effect. This suggests that support for teaching and learning should also reflect this, as the direct influence of teachers' professionalism, expectations, and academic feedback on longitudinal changes in mathematics academic achievement is different according to the characteristics and dispositions of students.

• Clinical and Experimental Pediatrics
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• v.57 no.5
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• pp.211-216
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• 2014

Asthma comprises a heterogeneous group of disorders characterized by airway inflammation, airway obstruction, and airway hyperresponsiveness (AHR). Airway inflammation, which induces AHR and recurrence of asthma, is the main pathophysiology of asthma. The fractional exhaled nitric oxide (FeNO) level is a noninvasive, reproducible measurement of eosinophilic airway inflammation that is easy to perform in young children. As airway inflammation precedes asthma attacks and airway obstruction, elevated FeNO levels may be useful as predictive markers for risk of recurrence of asthma. This review discusses FeNO measurements among early-childhood wheezing phenotypes that have been identified in large-scale longitudinal studies. These wheezing phenotypes are classified into three to six categories based on the onset and persistence of wheezing from birth to later childhood. Each phenotype has characteristic findings for atopic sensitization, lung function, AHR, or FeNO. For example, in one birth cohort study, children with asthma and persistent wheezing at 7 years had higher FeNO levels at 4 years compared to children without wheezing, which suggested that FeNO could be a predictive marker for later development of asthma. Preschool-aged children with recurrent wheezing and stringent asthma predictive indices also had higher FeNO levels in the first 4 years of life compared to children with wheezing and loose indices or children with no wheeze, suggesting that FeNO measurements may provide an additional parameter for predicting persistent wheezing in preschool children. Additional large-scale longitudinal studies are required to establish cutoff levels for FeNO as a risk factor for persistent asthma.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.519-524
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• 2003

In this report, a longitudinal adaptive flight control law is presented for the automatic landing system of a Japanese automatic landing flight experiment vehicle (ALFLEX). The longitudinal adaptive flight control law is designed to track an output of the vehicle to a guidance signal from the guidance portion of the automatic landing system. The proposed adaptive control law in the attitude control portion adjusts the controller gains continuously online as flight conditions change, in spite of the existence of unmodeled dynamics. The number of the controller gains to be adjusted is decreased to 1/2 from the previous studies. Computer simulation involving six-degree-of-freedom (DOF) nonlinear flight dynamics is performed to examine the effectiveness of the proposed adaptive control law. In order to verify the influence of the dispersion of the initial conditions, the Monte Carlo simulation is also applied. The initial conditions are more widely dispersed than the previous studies. As a result, except under the unsuitable initial conditions, the ALFLEX successfully landed on the runway.