• The korean journal of orthodontics
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• v.15 no.2
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• pp.175-195
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• 1985

Vertical and horizontal growth occur in the craniofacial complex which ensues continuous changes in facial morphology, until the end of active growth period. Longitudinal study for individual is essential, in the research on growth and development, however, the difficulties in obtaining long term subjects in Korea, the research has been limited. The author analyzed the cephalometric roentgenogrems of 43 boys and 47 girls taken from the ages 6 to 10. The subjects were divided into 3 groups according to SN-MP angle and 2 groups according to gonial angle. In this longitudinal study, 21 variables were measure 4. The obtained results were as follows: 1. SN-MP angle and genial angle had no significant changes in each group with age. 2. With age, facial convexity of hard tissue decreased in all groups, facial angle of hard tissue increased in low SN-MP angle group, but facial convexity of soft tissue had no significant changes in all groups with age. 3. In comparison of high SN-MP angle group and low SN-MP angle group, the former had greater facial convexity and smaller facial angle than the latter. 4. SN-MP angle and the ratio of posterior dental height to anterior dental height had reverse correlation in all groups. 5. High genial angle group revealed larger SN-MP angle, anterior dental height facial convexity, but smaller mandibular length, and the ratio of posterior dental height to anterior dental height compared with low genial angle group.

• Korean Journal of Clinical Pharmacy
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• v.34 no.2
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• pp.118-125
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• 2024

Background: Numerous studies have consistently demonstrated that depression can be associated with cognitive function decline, primarily focusing on older adults due to the neurodegenerative characteristics of dementia. With persistent depression frequently reported in patients with early-onset or young-onset dementia, this study aimed to assess the impact of depression, specifically the changes in depressive symptoms over time, on the risk of cognitive function decline in middle-aged adults in Korea. Methods: This retrospective study utilized data from the first four waves (2006-2012) of the Korean Longitudinal Study of Aging (KLoSA), focusing on middle-aged adults with normal cognitive function at baseline. Changes in depressive symptoms were categorized into four groups based on the CES-D score, and their association with cognitive function decline was evaluated using a multivariate logistic regression model. Results: Of the initial 10,254 participants, 3,400 were included in the analysis. Depressive status, particularly newly onset (adjusted odds ratio [aOR] 1.96; 95% confidence interval [CI] 1.32-2.93) and persistent depression groups (aOR 5.59; 95% CI 2.90-10.78), were significantly associated with cognitive function decline. In contrast, recovery from depressive symptoms was not significantly associated with cognitive function decline (p=0.809). Conclusions: Our study showed a significant association between changes in depressive symptoms and cognitive function decline in middle-aged Korean adults. This suggests that management of depressive symptoms could be crucial for the prevention of cognitive function decline in this population.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.4
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• pp.391-397
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• 2009

In this paper, longitudinal static stability is investigated, which is an essential requirement for the safety and the performance of the human powered hydrofoil boat (HPHB). In case a disturbance changes the trim angle of the boat, the derivative of the moment about the center of gravity must be negative in order to make the boat to be stable. The equation to evaluate the longitudinal static stability of the EPISODE, a HPHB of Chungnam National University with a height controlling system(HCS) is derived. From the derivative it is confirmed that a longitudinal and vertical position of the center of gravity is important for a HPHB. The range of a trim angle while the boat is foil-born was found with a HCS under the condition of mechanical restraint. And it is confirmed that the longitudinal static stability is satisfied for EPISODE in certain range of a trim angle. It is also shown that the longitudinal static stability and a range of the trim angle can be determined from the principal dimensions of a HPHB, therefore, it can be applied from the stage of the conceptual design of HPHB.

• The Journal of the Korean dental association
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• v.23 no.6 s.193
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• pp.527-538
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• 1985

The purpose of this study is to evaluate the chronologic changes of the soft tissue profile in 6 to 11 years children. The author analyzed 174 cephalometric roentgenograms of 13 boys and 16 girls taken from the ages of 6 to 11 to assess the growth changes of the soft tissue profile. The results were obtained as follow: 1. Means, standard deviation and coefficient of variation of children were obtained. 2. Items which showed difference between males and females in longitudinal study were prn. Sn. A', and Ls that were greater than females variation. 3. With age, thickness of the soft tissue were increased except Ls. 4. Nasolabial angle and facial convexity had no significant change with age and sex.

• Journal of Korea Association of Health Promotion
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• v.3 no.1
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• pp.13-23
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• 2005

In Korea, there is an urgent need to identify nutrition-related risk factors for obesity, because the prevalence of these conditions continues to rise among Koreans. While some studies suggest that westernized dietary pattern may increase the risk of obesity, others do not support these findings. Longitudinal studies examined the role of dietary patterns in relation to changes in body fat composition. Nowadays rapid changes in dietary patterns are related to socioeconomic status and westernized diet. Major dietary changes include a large increase in the consuming of at in the diet and a fall in total cereal intakes and fiber. This research showed remarkable decline in the consuming proportion of the grains and vegetables. These results fit closely with the trend toward increased prevalence of obesity in Korea. Most longitudinal studies on these relationships among children and adults showed that the dietary patterns affected obesity. In conclusion, we need programs to promote healthy Korean diet pattern in Korea.

• Safety and Health at Work
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• v.13 no.2
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• pp.213-219
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• 2022

Objective: The Job Demand & Resources model suggests work characteristics are related to mental well-being and work engagement. Previous work describes the development of a combined construct 'engaged well-being at work' (EWB). To what extent changes in measures of this construct are responsive to changes in job demands and resources or associated with changes in job-related attitudes has not been established. Methods: Longitudinal employee-level data from three waves (German Linked Personnel Panel) were used. Logistic and linear fixed effects regression analyses explored longitudinal associations between changes in EWB for participants over a three-year period with changes in job demands and resources and job-related attitudes (job commitment, satisfaction, and turnover intentions). Results: While job resources were associated with increased odds for a change into a healthier and/or more engaged category of EWB, job demands reduced them. Job resources were more strongly related to higher EWB (OR_range = 1.22 - 1.61) than job demands (OR_range = 0.79 - 0.96). Especially psychological job demands showed negative associations with improved EWB (OR = 0.79). A change from the least desirable category 'disengaged strain' to any other category of EWB was associated with greater odds by up to 20.6 % for increased commitment and job satisfaction and lower odds for turnover intentions. Discussion: Improving work characteristics, especially job resources, could increase employees' EWB, emphasizing the importance of job characteristics for a healthy workplace. Because EWB seems to be associated with job attitudes, an improvement of this indicator would be relevant for employees and employers.

• Korean Medical Education Review
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• v.25 no.2
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• pp.84-101
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• 2023

Longitudinal data can provide important evidence with the potential to stimulate innovation and affect policies in medical education and can serve as a driving force for further developments in medical education through evidence-based decisions. Tracking and observing cohorts of students and graduates using longitudinal data can be a way to link the past, present, and future of medical education. This study reviewed practical methods and technical, administrative, and ethical considerations for the establishment and operation of a longitudinal database and presented examples of longitudinal databases. Cohort study design methods and previous examples of research using longitudinal databases to explore major topics in medical education were also reviewed. The implications of this study are as follows: (1) a systematic design process is required to establish longitudinal data, and each university should engage in ongoing deliberation about this issue; (2) efforts are needed to alleviate "survey fatigue" among respondents and reduce the administrative burden of those conducting data collection and analysis; (3) it is necessary to regularly review issues of personal information protection, data security, and ethics regarding the survey respondents; and (4) a system should be established that integrates and manages a longitudinal database of medical education at the national level. The hope is that establishing longitudinal data and cohorts at individual medical schools will not be a temporary phenomenon, but rather that they will be well utilized at the national level to innovate and implement ongoing changes in medical education.

• Communications for Statistical Applications and Methods
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• v.28 no.4
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• pp.369-391
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• 2021

The vlda is an R (R Development Core team et al., 2011) package which provides functions for visualization of multidimensional longitudinal data. In particular, the R package vlda was developed to assist in producing a plot that more effectively expresses changes over time for two different types (long format and wide format) and uses a consistent calling scheme for longitudinal data. The main features of this package allow us to identify the relationship between categories and objects using an indicator matrix with object information, as well as to cluster objects. The R package vlda can be used to understand trends in observations over time in addition to identifying relative relationships at a simple visualization level. It also offers a new interactive implementation to perform additional interpretation, therefore it is useful for longitudinal data visual analysis. Due to the synergistic relationship between the existing VLDA plot and interactive features, the user is empowered by a refined observe the visual aspects of the VLDA plot layout. Furthermore, it allows the projection of supplementary information (supplementary objects and variables) that often occurs in longitudinal data of graphs. In this study, practical examples are provided to highlight the implemented methods of real applications.

• Korean Journal of Child Studies
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• v.37 no.6
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• pp.5-17
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• 2016

Objective: This study focused on the longitudinal associations between self-esteem and peer relationships in Korean adolescents while considering gender and timing-early and late adolescence-differences. Methods: The study made use of data from the Korean Children and Youth Panel Survey. Three waves of data collected from 2,351 adolescents were analyzed by means of autoregressive cross-lagged modeling. Results: The results indicated that self-esteem predicted subsequent changes in peer relationship but not vice versa. Further, the results that longitudinal associations between self-esteem and peer relationships differed between male and female adolescents and between early and late adolescence. Conclusion: The findings revaluated the longitudinal relationship between self-esteem and peer relationships. Both gender and timing should be considered when planning interventions related issues about self-esteem and peer relationships in adolescence.

• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.122-131
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• 2015

Recently, starting with the deep underground road construction plan in Seobu Expressway, Korea, there area many studies on deep underground roads to be newly built. However, there is an extreme lack of safety standards, which does not consider traffic conditions and road driving characteristics. Therefore, this study reviewed safety elements to reflect in the deep underground road planning by analyzing driving stability of longitudinal tunnels with road environments, which resemble deep underground roads. For comprehensive analysis, the characteristics and causes of the accidents that have occurred in seven longitudinal tunnels with a length of 2km or over in Gangwon area, were collected. Specifically, geometric structures and facilities of each tunnel were investigated. Also, the present state of facility installation and the changes in driving speed of vehicles passing through each tunnel were observed to analyze the causes for the traffic accidents in each tunnel and accident reduction alternatives. It was revealed that the most frequent accidents in the tunnels resulted from the changes of traffic flow due to the abrupt speed reduction of forward vehicles, or the failure in speed control of following vehicles during the traffic congestion situation. Moreover, installing facilities such as plane and longitudinal curves, median strips and marginal strips seem to induce consistent driving speed. These results mean that for accident prevention, speed management must be preceded and there is a need to develop and introduce safety facilities actively to control the driving flow of forward and following vehicles.