• Journal of the Korean Society of School Health
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• v.30 no.3
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• pp.274-283
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• 2017

Purpose: The purpose of this study was to investigate the mediating effects of self-esteem and self-resilience while identifying the relationship between bullying victimization (being bullied) and depression based on a longitudinal study design. Methods: Participants were adolescent cohort of 1,971 middle school students participating in 2013 and 2014 Korean Children and Youth Panel Survey conducted by National Youth Policy Institute. Data were analyzed by Pearson's Correlation and regression. Results: The major findings are as follows. First, self-esteem and self-resilience were positively related to each other and negatively related to depression and bullying victimization. Second, bullying victimization effected the level of depression of adolescents and self-esteem played a mediating role between bullying victimization and depression while self-resilience did not. Conclusion: The results suggest that emotional factors continue to play an important role in promoting psychological adjustment of victims of bullying. Therefore, interventions are more likely to be successful if they focus on emotional skills development of adolescents.

• Journal of the Korea Society of Computer and Information
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• v.24 no.6
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• pp.175-182
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• 2019

This study aims to identify causal variables by examining the mutual influences of community consciousness and life satisfaction. We used some data of KCYPS. A longitudinal study of 1952 adolescents selected as a sample was conducted using the Aautoregressive crossover delay model. The results of this study are as follows: First, it showed that life satisfaction is consistently affecting the later life satisfaction with the passage of time. Second, community consciousness showed that the previous community consciousness has a constant influence on the subsequent community consciousness as time passes. Third, the effect of previous life satisfaction on community consciousness was significant. Therefore, the cross-delay effect of life satisfaction on community awareness was stable with time. In other words, life satisfaction level was a causal variable that takes precedence over community consciousness, and the higher the life satisfaction of the previous time, the higher the level of community consciousness in the future. Fourth, the cross-delay effect of community consciousness on life satisfaction was not significant because community consciousness at previous time had no meaningful effect on life satisfaction at later time, so consciousness of community at previous time affects life satisfaction. This study provided some implications basing on this results.

• Advances in nano research
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• v.10 no.3
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• pp.271-280
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• 2021

The present work deals with an investigation on longitudinal wave propagation in nanobeams made of graphene sheets, for the first time. The nanobeam is modelled via a higher-order shear deformation theory accounts for both higher-order and thickness stretching terms. The general nonlocal strain gradient theory including nonlocality and strain gradient characteristics of size-dependency in order is used to examine the small-scale effects. This model has three-small scale coefficients in which two of them are for nonlocality and one of them applied for gradient effects. Hamilton supposition is applied to obtain the governing motion equation which is solved using a harmonic solution procedure. It is indicated that the longitudinal wave characteristics of the nanobeams are significantly influenced by the nonlocal parameters and strain gradient parameter. It is shown that higher nonlocal parameter is more efficient than lower nonlocal parameter to change longitudinal phase velocities, while the strain gradient parameter is the determining factor for their efficiency on the results.

• Asia Pacific Journal of Corpus Research
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• v.3 no.1
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• pp.1-20
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• 2022

As a milestone progression in China's space exploration history, Chang'e Project has attracted a lot of media attention since its first launching. This study aims to examine and compare the similarities and differences between the Chinese media and the British media in using nouns, verbs, and adjectives to report the Chang'e Project. After categorising the documents based on specific project phases, we created two diachronic corpora to explore the linguistic shifts and similarities and differences of diction employed by the Chinese and British media on the Chang'e Project ideology. This longitudinal study was performed with Lancsbox and the CLAWS web tagger through critical discourse analysis as the theoretical framework. The findings of the current study showed that the Chang'e Project coverage in both media increased on an annual basis, especially after 2019. In contrast to the objectivity and positivity in the Chinese Media, the British Media seemed to be more subjective with more appraisal adjectives in the news reports. Nonetheless, both countries were trying to be objective and formal in choosing nouns and verbs. Ideology-wise, the Chinese news media reports portrayed more positivity on domestic circumstances while the British counterpart was typically more critical. Notably, the study outcomes could catalyse future research on the Chang'e Project and facilitate diplomatic policies.

• Current Optics and Photonics
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• v.7 no.2
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• pp.127-135
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• 2023

Radially polarized beams with the ability to generate a sub-wavelength sized spot in a longitudinal field provides significant applications in microscopic imaging, optical tweezers, lithography and so on. However, this excellent property can also be achieved based on conventional circularly polarized beams. Here, we demonstrate its ability to create a strong longitudinal field by comparing the tight focusing characteristics of fractional-order vortex modulated radial polarized and left-handed circular polarized Bessel-Gauss beams. Additionally, the possibility of generating arbitrary fractional-order vortex modulated Bessel-Gauss beams with a strong longitudinal field is demonstrated. A special modulation method of left-handed circularly polarized Bessel-Gauss beams modulated by a fractional-order vortex is adopted creatively and a series of regulation laws are obtained. Specifically, the fractional-order phase modulation parameter n can accurately control the number of optical lobes. The ratio of the pupil radius to the incident beam waist β₁ can control the radius of the optical lobes. The first-order Bessel function amplitude modulation parameter β₂ can control the number of layers of optical lobes. This work not only adds a new modulation method for optical micromanipulation and optical communication, but also enriches the research on fractional vortex beams which has very important academic significance.

• 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.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.9
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• pp.427-433
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• 2001

A linear ultrasonic motor was designed by a combination of the first longitudinal and fourth bending mode, and the motor consisted of a straight aluminum alloys bar bonded with a piezoelectric ceramic element as a driving element. That is,$L_1-B_4$ linear ultrasonic motor can be constructed by a multi-mode vibrator of longitudinal and bending modes. Linear ultrasonic motors are based on an elliptical motion on the surface elastic body, such as bar or plates. In general, the natural resonance frequency of the stator is used as a driving frequency of the motor which provides a large elliptical motion. The corresponding eigenmode of one resonance frequency can be excited twice at the same time with a Phase shift of 90 degrees in space and time. And the rotation can be reversed by changing the phase between the two signals from sin$\omega$t to cos$\omega$t. Moreover, the tangential force pushes the slider(rotor) and, therefore, determines the thrust and speed of the motor. The experimental results of fabrication motors, bimorph-tyPe motor showed more excellent than unimorph-type. The maximum speed of TBL-200, TBL-300, TBL-400, TBL -220, TBL-310 and TBL-420 motors were 0.12, 0.37, 0.39, 0.14, 0.55 and $0.60ms6{-1}$, respectively. And the efficiency were reported 1.15, 7.9, 6.6, 2.36, 10.1 and 16.5%, respectively. That time, output thrust of the motor was a strong(1~2N) and the weight of stator was a lightness(5~7g).

• Survey Research
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• v.7 no.2
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• pp.71-95
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• 2006

This article presents strengths of Computer-Assisted Personal Interviewing(CAPI) in social surveys with complicated questionnaires, from examples of a pilot and the first year surveys of the Korean Longitudinal Study of Ageing(KLoSA). This study focuses on how to improve the quality of data by using CAPI and finds five strengths among others. First of all, CAPI can contribute to reducing response errors by structuring the logic and path of questionnaires, setting a response range, and maintaining response consistency. Second, CAPI enhances convenience of interviewing by allowing customized questions and automatic calculation and scoring. It also allows the 'help' function. Third, its random arrangement of questions prevents response order effect and/or questions order effect. Fourth, CAPI can raise the response rate by reducing item non-responses. Fifth, it makes it easy monitoring interviewing, thus helps supervising interviewers and modifying questionnaires when necessary. These merits of CAPI contribute to reducing possible errors in the process of interviewing, therefore improve the data quality.

• Korean Journal of Health Education and Promotion
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• v.26 no.3
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• pp.25-34
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• 2009

Objectives: This study has longitudinally analyzed male smokers in order to find out the trend rate of re-smoking after smoking cessation. Methods: The study was conducted with 800 male smokers who were provided with smoking cessation services for 3 years at public health centers from July 16, 2005 to July 15, 2008. Results: The results can be summarized as follows: First, the success rate of smoking cessation for at least 6 months during 3-year period was 54.4%. The failure rate of smoking cessation at the second year was 47.5% and the third 27.2%, which indicates that the failure rate diminishes as the period of smoking cessation extends. Second, the success rate of smoking cessation at the first trial was 35.0%, the second 24.3%, and the third 16.4%. The success rate diminished as the number of trial increased. Third, the continuation rate of smoking cessation for a year was 18.3%, for 2 years 13.4%. For the success group, the continuation rate of smoking cessation for a year was 52.5%, for 2 years 38.2%. For the failure group, the rate for a year was 21.5%. Fourth, in this longitudinal analysis, the most crucial variables that affect the success rate of smoking cessation are total number of consultation and the past experience of successful smoking cessation. Conclusion: This study shows that success of smoking cessation and the continuance of smoking cessation are both difficult, and that the past experience of smoking cessation plays an important role determining the present success of smoking cessation and continuance of smoking cessation. Thus, it is necessary to divide people into success group and failure group based on the results of the past experience of smoking cessation when they consult at smoking cessation clinics at public health centers. Further, in order to increase the continuation rate of smoking cessation, this study suggests that we need to consider ways to take care of those who successfully abstained from smoking for 6 months.