• Journal of Digital Convergence
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• v.19 no.12
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• pp.577-586
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• 2021

This study is objected to identify the influencing factors of adolescents' smartphone dependency and to determine the degree of influence on smartphone dependency through direct and indirect channels acting between factors. The data of the 2th Korean Child-Youth Panel Survey(KCYPS 2018) was analyzed using the SPSS 26.0 and 26.0 AMOS program. Six paths proved to statistically significant. Self-esteem and depression were the influencing factors of adolescents' smartphone dependency. Social withdrawal and the school environment influenced smartphone dependency through self-esteem and depression as mediators. Self-esteem and depression acted as mediating factors. Adolescents' smartphone dependency was influenced not only by personal factors but also by external factors such as the school environment. The results of this study will be presented as evidence for developing programs that can prevent adolescents from smartphone dependency.

• Journal of Korean Academy of Nursing
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• v.49 no.4
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• pp.411-422
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• 2019

Purpose: The purpose of this study was to adapt, modify, and validate the Nursing Anxiety and Self-Confidence with Clinical Decision-Making Scale ($NASC-CDM^{(c)}$) for Korean nursing students. Methods: Participants were 183 nursing students with clinical practice experience in two nursing colleges. The construct validity and reliability of the final Korean version of the $NASC-CDM^{(c)}$ were examined using exploratory and confirmatory factor analyses and testing of internal consistency reliability. For adaptation and modification, the instrument was translated from English to Korean. Expert review and a cross-sectional survey were used to test the instrument's validity. Results: The Korean version of the $NASC-CDM^{(c)}$ (KNASC-CDM) was composed of 23 items divided into four dimensions: (i) Listening fully and using resources to gather information; (ii) Using information to see the big picture; (iii) Knowing and acting; and (iv) Seeking information from clinical instructors. The instrument explained 60.1% of the total variance for self-confidence and 63.1% of the variance for anxiety; Cronbach's ${\alpha}$ was .93 for self-confidence and .95 for anxiety. Conclusion: The KNASC-CDM can be used to identify anxiety and self-confidence in nursing students' clinical decision-making in Korea. However, further research should be done to test this instrument, as it is classified differently from the original $NASC-CDM^{(c)}$ version.

• International Journal of Ocean System Engineering
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• v.3 no.1
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• pp.16-21
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• 2013

This paper presents a design of fuzzy PD depth controller for the autonomous underwater vehicle entitled KAUV-1. The vehicle is shaped like a torpedo with light weight and small size and used for marine exploration and monitoring. The KAUV-1 has a unique ducted propeller located at aft end with yawing actuation acting as a rudder. For depth control, the KAUV-1 uses a mass shifter mechanism to change its center of gravity, consequently, can control pitch angle and depth of the vehicle. A design of classical PD depth controller for the KAUV-1 was presented and analyzed. However, it has inherent drawback of gains, which is their values are fixed. Meanwhile, in different operation modes, vehicle dynamics might have different effects on the behavior of the vehicle. In this reason, control gains need to be appropriately changed according to vehicle operating states for better performance. This paper presents a self-tuning gain for depth controller using the fuzzy logic method which is based on the classical PD controller. The self-tuning gains are outputs of fuzzy logic blocks. The performance of the self-tuning gain controller is simulated using Matlab/Simulink and is compared with that of the classical PD controller.

• Journal of Life Science
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• v.20 no.9
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• pp.1420-1425
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• 2010

Innate immunity is the first line of host defense consisting of various molecules against infectious challenges. Mannose-binding lectin (MBL) belongs to the collectin protein family which takes part of innate immunity and is able to recognize specific carbohydrates on the surface of a variety of infectious agents acting as a pattern recognition molecule. In this way, MBL differentiates self from non-self and interacts with other molecules of the immune system. MBL genotype shows various MBL2 polymorphisms which are responsible for MBL deficiency in a substantial portion of the entire human population and for susceptibility to infectious disease. Therefore, it has been highlighted in the relationship between genetic variants and clinical significance. Here we focus on presenting anoverview of our understanding of MBL structure and functions.

• Research in Community and Public Health Nursing
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• v.20 no.2
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• pp.225-233
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• 2009

Purpose: This study was to analyse the factors affecting youth smoking, especially self-efficacy and perceived social norm, based on the stage of change. Methods: A self-reported survey was conducted during the period from the 21 st of April to the 17th of May, 2008. Data were collected from 10,707 students of 12 middle schools in Seoul, Gyeonggi-do, and Incheon. The data were analysed with SPSS/WIN 15.0. Results: The smoking possibility was 2.18 times higher in the male students than in female students, and 1.76 times higher in 8th-grade students and 2.48 times higher in 9th-grade students than in 7th-grade ones. Smoking possibility increased when students had more experience in alcohol, more friends who smoke, or worse relationship with their parents. Also this study showed that high-level self-efficacy and perceived social norm were acting as inhibiting factors of smoking. Conclusion: To reduce the youth's smoking rate, smoking prevention programs should provide educational chances to learn knowledge and skills on how to reject smoking temptation. Also, someone significant like parents should make it clear to the youth that they do not want their children to smoke.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.5
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• pp.76-84
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• 2021

In this study, an optimal stiffness model of the C-frame, which was supporting the mold and tool load, was proposed to obtain quality self-piercing riveting (SPR) joining. First, the load path acting on the C-frame structure was identified using topology optimization. Then, a final suggested model was proposed based on the load path results. Stiffness and strength analyses were performed for a rivet pressing force of 7.3 [t] to compare the design performance of the final proposed model with that of the initial model. Moreover, to examine the reliability of continuous and repeated processes, vibration analysis was performed and the dynamic stiffness of the final proposed model was reviewed. Additionally, fatigue analysis was performed to ascertain the fatigue characteristics due to simple repetitive loading. Finally, stiffness test was performed for the final proposed model to verify the analysis results. The obtained results differed from the analysis result by 2.9%. Consequently, the performance of the final proposed model was superior to that of the initial model with respect to not only the SPR fastening quality but also the reliability of continuous and repetitive processes.

• The Korean Journal of Emergency Medical Services
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• v.17 no.3
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• pp.149-168
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• 2013

Purpose: The purpose of this study is to develop a safety health education program for the upper graders of elementary school children and to evaluate the program. Methods: The study was designed for learner centered safety education and heath education based on a theory of lifelong education. After a model development of the program was set up, five major units were selected after five stages of program planning, design, acting, evaluation and feedback: school safety, traffic safety, home safety, life safety, and first-aid. Twenty things were selected as what to teach, and a lesson plan of 12 sessions was mapped out by arranging what to teach. The subjects in this study were 114 elementary school students who were in five different sixth-grade classes. Each class received education for five days, in four sessions each, according to the program. Results: The learners showed improvement in safety consciousness, safety knowledge, self-efficacy and safety behavior after they received education according to the safety health education program, and they expressed a lot of satisfaction with the program. Conclusion: It is important to develop the lifelong education for safety health education for the elementary school children.

• Steel and Composite Structures
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• v.36 no.2
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• pp.229-247
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• 2020

This study analyzed stresses in concrete and its reinforcement, computing the additional loading transferred by concrete creep. The loading varied from zero, structure exclusively under its self-weight, up to the critical buckling load. The studied structure was a real, tapered, reinforced concrete pole. As concrete is a composite material, homogenizing techniques were used in the calculations. Due to the static indetermination for determining the normal forces acting on concrete and reinforcement, equations that considered the balance of forces and compatibility of displacement on cross-sections were employed. In the mathematical solution used to define the critical buckling load, all the elements of the structural dynamics present in the system were considered, including the column self-weight. The structural imperfections were linearized using the geometric stiffness, the proprieties of the concrete were considered according to the guidelines of the American Concrete Institute (ACI 209R), and the ground was modeled as a set of distributed springs along the foundation length. Critical buckling loads were computed at different time intervals after the structure was loaded. Finite element method results were also obtained for comparison. For an interval of 5000 days, the modulus of elasticity and critical buckling load reduced by 36% and 27%, respectively, compared to an interval of zero days. During this time interval, stress on the reinforcement steel reached within 5% of the steel yield strength. The computed strains in that interval stayed below the normative limit.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.37.1-37.1
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• 2017

Since the seminal work of Perrin, physicists have understood in the context of kinetic theory how ink slowly diffuses in a glass of water. The fluctuations of the stochastic forces acting on water molecules drive the diffusion of the ink in the fluid. This is the archetype of a process described by the so-called fluctuation-dissipation theorem, which universally relates the rate of diffusion to the power spectrum of the fluctuating forces. For stars in galaxies, a similar process occurs but with two significant differences, due to the long-range nature of the gravitational interaction: (i) for the diffusion to be effective, stars need to resonate, i.e. present commensurable frequencies, otherwise they only follow the orbit imposed by their mean field; (ii) the amplitudes of the induced fluctuating forces are significantly boosted by collective effects, i.e. by the fact that, because of self-gravity, each star generates a wake in its neighbours. In the expanding universe, an overdense perturbation passing a critical threshold will collapse onto itself and, through violent relaxation and mergers, rapidly converge towards a stationary, phase-mixed and highly symmetric state, with a partially frozen orbital structure. The object is then locked in a quasi-stationary state imposed by its mean gravitational field. Of particular interests are strongly responsive colder systems which, given time and kicks, find the opportunity to significantly reshuffle their orbital structure towards more likely configurations. This presentation aims to explain this long-term reshuffling called gravity-driven secular evolution on cosmic timescales, described by extended kinetic theory. I will illustrate this with radial migration, disc thickening and the stellar cluster in the galactic centre.

• The Journal of Korean Academic Society of Nursing Education
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• v.17 no.2
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• pp.208-217
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• 2011

Purpose The purpose of this study was to explore the experience of service-learning in connection with the major of nursing. Method: This is qualitative research based on the application of a focus-group research method and Glaser's grounded theory. The nine participants of the research participated in the process of developing a service-learning program to promote health in the elderly. They operated the program by acting as instructors for more than 12 months. Results: The basic socio-psychological problems hared by the participants of the research is 'burden'. The basic social process required to solve the problem is 'self-realization' which has been successively shown in the order of the stage of experiencing a surge of will, the stage of recognizing the occurrence of internal and external changes, the stage of being confident, and the stage of obtaining self-respect. Throughout the process, the participants solved 'burden' in a positive way through reflections and reciprocity, developing and strengthening their capabilities. Conclusion: Based on the results, it is necessary to consider the development of a service-learning program in connection with the nursing major in order to provide the students studying nursing with the opportunity to have various learning experiences.