• Journal of Korean Biological Nursing Science
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• v.15 no.4
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• pp.173-183
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• 2013

Purpose: The purpose of this study was to compare the stress level and HPA axis activity of an internet game addiction group and non-addiction group in adolescents. Methods: A cross-sectional comparative study was performed with 140 male high school students from 9 vocational high schools at W city. Data were collected from July to September, 2012, using a questionnaire for measuring internet game addiction and stress level, blood samples for serum ACTH, and cortisol level for HPA axis activity. Data were analyzed using descriptive analysis, $X^2$-test, t-test, ANOVA, and Pearson correlation coefficient with SPSS/WIN 15.0. Results: The stress level of the internet game addicted group was significantly higher than that of the non-addicted group (p<.001). The serum cortisol level was also significantly higher in the internet game addicted group than in the non-addicted group (p<.026). The serum ACTH level was higher in the internet game addicted group more than in the non-addicted group (p<.072). Conclusion: These results showed that internet game addiction could increase stress level and HPA axis activity in high school adolescents. Thus, a nursing approach to prevent and relieve internet game addiction should be initiated to stabilize the HPA axis of internet game addicted adolescents.

• Journal of Technologic Dentistry
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• v.42 no.2
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• pp.173-185
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• 2020

Purpose: The purpose of this study was to investigate dental technicians' awareness of infections and to enhance their interest and commitment towards infection prevention. Methods: A self-reported questionnaire survey was conducted among dental technicians. Total of 195 responses were used for analysis. A cross-tabulation analysis was used to compare dental technicians' awareness of infections according to their levels of education on infection prevention (α=0.05). Results: Dental technicians were educated on infection prevention (40.5%). Most participants received infection prevention education from school (29.8%). Dental laboratories had an infection control guideline (34.9%). Dental technicians were not aware of infection risks at their workplaces or believed that they were not at risk of infections at their workplaces (59.3%). Conclusion: Dental technicians must be consistently educated on infection prevention and control through systematic education at school and wider promotion through media. Research is needed to economically and efficiently improve equipment used by dental technicians and to protect them from infectious diseases. A budget for infection prevention must also be determined. Institutional measures such as providing support for dental technicians at the policy level and developing a basic infection prevention manual are necessary. Solving these issues not only protects dental technicians from infections but also allows them to provide high-quality medical services.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.1
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• pp.58-66
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• 2002

Acousto-optical wavelength tunable optical filters in LiNbO$_3$ have been demonstrated using taperd directional weighted coupling acoustic waveguides and Ti double diffusion technique. Conversion efficiency in excess of 61%, 86% and sidelobe intensity of -14.29㏈, -14.99㏈ were measured at a wavelength of 1551.1nm RF frequency of 173.58MHz and RF power of 35㎽ for both TE and TM input polarizations, respectivelv. A spectral width of ~l.8nm and linear tuning late of 8.6nm/MHz were demonstrated. A 2.82$mutextrm{s}$ switching time has been measured. With two channels with 2.5nmseparation, channel cross-talk was lower than -l4㏈ for single wavelength filtering due to sidelobe.

• Structural Engineering and Mechanics
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• v.66 no.2
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• pp.173-183
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• 2018

This paper proposes a developed optimization model for steel frames with semi-rigid beam-to-column connections and fixed bases using teaching-learning-based optimization (TLBO) and genetic algorithm (GA) techniques. This method uses rotational deformations of frame members ends as an optimization variable to simultaneously obtain the optimum cross-sections and the most suitable beam-to-column connection type. The total cost of members plus connections cost of the frame are minimized. Frye and Morris (1975) polynomial model is used for modeling nonlinearity of semi-rigid connections, and the $P-{\Delta}$ effect and geometric nonlinearity are considered through a stepped analysis process. The stress and displacement constraints of AISC-LRFD (2016) specifications, along with size fitting constraints, are considered in the design procedure. The developed model is applied to three benchmark steel frames, and the results are compared with previous literature results. The comparisons show that developed model using both LTBO and GA achieves better results than previous approaches in the literature.

• Steel and Composite Structures
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• v.31 no.2
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• pp.173-185
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• 2019

This paper presents experimental and numerical investigations of aluminum tubular members subjected to combined bending and web crippling. A series of tests was performed on square hollow sections (SHS) fabricated by extrusion using 6061-T6 heat-treated aluminum alloy. Different specimen lengths were tested to obtain the interaction relationship between moment and concentrated load. The non-linear finite element models were developed and verified against the experimental results obtained in this study and test data from existing literature for aluminum tubular sections subjected to pure bending, pure web crippling, and combined bending and web crippling. Geometric and material non-linearities were included in the finite element models. The finite element models closely predicted the strengths and failure modes of the tested specimens. Hence, the models were used for an extensive parametric study of cross-section geometries, and the web slenderness values ranged from 6.0 to 86.2. The combined bending and web crippling test results and strengths predicted from the finite element analysis were compared with the design strengths obtained using the current American Specification, Australian/New Zealand Standard and European Code for aluminum structures. The findings suggest that the current specifications are either quite conservative or unconservative for aluminum square hollow sections subjected to combined bending and web crippling. Hence, a bending and web crippling interaction equation for aluminum square hollow section specimens is proposed in this paper.

• Smart Structures and Systems
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• v.30 no.2
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• pp.173-181
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• 2022

The current paper presents a technique to detect crack in non-uniform cantilever-type pipe beams, that have step changes in the properties of their cross sections, restrained by a translational and rotational spring with a tip mass at the free end. An equation for estimating the natural frequencies for the non-uniform beams is derived using the boundary and continuity conditions, and an equivalent bending stiffness for cracked beam is applied to calculate the natural frequencies of the cracked beam. An experimental study for a step-changed non-uniform cantilever-type pipe beam restrained by bolts with a tip mass is carried out to verify the proposed method. The translational and rotational spring constants are updated using the neural network technique to the results of the experiment for intact case in order to establish a baseline model for the subsequent crack detection. Then, several numerical simulations for the specimen are carried out using the derived equation for estimating the natural frequencies of the cracked beam to construct a set of training patterns of a neural network. The crack locations and sizes are identified using the trained neural network for the 5 damage cases. It is found that the crack locations and sizes are reasonably well estimated from a practical point of view. And it is considered that the usefulness of the proposed method for structural health monitoring of the step-changed non-uniform cantilever-type pipe beam-like structures elastically restrained in the ground and have a tip mass at the free end could be verified.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.2
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• pp.173-180
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• 2008

The influence of temperature and relative humidity in infection and cross-infection of Nosema bombycis and N. mylitta respectively in mulberry silkworm, Bombyx mori L. on larval mortality, multiplication of pathogens, larval weight and growth rate in three different seasons were studied. Seasons were selected in such condition, when very less fluctuations between minimum and maximum temperature and minimum and maximum relative humidity ($25{\sim}28^{\circ}C$ and $65{\sim}72%$ R.H) was observed i.e., season-1. Fluctuations between minimum and maximum temperature were less ($28.05{\sim}34.50^{\circ}C$) but R.H % was more ($55{\sim}81%$) in season-2. Fluctuations between minimum and maximum temperature and R.H % were more ($20.00{\sim}40.5^{\circ}C$ and $64.00{\sim}90.00%$) in season-3. Growth rate of microsporidian-infected silkworm is directly related to the prevailing temperature and relative humidity in silkworm. Silkworm can tolerate slight variation of temperature but slight variation of relative humidity disfavours the development of silkworm and favours the multiplication of pathogens.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.173-180
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• 1992

A feature typical of natural rivers is the bend. The purpose of this study is to examine hydraulic and morphometric characteristics in channel bend reach by the deterministic approach. Cross section shape factor, "As" is suggested for a new cahracteristic factor of channel bend reach analysis. The variation of this new factor along the river reach showed the location of the concentration of the force due to the current all over the reach, that is curved or not. Some general meander factors are used for correlation with new factor suggested, and the applicability of "As" is verified. The range R/W values are concentrated 2~4, the meanning of this value can be regarded to the warning for bank erosion or breaking. And this paper dealt with prediction of cross section bed shape variation.

• Speech Sciences
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• v.9 no.4
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• pp.165-173
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• 2002

Strong compression effects in a stressed vowel due to the addition of syllables have been adopted as evidence for stress-timing. In relation to this, Yun (2002) investigated the compression effects of number of syllables on Korean vowel. The results generally revealed that Korean had neither significant nor consistent anticipatory or backwards compression effects, especially when it came to the sentence level. This led us to claim that Korean would not be a stress-timed language. But the language investigated in the study was only Korean, and further cross-linguistic research was needed to confirm the claim. In this study, Yun's (2002) sentence level data are compared with Fowler's (1981) English data. The comparison reveals that Korean seems to be similar to English in the backwards compression effect, whereas the two languages are markedly different in the anticipatory compression effect. Thus, if English is a stress-timed language and the strong anticipatory compression effect is evidence in favour of stress-timing as is claimed, the present cross-linguistic study confirms Yun's (2002) suggestion-Korean is unlikely to be stress-timed. On the other hand, compression effects are revisited: the differences in vowel compression between English and Korean are discussed from the syntactic and phonological points of view.

• Journal of Korean Public Health Nursing
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• v.20 no.2
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• pp.163-173
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• 2006

Purpose: This is a descriptive study to identify the self esteem and career identity of nursing students. Method: The sample consisted of 416 junior nursing students of diploma programs in the cities of Seoul and Kyung-gi area, and Kyungbook province. Data were analyzed by the program of SPSS WIN 11.5. Results: Self esteem was significantly higher in the students attending rural school than in those attending urban school (F=3.46, p<.03), in those between the age of 24-25 years than in the rest (F=2,17, p<.05), and in those satisfied on admission to nursing school than in those less satisfied (F=3.12 p<.04). Career identity was significantly higher in the students between the age of 24-25 years than in the rest (F=6.10, p<.000), and in those satisfied on admission to nursing school than in those less satisfied (F=49.64, p<.000). The results of correlational analysis between self esteem and career identity revealed that career identity increased with increasing self esteem(r=.316 p<.001). Conclusion: Based on the above findings, programs are needed for the improvement of self esteem and career identity, and further research is suggested on the development of such programs.