• Korean Journal of Human Ecology
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• v.17 no.2
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• pp.271-278
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• 2008

This study was investigated elementary school children's cellular phone usage and relationships between the usage and their self-efficacy and self-control. The data were collected by boys(101) and girls(155) among 5th grades, boys(125) and girls(177) among 6th grades elementary school in Busan. The data analyzed with the frequency, percentage, mean, SD and t-test, ANOVA, Pearson's correlation in use of SPSS Win 12.0 program. The results from the research can be summarized as follows; First, there was no significant difference in the children's general usage of cellular phone in terms of grade and sex. Second, it was found in a couple of significant difference in the subcategories of the usage according to grades. The 6th grades children is higher scores than 5th grades in the 'control of cellular phone usage' and 'living trouble'. Third, there was correlated negatively between cellular phone usage and the children's self-efficacy/self-control.

• Journal of Families and Better Life
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• v.31 no.6
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• pp.83-96
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• 2013

The aim of this study was to identify the differences in cellular phone dependency and its use levels of usage purposes according to children's gender, and also to analyze the differences in individual and interpersonal relations development due to cellular phone dependency in children based on gender. Using the first year data of the Korean Child and Youth Panel Survey(KCYPS) 2010, this study analyzed 1,604 fourth graders who have their own cellular phones. For statistical analysis, descriptive statistics were calculated and mean difference analyses were conducted. The results showed that there was no difference between boys and girls in cellular phone dependency. The girls' total phone use level was higher than that of boys and meaningful gender differences in the phone use levels were found in the five phone usage purposes. In both boys and girls, the higher phone dependency groups demonstrated higher levels of phone use in more than eight usage purposes, lower self-resilience and self-regulating learning ability, and less positive peer and teacher relations. These findings show the importance of being concerned about and educating children in the fourth grade about the proper uses of cellular phones.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.10 s.89
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• pp.969-976
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• 2004

The wide and growing use of cellular phones has raised the question about the possible health risks associated with radio-frequency electromagnetic fields. It would be helpful for phone users to blow the exposure levels during cellular phone use. But it is very difficult to recognize the amount of exposure, because measuring accurate level of RF is a difficult matter. In this study, we developed a model to estimate the exposure level and the individual risk of exposure by utilizing the available informations that we can get. We used such parameters as usage time a day, total using period, distance between cellular phone and head, slope of cellular phone, hands-free usage, antenna pulled out or not SAR(Specific Absorption Rate) of cellular phone, and flip or folder type. We proposed a model presenting individual risk of RF exposure from level 0 to 10 by using a neural network.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.42-44
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• 2005

Many cellular phone volunteer studies have been conducted since such a social issue is raised that the long time usage of cellular phone may increase health risk. While there were various volunteer studies using GSM cellular phone on heart rate and blood pressure at abroad, very few studies using CDMA phone were conducted in domestic and abroad. In this study, the volunteer groups of 21 adults were exposed at 300 mW for half an hour, and the physiological parameters such as blood pressure, heart rate, respiration rate, and skin impedance were measured. All the parameters' results did not reveal any differences between exposure and non-exposure conditions in adults.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.3
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• pp.381-385
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• 2019

In this Study, as the structure of smart phone display becomes thin to catch up with slim product trend, the reliability of display module is on the rise as a issue for product design. Especially, almost part of cellular phone should undergo drop test when they fall 1.5m above ground. Thus many manufacturers have considered design guide line using CAE and simulation for more efficive usage of limited resources om the martket. This test simulates the case when cellular phone slips through user's flingers while he is talking on the phone. This paper studies a drop simulation of glass for display in smart phone. This design for reliability improvements are suggested on the basis of the results of FE Analysis and display of smart phone design.

• Science of Emotion and Sensibility
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• v.6 no.3
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• pp.1-11
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• 2003

The purpose of the present driving simulation study was to examine the effect of cellular-phone use on driving performance when required driving speeds were systematically varied(60, 80, 100, or 120km/h) while either using cellular-phones(experimental condition; Hands-Free or Hands-Held) or not(control condition). Driving performance was measured both by longitudinal vehicle control(i.e., variabilities in driving speed and headway) and lateral vehicle control(variabilities in lane position). The results can be summarized as followings: (1) The significant difference in driving speed variation between the two cellular-phone usage conditions was found only at relatively higher driving speed conditions(i.e., over 80km/h). (2) Only in the experimental condition where cellular-phone was required to be used while driving, the magnitudes of variation in driving speed, headway and lane position were gradually increased as the required driving speeds were increased(this tendency was not found in control condition). And. (3) the dependent measures of this study appeared to suggest that cellular-phone usage itself (rather than the types of cellular-phone) had significant impact on driving performance. Finally, implication and issues related to this study were discussed.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.427-431
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• 2020

In this Study, as the structure of IT module for smart phone display becomes thin to catch up with slim product trend, the reliability of display module is on the rise as a issue for product design. Especially, almost part of cellular phone should undergo thermal dissipation test. thus many manufacturers have considered design guide line using CAE and simulation for more effective usage of limited resources on the market. This test simulates the case when cellular phone slips through user's fingers while he is talking on the phone. This paper studies a thermal simulation of display module in smart phone. This design for reliability improvements are suggested on the basis of the results of FVM Analysis and display of IT module and smart phone design.

• Journal of Korean Academy of Nursing
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• v.37 no.6
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• pp.957-965
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• 2007

Purpose: The purpose of this study was to examine the degrees of cellular phone usage among middle school students and to identify discriminating factors of addictive use of cellular phones among socio-demographic and psychological variables. Methods: From 123 middle schools in Busan, potential participants were identified through stratified random sampling and 747 middle school students participated in the study. The data was collected from December 1, 2004 to December 30, 2004. Descriptive and discriminant analyses were used. Results: Fifty seven percent of the participants were male and 89.7% used cellular phones at school. The participants were grouped into three groups depending on the levels of the cellular phone usage: addicted (n=117), dependent (n=418), non-addicted (n=212). Within the three groups, two functions were produced and only one function was significant, discriminating the addiction group from non-addiction group. Additional discriminant analysis with only two groups produced one function that classified 81.2% of the participants correctly into the two groups. Impulsiveness, anxiety, and stress were significant discriminating factors. Conclusion: Based on the findings of this study, developing intervention programs focusing on impulsiveness, anxiety and stress to reduce the possible addictive use of cellular phones is suggested.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.5 s.96
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• pp.511-517
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• 2005

Many cellular phone volunteer studies have been conducted since such a social issue is raised that the long time usage of cellular phone by teenagers may increase health risk. While there were various adult volunteer studies using GSM cellular phone on heart rate and blood pressure, very few teenager studies using CDMA phone were conducted. In this study, two volunteer groups of 21 teenagers and 21 adults were exposed to 300 mW CDMA wave for half an hour, and the physiological parameters such as blood pressure, heart rate, respiration rate, and skin impedance were investigated. All the parameters fur both groups were unaffected during exposure except the skin impedance of teenager group.

• Journal of the Korea Society of Computer and Information
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• v.16 no.5
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• pp.147-152
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• 2011

The main Objectives of this paper are as follows. First, we investigated effects of Smart Phone quality on the usefulness and ease of use of Smart Phone. Then, we investigated effects of the usefulness and ease of use of Smart Phone on the intention of use. Our research model is based on TAM(Technology Acceptance Model). To accomplish the purpose of this paper effectively and efficiently, a survey was conducted based on the usage of Smart Phone. Then we conducted regression analyses on the collected data and found following results. First, Smart Phone quality have a significant effect on the usefulness and ease of use of Smart Phone. Second, the usefulness and ease of use of Smart Phone have significant effects on the intention of use. Third, Smart Phone users are more satisfied with the system quality than cellular phone users. And the continuous use intention of Smart-Phone users is higher than that of cellular phone users.