• Korean Journal of Human Ecology
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• v.24 no.6
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• pp.769-781
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• 2015

The purpose of this study was to examine the effects of self control and social support on the mobile phone dependence in elementary school students. The subjects were 392 children(187 boys, 205 girls) in 5, 6th grade from two elementary schools in Gyeonggi-do. The mobile phone dependence was assessed by the Mobile Phone Dependence Scale(Ko Seong-Ja, 2012), self control was measured by the Self-control Scale(Nam hyeon-mi, 1999) and social support was assessed by the Social Support Scale(Han mi hyun, 1996). Data were analyzed using descriptive statistics, t-test, Pearson correlations and hierarchical regressions. The major results of this study were as follows: First, there was no significant difference in mobile phone dependence by sex of the children. Second, children's mobile phone dependence were correlated with self control and social support. Finally, children's self control, family support and peer support significantly explained the mobile phone dependence. But peer support appeared to have negative corelation on mobile phone dependence, but appeared to have static effect in regression result by suppressor variables. So it needs to explore statistical function of suppressor variables in follow-up studies. Also research of this study indicate that self control enhancement program should be developed and parents should communicate more frankly and affectively with their children in order to prevent children's mobile phone dependence.

• Journal of the Korean Data and Information Science Society
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• v.10 no.2
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• pp.279-288
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• 1999

In many cases where the conventional binomial distribution fails to apply to real world data, it is mainly due to the lack of independence among Bernoulli trials. Several authors have proposed models that are useful when independence assumption is not satisfied. In this paper, one proposed model is adapted, and estimators of dependence related parameter that is crucial in defining that model are considered. Simulation is performed to compare two estimators(method of moment estimator and maximum likelihood estimator) of dependence related parameter, and conclusions are made.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.111-121
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• 2017

Smartphone use has become a part of everyday life, not only for adolescents but also for elderly and older people. Thus, this study explored the effect of demographic variables, the amount of smartphone usage, type of smartphone use and psychosocial variables on smartphone dependence of the elder group. We analyzed the data of 5627 (50s and 60s) of the Internet overdependence survey data of the Korea Information Society Agency in 2016. As a result of hierarchical multiple regression analysis, More frequency of smartphone use of weekday and weekend, and usage time of smartphone of weekday were related to greater smartphone dependence. More smartphone use for information seeking and games were associated with greater smartphone dependence. And, as loneliness and anxiety increased, smartphone dependence increased, while smartphone dependence decreased, as social capital increased. Through this study, it is necessary to understand characteristics related to smartphone dependence of elder and older group, and to use this knowledge to solve their smartphone dependence. Future studies also need to identify the causal relationship between predictors of smartphone dependence in elderly and older people.

• Journal of the Korean Institute of Gas
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• v.10 no.2 s.31
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• pp.7-13
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• 2006

In order to evaluate the fire and explosion involved and to ensure the safe and optimized operation of chemical processes, it is necessary to know combustion characteristics. The explosion limit, the heat of combustion, flame temperature and temperature dependence of the lower explosive limit are the major combustion characteristics used to determine the fire and explosion hazards of the flammable substances. The aim of this study is to investigate interrelationship of explosion characteristics and the temperature dependence of the lower explosion limit at elevated temperature for akylketones. By using the reference data, the empirical equations which describe the interrelationships of explosion properties of akylketones have been derived. Also, the new equations using the mathematical and statistical methods for predicting the temperature dependence of lower explosion limits of akylketones on the basis of the literature data are proposed. The values calculated by the proposed equations agreed with literature data within a few percent. From the given results, using the proposed methodology, it is possible to predict the explosion limits of the other flammable substances.

• Human Ecology Research
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• v.54 no.3
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• pp.321-332
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• 2016

This study clarified the maintenance of relationship between children and teachers based on longitudinal data and explored the latent classes. It clarified the latent classes connection with the children's peer play interaction. The subjects of this study were 194 children (aged 3) who attended 11 different kindergartens and daycare centers. We collected data three times (once every 6 months) until they reached age 4. The results of this study were: first, closeness, conflict, and dependence of child-teacher relationship that showed a continuous short-term connection. Second, we classified the child-teacher relationship into three groups according to longitudinal data. Those groups were, 'low level maintenance group' which had the lowest conflict and dependence compared to the highest closeness with teacher, 'middle level maintenance group' which had the teacher relationship in the middle level of the sub element area, and 'high level maintenance group' which showed high conflict and dependence compared to low closeness with the teacher. Third, the group which maintains a longitudinal high conflict.dependence showed more interruption and disruption behavior than the group which maintained a low conflict and dependence. In conclusion, the child-teacher relationship seemed to be the steady characteristic because it showed the early formation of a stable relationship. It was possible to predict the child's peer interaction through an early child-teacher relationship. Teachers need to be educated by the kindergarten and daily care center because the early formation of a child-teacher relationship can be the foundation of child's later peer and teacher relationships.

• Journal of the Korean Data and Information Science Society
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• v.25 no.1
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• pp.219-226
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• 2014

In this paper, we derived estimators of reliability P(Y < X) and the distribution of ratio in the bivariate exponential density. We also considered the means and variances of M = max{X,Y} and m = min{X,Y}. We finally presented how E(M), E(m), Var(M) and Var(m) are varied with respect to the ones in the bivariate exponential density.

• Korean Journal of Mathematics
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• v.27 no.4
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• pp.929-947
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• 2019

In the present paper, we investigate the convergence, equivalence of convergence, rate of convergence and data dependence results using a three step iteration process for mappings satisfying certain contractive condition in hyperbolic spaces. Also we give nontrivial examples for the rate of convergence and data dependence results to show effciency of three step iteration process. The results obtained in this paper may be interpreted as a refinement and improvement of the previously known results.

• Bulletin of the Korean Mathematical Society
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• v.45 no.1
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• pp.67-73
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• 2008

The purpose of this paper is to present some fixed point results for nonself multivalued operators on a set with two metrics. In addition, a homotopy result for multivalued operators on a set with two metrics is given. The data dependence and the well-posedness of the fixed point problem are also discussed.

• Communications of the Korean Mathematical Society
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• v.32 no.4
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• pp.1009-1024
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• 2017

In this paper, we consider the new faster iterative scheme due to Sintunavarat and Pitea ([32]) for further investigation and we prove its strong and ${\Delta}$-convergence theorems, data dependence and stability results in hyperbolic space. Our results extend, improve and generalize several recent results in CAT(0) space and uniformly convex Banach space.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1219-1224
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• 1999

This paper derived Montgomery's parallel algorithms for modular multiplication based on Walter's and Iwamura's method, and compared data dependence graph of each parallel algorithm. Comparing the result, Walter's parallel algorithm has small computational index in data dependence graph, so it is selected and used to computed spatial and temporal pipelining diagrams with each projection direction for designing expansible bit-level systolic array. We also evaluated internal operation of proposed expansible systolic array C++ language.