• Journal of KIISE:Information Networking
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• v.36 no.6
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• pp.481-491
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• 2009

In this paper, we proposed a hybrid P2P overlay structure for live media streaming. The proposed structure consists of the mesh overlay organized by peers according to the geographical proximity and similar bandwidth range and the tree overlay formed by the peers for which the stability of participation is approved. The proposed scheme enhances the robustness of tree overlay and the long delay of mesh overlay by intelligently combining the utilization of the tree overlay and the mesh overlay. Furthermore, the peers with a large up-link bandwidth are located near to the media source peer. Therefore, it reduces the height of tree, and as a result, the stream transmission delay. Through simulation, we evaluated the performance of the proposed scheme in terms of scalability and quality of services.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.181-188
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• 2011

With the rapid proliferation of wireless networks and mobile computing applications, the landscape of the network security has greatly changed recently. Especially, Vehicular Ad Hoc Networks maintaining network topology with vehicle nodes of high mobility are self-organizing Peer-to-Peer networks that typically have short-lasting and unstable communication links. VANETs are formed with neither fixed infrastructure, centralized administration, nor dedicated routing equipment, and vehicle nodes are moving, joining and leaving the network with very high speed over time. So, VANET-security is very vulnerable for the intrusion of malicious and misbehaving nodes in the network, since VANETs are mostly open networks, allowing everyone connection without centralized control. In this paper, we propose a weighted intrusion detection method using rough set that can identify malicious behavior of vehicle node's activity and detect intrusions efficiently in VANETs. The performance of the proposed scheme is evaluated by a simulation study in terms of intrusion detection rate and false alarm rate for the threshold of deviation number ${\epsilon}$.

• Journal of the Korean Society of School Health
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• v.22 no.1
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• pp.49-59
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• 2009

Purpose: The aim of this study was to identify the factors related with the intention of smoking abstinence among elementary students in a metropolitan city in Korea. Methods: All the elementary schools in the city were stratified by region, and then schools as a primary sampling units (PSU) were selected by probability proportional to size (PPS) sampling. One class per grade was sampled randomly from 5th and 6th grade in the sampled schools from October to December in 2004. The students completed a standardized self-administered questionnaire anonymously. A total number of 1,712 respondents who did not smoke was included in the final analysis. The dependent variable was an intention of smoking in the future, and it was dichotomized into 'absolutely confident in smoking abstinence' and 'others'. The risk of non-absolute confidence in smoking abstinence was calculated with simple and multiple logistic regression, which were conducted with STATA 9.0 by a design-based analysis considering strata variable, PSU, and sampling weight. Results: In the final model of multiple logistic regression analysis, those who were more likely to have non-absolute confidence in smoking abstinence were male students (OR=2.66, p<0.001); barely attending religious services (OR=3.32, p=0.002) or having no religion (OR=1.95, p=0.027); exposure to environmental tobacco smoke outside home 1${\sim}$2 days per week (OR=1.60, p=0.013); having friends who smoked (OR=1.93, p=0.011); non-absolute confidence in refusing to smoke (OR=5.35, p<0.001); having relatively less negative attitude (OR=2.88, p<0.001), positive attitude (OR=2.35, p<0.001), and indifference (OR=4.05, p=0.034) toward peer smoking; not good relationship with mother (OR=1.52, p=0.016). Conclusion: The factors related with non-absolute confidence in smoking abstinence were coincided with those of smoking among children. The results of this study suggest the smoking prevention education should be applied to the children more actively, especially who are not confident in smoking abstinence in the future.

• Journal of Korean Public Health Nursing
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• v.31 no.3
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• pp.505-517
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• 2017

Purpose: This study was conducted to investigate factors affecting the somatizationof 4th grade elementary school students in South Korea. Methods: The research used cross-sectional data of 2,031 first grade elementary school students that participated in 4th-year Korean Children and Youth Panel Survey (KCYPS). Data analysis, which included descriptive statistics, t-tests, one-way ANOVA, Pearson's correlation, and hierarchical regression,was performed using SPSS/WIN 23.0. Results: Aggression (r=0.60, p<.001) and depression (r=0.69, p<.001) showed significant positive correlation, while affection (r=-0.22, p<.001), reasonable explanation (r=-0.28, p<.001), peer relationship (r=-0.06, p=.001), and teacher relationship (r=-0.20, p<.001) were negatively correlated with somatization of elementary school students. Hierarchical regression analysis revealed that depression (${\beta}=0.52$, t=25.52, p<.001), aggression (${\beta}=0.27$, t=13.30, p<.001), reasonable explanation (${\beta}=0.05$, t=2.99, p=.002), and affection (${\beta}=0.04$, t=2.13, p=.031) were significant predictors of somatization. This regression model has an explanatory power of 52.8%. Conclusion: To reduce somatization, it is necessary to develop a therapeutic intervention to change student emotions into a positive coping mechanism and strategy. The results of this study will contribute to the development of programs and practices for healthy school life.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.5
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• pp.737-745
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• 2006

The goal of this study is to present an external pit corrosion rate($p_{ecr}$) model with considering both the age of pipe and the soil characteristics. The correlation of nonlinear exponential model among conventional empirical models was a little higher than other empirical models in the prediction of $p_{ecr}$ according to the age of pipe. However, there has been a limit to predict Peer with the model by using only a pipe age since installation as a variable. The soil analysis results from sixty nine samples showed that all of the samples were non corrosive in the assessment of ANSI/AWWA scoring system. The correlation of soil corrosion factors and $p_{ecr}$ was also low. The application result of linear and nonlinear regression models that soil characteristics only showed a low correlation with $p_{ecr}$ Proposed nonlinear regression model in this study, with considering both the age of pipe and the soil characteristics, showed a little higher correlation ($R^2=0.46$) than conventional model.

• The Journal of Korean Academic Society of Nursing Education
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• v.30 no.2
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• pp.101-112
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• 2024

Purpose: The study aimed to examine doctoral students' degree acquisition paths and postgraduate research achievements and explore whether there are differences in the research achievements of doctoral degree holders in relation to the dissertation format. Methods: This study is a retrospective cohort study of nursing doctoral graduates whose degree conferral dates were between August 2013 and August 2023 that compared two dissertation tracks: traditional and publication. We evaluated the proportion of graduates in each track, publication of their dissertations, time to graduation, and the number of peer-reviewed journal publications after graduation. Results: Of the sample, 160 (87.4%) graduated in the traditional track, with only 56 (35.0%) of them publishing their dissertations after graduation. Excluding dissertations, 114 of the graduates (71.3%) published first-authored articles in the traditional track, while 12 (52.2%) did so in the publication track. The time to graduation was significantly shorter in the traditional track, with an average of 5.47±2.45 years, compared to 6.61±2.57 years in the publication track (z=2.26, p=.023). In the traditional track, 64 of graduates (40.0%) majored in adult health nursing, whereas in the publication track, 8 (34.8%) studied community health nursing. Conclusion: This study emphasizes the significance of the publication track for nursing doctoral dissertations in terms of research dissemination. Despite its numerous advantages, it is not yet the preferred choice for both students and faculty. Maintaining the publication track as an additional graduation option is worthwhile, as it allows students to gain research publishing experience before graduation and to effectively disseminate scientific findings in nursing.

• Journal of Intelligence and Information Systems
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• v.13 no.3
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• pp.119-140
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• 2007

Recommender systems enable a user to decide which information is interesting and valuable in our world of information overload. As the recent studies of distributed computing environment have been progressing actively, recommender systems, most of which were centralized, have changed toward a peer-to-peer approach. Collaborative Filtering (CF), one of the most successful technologies in recommender systems, presents several limitations, namely sparsity, scalability, cold start, and the shilling problem, in spite of its popularity. The move from centralized systems to distributed approaches can partially improve the issues; distrust of recommendation and abuses of personal information. However, distributed systems can be vulnerable to attackers, who may inject biased profiles to force systems to adapt their objectives. In this paper, we consider both effective CF in P2P environment in order to improve overall performance of system and efficient solution of the problems related to abuses of personal data and attacks of malicious users. To deal with these issues, we propose a multi-agent framework for a distributed CF focusing on the trust relationships between individuals, i.e. web of trust. We employ an agent-based approach to improve the efficiency of distributed computing and propagate trust information among users with effect. The experimental evaluation shows that the proposed method brings significant improvement in terms of the distributed computing of similarity model building and the robustness of system against malicious attacks. Finally, we are planning to study trust propagation mechanisms by taking trust decay problem into consideration.

• Journal of Korean Academy of Nursing
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• v.44 no.5
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• pp.495-503
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• 2014

Purpose: The purpose of this study was to identify factors affecting the social competence of school-aged children according alcohol consumption by their parents. Methods: The participants were 558 5th grade elementary school students. Data were collected using structured questionnaires from September 17 to October 2 2013, and analyzed using descriptive statistics, ${\chi}^2$-test, t-test, ANOVA, Pearson correlation coefficients, and Stepwise multiple regression analysis with the SPSS PC+ 21.0 program. Results: Participants were classified into three groups according to alcohol use; Non-use parent group (52.7%), social use parent group (31.0%), and problem use parent group (16.3%). Participants whose parents were problem users had significantly lower scores on emotional awareness and expression (F=14.45, p<.001), social support (F=5.82, p=.003), and social competence (F=16.33, p<.001) compared to students in the other two groups. In school-aged children with parents who were alcohol abusers, the variables that predicted social competence was friend support (66.0%). Conclusion: These results emphasize the importance of focusing on the crucial role of peer support in the development of social competence in school-aged children of parents who abuse alcohol. Further, for these children, interventions aimed at improving social support and children's emotional awareness and expression may be most beneficial.

• The Korean Journal of Emergency Medical Services
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• v.25 no.2
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• pp.129-143
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• 2021

Purpose: This study aimed to identify the current status of school safety education and the differences in knowledge and practice of middle school students. Methods: A structured questionnaire was distributed to 418 middle school students in J province. The questionnaires consisted of 35 questions on the status of school safety education as well as the four school safety education domains of first aid, disaster safety, traffic safety, and daily life. Data were analyzed using frequency analysis, cross-tabulation analysis, a t-test, analysis of variance, and Pearson's correlations. Results: Awareness regarding the top seven standards for school safety and interest in school safety education were both relatively low. Among all the different kinds of safety accidents, those related to school violence(33.8%) and life safety(24.9%) were experienced the most in school. A more pleasant school life and better peer relationships led to interest in school safety(p=.000)(p=.000), awareness regarding the top seven standards for school safety(p=.022)(p=.009), adoption of coping measures(p=.000)(p=.000), and practice(p=.000)(p=.000) in case of safety accidents(p=.000)(p=.000). Conclusion: To increase awareness regarding the seven standards for school safety education and raise interest in safety education, it is necessary to cultivate experts and actively utilize them and to prepare systematic and continuous school safety education programs.

• Journal of the Korea Convergence Society
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• v.12 no.7
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• pp.349-359
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• 2021

This study was aimed to investigate the factors influencing COVID-19 practice of COVID-19 knowledge, COVID-19 attitude, COVID-19 perceived risk among adolescents. A descriptive study design was used. Participants were 164 high school students in D and K city. The data were collected from October 26 to November 6 2020. Collected data were analyzed by t-test, one-way ANOVA, Pearson's correlation coefficient, multiple regression using SPSS WIN 21.0 program. Results: The influential factor for COVID-19 practice was COVID-19 attitude (β=0.28, p<.001). It was found that satisfaction with peer relationship (β=-0.05, p=.493), economic status (β=-0.08, p=.270), subjective health status (β=-0.06, p=.438), COVID-19 knowledge (β=0.04, p=.571), COVID-19 perceived risk (β=0.05, p=.126) had no significant effect on COVID-19 practice. In order to develop a program to increase the COVID-19 practice for youth, it is necessary to prepare a plan to improve the attitude of COVID-19.