• ETRI Journal
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• v.43 no.5
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• pp.932-940
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• 2021

Currently, research on network functions virtualization focuses on using microservices in cloud environments. Previous studies primarily focused on communication between nodes in physical infrastructure. Until now, there is no sufficient research on group key management in virtual environments. The service is composed of microservices that change dynamically according to the virtual service. There are dependencies for microservices on changing the group membership of the service. There is also a high possibility that various security threats, such as data leakage, communication surveillance, and privacy exposure, may occur in interactive communication with microservices. In this study, we propose an ID-based group key exchange (idGKE) mechanism between microservices as one group. idGKE defines the microservices' schemes: group key gen, join group, leave group, and multiple group join. We experiment in a real environment to evaluate the performance of the proposed mechanism. The proposed mechanism ensures an essential requirement for group key management such as secrecy, sustainability, and performance, improving virtual environment security.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.7
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• pp.51-57
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• 2012

This paper proposes a group key design based on ECDH(Elliptic Curve Diffie Hellman) which guarantees secure V2V and V2I communication. The group key based on ECDH generates the VGK(Vehicular Group key) which is a group key between vehicles, the GGK(Global Group Key) which is a group key between vehicle groups, and the VRGK(Vehicular and RSU Group key) which is a group key between vehicle and RSUs with ECDH algorithm without an AAA server being used. As the VRGK encrypted with RGK(RSU Group Key) is transferred from the current RSU to the next RSU through a secure channel, a perfect forward secret security is provided. In addition, a Sybil attack is detected by checking whether the vehicular that transferred a message is a member of the group with a group key. And the transmission time of messages and the overhead of a server can be reduced because an unnecessary network traffic doesn't happen by means of the secure communication between groups.

• Journal of Korean Academy of Nursing
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• v.39 no.4
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• pp.528-538
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• 2009

Purpose: This study was done to develop and test a palliative care program based on home care nursing. Methods: A quasi-experimental design was employed. Changes in the variables were evaluated to test effects of the developed program. Participants were patients with terminal cancer and their families receiving home care nursing from six hospitals (experimental group: 24 and control group: 22). Data collection was conducted from February to October, 2006. Chi-square test, Fisher's exact test, t-test, Mann-Whitney U test and repeated measures ANOVA were used to analyse the data. Results: Hypothesis 1, the experimental group receiving this program will experience less pain (severe, average, weak pain) than the control group, was supported. Hypothesis 2, the experimental group will have less symptom experience than the control group, was supported. Hypothesis 3, the experimental group will have higher QOL than the control group, was supported and the last hypothesis 4, family burden in the experimental group will be less than the control group, was supported. Conclusion: The home care nursing based palliative program developed in this study was found to be an effective program to reduce patient pain and symptom experience, to improve patient QOL and to decrease family burden.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2005.11a
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• pp.183-192
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• 2005

Recently, community computing has been proposed for group formation and group decision-making. However, legacy community computing systems do not support group need identification for ad hoc group formation, which would be one of key features of ubiquitous decision support systems and services. Hence, this paper aims to provide a multi-agent based methodology to enable nomadic community computing which supports ad hoc need identification and group formation. Focusing on supporting group decision-making of relatively small sized multiple individual in a community, the methodology copes with the following three characteristics: (1) ad hoc group formation, (2) context-aware group need identification, and (3) using mobile devices working in- and out-doors. NAMA-US, an RFID-based prototype system, has been developed to show the feasibility of the idea proposed in this paper.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.185-193
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• 2019

In this paper, we propose the effects of programming-based TPACK educational program on the pre-service teacher's self-efficacy beliefs for technology integration. For this study, pre-service teachers who received programming education and TPACK education based on ICT were set as control group and pre-service teachers who received programming-based TPACK education as experimental group. In order to observe the change, the pre-service teachers conducted the test tool to measure the self-efficacy beliefs for technology integration before and after applying the educational program. As a result of the study, only the pre-service teachers who received the programming-based TPACK education showed significant improvement in the self-efficacy beliefs for technology integration. Furthermore, in the post-test, the experimental group showed a significantly higher difference than the control group. Through this study, it was concluded that programming-based TPACK educational program is effective in enhancing pre-service teacher's self-efficacy beliefs for technology integration.

• International Journal of Control, Automation, and Systems
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• v.6 no.5
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• pp.722-730
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• 2008

This paper proposes two novel algorithms enabling mobile robots to cooperate with each other in a reliability-based system and a time-critical system. In the reliability-based cooperative system, the concepts of a mobile ad hoc network (MANET) and an object entropy are adopted in order to coordinate a specific task. A logical robot group is created based on the exchange of request and reply messages in a robot communication group whose organization depends on transmission range. In the time-critical cooperative system, relational entropy is used to define the relationship between mobile robots. A group leader is selected based on optimizing power consumption. The proposed algorithm has been verified based on the computer-based simulation and soccer robot experiment. The performance metrics are defined. The metrics include the number of messages needed to make a logical robot group and to obtain the relationship of robots and the power consumption to select a group leader. They are verified by simulation and experiment.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.24 no.1
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• pp.39-50
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• 2017

Purpose: The purpose of this study was to identify the effects simulation-based education combined team-based learning (SBE combined TBL) compared to simulation-based education (SBE) on undergraduate nursing students. Methods: A non-equivalent control group design with pre-and posttest measures was used. The participants in the study were 181 students. The SBE combined TBL group consisted of 84 senior students in 2013, and the SBE group consisted of 97 seniors in 2014. Collected data were analyzed using chi-square, independent t-test and ANCOVA with the statistical package SPSS 22.0 for Windows. Results: There was a significant improvement in communication skills, nursing performance confidence, team efficacy, and team performance scores in the SBE combined TBL group compared to the SBE group (t=2.45, p=.015; F=4.30, p=.040; t=3.06, p=.003; t=8.77, p<.001). However, there was no statistically significant difference in self-directed learning between the groups. Conclusion: SBE combined TBL compared to SBE is an effective teaching and learning method to enhance various positive educational outcomes for nursing students. Therefore, we suggest that future studies investigate the development of an integrated course in which team-based learning is applied to theoretical sessions and simulation-based training.

• Korean Journal of Childcare and Education
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• v.20 no.3
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• pp.125-147
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• 2024

Objective: This study aims to implement an ecological transition education program for young children, based on a project approach, to investigate its effectiveness in enhancing sustainable development awareness, ecological literacy, and problem-solving skills. Methods: In this study, 56 five-year-old children from a preschool in S City were assigned to either a quasi-experimental group or a control group, with 28 children in each group. The project-based ecological transition education program for young children was conducted from July 14 to September 15, 2023. The experimental group explored the themes of 'marine life' and 'pets and animal welfare,' while the control group focused on different topics. The research employed independent sample t-tests and analysis of covariance (ANCOVA) for data analysis. Results: The project-based ecological transition education program effectively enhanced young children's awareness of sustainable development, ecological literacy, and problem-solving skills. Conclusion/Implications: This study is significant in developing an integrated, project-based ecological transition education program within a play-centered curriculum. It demonstrates how sustainable values can be effectively incorporated into play. Furthermore, the findings can serve as foundational data for implementing educational and childcare programs that nurture young children to become ecological citizens, leading sustainable futures.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.4
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• pp.143-152
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• 2019

PURPOSE: This examined the effects of a sling exercise based on music on the cognition, physical performance of patients with dementia. METHODS: Thirty subjects with dementia volunteered to participate in this study. All subjects were allocated randomly to either the experimental group or control group, with 15 subjects in each group. All subjects underwent the exercise program for an average of 60 minutes per day for 16 weeks. The experimental group performed sling exercise based on music, and the control group performed the general exercise program. Assessments were made using the Korean version of mini-mental state examination (MMSE-K), 10 m walk test (10MWT), Tinetti mobility test (TMT), and Katz's Index of Independence in activity daily living (KIIADL) to detect changes in the cognitive level and physical performance before and after the 16-week training period. A paired t-test was conducted to compare the within-group change before and after the intervention. An independent t-test was performed to compare the between-group difference. The statistical significance level was set to α=.05 for all variables. RESULTS: The experimental group showed significant within-group changes in the MMSE-K, 10MWT, TMT, and KIIADL (p<.05). The control group showed a significant change in only the KIIADL (p<.05). A significant difference was observed between the experimental group and the control group regarding the change in MMSE-K and KIIADL after the interventions (p<.05). CONCLUSION: A music-based sling exercise program effectively improves cognition, physical performance, and ADL in patients with dementia. Further studies with a wider range of subjects and scientific equipment will be needed to strengthen the results of this study.

• Tribology and Lubricants
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• v.31 no.5
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• pp.195-204
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• 2015

Several researches are focused on improving the value of fine chemicals based on biomass resources due to environmental and other concerns associated with the use of petroleum-based products. Therefore, the synthesis and application of estolides derived from plant-based waste oil materials and their application as lubricants and as processing oil for butyl rubber products have been studied. Four kinds of estolide were prepared with conversions of 71~92% over 24h using various vegetable oils, as determined by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) spectroscopy. FT-IR spectroscopy determines the esterification of estolides using 2-ethylhexyl alcohol. The estolides have iodine values of 35~90, α-ester/α-acid ratios of 0.45~0.55, and total acid number of 114~134 mg KOH g^–1. Four ball wear tests show that the wear scar diameters (WSDs) of estolides as base oil significantly decreased to 0.328~0.494 mm, compared to WSDs of 0.735 and 0.810 mm of WSD for 150N and Yubase 6, respectively, as general base oil. Thus, the estolides have better wear resistance and satisfying design objectives for the engineering of a variety of lubricant base oils.