• Journal of Korea Society of Industrial Information Systems
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• v.11 no.1
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• pp.21-28
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• 2006

This paper describes the design and implementation of video conference system using hybrid type P2P(Peer to Peer). The proposed video conference system has hybrid type P2P architecture based on a client-server and P2P(Peer to Peer), where client-server is used for exchange of account management, client list and status information and P2P is used for the real time video conference. The proposed video conference system decreases the traffic of server, and cuts down the load of a network. Because the multimedia data is decentralized to client by P2P. Also, this system is tested by the multi-party video conference system using communication protocol and application software through high speed networks.

• Korean Journal of Childcare and Education
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• v.18 no.6
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• pp.127-144
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• 2022

Objective: The purpose of this study was to examine the relative influences of senior elementary school children's communication level with their fathers and peer competence on their happiness. Methods: The subjects of this study were 310 fifth and sixth grade students attending elementary school in Jeollanam-do. They responded to the level of communication with their fathers, peer competence, and happiness. For the data, t-test, Pearson's correlation analysis, and hierarchical regression analysis were performed. Results: First, there were some statistically significant differences according to gender differences in self-esteem and a sub-factor of happiness and the differences according to grades in open-type communication and problem-type communication. Second, it was found that children's happiness was highly correlated with communication with their fathers and peer competence. Third, the factors having the greatest relative influence on overall happiness were in the order of peer competence, open-type communication, problem-type communication, and gender. The variables influencing and the order of relative influence differed according to sub-factors of happiness. Conclusion/Implications: The present study revealed that peer competence has a significant impact on children's happiness. The results of this study suggest that research and development of convergent programs that can improve communication with fathers, peer competence, and children's happiness are necessary.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4B
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• pp.311-322
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• 2006

Peer-to-peer (P2P) systems have become a popular medium through which to share huge amounts of data. On the basis of network topology, P2P systems are divided into three types: centralized, structured distribution, unstructured distribution. Unstructured P2P systems such as Gnutella are novel in the sense that they are extensible and reliable. However, as the number of nodes increases, unstructured P2P systems would suffer from the high complexity of search operations that have to scan the network to find the required data items. Efficient replication of data items can reduce the complexity, but it introduces another problem of maintaining consistency among replicated data items when each data item could be updated. In this paper, we propose a new update propagation algorithm that propagates an updated data item to all of its replica. The proposed algorithm can reduce the message transfer overhead by adopting the notion of timestamp and hybrid push/pull messaging.

• Korean Journal of Human Ecology
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• v.7 no.2
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• pp.97-113
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• 2004

This study was to investigate the relationship between parent attachment, peer support and behavior problems of middle school students. The subjects were 591 male and female students in the first and third grade of the middle school and their mothers in Busan. The instruments used for this study were Inventory of Parent Attachment Scale, Peer Support Scale and Behavior Checklist for Adolescents. The results were as follows: 1. The first grade students had stronger attachment on father and mother than third grade. The third grade students had perceived peer support more than first grade. Female students had stronger attachment on mother and perceived peer support more than male students. And there was no significant sex difference in attachment on father. In the case of female students, internalizing and externalizing behavior problems increased grade. But, in the case of male students, there was no grade difference in internalizing and externalizing behavior problems. In the case of first grade students, there was no sex difference in internalizing behavior problems. In the case of first grade students, males had more externalizing behavior problems than females. But in the case of third grade students, females had more externalizing behavior problems than males. 2. As parent's education level was higher, students had stronger attachment on parents and perceived more peer support. As family income was higher, students had stronger attachment on father and perceived more peer support. 3. In case of female students, parent attachment and peer support were correlated negatively with internalizing and externalizing behavior problems. In case of male students, attachment on fathers and peer.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.4
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• pp.389-400
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• 2008

As the wireless network technologies and the capability of the mobile terminals are evolving, advanced peer to peer applications for mobile users are attracting interests. In this paper, we propose the mobile P2P communication platform(MPCP) which provides transparency to the wireless network technologies and solutions to the limited resources of the mobile terminals. MPCP classifies the connection into two levels: a virtual channel and a session. A virtual channel is the network layer connection between the terminals whereas a session is the application layer connection. MPCP classifies the sessions into four types and applies different scheduling priority and data processing policies such as segmentation and reassembly. It selects proper wireless network technologies depending on the distance between the communication endpoints. To acquire dynamically changed access address, we harness the Session Initiation Protocol. We implemented MPCP on embedded Linux simulator and utilized the implementation in mobile P2P service development. For the quantitative analysis, we compared the performance of MPCP with that of ftp. Regardless of the number of simultaneous sessions, MPCP maintains the relative performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.728-733
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• 2009

An ubiquitous environment has features like peer-to-peer and nomadic environments. Such features can be represented by peer-to-peer systems and mobile ad-hoc networks. P2P systems and MANETs share similar features, appealing for implementing P2P systems in MANET environment. However, if a P2P system designed for wired networks was applied to mobile ad-hoc environment, its performance was not good enough. Subsequently, this paper proposes a P2P system to improve performance using cross-layer design and the goodness of a node as a peer by using routing metric and P2P metric to choose favorable peers to connect. It also utilizes proactive approach for distributing peer information. The simulation results showed that the proposed system produced better performance in query success rate, query response time and energy consumption by reducing the routing path length.

• International journal of advanced smart convergence
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• v.4 no.2
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• pp.38-45
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• 2015

Peer-to-Peer(P2P) systems are generally classified into two categories; hybrid and pure P2P. Hybrid systems have a single central index server keeping the details of shared information, so that undesirable effects such as heavy load on that server and lack of fault-tolerance can be caused. Pure P2P causes the other problems such as message flooding and scalability although it shows high degree of fault-tolerance. Recently, mobile agent-based distributed computing has been receiving wide attention for its potential to support disconnected operations, high asynchrony, and thus saving network bandwidth. In this paper, a new scheme of peer coordination is proposed for a decentralized P2P network with self-organizing structure. We deployed mobile agents for incorporating the advantages of usage of mobile agents into our P2P network. Proposed P2P network has both advantages of hybrid and pure P2P. The problems of heavy load on the server and lack of fault-tolerance are improved by using multiple special peers called super-peers. And the problems of pure P2P can be reduced by using mobile agents.

• Korean Medical Education Review
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• v.23 no.1
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• pp.3-10
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• 2021

Learning by teaching (LbT) has long been recognized as an important learning behavior that constructs meaning based on interactions between learners. This study aimed to explore the meaning of LbT as an important learning activity for future implementation in education. LbT is based on the cultural historical activity theory and sociocultural learning theory, as developed by scholars including Vygotsky. These frameworks value the construction of meaning based on language, and LbT is reported to be effective in constructing meaning. In addition, within the zone of proximal development posited by Vygotsky, learning through interaction between learners improves academic achievement, higher-order thinking, deep learning, and reflective learning. LbT also promotes students' learning presence, and strengthens various competencies such as collaboration and communication skills. Interactive behavior between learners in the form of LbT has been explored as an approach to teaching and learning, with methods including peer learning, peer tutoring, peer teaching, peer mentoring, Lernen durch Lehren, and peer-assisted learning. LbT has also been applied as a learning method. In the future, LbT has boundless potential to improve learning through activities such as flipped learning or online learning based on interactions between learners.

• Korean Journal of Childcare and Education
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• v.8 no.3
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• pp.91-111
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• 2012

The purpose of this study was to investigate the effects of mothers' parental intelligence on children's peer play interaction and peer acceptance. The participants were 197 fiveyear- old children and their mothers of six kindergartens and child care centers in Seoul and Gyeonggi province. The Penn Interactive Peer Play Scale(Choi & Shin, 2008), the Peer Rating Scale(Asher et al., 1979), and the Parental Intelligence Scale(Hyon, 2004) were used as measurements. The results of this study were as follows. Firstly, the higher scores in mothers' parental intelligence of encouragement, enhancement, rational authoritativeness, acceptance, control, and avoiding rejection roles, the more the children's positive behaviors were exhibited during the peer play. Secondly, children whose mothers provided higher levels in parental intelligence of empathy, encouragement, rational authoritativeness and enhancement roles were rated as displaying higher levels of children's peer acceptance. On the other hand, children whose mothers expressed higher parental intelligence level of the rejection role tended to have lower levels of peer acceptance.

• Journal of Digital Contents Society
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• v.12 no.1
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• pp.133-139
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• 2011

Structured P2P (peer-to-peer) networks have received much attention in research communities and the industry. The data stored in structured P2P networks can be located in a log-scale time without using central severs. The link-structure of structured P2P networks should be maintained for keeping log-scale search performance of it. When nodes join or leave structured P2P networks frequently, some links become unavailable and search performance is degraded by these links. To sustain search performance of structured P2P networks, periodic link recovery scheme is generally used. However, when the link recovery period is short or long compared with node join and leave rates, it is possible that sufficient number of links are not restored or excessive messages are used after the link-structure is restored. We propose the adaptive link recovery determination algorithm to maintain the link-structure of structured P2P networks when the rates of node joining and leaving are changed dynamically. The simulation results show that the proposed algorithm can maintain similar QoS under various node leaving rates.