• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.13-15
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• 2005

P2P(Peer-to-Peer) 시스템은 대용량의 데이타를 공유하는데 유용하며, 네트워크 구조에 따라 중앙 집중형, 구조적 분산형, 그리고 비구조적 분산형으로 분류된다. 이 중 Gnutella와 같은 비구조적 분산형 P2P 시스템은 확장성과 신뢰성 측면에서 장점을 갖지만, 참여하는 노드의 수가 증가함에 따라 원하는 자원을 액세스하는 비용도 증가하는 문제를 가진다. 데이터 중복을 이용해 이러한 문제를 해결할 경우 중복된 데이타들의 일관성 유지를 위한 기법이 필요하다. 본 논문에서는 특정 노드가 갱신한 데이타를 중복된 사본을 저장하고 있는 다른 노드에 전파하기 위한 하이브리드 push/pull 기반의 갱신 전파 기법을 제안한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.437-440
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• 2003

본 논문은 P2P 네트워크에서 어플리케이션 레벨의 영속성있는 저장 시스템에 대해서 살펴본다. 인터넷 클라이언트의 성능 향상과 인터넷 접속 기술의 발달로 Peer-to-Peer (P2P)라는 키워드로 대표되는 다양한 파일 저장, 검색, 공유 어플리케이션이 소개되었다. 그러나, 기존의 서버 기반의 분산 저장 방식은 xDSL 기반의 가변 IP 기반의 현재 인터넷 환경에서 불안정한 성능을 보이고, 파일을 저장하고 나서 검색 발견의 확률이 떨어지는 문제점을 가진다. 본 논문에서는 시스템의 가용성(Availability)을 높이기 위한 파일의 분할 저장, 중복 저장 방법을 소개하고 이의 효과를 분석해 보인다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1216-1223
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• 2014

Internet traffic is rapidly increasing due to the spread of personal smart devices and the demand for multimedia contents. When designing a large ship such as cruise, network architecture is also considered which supports various IT services in a maritime environment similar to the ground environment. In this paper, we consider wireless P2P (peer-to-peer) communication for efficient multimedia content sharing and propose novel handover scheme for efficient download service. The proposed handover method shows that it can improve the download symbol rates for handover in a wireless P2P system considering the signal strength and quality of peers as well. The proposed system is expected to provide efficient contents distribution and reliable communication in the ship-area-network (SAN).

• 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.

• 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.

• Human Ecology Research
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• v.54 no.3
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• pp.293-305
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• 2016

This study examines the mediation effect of teacher-child interactions in the process of the impact of teacher's teaching-efficacy on childhood education institutions and classroom environment on peer-play interactions. We used data from 970 children aged between 49 and 55 months and 970 homeroom teachers from the fifth Korean Child Panel (2012) of the Korea Institute of Child Care and Education. The model fitness was excellent after data were statistically analyzed with model of structure to testify the relationship and effect among teaching efficacy, classroom environment, teacher-child interactions, and peer-play interactions. First, the analysis also showed that the teacher's teaching efficacy did not influence peer-play interactions directly, but gave an indirect effect on the peer-play interactions with the mediation of the teacher-child interactions. Second, the classroom environment directly and indirectly influenced the peer-play interactions with the mediation of the teacher-child interactions. Third, the variable of teacher-child interactions was fully effective as a mediating variable in the process of the teaching efficacy and classroom environment influence on teacher-child interactions. Teaching efficacy and classroom environment influenced the peer-play interactions through the mediation of the teacher-child interactions. The significance of mediation effect of the teacher-child interactions was verified through a bootstrapping method.

• Korean Journal of Childcare and Education
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• v.11 no.6
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• pp.1-18
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• 2015

The purpose of this study was to investigate the effects of the home environment of young children on their language and the quality of peer competence. The current study hypothesized that when the home environment of young children is desirable, the young children would be more likely to develop better language skills, which in turn, predict greater peer competence and lower levels of aggression and withdrawal in the interaction with peers at child care settings. The study used data of 1,802 families who have been participating in the Korean Child Panel Study since 2008. The results revealed that there was a significant relation from both positive home environment and better language skills to more positive play interaction and reduced play disruption and play disconnection. Home environment significantly predicted better expressive language development of young children and, in turn, higher scores on expressive vocabulary tests predicted greater peer competence and less negative play behaviors rated by child care providers. Statistical tests proved that the mediational effects of language skills between home environment and toddler's peer relationships were statistically significant. The study results emphasized the importance of language development in children's expanding social settings and the supporting role of rich and stimulus home environments in children's development.

• Korean Journal of Childcare and Education
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• v.9 no.2
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• pp.311-330
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• 2013

This study investigated the relationships of preschool children's interactive peer play, stimulated home environment, and mother-child interaction. A total of 255 children were selected in this study. Data were analyzed with Pearson correlations and covariance structural analysis by using SPSS and AMOS, a statistical program for structural equation modeling. The major findings of this study were as follows: First, interactive peer play was associated with stimulated home environment and mother-child interaction. Second, the results confirmed the pathway from stimulated home environment via mother-child interaction to interactive peer play showing a significantly good model fit. The paths from stimulated home environment to children's interactive peer play were mediated by mother-child interaction.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.553-555
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• 2001

본 논문에서는 분산 가상 환경을 기반으로 한 원격교육시스템을 제안한다. 기존에 제안되었던 대부분의 원격교육시스템 들은 클라이언트/서버 구조를 택함으로써 시스템의 확장성과 속도에 많은 단점을 가지고 있었다. 이러한 단점을 보완하고자 본 논문에서는 분산 객체 모델을 기반으로 peer-to-peer 구조를 가지는 새로운 원격교육시스템을 소개한다. DOVE(Distributed Object-oriented virtual computing environment)라는 분산 가상 환경 상에서 설계된 본 시스템은 peer-to-peer 구조를 가짐으로써 기존 시스템들의 확장성 문제를 해결했을 뿐만 아니라 DOVE의 가장 큰 장점 중에 하나인 객체 그룹(Object Group)의 개념을 도입하여 객체간에 멀티캐스트를 기반으로 한 상호작용을 가능케 함으로써 속도와 부하 문제도 해결하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.448-459
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• 2019

The purpose of this study is to investigate the differences between children's internal variables (gender, temperament, development) and environmental variables (teaching efficacy, teaching - child interaction, classroom environment) The data collected for this study were analyzed using descriptive statistics, reliability analysis, correlation analysis, cluster analysis, and t-test using the SPSS 22.0 program. The results are as follows. First, the peer interaction of the infant showed a difference in sex between the types. Second, children's peer interaction showed differences in interstitial temperament, language development, and cognitive development. Third, the peer interaction of young children was different between the types of environment variables such as teaching efficacy, teacher - infant interaction, and classroom environment. As a result, it is suggested that the children's social temperament will lead to healthy peer interaction, and that language development and cognitive development will lead to a positive developmental process. In this study, the meaning and meaning of children's intergenerational behaviors in children's gender and temperament, language and cognitive development, and environmental variables such as teaching efficacy, teacher - infant interaction, I checked. In addition, it is meaningful that the positive and negative peer interactions are segmented and analyzed in detail to examine the peer interaction of infants. However, the limitation of this study is that it is not possible to investigate all the fields belonging to the infant's personal variables and environmental variables.