• Korean Journal of School Psychology
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• v.17 no.2
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• pp.223-241
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• 2020

The purpose of this study was to explore the latent profiles of social achievement goals and to investigate the differences in peer status (perceived popularity, social preference) and aggression (overt, relational, cyber) among those profile groups. Social achievement goals and cyber aggression data was acquired through self-reporting, and perceived popularity, social preference, and overt and relational aggression were assessed through peer nomination. Applying the latent profile analysis(LPA) to 1,239 elementary school students, three distinct groups of social achievement goals were identified: a development-oriented achievement goal group, an average social goal group, and a overall-high social achievement goal group. Using logistic regression analysis, the relationships between the latent group, peer status, and aggression were examined. The result indicated that the higher the social preference, the lower the probability of belonging to the 'overall-high social achievement goal group'. And the higher the cyber aggression, the lower the probability of belonging to the 'development-oriented achievement goal group'. In addition, the higher the relational aggression of the second time, the higher the probability of belonging to the 'overall-high social achievement goal group' as compared to the 'average social goal group'.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.1
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• pp.5-25
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• 2009

In recent years the popularity of multi-hop wireless networks has been growing. Its flexible topology and abundant routing path enables many types of applications. However, the lack of a centralized controller often makes it difficult to design a reliable service in multi-hop wireless networks. While packet routing has been the center of attention for decades, recent research focuses on data discovery such as file sharing in multi-hop wireless networks. Although there are many peer-to-peer lookup (P2P-lookup) schemes for wired networks, they have inherent limitations for multi-hop wireless networks. First, a wired P2P-lookup builds a search structure on the overlay network and disregards the underlying topology. Second, the performance guarantee often relies on specific topology models such as random graphs, which do not apply to multi-hop wireless networks. Past studies on wireless P2P-lookup either combined existing solutions with known routing algorithms or proposed tree-based routing, which is prone to traffic congestion. In this paper, we present two wireless P2P-lookup schemes that strictly build a topology-dependent structure. We first propose the Ring Interval Graph Search (RIGS) that constructs a DHT only through direct connections between the nodes. We then propose the ValleyWalk, a loosely-structured scheme that requires simple local hints for query routing. Packet-level simulations showed that RIGS can find the target with near-shortest search length and ValleyWalk can find the target with near-shortest search length when there is at least 5% object replication. We also provide an analytic bound on the search length of ValleyWalk.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.586-588
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• 2005

P2P (Peer-to-peer) 파일 공유 시스템에서 컨텐츠의 복제는 Hot Spot의 방지와 가용성의 보장, 검색 속도의 향상을 위해 사용되고 있다. 컨텐츠의 복제본의 수(공간 효율성)와 검색 성능은 일종의 trade-off로써 이 논문에서는 가능한 검색 성능을 향상시키면서 적절한 양의 복제본의 수를 유지하는 방법인 SRoD 알고리즘을 제안한다. SRoD는 DHT 기반 파일공유시스템에서 전반적으로 간단하게 접목하여 사용할 수 있다는 장점을 가지고 있다. 이러한 특징은 P2P가 추구하는 자율성과 평등성을 보장하기 위한 것이다. 본 논문에서는 SRoD 알고리즘을 설명하고 이것의 장점과 보완해야 할 점에 대해 논하게 될 것이다.

• Journal of Korea Multimedia Society
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• v.17 no.4
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• pp.405-412
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• 2014

Due to the popularity of mobile phones, Peer-to-Peer (P2P) content sharing in mobile phones is highly desirable, especially in a mobile data connection. In addition, there has been an increasing demand for content sharing applications for P2P communication in Android-based smartphones as ubiquitous mobile devices. However, due to wireless network limits, unstable characteristic and restricted storage space, mobile users confront challenges in establishing connections and sharing video frames with other users. To solve this issue, we propose an architectural design and implementation of key frame sharing application that uses Chord, a distributed lookup protocol to establish a content sharing platform for mobile devices, combined with the Chord SDK based on Android. Our proposed system enables users easily to share key information on video data in real-time over a wireless network without manual processing of devices which join or leave the group and cost associated with the 3G/4G network.

• Journal of Digital Contents Society
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• v.8 no.3
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• pp.393-401
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• 2007

P2P systems have gained a lot of research interests and popularity over the years and have the capability to unleash and distribute awesome amounts of computing power, storage and bandwidths currently languishing - often underutilized - within corporate enterprises and every Internet connected home in the world. Since there is no central control over resources or devices and no before hand information about the resources or devices, device discovery remains a substantial problem in P2P environment. In this paper, we cover some of the current solutions to this problem and then propose our feed forward neural network (FFNN) based solution for device discovery in mobile P2P environment. We implements feed forward neural network (FFNN) trained with back propagation (BP) algorithm for device discovery and show, how large computation task can be distributed among such devices using agent technology. It also shows the possibility to use our architecture in home networking where devices have less storage capacity.

• Journal of the Korean Home Economics Association
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• v.36 no.6
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• pp.27-40
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• 1998

The purpose of this study was to examine the role of children's characteristics, family environment and child care quality in socio-emotional development of children among dual-worker families. The sample consisted of 138 children aged 5-7 and their parents. Descriptive statistics, t-tests, correlation analysis, one-way ANOVAs, and stepwise regression were used to analyze data. Results showed that there were significant sex differences in children's temperament and popularity. Mother's marital satisfaction had a negative correlation with peer rejection. Low maternal role conflict and child's age had effects on children's self-perception. Moreover, sex and age of the child, mothers' responsive parenting, number of teachers in the classroom were significant predictors for children's peer rejection.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.639-640
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• 2011

P2P VoD 스트리밍에서 비디오를 순차적으로 시청하는 패턴과 더불어 비디오 재생지점의 임의 변경을 허용하는 VCR 기능과 같은 사용자 interactivity 지원 및 재생지점 변경 시 스트리밍 지연을 최소화 하기 위한 연구가 활발하게 진행되어 왔다. 본 논문에서는 VCR 기능 지원을 위해 비디오 전 구간에 대해 피어들이 소유한 오프셋을 오버레이에 확률적으로 등록과 상승을 수행함에 따라 인기도가 누적되며 이를 통해 오프셋을 기반으로 하여 피어들이 논리적으로 오버레이상에 형성 및 유지되게 된다. 이에 따라, 인기지점의 오프셋들은 높은 계층에 유지되므로 피어들은 재생확률이 높은 인기 오프셋을 우선적으로 선반입하여 VCR 동작 요청 시 스트리밍 성능을 향상시키는 계층 상승기법 기반의 오버레이를 제안한다.

• The Journal of Korean Association of Computer Education
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• v.15 no.2
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• pp.19-28
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• 2012

Recent popularity of smart devices and social media seem to increase much interests on social learning, Despite of positive expectation on technology-based social learning, there are not many successful cases and practices of how to apply hands-on technologies and measure educational results. In this study, we tried to promote idea-sharing among learners in a classroom using web-based peer-review of assignments on a specific topic. Then we investigated effects of idea-sharing among learners in terms of individual knowledge construction. Experimental results show that idea-sharing promotes knowledge convergence and divergence, and then knowledge construction at learner's own.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.253-261
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• 2006

In spite of the popularity of P2P technology, a multimedia streaming using the P2P technology has been neglected. The reason for this is that the P2P multimedia streaming has suffered from several inherent problems especially poor bandwidth and unreliable connection among peers. We suggest a Multi-Peer Binding Protocol (MPBP) in this paper that provides a virtual single channel composed of multiple connections to several peers to ease these problems. The protocol enables applications to download data from multiple peers simultaneously, so they can achieve throughput improvement and reliable streaming. For this, the MPBP splits media files into small chunks and provides a mechanism for identifying and transmitting each chunk. Implemented MPBP engine focuses on handling an abrupt disconnection from data sending peers and the evaluation result shows the MPBP is able to handle it gracefully. The MPBP is also desisted to support various media types. To verify this, video and audio applications are implemented using the MPBP engine in this paper.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.6 no.1
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• pp.90-99
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• 1995

This study was intended to investigate the effects of shyness, which is regarded as one of the former and comprehensive factors of social anxiety disorder, on interpersonal relationship. Particularly, the relations among Social Skill Factor, Motivation Factor, and Shyness were examined in order to verify a conventional belief('the most shy people have both low social skill and high motivation.') 497 middle school students(231 males and 266 females) in seoul were administrated with Snyder's Self-Monitoring Scale and Shyness Scale, and Peer-Group Popularity was measure. The results are : 1) the lower social skill is and hight Motivations is the more he or she is shy. 2) influence of Social Skill Factor is greater than that of Motivation Factor. 3) interaction effect among sex, shyness, and peer-group popularity was found.