• The Journal of Korean Academic Society of Nursing Education
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• v.25 no.2
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• pp.186-196
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• 2019

Purpose: This study was conducted to identify types of peer feedback in nursing skills performance training and to investigate emotional response, perceived quality of feedback and self-efficacy for learning from peer feedback. Methods: A total of 110 second-year nursing students attending fundamentals of nursing classes at a university participated in 2017. Participants received peer feedback from one selected colleague who observed their skills performance, and completed a questionnaire. Contents of peer feedback video recordings were transcribed and classified into seven types of feedback. Data were analyzed using an independent t-test, ANOVA and Pearson correlation. Results: Participants mostly received feedback of 'correcting' and 'providing information.' Positive emotional responses from peer feedback were above medium, and negative emotional responses were low. The perceived quality of peer feedback was moderate and self-efficacy for learning was high. Quality of feedback correlated with negative emotional response (r=-.24, p=.014), and self-efficacy for learning (r=.35, p<.001). Self-efficacy for learning correlated with intimacy with peers (r=.24, p=.011) and positive emotional response (r=.21, p=.028). Conclusion: The results suggest that peer feedback in skill training could be used in terms of emotional response and self-efficacy for learning.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.7
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• pp.1638-1656
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• 2013

The demand for multimedia streaming services is increasing rapidly. To meet this demand, there has been much research and many practical developments for providing multimedia services. A push-to-talk (PTT) service is one of the multimedia streaming services that have been deployed not only over IP multimedia subsystem (IMS) but also in peer-to-peer (P2P) overlay networks. The benefit of PTT has been demonstrated in the literature. However, the need for using PTT service in communication can be arbitrary among users, regardless what kind of PTT services they use. This demand does not support current PTT systems, so an expansion of PTT services still be limited. Moreover, the combination of PTT services in IMS and P2P networks will help operators to provide more scalable PTT services. Therefore, in this paper, we proposed a model to support PTT service interworking between IMS and P2P overlay networks. We also introduced our system design and some interworking service scenarios. We confirmed our architecture through implementation and testing.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.1035-1056
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• 2015

The efficiency of live Peer-to-Peer (P2P) streaming protocols depends on the appropriateness and the management abilities of their underlying overlay multicast. While a tree overlay structure confines transmission delays efficiently by maintaining deterministic delivery paths, an overlay mesh structure provides adequate resiliency to peers dynamics and easy maintenance. On the other hand, content freshness, playback fluidity and streaming continuity are still challenging issues that require viable solutions. In this paper, we propose a Hybrid Live P2P Streaming Protocol (HLPSP) based on a hybrid overlay multicast that integrates the efficiency of both the tree and mesh structures. Extensive simulations using OMNET++ are conducted to investigate the efficiency of HLPSP in terms of relevant performance metrics, and position HLPSP with respect to DenaCast the enhanced version of the well-known CoolStreaming protocol. Simulation results show that HLPSP outperforms DenaCast in terms of startup delay, end-to-end delay, play-back delay and data loss.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.139-143
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• 2005

The P2P is a network environment supporting data exchange which is directly connected peers without limit of existing server-client and intervening central server for resource or offered service with each peer. JXTA is a representative of P2P system. JXTA is a typical distributed computing model that proposed by Sun Microsystems. JXTA that doesn't require centralized services or resources is adaptable in extreme changes of network organization. MANET(Mobile Ad Hoc Network) is a representative wireless network that is composed of mobile nodes without infrastructure. So MANET establishes the path for the communication of each peers and maintains the newest routing information by exchanging routing information. In this paper, we propose a technique of JXTAMAUET which implements JXTA which is the P2P network system from the wireless network which is becoming the foundation of ubiquitous computing. For the performance evaluation of the JXTAMANET, we use simulation.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.9
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• pp.209-216
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• 2019

Publish-subscribe communication model is popular for various type of distributed applications because of its loosely coupled style connections. Among the various architecture style for publish-subscribe system, peer-to-peer architecture has been used for the mission critical application domain since it provides high scalability and real-timeness. On the other hand, to utilize the bandwidth of given networks, message filtering is frequently used to reduce the number of messages on the system. Even if P2P provides superior scalability, it is hard to apply filtering to the its messaging system because the filtering process should be done on the peer-side in P2P architecture that are usually done on the broker server in conventional pub/sub architecture. In this paper, we propose a hierarchical subscription management structure as well as message forwarding scheme for efficient data dissemination. Our proposed scheme reduces the number of received messages by filter-out un-wanted messages and offloading the message dissemination work to other subscribers to enhance the messaging throughput.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.295-300
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• 2010

Recent researches of network structure are moving to high-level networks because there are already many research results of low-level network. Especially, current network services has been changed to the multimedia service using multicast routing such as IPTV(Internet Protocol Television) service. And then previous multicast services were provider oriented. So previous multicast structures were organized server/client model. But future multicast services will make user oriented services. Therefore there will be many service providers in the future. At this point, we study P2P network for supporting multi provider. So we research load balancing and contents lookup protocols in P2P network. In this paper, we propose network protocol and system based on super peer P2P for load balancing and efficiently service search. And we considered mobile environment for mobile IPTV.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.171-179
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• 2014

Among the P2P based multimedia streaming architecture, multiple chain architecture has advantage in adapting to dynamically changing network topology simply and rapidly, so this architecture is used for UCC broadcasting system. In UCC broadcasting system, general peer involved in DSLAM becomes UCC server rather than broadcasting system that transfers data from ISP servers. Therefore UCC data generated from UCC server peers is transmitted to peers through DSLAM, and this transmission uses uplink bandwidth of DSLAM. In this paper, I propose an efficient management method of DSLAM uplink bandwidths through negotiating tracker and UCC server peer or head peers of DSLAM. I propose the method that tracker restricts a bitrate of uplink stream of UCC servers when used uplink bandwidth of DSLAM exceeds a certain point of maximum uplink bandwidths. I will show the improved performance of proposed scheme rather than general method with respect to the uplink bandwidth of DSLAM by numerical analysis and simulation.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.33-42
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• 2013

In the early stage of P2P, the technology was limited to narrow usage of file sharing, but currently, P2P technology has become essential to maximize the efficiency between associated technologies without additional deployment of high costly infrastructure and also the burden of the server. Especially, P2P media streaming service is a highly attractive service to mobile users. which requires a higher quality in the mobile environment in accordance with the development of technology of wired network as well as better mobile terminals. However, P2P technology should consider the trade-off between 'peer selfishness' and QoE for providing fairness. The P2P system also try to maximize the resource utilization through an incentive mechanism for service differentiation and encourage peers to contribute continuously for improving the overall system performance. In this paper, we propose an point-based incentive mechanism based on peer's contribution level and energy availability for service differentiation. We also introduce that the proposed mechanism efficiently enhances the system performance as the peer with incentive using contribution and energy obtains more effective resource distribution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.9
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• pp.4463-4483
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• 2019

Privacy-preserving collaborative filtering schemes take privacy concerns into its primary consideration without neglecting the prediction accuracy. Different schemes are proposed that are built upon different data partitioning scenarios such as a central server, two-, multi-party or peer-to-peer network. These data partitioning scenarios have been investigated in terms of claimed privacy promises, recently. However, to the best of our knowledge, any peer-to-peer privacy-preserving scheme lacks such study that scrutinizes privacy promises. In this paper, we apply three different attack techniques by utilizing auxiliary information to derive private ratings of peers and conduct experiments by varying privacy protection parameters to evaluate to what extent peers' data can be reconstructed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.716-719
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• 2003

P2P (Peer to Peer) is part that is discussed much in the latest Internet and is interested. P2P changes the structure of Client-Server into Information sharing between client that is the structure of p2p. But perfect P2P system has many problems awaiting solution. In this treatise we can realize network communication to compose one virtual server and one virtual client which is intergrated several client and distributed computer that decentralize network traffic into the traffic of several pc by sharing resource and cpu between client. Our nam purpose is not real P2P system but realization, organization of the P2P internet system which is composed by distributed computing and network load balancing in P2P internet system environment.