• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10A
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• pp.816-822
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• 2011

This paper provides the performance measurement and analysis of Wireless LAN IEEE 802.11 in a mobile environment. The performance of IEEE802.11b/g and IEEE802.11p that is designed for Vehicle-to-Vehicle(V2V) communication is measured and analyzed. Diameter of communication, link access time and delay are measured as vehicle's speed varies. Also, the performance is checked in a situation that the load to network varies. In conclusion, the futher research topics are discussed.

• 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).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.813-818
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• 2015

In this paper, WiMedia Distributed-MAC protocol is adopted for development of a seamless N-screen wireless service. Furthermore, to provide the OSMU (One Source Multi Use) N-screen service through P2P streaming in the seamless D-MAC protocol, a new Multicast-free DRP Availability IE is proposed and analyzed. In this Multicast-free DRP Availability IE, indicating Multicast DRP Owner and Receiver is required. The ACK frame transmissions are not required for Multicast transmissions in P2P N-screen services. Using this property, the Multicast-free DRP Availability IE scheme is proposed to expand the number of time slots available for unicast and multicast DRP reservations. Simulation results show that our Multicast scheme enhances performances in vewpoints of DRP reservation conflict and throughput.

• The Magazine of the IEIE
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• v.31 no.3
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• pp.88-97
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• 2004

최근 통계에 따르면 현재 셀룰러 이동 통신 사용자는 전 세계적으로 수십 억 명에 달하고 있으며, 증가량도 매년 7%에 이른다고 한다. 무선 이동통신은 단순히 편하다는 것 이상의 의미를 지니고 있다. 범지구적인 관점에서 살펴보면 보다 많은 사람들이 무선 기술을 이용하여 인터넷에 접속하려 하고 있다. 따라서 우리가 오늘날 World Wide Web - 스트리밍 서비스, 단문 메시지, 전자상거래, P2P- 을 이용하여 얻는 모든 이득들이 무선으로 확장되고 있는 상황이다.(중략)

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.81-88
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• 2012

As the performance of the next-generation broadband wireless networks is dramatically enhanced, various services (i.e., education, Live video streaming, Live video conferencing, online games, etc.) have been provided to users through a smart mobile platform. Those services are usually provided by using the centralized communication server. However, since all multimedia traffic is exchanged through a communication server, it often has the scalability problem with regard to traffic management. Our main purpose is for group smart users to provide scalable live multimedia streaming service based on P2P network. To do this, we have designed an architecture of P2P-based service management for mobile group communication management and service management protocol. In order to verify the performance of the proposed scheme, we have mathematically analyzed the performance in terms of the average transmission delay and bandwid th utilization.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.2
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• pp.81-89
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• 2022

Purpose: Wireless endodontic handpieces (WEH) are widely used in dental clinics due to their convenience and portability. This study aimed to compare the vibration magnitudes and patterns generated by five WEH. Materials and Methods: Vibration acceleration of five WEH (X-Smart IQ, E connect S, Endo A Class, ENDOIT, and TRAUS ENDO) in the rotary and reciprocating motion was measured with accelerometer The average vibration acceleration was analyzed using the t-test, Welch's ANOVA test, and Dunnett T3 test at P < 0.05. Results: In all WEH, the average vibration acceleration in reciprocating motion was significantly higher than that in rotary motion (P < 0.001). In rotary motion, repeated vibration graphs of constant amplitude were obtained without sudden changes in the magnitude of vibration, and the average vibration acceleration value was high in the order of X Smart IQ, Endo A Class, ENDOIT, E Connect S, and TRAUS ENDO (P < 0.001), there was no statistically significant difference between X Smart IQ and Endo A Class. In reciprocating motion, a vibration graph was obtained in which large amplitude peaks appear at specific points within one cycle are repeated. The average vibration acceleration value was highest in the order of X Smart IQ, E Connect S, Endo A class, ENDOIT, and TRAUS ENDO (P < 0.001). Conclusion: Regardless of the type of WEH, greater vibration occurred in the reciprocating motion than in the rotary motion (P < 0.001). In the reciprocating motion, there was a difference in vibration for all handpieces (P < 0.001).

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2003.11a
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• pp.167-172
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• 2003

무선 인터넷 서비스는 디지털화된 정보 및 컨텐츠를 유무선 네트워크를 이용하여 최종 사용자의 핸드폰 또는 PDA와 같은 이동 단말기에 제공하는 서비스라고 정의할 수 있다. 본 논문에서는 이러한 무선 인터넷 기술과 은행업무를 분석하여 모바일 뱅킹시스템을 설계 및 구현하였고, 특히 가상계좌 개념을 이용하여 무선 인터넷 환경에서의 실제적으로 응용 가능한 P2P 뱅킹 시스템에서의 최적 솔루션 모듈을 설계 및 구현하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.18-26
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• 2012

As the performance of the next-generation broadband wireless networks is dramatically enhanced, various services (i.e., education, video conferencing, online games, etc.) have been provided to users through a smart mobile platform. Since those services are usually provided by using the centralized architecture, it is difficult for a lot of users to provide the scalable communication service with regard to traffic management. To solve these problems, we have proposed an architecture of P2P-based group communication management scheme using smart mobile device. More specifically, we design the group management protocol and algorithm for the group member management and the traffic management. By using these methods, the mobile multimedia streaming service can be provided with scalability. In order to verify the performance of the proposed scheme, we have mathematically analyzed the performance in terms of the average transmission delay and bandwidth utilization.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1669-1675
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• 2005

Recently, the small sized wireless terminals have problems of processing of large sized file because of the trends of a small sized terminals and a large sized files. Moreover, the web servers or the file servers have problems of the overload because of the concentration with many number of files to the them. Also, There is a security vulnerability of the data processing caused by the processing with a unit of the independent file. To resolve the problems, this paper proposes a new scheme of fat splining distribution using the P2P networks with the mesh topology. The proposed scheme is to distribute blocks of file into any peer of P2P networks. It can do that the small sized wireless terminals can process the large size file, the overload problems of a web or file servers can solve because of the decentralized files, and, the security vulnerability of the data processing is mitigated because of the distributed processing with a unit of the blocks to the peers.

• The KIPS Transactions:PartA
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• v.17A no.5
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• pp.237-248
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• 2010

UPnP(Universal Plug and Play) is a middleware of DLNA (Digital Living Network Alliance) services a home network. UPnP supports the connections between each other devices in networks and also provides service discovery and advertisement with SSDP(Simple Service Discovery Protocol), which is generally designed for wired networks. SSDP operates on multicasting discovery request and advertisement and unicasting a reply in networks. It is a challenge issue for service discovery protocol such as SSDP to provide a stable and effective service in wireless ad-hoc networks. Wired based service discovery protocol does not consider the dynamics of wireless ad-hoc network. In that case, the nodes are freely in or out. Therefore, this paper proposes a flexible SSDP(fSSDP) which is a peer-to-peer(P2P) discovery protocol adopted for wireless ad-hoc Networks. It is implemented on the extension of SSDP. fSSDP supports a functionality that the broadcast area of service discovery dynamically changes with the periodically updated area of advertisement. It is good for reducing messaging overhead caused from the broadcast flooding of service discovery in wireless ad-hoc network.