• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.208-212
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• 2002

통신기술의 발달에 따라 기존의 통신망은 TP 기반의 NGN 구조로 통합이 추진되고 있으며, 서비스 형태도 음성주도형 서비스에서 음성과 데이터가 혼합된 멀티미디어형 서비스로 전환되는 추세이다. 또한 기존 PSTN 서비스를 인터넷기반으로 대체하는 인터넷전화 서비스가 출현하게 되었다. 인터넷전화 서비스는 VoIP 관련 번호 제도가 체계적으로 도입되고 사업자 역무가 구체화될 경우 본격적인 활성화 단계에 진입할 것으로 예상된다. 기업측면에서는 통신 요금을 절감하고 음성과 데이터를 통합하여 사용할 수 있는 사설망 구축을 적극적으로 도입하거나 활용을 검토하고 있는 추세이며 개인 고객들도 향후 IP 기반의 유무선 인터넷전화 서비스를 많이 활용하게 될 것이다. 결국 ITSP와 사설기업망이 많이 생겨나게 되고, 이러한 환경에서는 ITSP(Internet Telephony Service Provider)와 사설 기업망 가입자들은 모든 타사업자 (ITSP, 무선통신사업자. PSTN 사업자, 사설 기업망 등)들간 통신을 위하여 협약을 체결하고, 호 라우팅을 위한 정보를 유지하고 과금 정산 기능을 지원하여야 하는 문제점이 있다. 이를 위한 방안으로서 사업자간 정산 시스템을 중심으로 ITSP와 사설기업망 가입자를 연동하도록 구성할 수 있다. 프로토콜로서는 ETSI 표준 프로토콜 OSP을 사용하도록 한다. 본 고에서는 사업자간 정산 시스템(OSPs : OSP 서버)을 통한 ITSP와 사설 VoIP 망들간의 호 서비스 연동 방안을 제시하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1696-1702
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• 2005

Real Time Transport Protocol (RTP) is the Internet standard protocol for transport of real time data audio/video IP Telephony, Multimedia Seivece. In case of 8kbps voice codec, the size of packet per data is 20bytes and become more large to minimal 40bytes with adding each layer's header in RTP/UDP/IP. To solve this problem, various header compression skill were suggested on point-to-point networks. But it compress even IP header and cannot be suitable to apply to end-to-end network Thus, We will renew header compression protocol to apply wired router-based network.

• Journal of the Korea Convergence Society
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• v.3 no.3
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• pp.7-12
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• 2012

mVoIP (mobile Voice over Internet Protocol) service is a technology to transmit voice data through an IP network using mobile device. mVoIP provides various supplementary services with low communication cost. It can maximize the availability and efficiency by using IP-based network resources. In addition, the users can use voice call service at any time and in any place, as long as they can access the Internet on mobile device easily. However, SIP on mobile device is exposed to IP-based attacks and threats. Observed cyber threats to SIP services include wiretapping, denial of service, and service misuse, VoIP spam which are also applicable to existing IP-based networks. These attacks are also applicable to SIP and continuously cause problems. In this study, we analysis the threat and vulnerability on mVoIP service and propose several possible attack scenarios on existing mobile VoIP devices. Based on a proposed analysis and vulnerability test mechanism, we can construct more enhanced SIP security mechanism and stable mobile VoIP service framework after eliminating its vulnerability on mobile telephony system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.5
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• pp.85-90
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• 2015

Work environments within the firm with a concept of mobile office is growing divided into two sections. It's Wi-Fi FMC(Fixed Mobile Convergence) field Which are implemented in a telephone service available from existing fixed-line service in the center of the smart phones and the EMS(Enterprise Mobility Service) field to make people will be able to handle PC the center of the information system within an enterprise using a smart phone instead of terminal facility connects to a system in the workplace and external. This paper developed FMC controller to allow execution IMS(IP Multi-Media Subsystem) services to complement the issues of the FMC corporation, telephony service associated. The controller includes FMC automatic enrollment services, voice quality enhancement of the mobile phone, anywhere within the firm on his mobile phone calls can provide mobility and is also implemented FMC LCR function that use status information from mobile soft-phone within the IP-PBX.

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.375-384
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• 2002

In the current Internet, the QoS of interactive applications is hardly guaranteed because of variable bandwidth, packet loss and delay. Moreover, VoIP which is becoming an important part of the information infra-structure in these days, is susceptible to network packet loss and end-to-end delay. Therefore, it needs error control mechanisms in network level or application level. The FEC-based error control mechanisms are used for interactive audio application such as VoIP. The FEC sends a main information along with redundant information to recover the lost packets and adjusts redundant information depending on network conditions to reduce the bandwidth overhead. However, because most of the error control mechanisms do not consider end-to-end delay but packet loss rate, their performances are poor. In this paper, we propose a new error control algorithm, SCCRP, considering packet loss rate as well as end-to-end delay. Through experiments, we confirm that the SCCRP has a lower packet loss rate and a lower end-to-end delay after reconstruction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4A
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• pp.310-315
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• 2002

The Bark Coherence Function (BCF) defies a coherence function within perceptual domain as a new cognition module, robust to linear distortions due to the analog interface of digital mobile system. Our previous experiments have shown the superiority of BCF over current measures. In this paper, a new BCF suitable for VoIP is developed. The unproved BCF is based on the wavelet series expansion that provides good frequency resolution while keeping good time locality. The proposed Wavelet based Bark Coherence function (WBCF) is robust to variable delay often observed in packet-based telephony such as Voice over Internet Protocol (VoIP). We also show that the refinement of time synchronization after signal decomposition can improve the performance of the WBCF. The regression analysis was performed with VoIP speech data. The correlation coefficients and the standard error of estimates computed using the WBCF showed noticeable improvement over the Perceptual Speech Quality Measure (PSQM) that is recommended by ITU-T.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.1055-1057
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• 2013

Routers currently used in homes and institutions have a function of multiple computers to connect to the Internet with a single IP address. It is possible only through setting or establishing a separate operation in a used PC or server to function as a web/printer server, web hard, and P2P. In this paper, by utilizing the OpenWRT Linux-based through the construction of the Web server through a router OpenWRT of (Open Wireless Router) base, to build a server simple compact, low power consumption, low cost, to operate by reliability to provide Internet telephony and multimedia services high securely over the server security, which is based on the setting of policy and various firewall at the same time the configuration of the network utilizing OpenWRT router that can be enhanced, to construct a Web server through a router multi functional can receive the provision of services using the program PC and mobile APP.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.277-280
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• 2011

VoIP is a technology of voice communication, using the existing internet network which sends and receives voice packets. VoIP has an advantage that VoIP is cheaper than an existing telephony, and the tech is vitalized lately. But recently you can download Volp Application in the Market that have a vulnerability(Anyone Can Upload). This weakness is wrongfully used that People are downloaded by encouraging about malignant code is planted. Signal intercepts indicates from this case. and paralysis by DDoS Attack, bypass are charged for hacking. Judging from, security threat of VolP analysis and take countermeasures. In the thesis we analyze the VoIP security caused on 'Soft Phone' and 'Smart Phone', and figure out security policies and delineate those policies on the paper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1911-1918
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• 2011

Internet banking, electronic financial services and internet telephony service can be available on smart phone recently. In this case, more robust authentication mechanisms should be provided for enhancing security on it. In this study, a facial biometric ID based one-time password generation mechanism is designed and implemented for enhancing user authentication on smart phone. After capturing a facial biometric data using camera module on smart phone, it is sent to server to generate one-time biometric ID. Finally one-time password will be generated by client module after receiving the one time biometric ID based challenge token from the server. Using proposed biometric ID based one-time password mechanism, it is possible for us to provide more secure user authentication service on smart phone for SIP protocol.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.7-16
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• 2006

IPTV is referred to the service which provide integrated IPTV services for providing video, 10/100-Mbit/sec Internet, voice, video-on-demand (VOD), and other broadband applications including home security, video conferencing, and telemedicine. All services are integrated into an IP (Internet Protocol) architecture designed specifically for Gigabit Ethernet FTTH systems, HFC or xDLC. It is absolutely necessary that telecon operators provide IP video delivery platforms that enable service providers to transform their business. With their own products, they can better manage their existing services and generate new revenues from broadcast TV, movies on demand and multimedia. Triple-play is a combination of broadcast, telephony and broadband services offered through IPTV networks. With cable operators allowed to offer a triple-play bundle, the nation's telecom operators are beginning to get a little anxious. Cable operators assert that triple-play is a must-have and natural extension of the cable service bundle. The Korean Cable TV Association asserts that the triple-play model is of paramount importance to the cable industry's future growth. But the telecom sector considers itself unfairly disadvantaged, saying they cannot compete until regulatory issues are resolved. The start of web-based television in Korea may still be some time off with a confrontation between the nation's IT regulator and broadcasting sector over the service's legal boundaries shows no signs of being resolved my time soon. korea should be is the fastest-growing provider of IPTV solutions in the industry, with over worldwide customers.