• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.12C
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• pp.1238-1244
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• 2002

In this paper, H.235-based security mechanism for H.323 multimedia applications was implemented. H.235 covers authentication using HMAC, Diffie-Hellman key exchange, session key management for voice channel, and encryption functions such as DES, 3DES, RC2. Extra encryption algorithms such as SEED, and AES were also included for possible use in the future. And, we also analyzed the quality of service (QoS), the requirement of implementation, and interoperability to the result in this study. The results could be applied to secure simple IP phone terminals, gateways, or gatekeepers.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.5 no.3
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• pp.110-116
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• 2012

As rapid development of the Internet, there are increasing interests about quality of service of VoIP using the Internet network and established PSTN. There was some study going on to improve the quality of service from the point of view of supplier's mainly. However recently, the demand for setting up the objective standards that service provider can offer to customers is needed as the interests from customers has been going up. In this study, we analysed the results from the test using PESQ which is a parameter of quality of service. we offer the conditions of network which guarantees the minimum quality of phone call using VoIP.

• Smart Media Journal
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• v.12 no.3
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• pp.93-101
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• 2023

In this paper, we investigate the relationship between a company's Intellectual Property (IP) portfolio strength and its success in obtaining venture funding in the Korean digital media & entertainment industry. Using data from 685 Korean digital media & entertainment companies registered in Crunchbase, a global database provider of venture funding information, we found that a strong IP portfolio is positively associated with funding success. Furthermore, our study revealed that the effect of IP portfolio strength on funding success is stronger for younger companies, suggesting that IP portfolio is more critical for firms that have less reputation and track record.

• Information and Communications Magazine
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• v.22 no.5
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• pp.130-140
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• 2005

3G 이동통신 시스템 표준화 단체인 3GPP ($3^{rd}$ Generation Partnership Project)와 3GPP2 ($3^{rd}$ Generation Partnership Project 2)는 이동통신망에서의 무선 IP 멀티미디어 서비스 확산을 위하여 유선 인터넷의 핵심 응용 서비스인 실시간 서비스를 도입하기 위한 표준화 작업을 진행하고 있다. 그리고, 현재 개발 중인 HSDPA (High Speed Downlink Packet Access)와 IMS (IP Multimedia CN Subsystem)는 궁극적으로 All IP 기반 광대역 멀티미디어 서비스 제공을 추구하고 있으며 Parlay API(Application Programming Interface)를 이용한 다양한 $3^{rd}$ party 응용서비스 제공 환경을 제공할 수 있을 것이다. 이에 본 고에서는 HSDPA 및 IMS를 포괄하는 All IP관련 표준화 현황을 조사하고 나아가 IMS와 HSDPA 기반 서비스 진화에 대한 고찰을 통해 향후 이동통신 서비스의 개발 방향을 예측해 보고자한다.

• TTA Journal
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• s.73
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• pp.116-122
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• 2001

현재 3G 기술의 주된 진전은 IP기반은 프로토콜을 기반으로 하는 핵심망의 부분이라고 해도 과언이 아니다. 30GPP2의 경우, IETF의 Mobile IP를 호스트의 매끄러운 로밍을 위한 핵심망의 라우팅 프로토콜로 채택하고 있으며 3GPP 역시 기존의 GTP기반의 GPRS 망에서 인터넷과의 글로벌한 로밍을 위해 IETF의 Mobile IP를 채택하려고 하는 입장이다. 본 글은 3G 기술, 특히 핵심망에서 호스트의 매끄러운 로밍을 지원하기 위한 기술지원 동향을 ITU의 입장이 아닌 IETF의 입장에서 고찰하도록 한다. 이를 위해 본 글은 IETF에서 3G 셀룰러망을 위한 표준규격 워킹그룹을 분류하고 각 워킹그룹의 역할을 고찰해 보도록 한다.

• The Journal of the Korea Contents Association
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• v.2 no.2
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• pp.85-90
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• 2002

This paper presents tuo implementation models for wireless service operators to offer Mobile-IP over IMT-2000 Data service under IMT-2000 network by taking advantage of the existing infrastructure for IMT-2000 services. For this purpose, a new Mobile-IP over IMT-2000-based protocol architectures are introduced and service operation schemes and handoff schemes according to various scenarios of packet data services in the IMT-2000 core network are presented. Also, this paper describes the handoff scheme in terms of channel states.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.245-250
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• 2008

Recently, mobile devices have supported wireless LAN as well as bluetooth, where the services such as heterogeneous network access and seamless mobility connection are important. Even though the mobility and physical network might be varied, an efficient communication mechanism for the network access and a robust mobility management of mobile devices are needed. In this paper, we design and implement a Bluetooth system with mobile LAN access capability. The proposed system has the following features; 1) IP connection is enabled by BENP in the link layer, 2) The networks devices of heterogeneous mobile devices are integrated into a single virtual network interface, 3) IP mobility between the bluetooth and wireless LAN is supported by mobile IP. The experimented results show that the packet loss and delay time during the handover duration is reduced by predicting the handover among different networks followed by the setup of any required parameters in advance.

• Journal of Communications and Networks
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• v.3 no.4
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• pp.374-382
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• 2001

Nowadays, the commonly used table lookup scheme for IP routing is based on the sc-called classless interdomain routing (CIDR). With CIDR, routers must find out the best matching prefix (BMP) for IP packets forwarding, this complicates the IP lookup. Currently, this process is mainly performed in software and several schemes hale been proposed for hardware implementation. Since the IP lookup performance is a major design issue for the new generation routers, in this article we investigate the properties of the routing table and present a new approach for IP lookups, our approach is not based Gn BMP and significantly reduces the complexity, thus the computation cast of existing schemes can be significantly reduced. We also propose an efficient IP lookup algorithm, with which we improve the binary search on prefixes to 30 millions of packets per second (MPPS) and 5,000 route updates/s under the same experiment setup with an even larger routing table.

• Electronics and Telecommunications Trends
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• v.23 no.3
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• pp.163-174
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• 2008

차세대 전화로 각광을 받고 있는 유선 VoIP는 국내에서 저렴한 요금과 다양한 부가서비스를 통하여 AII-IP 시대를 주도할 것으로 전망되고 있다. 특히 2008년도는 시내전화 번호이동성으로 인해 본 서비스가 크게 확산될 가능성이 높아졌다. 본 글에서는 조사자료를 바탕으로 국내 유선 VoIP 이용자, 잠재 이용자, 비지용자의 수용특성과 영향 요인을 분석하였다. 분석 결과, 세분된 고객군인 이용자, 잠재 이용자, 비이용자간의 인구통계나 기존 통신비 이용특성이 차별화 되었으며 주된 이용 이유는 역시 저렴한 요금수준으로 나타났고 품질과 부가서비스의 개선, 번호이동성으로 인한 식별번호의 해결이 서비스 촉진요인으로 드러났다. 특히 현 유선전화와 비교하여 20-30% 정도 저렴한 요금이 유선 VoIP의 WTP로 나타났다. 본 분석 결과를 바탕으로 국내 유선 VoIP 시장확산을 위한 전략적 시사점을 본 글에서 제시하였다.

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.309-313
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• 2009

In this paper, end-to-end VoIP(Voice over Internet Protocol) performance is evaluated by simulation with NS-2 simulation tool. There are many results studied and published for VoIP performance over TCP/IP networks. But, almost all of them were focused on wired or wireless Internet environments. About MANET (Mobile Ad Hoc Network), VoIP is currently studying several points of research. In this paper, analysis of VoIP performance is done with focusing on the mobility of MANETs. MOS(Mean Opinion Score), network delay, packet loss rates are considered as end-to-end QoS performance parameters.