• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2006년도 하계학술대회
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• pp.73-76
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• 2006

International Roaming is a kind of telecommunication service that enables subscribers use the same mobile number when they go abroad and access other service provider's network. International roaming call is made through three network parts-home (original service provider) network, intermediate network, and local (overseas service provider) network. It is not possible to monitor every section of whole roaming service network because service providers do not provide their network management information to other service providers. The limitation causes harsh problem when a service anomaly arises and operators have to confirm the reason of failure. To solve this problem, we propose a scheme that deduces roaming service status of each overseas service provider using internal network management information. SK telecom implemented a international roaming service management system based on the scheme using performance measurement of signaling points, roaming service nodes, and charging data from existing network management systems.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1454-1460
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• 2006

본 논문에서는 무선통신기반 열차제어시스템을 위한 지상무선통신장치와 차상무선통신장치사이에 로밍시 통신성능을 평가하기 위해 개발한 로밍시뮬레이터를 소개한다. 일반적으로 무선통신기반 열차제어시스템이라 하면 지상에 위치하는 제어장치가 각 열차로부터 위치와 속도를 주기적으로 수집하고, 선행열차와 속도 제한 지점까지의 거리정보를 열차로 전송하고, 차상의 제어장치가 열차성능에 맞는 최적의 속도제어를 수행하는 시스템으로 정의된다. 열차의 이동시 지상의 제어장치와 열차제어정보 송수신을 위하여 연속적으로 통신을 하기 위해 로밍이 이루어진다.

• 국제지역연구
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• 제18권3호
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• pp.249-265
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• 2014

지난 10년 동안 국제모바일로밍서비스가 제공되어 왔으나, 그 요금수준은 여전히 높은 수준에 있다. 이러한 국제모바일로밍서비스 요금수준에 대한 인식이 국제적으로 확산됨에 따라 국제기구 등에서는 로밍요금에 대한 다양한 개선방향 및 정책을 제시하고 있다. EU의 경우 로밍 이용요금 상한선 등에 대한 규제정책을 시행하고 있으며, OECD의 경우 강제적인 규제정책은 가지고 있지 않으나, 높은 로밍 요금 원인분석 및 이러한 요금에 대한 해결책의 회원국에 강구를 요구하고 있다. WTO는 서비스 무역 이사회를 중심으로 국제서비스무역을 저해하는지에 대한 검토를 하고 있으며, ITU에서도 요금에 대한 권고(D.98) 제시를 통하여 문제를 해결하려고 하고 있다. 본고의 목적은 국제모바일로밍서비스에 대한 주요 국제기구의 논의사항을 살펴보고 이를 통한 우리나라가 취할 수 있는 요금인하를 위한 규제정책방향을 제시하는 데 있다.

• 한국멀티미디어학회논문지
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• 제23권10호
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• pp.1258-1269
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• 2020

The IoT(Internet of Things) service provides users with valuable services by collecting and analyzing data using Internet-connected IoT devices. Currently, IoT service platforms are accomplished by using edge computing to reduce the delay time required to collect data from IoT devices. However, if a user moves to another network with IoT device, the connection will be lost and IoT service will be suspended. To solve this problem, we proposes a service that automatically roaming IoT service when IoT device makes move. IoT roaming service provides a device automatic tracking management technique designed to continue receiving IoT services even if users move to other networks. To check if the proposed roaming service was effective, we implemented IoT roaming service and measured the data transfer time while move between networks along with devices while using IoT service. As a result, the average data transfer time was 124.62ms, and the average service interrupt time was 812.12ms. with this result, we can assume that the user could feel service interruption time very shortly and it will not affect the service experience. with IoT roaming service, we expect that it will present a method that stably providing IoT services even if user moves networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권8호
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• pp.2061-2080
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• 2013

Roaming authentication protocol is widely used in wireless network which can enable a seamless service for the mobile users. However, the classical approach requires the home server's participation during the authentication between the mobile user and the foreign server. So the more the roaming requests are performed the heavier burden will be on the home server. In this paper, we propose a new roaming authentication framework for wireless communication without the home server's participation. The new roaming authentication protocol in the new framework takes advantage of the ID-based cryptography and provides user anonymity. It has good performance compared with the roaming authentication protocols whose authentication do not need the home server's participation in terms of security and computation costs. Moreover, a new User-to-User authentication protocol in the new framework is also present. All the authentications proposed in this paper can be regarded as a common construction and can be applied to various kinds of wireless networks such as Cellular Networks, Wireless Mesh Networks and Vehicle Networks.

• Journal of information and communication convergence engineering
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• 제8권1호
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• pp.77-82
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• 2010

Residential network is the hybrid technology of wireless, Ethernet, Bluetooth and RF to the internet via broadband connection at home to facilitate the convenient, safe and pleasant daily lives of home user with various home network services regardless of device, time and place. For ubiquitous development more devices will be wireless and most of them will be roaming. Since these roaming devices carry private information of daily life of residential users, the interaction among the roaming devices of residential network must be secure. This paper presents to secure registration of roaming devices using IP Security (IPSec) Protocol Suite without the need to trust foreign agents.

• Journal of Communications and Networks
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• 제4권4호
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• pp.363-369
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• 2002

Towards the deployment of 3rd generation systems, Virtual Home Environment (VHE), stemming from 3GPP, appears to be a powerful concept advocating the provision and delivery of personalized services to roaming users across network and terminal boundaries. This paper aims to expose the pathway for materializing the VHE concept, via the specification, implementation and evaluation of a prototype. Core aspects for realizing the concept such as the business and roaming models are presented, while a VHE enabling architecture utilizing key technologies (OSA/Parlay, MExE, and USAT) is introduced. The proposed architecture has already been evaluated by performing an initial trial demonstration. Currently it is being extended to support VHE service provision to roaming users, an aspect to be addressed by the final trial.

• 한국전자통신학회논문지
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• 제7권4호
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• pp.747-752
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• 2012

본 연구에서는 음성 및 데이터 단말의 로밍이 VoIP 호의 품질에 미치는 영향을 컴퓨터 시뮬레이션으로 분석하였다. MIPv4와 MIPv6에 상관없이 최대 용량의 VoIP 호가 진행중인 상태에서 한 단말의 로밍이 시작되면 무선구간 다운링크에서 재전송이 증가하게 되어 모든 VoIP 호의 품질이 급격히 최저수준으로 저하되었다. 또한 로밍해서 진입하게 된 셀에서도 최대용량의 호가 진행중인 경우에는 모든 호의 품질이 급격히 저하되므로 로밍서비스를 하는 경우에는 일종의 호수락 제어의 필요성이 제기된다. 데이터 트래픽의 경우에 로밍해서 들어가는 쪽의 품질이 더 많이 저하되었다.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1285-1293
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• 2014

Several interesting features in trajectory were observed in the direct dynamics study of formaldehyde dissociation above radical dissociation limit. The hydrogen atom deliberately placed on the radical dissociation path can turn around at some distance from C without completion of dissociation and return to HCO moiety, colliding with it just as in a radical-radical recombination and producing a highly energized molecule. Excursion of a hydrogen atom to a distance of 6-8 bohrs and migration of a hydrogen atom back and forth between C and O are two of the most interesting features exhibited by the energized molecule. A series of excursions is seen to lead to a different kind of dissociation resembling roaming-like dissociation characterized by high vibrational excitation of $H_2$ fragment. It is suggested that excursion occurs due to involvement of two different force field systems that exhibit discontinuity in 6-8 bohrs from HCO moiety. We argue that roaming is a non-zero impact parameter version of the excursion.

• 융합보안논문지
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• 제4권2호
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• pp.53-60
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• 2004

본 논문에서는 무선 인터넷 환경에서 CHAP 인증 기법을 이용한 로밍 서비스 지원 방법을 기술한다. 이를 위해 특별히 GPRS 망으로 이동한 이동 ISP 망 가입자가 자신의 홈 ISP 망을 접속하여 인증을 받기 위한 기법을 제시한다 또 이동 ISP 망 가입자의 단말에서 정의되어야 할 인증 메시지 구조와 GPRS 망 게이트웨이에서 구현될 메시지 구조를 제시한다. 아울러 GGSN과 ISP 망간의 인증 메시지 구조를 정의하며 이들 제안된 내용에 대해 시험 환경 구축을 통해 실제 시뮬레이션 결과를 보였다.