• The KIPS Transactions:PartC
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• v.17C no.1
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• pp.37-46
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• 2010

In an IPTV system, the rights of the content and service provider can be protected by using Conditional Access System (CAS) and Digital Right Management (DRM). In case of the CAS, only the authorized user who has structured authentication keys can decrypt the encrypted content. However, since the CAS establishes a secure channel only between content provider and Smart Card (SC), it cannot protect the system against McCormac Hack attack which eavesdrops on unsecure channel between SC and Set-Top Box (STB) and SC cloning attack. In this paper, we propose a robust multi-STB assisted SC / STB authentication protocol which can protect the IPTV system against not only McCormac Hack attack, but also SC cloning attack. The previous works which bind a STB and a SC during the SC registration phase against the SC cloning attack does not support multi-STB environments. The proposed system which dynamically updates the STB information in subscriber management system using the bi-directional channel characteristic of IPTV system can support the user's multi-STB device effectively.

• Journal of Advanced Navigation Technology
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• v.11 no.3
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• pp.252-258
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• 2007

There has been a lot of research done in scheme guaranteeing user's mobility and effective resources management to satisfy the requested by users in the wireless/mobile networks. In this paper, we propose a predictive resource allocation scheme based on ARMA(Auto Regressive Moving Average) prediction model to meet QoS requirements(handoff dropping rate) for guaranteeing users' mobility. The proposed scheme predicts the demanded amount of resource in the future time by ARMA time series prediction model, and then reserves it. The ARMA model can be used to take into account the correlation of future handoff resource demands with present and past handoff demands for provision of targeted handoff dropping rate. Simulation results show that the proposed scheme outperforms the existing RCS(Reserved channel scheme) in terms of handoff connection dropping rate and resource utilization.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.59-66
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• 2003

We propose the novel optical burst switching scheme to guarantee a minimum bandwidth for multiple classes. To date, QoS studies on OBS network are capable of differentiating two classes, but have difficulties in providing a minimum bandwidth lot several classes because of lower classes' collision with the highest class bursts in the networks. To solve that problem, in our proposed scheme we assign time zones in a data channel for each class periodically, making one burst have top priority at least its zone. Also, the new burst assembling algorithm, as well as the way of managing data channel, is necessarily proposed to coordinate with the proposed OBS scheme. Through the evaluation, we show that the worst-case end-to-end delay is small enough and the received bandwidth of the lower classes is still assured regardless of the traffic load of the highest class.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.256-261
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• 2008

We developed an authoring tool for designing vibrotactile patterns quickly and easily by using the drag-and-drop paradigm in mobile devices. Designed vibrotactile patterns are registered into a data pool in the XML format, improving the reusability and extensibility of vibrotactile patterns. A multi-channel timeline interface is also incorporated to provide time-synchronized pattern editing for multiple vibration patterns (for multiple vibration actuators). In addition, an internal vibration player is embedded in the authoring tool in order to evaluate the patterns on the spot. A transform function for perceptually transparent vibration rendering can also be set in the editor. Although the authoring tool was developed for mobile devices, it can be used for other applications such as haptic interaction m virtual reality.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.62-65
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• 2007

3GPP(3rd Generation Partnership Project) 주도의 유럽형 3세대 이동통신인 UMTS 시스템에서 제공하는 멀티미디어 방송 서비스(Multimedia Broadcast/Multicast Service)는 무선 네트워크상에서 동일한 정보를 하나의 링크를 통해 다수의 사용자에게 제공하는 point-to-multipoint 서비스이다. 콘텐츠가 무료로 제공되면 임의의 사용자들이 콘텐츠가 제공되는 채널에 액세스할 수 있다. 그러나 채널 액세스가 가입(subscription)기반이면, 가입하지 않은 사용자들은 콘텐츠를 이용할 수 없어야 한다. 이를 위해 사용자를 인증하고 안전한 방법으로 콘텐츠를 전송할 수 있는 보안 서비스가 필요하다. 본 논문은 MBMS의 전반적인 개요를 설명하여 앞으로 논의될 내용인 MBMS 보안구조에 대한 배경지식을 제공한다. 또한 브로드캐스트와 멀티캐스트 모드 각각에 대한 MBMS 구조를 설명하고, 멀티캐스트 모드에서의 보안 기능과 키관리 기법, 콘텐츠 보호 기술에 대해 상세히 분석한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2708-2716
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• 2013

This paper presents implementation of embedded remote monitoring diagnosis system which has effective wireless channel structure and communication protocols with user-friendly UI for intelligent digital vessel. Developed system contains integrated vessel monitoring system, server, exclusive mobile terminal and smart phone. We designed an effective dual structure communication channel and simple but effective communication protocol on the monitoring system. Failures of the wireless communication are minimized and the wrong wireless communication channel is immediately replaced. In addition, we developed an effective embedded Linux UI for LCD. The implemented wireless monitoring system was tested and verified on digital vessel.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.389-395
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• 2006

이 연구는 사회관계망의 형태와 구성원에 관한 정보를 분석하여 모바일로 서비스하는 것에 관한 연구이다. 사람들은 얽히고 설킨 다양한 인간 관계를 갖고 있다. 인간 관계를 유지하기 위해 여러 채널을 통해 커뮤니케이션을 하게 된다. 실생활에서 갖게 되는 인간 관계의 형태와 가장 비슷한 형태의 커뮤니케이션 채널은 휴대전화이다. 사회관계망 이론의 관점에서 보면 휴대전화의 사용은 기존의 인맥에서 친밀도가 적은 사람에게는 영향이 크지 않지만 친밀도가 높은 사람에게는 더욱 친밀하게 만드는 영향을 준다. 이 연구에서는 휴대전화의 통화상대, 통화시간, 통화량 등의 정보가 나타나있는 통화기록에 기반하여 일정기간 동안 통화한 상대들을 추출하였다. 통화기록의 정보를 사회 관계망 분석 도구인 UCINET으로 분석한 결과 휴대전화를 매개로 한 사회관계망의 형태가 자아 중심적 관계망과 같은 형태를 지니고 있다는 사실을 도출해냈다. 그리고 자아 중심적 관계망의 분석 기법을 이용하여 관계망의 중심에 있는 자아와 통화상대와의 관계를 분석하였다. 또한 통화상대들의 휴대전화 통화기록을 통해 서로 관계가 있는지에 대해 알아보았다. 그 결과 자아의 인맥 네트워크 안에 있는 사람들을 그룹화하고 그들의 나이, 성별, 직업에 의해 어떠한 특징을 갖는 그룹인지 분석하였다. 이러한 연구는 휴대전화를 통해 자신의 인간 관계 형태를 파악하여 관계를 관리하고 유지할 수 있는 새로운 모바일 서비스 개발을 위해 활용될 수 있을 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.198-201
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• 2012

The rapid advancements of information technology and popularization of smart phones make people obtain the desired information through a variety of channels. In particular, consumers become to use a smart phone in their shopping in order to spend their money rationally. However, they have experienced inconvenience at being shopping by a smart phone because shopping information - reward(stamp), coupon, discount information, and so on - is distributed over multiple applications. To solve this problem, we propose the mobile stamper system that consumers can make good use of the reward(stamp) which is provided by various stores. The proposed system can improve the convenience of consumers by managing and integrating all stamps of multiple stores into our application.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.8
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• pp.1612-1627
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• 1994

There is a synchronization function which deals with only single media of text in the OSI Session Layer. So new synchronization schem and synchronization protocol are required for multimedia communications which include audio, video and graphic as well as text information. In this paper, conceptional Multmedia Synchronization Layer(MS layer) environment is composed and its service primitives and protocols based on 'multi-channel, base media scheme' are designed and proposed for multimedia synchronization services. This MS layer Manager (MSM) establishes the MS layer connection to the peer MS layer and manages each media channel which is created in MS layer media by media. The MSM also finds the synch-position through the media frame number by utilizing it like the time stamp to provide inter-media synchronization services as well as intra-media synchronization services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.517-525
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• 2010

The IPTV Service provides various interactive services beyond the level of being able to substitute cable TV. The IPTV system is to be decentralized gradually in which one server conducts all tasks. Primarily, deliberation of media needs to be changed into a system in which relayer and peer from the central server is utilized. Secondarily, the way of controling IPTV network need to be decentralized. Unlike the current client-server system, P2P(Peer To Peer), the main technology of decentralized IPTV is able to provide a service by cooperation of each node. Dealing with live streaming IPTV system which is based on the P2P protocol, this paper design the pure P2P IPTV structure and does verify the performance of P2P IPTV structure by realizing real system.