• 한국통신학회:학술대회논문집
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• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
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• pp.613-613
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• 2006

• 한국컴퓨터정보학회논문지
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• 제15권5호
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• pp.83-92
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• 2010

우리나라 이동통신 시장은 기술의 발전과 다양해지는 소비자의 욕구 등으로 가입자 수의 급증만큼이나 경쟁 양상도 심화되고 있다. 또한 HSDPA라는 3G 이동통신서비스의 등장으로 세대 간 고객전환을 위한 치열한 마케팅 활동이 펼쳐지고 있다. 이러한 상황 속에서 이동통신 사업자에게 장기적인 경쟁우위를 안겨줄 원천에 대한 해답으로 가입의 활성화와 함께 이용의 활성화가 대두되고 있다. 이에 본 연구에서는 다중판별분석을 이용하여 이동통신서비스 시장을 가입의향과 이용의향이 모두 높은 고객과 그렇지 않은 고객으로 세분화하고 가입의향과 이용의향이 모두 높은 주요고객을 판별하는 판별함수를 도출하였다. 이를 통해 치열한 경쟁을 겪고 있는 HSDPA 서비스 시장에 유용한 전략 포인트를 제시하였다.

• ETRI Journal
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• 제34권4호
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• pp.492-502
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• 2012

We consider an overlaid broadcast service, where a spread spectrum (SS)-based broadcast signal is overlaid onto the existing terrestrial Digital Multimedia Broadcasting (T-DMB) band. The system is similar to the augmented data transmission in the ATSC DTV, for which it was investigated mostly in terms of link level performance, such as bit error rate. Our focus in this paper is on the system-level performances. More specifically, utilizing both a large scale path loss and a small scale fading channel model, the primary objective is to explore the tradeoff between the coverage and the achievable rate of the overlaid service and, finally, to determine the achievable rate in the overlaid service for marginal coverage reduction in the existing broadcast service. The analytical and simulation results show that an SS-based add-on service of 10 kbps to 20 kbps can co-exist with the T-DMB service while resulting in only a marginal degradation in T-DMB coverage (for example, less than one percent reduction).

• Journal of Communications and Networks
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• 제17권2호
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• pp.110-117
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• 2015

In mobile social network, it is a critical challenge to select an optimal set of devices to supply high quality service constantly under dynamic network topology and the limit of device capacity in mobile ad-hoc network (MANET). In this paper, a multi-devices composition and maintenance problem is proposed with ubiquitous service model and network model. In addition, a multi-devices composition and maintenance approach with dynamic planning is proposed to deal with this problem, consisting of service discovery, service composition, service monitor and service recover. At last, the simulation is implemented with OPNET and MATLAB and the result shows this mechanism is better applied to support complex ubiquitous service.

• Journal of Information Technology Applications and Management
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• 제9권3호
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• pp.57-78
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• 2002

This paper studios billing mechanisms of value-added telephone services In Korea and major foreign countries. The billing methods of toll-free phone service, voice Information service, one number service, personal number service and calling card service ate compared with each other. The results show that several differences are identified among service providers due to the difference of the regulation, numbering mechanism and underlying networks employed. This paper also provides implications and suggestions to incumbent Korean value-added service providers and regulators

• ETRI Journal
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• 제31권4호
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• pp.365-375
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• 2009

In this paper, a terrestrial digital multimedia broadcasting (T-DMB) multichannel audio broadcasting system based on spatial audio coding is presented. The proposed system provides realistic multichannel audio service via T-DMB with a small increase of data rate as well as backward compatibility with the conventional stereo-based T-DMB player. To reduce the data rate for additional multichannel audio signals, we compress the multichannel audio signals using the sound source location cue coding algorithm, which is an efficient parametric multichannel audio compression technique. For compatibility, we use the dependent property of an elementary stream descriptor, and this property should be ignored in a conventional T-DMB player. To verify the feasibility of the proposed system, we implement the T-DMB multichannel audio encoder and a prototype player. We perform a compatibility test using the T-DMB multichannel audio encoder and conventional T-DMB players. The test demonstrates that the proposed system is compatible with a conventional T-DMB player and that it can provide a promisingly rich audio service.

• ETRI Journal
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• 제36권5호
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• pp.791-798
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• 2014

As a new hybrid broadcasting service, augmented broadcasting shows enhanced broadcasting content on a large TV screen, while augmented reality (AR) on a mobile device augments additional graphical content onto an input image from the device's own camera to provide useful and convenient information for users. A one-sided broadcasting service using AR has already been attempted in virtual advertisements during sport broadcasts. However, because its augmentation is preprocessed before the video image is transmitted, the viewer at home may have no influence on this formation; and no interaction for the user is possible unless the viewer has a direct connection to the content provider. Augmented broadcasting technology enables viewers to watch mixed broadcasting content only when they want such service and to watch original broadcasting content when they do not. To realize an augmented broadcasting service, the most important issue is to resolve the hybrid content synchronization over heterogeneous broadcast and broadband networks. This paper proposes a novel hybrid content synchronization scheme for an augmented broadcasting service and presents its implementation and results in a terrestrial DTV environment.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2007년도 추계학술발표대회
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• pp.482-484
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• 2007

YouFree 는 이동형 SW 플랫폼을 기반으로 개인 맞춤형 지식 관리 및 개발 환경을 제공하고자 한다. YouFree 내의 브라우저 기반 SW 실행 엔진은 사용자가 이동한 곳에서 YouFree 가 실행될 수 있도록 이동성을 지원한다. 본 논문에서 제안하는 브라우저 기반 SW 실행 엔진은 설치 시 레지스트리의 변경하지 않으며, 실행을 위해 사용자의 추가적인 구성을 필요로 하지 않는다. 또한, 먼저 실행된 엔진이 존재하더라도 충돌 없이 새로운 엔진을 실행하여 사용자가 편리하게 브라우저 기반 SW 를 사용할 수 있도록 한다. 따라서 사용자는 YouFree 를 이용해 브라우저 기반 SW 를 서비스하거나, 또는 SW 의 개발도구, 개인 컨텐츠 관리 도구로 YouFree 를 이용할 수 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.11-14
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• 2005

In this paper, we propose a method for transmitting SMS(Short Message Service) for VoIP(Voice over IP) service supporting multi-protocol. The multi-protocol VoIP under consideration are generally composed of H.323, SIP and MGCP and Most ITSPs(Internet Telephony Service Provider) provide VoIP service with H.323 and SIP now. SMS is killer application in mobile telecom service and many people of various field use that service. For example, user can send many SMS messages and substitute e-mail. Also SMS can be provided with various internet application. Ahn, legacy phone of KT, can use SMS. Therefore VoIP phone also can be required with the same requirement. With the multi-protocol VoIP we will propose several methods sending efficiently SMS. To show the validity of the proposed method some examples are given in which the results can be expected by intuitive observation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권6호
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• pp.2680-2696
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• 2018

The collaborative content caching system is an effective solution developed in recent years to reduce transmission delay and network traffic. In order to decrease the service end-to-end transmission delay for future 5G ultra-dense networks (UDN), this paper proposes a novel service migration method that can guarantee the continuity of service and simultaneously reduce the traffic flow in the network. In this paper, we propose a service migration optimization model that minimizes the cumulative transmission delay within the constraints of quality of service (QoS) guarantee and network condition. Subsequently, we propose an improved firefly algorithm to solve this optimization problem. Simulation results show that compared to traditional collaborative content caching schemes, the proposed algorithm can significantly decrease transmission delay and network traffic flow.