• ETRI Journal
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• v.33 no.1
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• pp.110-120
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• 2011

As information technology rapidly develops and the period required to enter new technology shortens, there emerges a wide variety of alternatives for consumers. When there are many alternatives in the market, users choose after making comparisons. This process of making comparisons is our research key. We established a research model to find a mixed effect that comes from new attitudes to technology adoption and alternative's continuous usage intention. The effect is revealed through a relative attractiveness (RA) factor to explain a user's process of comparison. We empirically test our research model in the new media services, such as mobile TV, web TV, and mobile IPTV. According to our research results, a continuous usage intention of an existing technology is an important factor to explain the adoption of a new technology. So, the contribution of our research is in finding a role for the RA factor in research in new technology adoption.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.4
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• pp.473-479
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• 2008

With the advent of mobile phone, digital multimedia broadcasting(DMB) service is to be realized for multimedia data communication. For an acoustic part, a smaller and lighter microspeaker is also soon to be realized as an MP3 song player and a speakerphone. Sound quality in the microspeaker is becoming more important in mobile phones. It is evaluated by total harmonic distortion(THD). THD is the proportion of higher order frequencies output response to sinusoidal input signal. It is affected by uneven magnetic distribution and nonlinear response of diaphragm. In this paper, harmonic distortion is analyzed by considering magnetic and mechanical coupling effects. Simulated results of THD are compared with experimental data. Results show that THD in lower frequency range is higher due to high displace on voice coil and high mechanical response of high order frequency.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06b
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• pp.191-195
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• 2008

최근 데이터 방송은 새로운 콘텐츠의 부재로 어려움을 겪고 있지만 사용자 중심의 서비스와 플랫폼을 지향하는 웹 2.0의 개념과 기술의 도입을 통해 콘텐츠 활성화에 기여할 것으로 보인다. 그에 대한 기대와 요구가 있으나 구체적인 구현 사례는 존재하지 않으므로 이에 본 논문에서는 웹 2.0으로 각광받고 있는 RSS를 통해 웹에서 지속적으로 업데이트가 이루어지는 최신 정보를 별도의 수집과정 없이 데이터 방송서비스를 생성하는 시스템을 개발했다. 지상파 DMB 데이터 방송의 경우 실시간으로 업데이트가 이루어지는 콘텐츠의 경우 지속적인 반영이 어렵지만 RSS를 통해 콘텐츠를 생성함으로써 저작 단계 및 시간을 줄여 보다 웹의 다양한 내용의 최신 정보를 사용자에게 제공할 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.160-161
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• 2011

최근 IT 기술의 발전으로 TV, DMB, 이동통신망 등을 이용한 효율적인 재난문자방송 서비스가 국내외에서 관심을 받고 있다. 특히. 이동통신망은 지역단위 전송이 가능하기 때문에 지진, 해일 등의 심각한 재난이 예상되는 지역에 신속한 경보 서비스를 가능하게 해준다. 국내에서는 이미 2G 이동통신망을 이용하여 대국민 재난문자방송 서비스를 실시하였다. 그러나 국내외적으로 3G/4G 이동통신망 서비스가 본격화 되었으며, 이에 맞는 재난문자방송 서비스가 필요한 실정이다. 이에 본 논문에서는 이동통신망을 이용한 재난문자방송 서비스인 CBS의 국내외 동향과 표준안 등을 소개하며, 국내 CBS의 향후 나아갈 방향을 제시하고자 한다.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.87-90
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• 2004

Telematics is an emerging industrial field made up of the convergence of technologies. The key technologies for Telematics are server-side technology, terminal-side technology, communication-related technology, and positioning technology. Standardization in Telematics is now getting more notice these days. Domestic situation is explained for several related facilities such as ETRI, TTA, and Telematics Standardization Forum. In this paper, we will focus especially on the standard reference model that is the most fundamental framework of Telematics technology standardization. In the reference model, the Telematics system is composed of Telematics client part, communication part, and Telematics server part. The Telematics client part consists of terminal, positioning device, and car electronic devices. Communication part can be composed of various telecommunication channels such as CDMA, WLAN, DMB, WiBro, etc. which can guarantee the seamless two-way communication. Telematics server part is composed of TSP(Telematics Service Provider) server and CP(Contents Provider) servers gathering and managing the various Telematics services. This Telematics reference model is expected to be utilized as the base architecture in developing the technology and standards from now on.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.236-241
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• 2008

With the advent of mobile phone, Digital multimedia broadcasting (DMB) service is to be realized for multimedia data communication. For an acoustic part, a smaller and lighter microspeaker is also soon to be realized as an MP3 song player and a speakerphone. Sound quality in the microspeaker is becoming more important in mobile phones. It is evaluated by total harmonic distortion (THD). THD is the proportion of higher order frequencies output response to sinusoidal input signal. It is affected by uneven magnetic distribution and nonlinear response of diaphragm. In this paper, harmonic distortion is analyzed by considering magnetic and mechanical coupling effects. Simulated results of THD are compared with experimental data. Results show that THD in lower frequency range is higher due to high displace on voice coil and high mechanical response of high order frequency.

• Journal of Korea Multimedia Society
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• v.18 no.12
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• pp.1427-1431
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• 2015

In the salvage area, the location of the incident vessel and diver to rescue the victim are very important. But there are no ways but to rely on the GPS satellites to obtain the location in the salvage sites. Because the positioning using GPS satellites has a measurement error of up to 50 meters caused by the status of the atmosphere, a new positioning method with more accuracy should be devised. So if studies on measuring the position of the ships and divers accurately in the sea are performed, it will be helpful in the field of the salvage positioning. In this paper, a high precision positioning system in salvage using DGPS signal through mobile broadcasting is proposed with positioning error of up to 1 meter.

• Annual Conference of KIPS
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• 2005.11a
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• pp.1129-1132
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• 2005

텔레매틱스 무선접속기술은 텔레매틱스 단말기와 텔레매틱스 서비스 사업자간 정보를 전달하기 위한 무선채널을 제공하는, CDMA 기반으로 활용되고 있다. 또한 다양한 텔레매틱스 서비스를 제공하기 위해 DSRC, WLAN, DMB 기술이 활용되고 있다. 본 논문에서는 텔레매틱스 서비스를 제공 받기를 원할 때 그 서비스를 제공할 서버를 발견할 수 있고 서비스 위치탐색 기능을 제공할 수 있는 MANET 이라는 환경에서 다양한 텔레매틱스 서비스를 할 수 있는 릴레이 홉 방식을 적용해서 효율적인 텔레매틱스 서비스 전송 방식을 제안하고자 한다.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2008.10b
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• pp.634-642
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• 2008

Radio wave is the valuable resources in $21^{st}$ century. It will be widely used in various applications such as DMB, USN, telematics, and home network as well as mobile and wireless communications. Cognitive Radio technology is devised to maximize the utilization of radio resources by sensing near-by spectrum and dynamic and allocating free resources dynamically and adaptively. Wireless links for the secondary user need to be frequently switched to idle frequencies during the transmission of multimedia data in the cognitive radio based system. This may cause delay and information loss, and QoS degradations occur inevitably. The efficient frequency allocation scheme is necessary to support the seamless multimedia service to the secondary user while maintaining QoS of the primary user. This paper suggests a frequency selection scheme which considers other parameters such as cell load, data rate, and available bandwidth than just received signal strength during the frequency selection process. The performance of our proposed scheme is analyzed by simulation.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.952-953
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• 2006

As car industry takes the DMB, geographical feature information and Internet service recently, the need of an electricity energy is the trend to increase. But existing 12V car electricity system is difficult to be satisfied rapidly increasing electricity need. A relation component company is adding the spur at a high electricity system development. In this paper we accomplished the hi-directional DC-DC Converter for high electricity system composed 42V configuration device. Through a simulation experiment, We looked into the control method and the operation characteristic of the circuit, We accomplished the comparison analysis for fit topoloy selection.