• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.251-257
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• 2014

An actuator system is a type of motor designed to control a mechanism operated by a source of energy, in the form of an electric current by converting energy into some kind of motion. As audio actuators, transforming electric voltage signal into audio signal, speakers and amplifiers are commonly used. In applications of industry, high output power systems are required. For these systems to generate high-quality output, it is essential to control output impedance of audio systems. We have developed an adaptable power supply for driving active amplifier systems with variable loads. Depending on the changing values of resistance of the speaker which produces audible sound by transforming electric voltage signal, the power supply source of the active amplifier can generate the maximum power delivered to the speaker by an adaptable change of loads. The amplifier is well protected from the abrupt increment of peak current and an excess of current flow.

• Broadcasting and Media Magazine
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• v.25 no.3
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• pp.68-83
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• 2020

1990년대말, 한국은 북미 ATSC 방송표준을 사용하여, 세계최초 HD Digital TV 방송시대를 시작하였고, 이동방송을 위해서는 DMB를 이용한 모바일 방송을 상용화하여, 이는 디지털 방송미디어 산업의 발전과 함께 글로벌 기술 경쟁력을 만드는 계기가 되었다. 이후, 20여년이 지난 최근, 한국은 북미 최신 방송표준기술인 ATSC3.0을 세계 최초로 국내에 상용화하여 4K UHD 지상파 방송시대를 여는 성과를 또다시 이루었다. 하지만, 그동안 통신기술의 눈부신 발달로 고해상도 몰입형 컨텐츠의 IP 스트리밍 서비스가 대중화되었고, 이에 따른 젊은 소비자들을 중심으로 미디어 소비 성향 변화가 확산되어, 이제는 새로운 형태의 미래 융합 방송미디어 서비스를 위한 기술과 정책이 요구되고 있다. 이에, 정부는 관련 산학연 전문가들과 2027년 ATSC3.0 UHD로의 모든 전환 정책을 위해서 다양한 요구사항을 고려한, 미래형 모바일 방송을 포함한 UHD 활성화 방안을 논의하고 있다. 미래형 모바일 방송은 스마트폰뿐만 아니라, 자동차와 사이니지, 홈 TV에서도 서비스 영역이 확장되어야 하며, IP와 연동하여 인터렉티브 양방향 서비스가 가능하여야 하고, 오디오, 비디오 엔터테인먼트뿐만 아니라 인터넷 데이터와 공공, 관심 정보의 데이터 캐스팅 서비스까지 가능하여야 한다. 본 고에서는 미래형 모바일 방송을 위하여, 현재 상용 서비스가 가능한 최신의 방송과 통신기술인 ATSC3.0과 5G를 통한 방송의 서비스와 기술에 대하여 살펴보고, 이들의 미래융합 서비스의 가능성에 대하여 생각해 보는 기회를 삼고자 한다. 본 고의 구성은 서론에서는 방송미디어의 서비스 트렌드를 분석하여 모바일 방송의 복합적 요구사항을 도출해 보고, 본론에서는 현재, 한국의 지상파 UHD 방송표준 기술인 ATSC3.0의 이동방송으로서의 특성을 살펴보고, DMB 기술과 비교해 본다. 또한, 전세계적으로 관심과 실험이 시작되고 있는 5G 방송에 대해서도 그 내용과 동향을 살펴보았다. 그리고, 결론으로는 미래의 융합서비스에 대한 예측과 연구사항에 대하여 생각해 본다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.17-22
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• 2010

In this paper, integral TS(Transport Stream) demultiplexer of a multi-modal receiver is proposed according to the multiple standards of European terrestrial digital broadcasting DVB-T(Digital Video Broadcasting Terrestrial), and mobile terrestrial digital broadcasting T-DMB(Terrestrial Digital Multimedia Broadcasting). This USB based integral receiver could recover the multi-modal broadcasting audios by memory sharing technique which was utilized to decrease the load by the control of streaming multi-modal broadcasting. As a result of performance analysis for a proposed integral TS demultiplexer, the CPU occupational efficiency of windows based integral demulitiplexing is improved compared with DVB-T, and T-DMB respectively.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.481-483
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• 2001

향후 인터넷은 이동 환경에서 메일, 파일 전송 등의 비실시간성 응용뿐만 아니라 오디오, 비디오, 인터넷 방송 등의 실시간성 응용 서비스를 이용할 것으로 예상되며, 이를 위해 광대역 서비스뿐만 아니라 사용자의 QoS 보장이 요구된다. 본 논문에서는 멀티미디어 서비스를 위한 WDM IP전송망 기반 이동 인터넷에서 무선 접속망의 QoS 제공 방안을 제시한다. 멀티미디어 서비스를 위한 인터넷망의 모델을 제시하고, 무선 접속 구간의 트래픽의 특성 및 QoS 파라메타를 분석하며, 무선접속구간의 QoS 제공 방안을 제시한 다음, 무선접속망의 QoS 제어를 위한 프로토콜 모델 및 각 계층별 기능을 기술한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.39-44
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• 2014

IMS(IP Multi-Media Subsystem) base on the IP service platform which can offer multimedia as the voice, audio, video, and data is service platform. In 3G mobile communication in the early day, IMS had a suggestion for supporting to multimedia service in the 3GPP. But now It is broadly substituting in the IPTV, wire phone company and it is substituted in internet platform base on the soft-switch in currently. Especially nowadays, 4G LTE in a mobile communication company is rapidly growing in market. Therefore, in this study, we had designed to the main prosser that can admit to 1,000 user over and SIP gateway which can link the IMS 코어 that can link SIP Device which adopt the standard protocol on the SIP.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.21-31
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• 2014

In this paper, we propose VLC(visible light communication) based multi-hop multimedia data transmission system. The main contributions and features of the proposed system are as follows. First, the contribution of this research is to develope the LED communication based multi-hop transmission network system which can transmit multimedia data(audio data, video data) with long distance. Second, the developed system has the following features: In transmitter, audio data and video data are transmitted via multi-hops using two channels. The relay in audio channel receives digital audio signal by using photo diode and then transmits the signal to receiver after error checking and amplifying. The receiver receives the encoded audio data via photo diode and then converts to analog audio signal by using decoding and amplifying. The relay in video channel receives video signal by using photo diode and then amplify the video signal using OP-AMP and then transmits the signal to receiver. The receiver amplifies the received signal from photo diode and then sends it to the monitor. The performance evaluation of the proposed system is conducted in the laboratory with fluorescent light source. The results of the performance evaluation confirm that the system can provide high quality multimedia data transmission from transmiter to receiver via multi-hop relays in a long distance while we can see there are differences in the transmitted multimedia(audio and video) quality according to the used LED colors.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.35-41
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• 2008

This paper presents the design method of current-mode signal processing for high speed and low power digital audio signal processing. The digital audio processor requires a digital signal processing such as fast Fourier transform (FFT), which has a problem of large power consumption according to the settled point number and high speed operation. Therefore, a current-mode signal processing with a switched Current (SI) circuit was employed to the digital audio signal processing because a limited battery life should be considered for a low power operation. However, current memory that construct a SI circuit has a problem called clock-feedthrough. In this paper, we examine the connection of dummy MOS that is the common solution of clock-feedthrough and are willing to calculate the relation of width between dummy MOS for a proposal of the design methodology for improvement of current memory. As a result of simulation, in case of that the width of memory MOS is 20um, ratio of input current and bias current is 0.3, the relation of width between switch MOS and dummy MOS is $W_{M4}=1.95W_{M3}+1.2$ for the width of switch MOS is 2~5um, it is $W_{M4}=0.92W_{M3}+6.3$ for the width of switch MOS is 5~10um. Then the defined relation of MOS transistors can be a useful design guidance for a high speed low power digital audio processor.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.107-114
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• 2002

In these days, rapid advances of the computer system and the high speed network have made the multimedia services popularized among various applications and services in the internet. Internet live broadcasting, a part of multimedia services, makes it possible to provide not only existing broadcasting services including audio and video but also interactive communications which also expand application scopes by freeing from both temporal and spatial limitation. In the Paper, an interned Personal-live broadcasting server system is developed by allowing individual users to actively create or join live-broadcasting services with such basic multimedia devices as a PC camera and a sound card. As the number of broadcasters and participants increases, concurrent multiple channels are established and groups are to be expanded. The system should also guarantee High Availability (HA) for continuous services even in the presence of partial failure of the cluster. Furthermore, a transmission mode switching is supported to consider network environments in the user system.

• Review of KIISC
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• v.12 no.1
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• pp.11-18
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• 2002

인터넷과 컴퓨터 기술의 발달로 멀티미디어 컨텐츠의 불법유통이나 복제가 심각해지면서 디지털 저작물의 저작권 보호를 위한 기술들이 개발되기 시작하였다. 디지털 워터마킹 기술은 이러한 저작권 보호기술의 하나로 원본 컨텐츠에 저작권자에 대한 정보를 은닉함으로써 저작권자를 확인시켜주고 불법복제나 유통여부를 가려주는 기술로 개발된 것이다. 디지털 워터마킹 기술이 필요한 정보를 은닉한다는 측면에서 정보은닉 기술의 하나로 활용이 가능하며, 이는 단순히 저작권 보호 이외의 분야에 대해서도 응용이 가능하다는 것을 나타낸다. 본 고에서는 오디오 워터마킹 기술을 이용하여 중앙 방송국과 지방 방송국간의 방송전환 시점을 자동으로 검지하는 데 응용하는 예와 신분증에 있어서의 위변조를 방지하기 위한 응용 예를 다루었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.524-527
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• 2008

Recently, digital and the Internet are widespread out of the world, and multimedia processing technology and the development of information and communication technology in education using the Internet as the demand is rapidly increasing. Also, we tan easily use informations with less restrictions of time and space. however, several kinds of audio, media to integrate multimedia data, such as the proliferation of demands for representation. Therefore, in 1998, W3C presented an international standard, SMIL in order to solve multimedia object representation and synchronization problems. By using SMIL, various multimedia elements can be integrated as a multimedia document with proper view in a spate and time. Using this SMIL document, we can create new internet radio broadcasting service that delivers not noly audio data but also various text, image and video. In this paper, with the system, teachers can easily create multimedia courseware and living broadcast their torture on network, students can receive audio-video information of the teacher, screen displays of the teachers computer. Moreover students can communicate with teacher simultaneously by text editor windows. Students can also order courseware after class.