• Journal of Korea Technology Innovation Society
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• v.9 no.1
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• pp.52-83
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• 2006

This study is to analyze the differences of consumer preferences between the terrestrial DMB and satellite DMB in various segment groups by using survey data. We categorized the consumers by the DMB preference patterns into four groups, i.e., non users group, terrestrial only users group, satellite only users group, dual users group. And then we analyzed the differences among these four segment groups in demographic characteristics, behavior patterns on telecommunication and broadcasting services, life-style, attitudes to DMB services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9B
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• pp.1126-1142
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• 2011

This paper addresses the stereoscopic 3D broadcasting technology that delivers the 3DTV contents through the digital cable networks. In order to convey the 3D contents via DCA TV network, specifications of 3D video format, compression, multiplexing, signalling and transport are to be developed. Since 3D has some constraints unlike 2D, it is required to be well designed by considering the capacity of the additional view and the backward/forward compatibility. This paper goes with the latest trends of 3D standard, requirements and service scenarios and then covers the 3D format, compression, multiplexing and signaling, service information and transport/reception technologies.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.187-197
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• 2010

The fusion stream of recent broadcasting and communication make multimedia content served in the area of broadcasting into IPTV service which transmits it through high-speed internet, cable TV net and satellite net in realtime. However, as the digital broadcasting service is extended to various media, the security of IPTV service content provided to users by service provider is not fully supported by CAS(Conditional Access System) provided by existing broadcasting system. This paper proposes interactive certification protocol which can efficiently distinguish the receiving-qualification of user between Set-Top Box and Smart Card which are parts of configurations for IPTV system. The proposed protocol uses hash function to make Set-Top Box transmit receiving-qualification about the channel fee which user pays more properly than existing protocol. Also, the proposed protocol uses session key generated between receiver and smart card through inter certification process and encrypts EMM not the service to be used by anyone illegally.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.117-124
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• 2004

Various multimedia systems have been developed and their application areas widely proliferate. Thus, the interoperability is getting important among various networks and devices. The video transcoding is a technology to solve this interoperability problem among various coding standards. Transcoding can be defined as the conversion of one compressed coded data to another. In this paper, MPEG-2 to MPEG-4 transcoder in the spatial domain is compared with that in the DCT domain. The transcoder is very useful when a video sequence that is originally encoded for digital TV, DVD or satellite broadcasting is served in mobile environment. In order to compare two transcoders, all modules except motion compensation and down sampling are implemented identically. In addition, both transcoders do not search for motion vector. Instead, the decoded information is reused to the encoder. The experimental results show that the transcoder in the spatial domain is usually better than that in the DCT domain with respect to PSNR (Peak Signal-to-Noise Ratio), bitrate and execution time.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.1
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• pp.52-59
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• 2010

This paper proposes a high-resolution and high-frame rate CMOS image sensor with column-wise cyclic ADC. The proposed ADC uses the sharing techniques of OTAs and capacitors for low-power consumption and small silicon area. The proposed ADC was verified implementing the prototype chip as QVGA image sensor. The measured maximum frame rate is 120 fps, and the power consumption is 130 mW. The power supply is 3.3 V, and the die size is $4.8\;mm\;{\times}\;3.5\;mm$. The prototype chip was fabricated in a 2-poly 3-metal $0.35-{\mu}m$ CMOS process.

• Journal of Broadcast Engineering
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• v.15 no.3
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• pp.414-425
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• 2010

When we implement the single frequency network (SFN) in ATSC terrestrial DTV system, there is an interference problem to DTV receivers due to the use of same frequency channel among transmitters and repeaters. To resolve this problem, it is recommended to adopt the transmitter identification signals in transmitting equipments. In this paper, we analyzed the influence suffered by legacy DTV receivers when the TxID signal is added to the DTV transmitting signals and the results were further verified by computer simulation, laboratory test and field test. The above tests show that if the TxID signal is added to the level of -30dB compared to the original DTV signal, the TOV(Threshold Of Visibility) increment in legacy receivers is about 0.17 dB. It means that we can insert and transmit the TxID signal in ATSC terrestrial DTV system without making the negative effect to the legacy DTV receivers.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.297-310
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• 2013

In this paper, we present a model-based video bit rate estimation scheme for reducing the bit rate while maintaining a subjective quality in many video streaming services limited by network bandwidth, such as IPTV services. First, we extract major parameters which serve as an indirect measurement of frame's bits. Using those parameters, the proposed bit rate estimation scheme can extract candidate frames. Finally, the bit rate of each segment is estimated by statistical analysis and a mathematical model based on a given target quality. In experimental results, we show that the proposed scheme can reduce the bit rate on average by 43% in low-complexity video while maintaining the subjective quality. To find the appropriate bit rate based on video contents, the proposed schemes can estimate the bit rate with neither the repeated full encoding nor subjective quality test. On average, the bit rate can be automatically estimated by encoding the candidate frames of 4%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.511-514
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• 2012

IPTV는 기술적으로 TV에 PC적 기능이 더해지고 인터넷 프로토콜(IP)을 통해 인터넷과 연결되는 서비스로, 국내 초고속인터넷의 속도가 VDSL, 광랜과 같은 서비스의 등장으로 최대 100Mbps에 이르러 동영상 콘텐츠의 실시간 스트리밍 서비스가 가능한 환경이 구현되었다. IPTV 도입을 통해 산사건 방송, VOD 등의 기본적인 서비스뿐만 아니라, 양방향 광고, IPTV 민원발급 및 IPTV 공공서비스 제공 등 다양한 응용서비스의 개발 및 활성화를 기대하였다. 또한 IPTV를 통해 유료방송의 경쟁을 촉진시키고 케이블TV의 디지털 전환을 촉진시킴으로써 시청자들의 복지를 향상시킨다는 취지도 함께 있었다. 정량적으로는 IPTV가입자가 2012년에 이르러 보수적으로 290만가구, 낙관적으로는 450만 가구에 이를 것으로 예상하였으며, 관련 시장규모도 동년도에 약 7,515억원에 이를 것으로 전망하였다. 하지만, 2011년 말이 이미 450만 가입자를 돌파하고 2012년 8월 500만 가입자를 유치하면서 IPTV 서비스는 본격적인 mass market을 형성해 나가고 있다. IPTV 시장이 확대해 나가면서 유료방송 가입가구 수도 증가하였는데, 도입당시인 2008년 말 1,740만 가구가 유료방송에 가입하여 104%의 보급률을 보였으나 2011년 6월말 현재 가구수 대비 유료방송 가입자구수는 127%로 증가하였다. 이렇게 IPTV서비스 시장이 확대되고는 있으나, 정부의 신규 서비스에 대한 과도한 요금규제, IPTV와 경쟁하는 케이블방송사(SO) 계열의 콘텐츠 사업자(CP)들의 방송채널 공급거절 및 지상파 방송사의 과도한 재전송 대가, 전국 권역사업자인 IPTV에 대한 권역별 가입자점유율 규제, IPTV의 차별성으로 내세웠던 T-Commerce 및 양방향 광고에 대한 규제는 앞으로 개선해 내가야할 과제이다. 이에 본고는 IPTV의 시장성과를 조망하고, 시장의 지속성장을 위해 필요한 제도개선 방향을 살펴보았다.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.2
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• pp.187-195
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• 2000

Embedded software generates its outputs using current states of the system as well as external inputs. When a module in embedded software is tested, we need an automated testing tool, which generates possible sequences to reach the module as well as input data of the module, to reduce the testing time and to improve the quality of software. In this paper, we use decision table to specify the functionality of the module and data-annotated MSC (Message Sequence Charts) to describe scenarios, and implement a tool, which we call MSCTest, to automate the testing process. MSCTest consists of MSC graphic editor, test sequence and data generator, and test driver generator. MSCTest is effectively applied to test EsWin which is a kind of window library used in embedded systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4B
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• pp.687-694
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• 2010

IPTV(Internet Protocol Television) is an emerging technology in which telecommunication and broadcasting technologies are converged. IPTV service providers usually multicast scrambled contents. And only legitimate subscribers who pass the access control can de-scramble and use the contents. In order to ensure revenues, providers oftentimes employ password-based authentication protocols that ensure secure authentication processes between set-top box and smart card. In this paper, we propose a fingerprint-based 1-out-of-n authentication protocol which provides convenient and more secure authentication process in some organizational environments. The proposed scheme shows that only those who provide legitimate fingerprint information can be authenticated even in a situation that both password and smart card are compromised.