• Title/Summary/Keyword: DMB+

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Channel Estimation in E-OCR for T-DMB System (T-DMB 시스템을 위한 E-OCR에서의 채널추정)

  • Park, Sung-Ik;Lim, Hyoung-Soo;Kim, Heung-Mook;Oh, Wang-Rok
    • Journal of Broadcast Engineering
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    • v.13 no.5
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    • pp.565-573
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    • 2008
  • This paper proposes noise reduction methods to improve the channel estimation performance in Equalization On-Channel Repeater (E-OCR) for Terrestrial-Digital Multimedia Broadcasting (T-DMB) system. In the E-OCR for T-DMB system, the channel estimation is performed by the pilot signal extraction and the channel coefficient estimation. Since the performance of the channel estimation highly depends on the estimated channel coefficients whose accuracy is associated with the received signal-to-noise ratio (SNR), it is important to reduce noise existing at the estimated channel coefficients. To reduce such noise components, various noise reduction methods of the estimated channel coefficients based on the M -point weighted moving average are proposed. Computer simulations show that the proposed methods improve the estimation performance by more than 2 to 3 dB in terms of the symbol error rate after equalization.

Property of hfac(hexafluoroacetylacetonate) Cu(I) DMB (3,3-dimethyl-1-butene) as a Liquid Precursor for Chemical Vapor Deposition of Copper Films (액상 구리 전구체 hfac (hexafluoroacetylacetonate) Cu(I) DMB (3,3-dimethyl-1-butene)의 특성 평가)

  • Lee, Si-U;Gang, Sang-U;Han, Sang-Ho
    • Korean Journal of Materials Research
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    • v.9 no.11
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    • pp.1148-1152
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    • 1999
  • An organometallic precursor, hfac(hexafluoroacetylacetonate) Cu(I) DMB (3,3-dimethyl- 1-butene) was synthesized, evaluated and compared with other precursors for metal organic chemical vapor deposition of copper thin films. It was found that at $40^{\circ}C$, the vapor pressure was an order of magnitude higher (about 3 torr) than (hfac) Cu vinyltrimethylsilane (VTMS) and films could be deposited at the substrate temperature of 100-$280^{\circ}C$ with deposition rate substantially higher. The copper films contained no detectable impurities as measured by Auger electron spectroscopy and had a resistivity of about 2.0$\mu\Omega$-cm in the deposition temperature range of 150 to $250^{\circ}C$. From the thermal analysis, (hfac)Cu(I)(DMB) is believed to be quite stable and no appreciable amount of precipitation was observed at $65^{\circ}C$ heating for more than a month.

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Comparison of tube-assisted mapping biopsy with digital single-operator peroral cholangioscopy for preoperative evaluation of biliary tract cancer

  • Tsuyoshi Takeda;Takashi Sasaki;Takafumi Mie;Takeshi Okamoto;Chinatsu Mori;Takaaki Furukawa;Yuto Yamada;Akiyoshi Kasuga;Masato Matsuyama;Masato Ozaka;Naoki Sasahira
    • Clinical Endoscopy
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    • v.55 no.4
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    • pp.549-557
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    • 2022
  • Background/Aims: Digital single-operator cholangioscopy (DSOC)-guided mapping biopsy (DMB) and tube-assisted mapping biopsy (TMB) are two techniques used for preoperative evaluation of biliary tract cancer (BTC). However, data regarding the diagnostic performance of these techniques are limited. Methods: We retrospectively examined consecutive patients with BTC who underwent either technique at our institution between 2018 and 2020. We evaluated the technical success rate, adequate tissue acquisition rate, and diagnostic performance of these techniques for the evaluation of lateral spread of BTC. Results: A total of 54 patients were included in the study. The technical success rate of reaching the target sites was 95% for DMB and 100% for TMB. The adequate tissue acquisition rate was 61% for DMB and 69% for TMB. The adequate tissue acquisition rate was low, especially for target sites beyond the secondary biliary radicles. The sensitivity of DMB alone was 39%, which improved to 65% when combined with visual impression. Experts demonstrated a higher negative predictive value and diagnostic accuracy with respect to both DSOC visual impression and DMB for the evaluation of lateral spread of BTC compared to trainees. Conclusions: Adequate tissue acquisition rates were similar between the two techniques. Since DMB requires expertise, TMB may be an acceptable option when DSOC is unavailable or when DSOC expertise is limited.

Research for Application of Interactive Data Broadcasting Service in DMB (DMB에서의 양방향 데어터방송 서비스도입에 관한 연구)

  • Kim, Jong-Geun;Choe, Seong-Jin;Lee, Seon-Hui
    • Broadcasting and Media Magazine
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    • v.11 no.4
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    • pp.104-117
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    • 2006
  • In this Paper, we analyze the application of Interactive Data Broadcasting in DMB(Digital Multimedia Broadcasting) in the accordance with convergence of service and technology. With the acceleration of digital convergence in the Ubiquitous period substantial development of digital media technology and convergence of broadcasting and telecommunication industry are being witnessed. Consequently these results gave rise to newly combined-products such as DMB(Digital Multimedia Broadcasting), WCDMA(Wide-band code division multiple access), Wibro(Wireless Broadband Internet), IP-TV (Internet protocol TV) and HSDPA(High speed downlink packet access). The preparatory stage for the implementation of Interactive Data Broadcasting Service will be reached by the end of December, 2006. DMB is the first result of a successful convergence service between Broadcasting and Telecommunication in new media era. Multimedia technology and services are the core elements of DMB. The Data Broadcasting will not only offer various services of interactive information such News, Weather, Broadcasting Program etc, but also be linked with characteristic function of mobile phone such as calling and SMS(Short Message Service) via Return Channel.

The viterbi decoder implementation with efficient structure for real-time Coded Orthogonal Frequency Division Multiplexing (실시간 COFDM시스템을 위한 효율적인 구조를 갖는 비터비 디코더 설계)

  • Hwang Jong-Hee;Lee Seung-Yerl;Kim Dong-Sun;Chung Duck-Jin
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.2 s.332
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    • pp.61-74
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    • 2005
  • Digital Multimedia Broadcasting(DMB) is a reliable multi-service system for reception by mobile and portable receivers. DMB system allows interference-free reception under the conditions of multipath propagation and transmission errors using COFDM modulation scheme, simultaneously, needs powerful channel error's correction ability. Viterbi Decoder for DMB receiver uses punctured convolutional code and needs lots of computations for real-time operation. So, it is desired to design a high speed and low-power hardware scheme for Viterbi decoder. This paper proposes a combined add-compare-select(ACS) and path metric normalization(PMN) unit for computation power. The proposed PMN architecture reduces the problem of the critical path by applying fixed value for selection algorithm due to the comparison tree which has a weak point from structure with the high-speed operation. The proposed ACS uses the decomposition and the pre-computation technique for reducing the complicated degree of the adder, the comparator and multiplexer. According to a simulation result, reduction of area $3.78\%$, power consumption $12.22\%$, maximum gate delay $23.80\%$ occurred from punctured viterbi decoder for DMB system.

Design of T-DMB Automatic Emergency Alert Service Standard : Part 1 Requirements Analysis (지상파 DMB 자동재난경보방송표준 설계 : Part 1 요구사항 분석)

  • Choi, Seong-Jong;Kwon, Dae-Bok;Kim, Jae-Yeon;Oh, Keon-Sik;Chang, Tae-Uk;Hahm, Young-Kwon
    • Journal of Broadcast Engineering
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    • v.12 no.3
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    • pp.230-241
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    • 2007
  • This paper presents the requirements analysis for the Terrestrial DMB Automatic Emergency Alert Service (AEAS) Standard. First, the basic concepts in disaster management and the AEAS system structure are presented as a background. Next, other emergency alert systems and the related standards are analyzed. We propose taxonomy to categorize the emergency alert systems and analyze the characteristics of each system. Next, we analyze advantages of T-DMB for the delivery medium of emergency alert message and problems to resolve for the enhanced performance. Finally, we propose service requirements which will achieve general/special-purpose, non-interrupting, location-adaptive, automatic, message delivery service. The paper will contribute as a guideline to the development for emergency alert service standards for other broadcasting media.

A Compact Two-Wire Helical Antenna with an Open Stub for a T-DMB Antenna of Mobile Devices (단말기 T-DMB용 안테나로 사용될 수 있는 Open Stub를 가지는 소형 Two-Wire Helical 안테나)

  • Lee, Dong-Hyun;Park, Se-Hyun;Kim, Young-Eil;Park, Wee-Sang
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.2 s.117
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    • pp.151-157
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    • 2007
  • We have presented a compact two-wire helical antenna adopted an open stub in opposite to a feeding point, which is for a T-DMB antenna of mobile devices. By adjusting the length of the open stub or pasting a dielectric material on the open stub, the input impedance around 200 MHz, bands of the T-DMB, can be easily control, even though the total height of the antenna is less than 8 cm(0.053 $\lambda$ at 200 MHz). The operating mechanism of the antenna is explained by using equivalent circuits of two modes, an unbalanced mode and a balanced mode. Based on the analysis of the equivalent circuits, the effects of using the open stub are validated. Several proposed antennas have been fabricated and measured. One of the fabricated antennas has -10 dB impedance bandwidth of $196{\sim}204$ MHz(8 MHz) whose value covers one channel of the T-DMB(6 MHz). The measured $S_{21}$ of the antenna is -38.6 dB which is about 17 dB higher than that of a monopole antenna whose height is same with the proposed antenna.

위성 DMB.와이브로, 각국 정상들에게 알린다

  • Sim, U-Seong
    • 정보화사회
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    • s.177
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    • pp.1-4
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    • 2005
  • 이달 11월 15일부터 부산에서 APEC 정상회의가 열린다. 정보통신부를 비롯한 국내 IT업계는 이번 행사에 방한하는 각국 정상들에게 국내 IT를 홍보하기 위해 IT전시회 및 체험 프로그램을 마련했다. 특히 국내 위성 DMB와 와이브로 기술을 집중적으로 홍보할 계획이다. 이를 통해 국가 브랜드 제고 및 산업경쟁력 향상의 기회로 활용한다는 계획이다.

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DAB 정책방향

  • 조광휘
    • Broadcasting and Media Magazine
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    • v.8 no.1
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    • pp.4-11
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    • 2003
  • 방송위원회는 산하 특별위원회로 운영한 2002년 디지털 방송추진위원회(제3기)의 논의사항을 토대로 최근 'DMB.데이터방송 및 DMC 등 디지털방송에 관한 종합계획'(심의의결: 2003년 2월 24일)을 마련하였다. 그 내용중 DMB 부문에 대한 방송위원회의 정책수립 배경과 결정사항을 설명하고자 한다.

Design and Implementation of the Interface between TS Demux and MPEG-4 System (TS Demux와 MPEG-4 시스템의 인터페이스 설계 및 구현)

  • 박주희;서주희;전종구
    • Proceedings of the Korea Multimedia Society Conference
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    • 2003.11b
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    • pp.998-1001
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    • 2003
  • DMB 단말 시스템에서는 Delivery Layer로 다중화 방식인 MPEG-2 TS 와 MPEG-4 System SL를 이용하도록 제안되었다. 본 논문에서는 DMB 단말 시스템에서 사용되는 MPEG 2 $\square$TS는 H/W로 구현하고 MPEG 4 System S/W로 구현하는데 있어서 효율적인 인터페이스를 제안한다.

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