• Journal of Digital Convergence
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• v.14 no.2
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• pp.389-396
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• 2016

This study analyzes factors that influence use diversity or usage of mobile video services. This study conducts multiple regression analysis to draw the major factors that affect use diversity or usage of mobile video services. The major findings of this study are as follows. First, IPTV membership status, DMB watching status, and TV contents broadcasting status affect the use diversity of mobile video services. Second, TV contents broadcasting status and video streaming quality affect the usage of mobile video services. This study provides some implications that TV contents broadcasting is a core element in mobile video services. The future research is discussed.

• KIISE Transactions on Computing Practices
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• v.21 no.12
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• pp.798-803
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• 2015

DGPS is a technology that can improve the positioning precision of the existing GPS based on the correction information regarding reference station. Although the country is currently building infrastructure for DGPS correction information to be transmitted, it is being used only in limited areas for which DGPS expensive equipment is required. By enabling the development of the DGPS device using the smart phone, this limitation can be overcome, DGPS can be applied for various location-based services, and the implementation of the new model of location-based services may be enabled. In this paper, we introduce the development of a DGPS device for which high-precision positioning is possible using DGPS correction information received via the DMB network or mobile network in the smart phone environment.

• 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.

• Journal of Digital Contents Society
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• v.14 no.2
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• pp.223-233
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• 2013

This paper studied the effects of service quality and system quality that affect customer's satisfaction and continued usage intention regarding mobile network conditions. The hypotheses and research models were completed using research factors of service quality(reactivity, empathy) and system quality(connectivity, ease of use, channel-mobility) borrowed from previous studies on DMB and IPTV. The hypotheses and research models were verified through experiments and surveys. The key finding showed that customer's expectation on service quality and system quality under fast network(Wifi) was higher than that of under slow network(3G). Furthermore, it showed that users react more sensitive to service quality than to system quality such as network speed. Based on the results, this study has the implication for expanding the understanding of the factors used in previous DMB and IPTV studies by applying them in N-screen domain.

• Electronics and Telecommunications Trends
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• v.22 no.6
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• pp.170-181
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• 2007

TPEG는 디지털방송 매체를 통해 교통 및 여행정보를 전송하는 표준 프로토콜로 이동환경에서 운전자들에게 실시간으로 교통정보를 제공할 수 있는 킬러 애플리케이션으로 기대를 모으고 있다. 교통정보를 데이터화해 지상파 DMB, DAB 등의 매체를 통해 이용자의 위치와 주변 정보를 실시간으로 전달하는 기술로 데이터의 부호화, 복호화 및 필터링 등 다양한 규격을 포함한다. TPEG는 DMB 등 휴대이동방송이 시작되면서 디지털 방송신호를 통해 개인 단말기에 멀티미디어 교통정보를 제공할 수 있어 최근 각광을 받고 있다. 본 고에서는 TPEG 서비스의 개요 및 개발현황, 사업자들의 TPEG 서비스 추진현황을 살펴보고, TPEG 서비스의 문제점 및 개선방안을 제시하고자 한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1021-1029
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• 2006

In this paper, we designed and implemented a dual wideband dipole type antenna for the reception of S-DMB (Satellite Digital Multimedia Broadcasting) and 2.4/5 GHz WLAN(Wireless Local Area Network) signals. The proposed antenna based on conventional monopole type dual band antenna was implemented as planar wideband dipole type antenna with the volume of $8{\times}33.8{\times}1.68mm^3$. The proposed antenna is printed type on FR4 substrate of 1.6 mm thick and composed of a dipole type antenna for low frequency band and two symmetric structured resonance elements for high frequency band. We confirmed antenna area with dense surface current for each frequency band with simulation. By varying the length of the antenna area with dense surface current, we could vary resonance frequency of each frequency band separately. Impedance bandwidths$(VSWR{\leq}2)$ are 362 MHz(14.23 %) for 2 GHz band and 1188 MHz(22.13, %) for 5 GHz band which show wideband characteristic. Measured maximum gains were 4.33 dBi for 2 GHz band and 5.48 dBi for 5 GHz band which showed improved performance. And the implemented antenna has a good omni-directional radiation pattern characteristic.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.664-672
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• 2009

In this paper we propose an on-glass antenna which consists of conducting dual center striplines and multi-loaded striplines. Multi-loaded striplines and dual center lines were employed for achieving a broad matching bandwidth and improving a vertical radiation gain, respectively. The detail design parameters were determined using the Pareto genetic algorithm with an full wave EM simulator. The optimized design was built and installed on a commercial vehicle, and the antenna performances such as the return loss and the radiation gain were measured in a semi-anechoic chamber. The measurement results showed the matching bandwidth($S_{11}$<-3 dB) of about 49 % in the T-DMB frequency band, the vertical gain of about -3 dBi along the bore-sight direction, and the average gain of about -10 dBi along the azimuth direction.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.81-88
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• 2004

In this paper, we designed the outer encoder/decoder for the terrestrial DMB that is an advanced digital broadcasting standard, implemented, and verified by using ALTERA FPGA. In the encoder part, it was created the parity bytes (16 bytes) from the input packet (188by1e) of MPEG-2 TS and the encoded data was distributed output by the convolutional interleaver for Preventing burst errors. In the decoder part, It was proposed the algorithm that detects synchronous character suitable to DMB in transmitted data from the encoder. The circuit complexity in RS decoder was reduced by applying a modified Euclid's algorithm. This system has a capability to correct error of the maximum 8 bytes in a packet. After the outer encoder/decoder algorithm was verified by using C language, described in VHDL and implemented in the ALTERA FPGA chips.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.4
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• pp.453-461
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• 2011

In order to use more efficiently limited frequency resources at the broadcasting band and to eliminate blanket area of the terrestrial broadcasting and to improve broadcasting quality. The importance of repeaters has increasing continuously. However, in case of T-DMB digital on channel repeater in OFDM systems, some of the signal radiated feedback again at the receiver antenna. So it generates feedback signal interference in repeater system. Also phase noise increases ICI(Inter Carrier Interference). It affects seriously the frequency domain equalizer. In this paper, we remove the feedback signal interference by LMS with correlation. Also we propose an effective equalizer algorithm that can remove ICI caused by phase noise and the power amplifier's back-off. In this simulation results, this system is satisfied the performance of BER=$10^{-4}$ at less than SNR=14 dB after compensation of phase noise.

• Journal of Korea Multimedia Society
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• v.11 no.12
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• pp.1765-1774
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• 2008

Due to recent increase of product placement(aka. PPL) in TV drama and entertainment program, the audience of these programs is exposed to the advertisement in the form of the props and backgrounds without discernment. Advancement in digital data broadcasting technology enabled advertisers to insert detailed information of the product or associated advertisement link into the content of the broadcast program as an interactive advertisement. With the interactive advertisement, the audience can focus on the content of the program and the advertiser can create an advertisement with a rich content through the interaction between the advertisement and the audience. It is possible because the interactive advertisement is dynamic advertisement behavior only activated by the audience's intention. In this research, we develop a Hot-spot generator to insert interactive advertisement in the DMB broadcast program. We also suggest dynamic Hot-spot generation technique that allows the Hot-spot object to follow not only the shape of the advertising object in the program, but also the movement of the object as the program progresses.