• ETRI Journal
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• v.38 no.5
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• pp.868-878
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• 2016

A multi-screen environment provides a new opportunity for digital signage applications, where various irregularly shaped screens are employed as an effective means for advertisements and information. A formation method applicable to numerous irregularly shaped screens is proposed to provide a new perspective on digital signage applications. The crucial part of the proposed method comes from the geometric sensing of each screen and the formation of a virtual screen where geometrically aligned content extraction and encoding are employed for content transmission to each screen. In addition, a software-based synchronization method for the proposed system is proposed to address the frame-level synchronization between screens. The experimental results of the proposed method show an improved performance of the frame-level synchronization, where the inconsistency between frames is not identified.

• Journal of Information Processing Systems
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• v.15 no.4
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• pp.890-903
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• 2019

The single carrier frequency domain equalization (SC-FDE) technology is an important part of the broadband wireless access communication system, which can effectively combat the frequency selective fading in the wireless channel. In SC-FDE communication system, the accuracy of timing synchronization directly affects the performance of the SC-FDE system. In this paper, on the basis of Schmidl timing synchronization algorithm a timing synchronization algorithm suitable for FPGA (field programmable gate array) implementation is proposed. In the FPGA implementation of the timing synchronization algorithm, the sliding window accumulation, quantization processing and amplitude reduction techniques are adopted to reduce the complexity in the implementation of FPGA. The simulation results show that the algorithm can effectively realize the timing synchronization function under the condition of reducing computational complexity and hardware overhead.

• Journal of Digital Contents Society
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• v.14 no.3
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• pp.357-365
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• 2013

The popularization of smart phones changes the usage patterns of mobile communication from voice-centric to data-centric communication. The demand for wireless data communications is rapidly increasing, and thus the need for expanding infrastructure for mobile communication is also rapidly increasing. In this paper, we propose a scheme for reducing the cost for the mobile communication infrastructure by exploiting opportunistic networks in dissemination of multimedia contents. By using this scheme, the large portion of the cost for mobile communication infrastructure could be saved, and the need of users for multimedia contents could be also fulfilled. Our scheme is evaluated using agent-based simulations. The simulation results show that about 70% of mobile communication can be replaced with the data communication through opportunistic networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.873-892
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• 1998

In this paper, we propose an architecture of multimedia communication terminal that can e used in broadband ISDN environments. To design and implement the multimedia communication terminal, we analyzed the structure of multimedia terminals and the types of services which is recommended by public and private standard or ganization, such as ITU-T, Digital Audio-Visual Council(davic) and ATM Forum. The multifunctional communication terminal designed in this paper could allow inter-working between existing communication terminals on the heterogeneousnetwork and accept current and advanced multimedia communication application flexible. An implemented terminal is consisted of the multimedia processing board and the ATm interface board that is installed in PCI bus on personal computer. The integrated service multimedia communication terminal that is implemented supports retrieval, distributive and conversational communication service simultaneously. And then we performaned functional module test according to the individual communication services.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.899-903
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• 1994

This paper describes two methods to assess the output speech, quality of vocoders for telephone conferencing in digital mobile communication networks. The proposed methods are the sentence discrimiantion method and the modified degraded mean opinion score (MDMOS) test. We apply these two methods to Qualcomm code excited linear prediction (QCELP), vector sum excited linear prediction (VSELP) and regular pulse excited-long term predictin (RPE-LTD) voceders to evaluate which vocoding algorithm can process mixed voice signal from two speakers better for telephone conferencing. From the experiments we obtain that the VSELP vocoding algorithm reveals superior output speech quality to the other two.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.364-364
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• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.239-239
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• 2004

• 한국디지털정책학회:학술대회논문집
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• 2004.05a
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• pp.37-49
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• 2004

According as the use of information and communication technologies and the Internet are advancing rapidly, the digital economy are no longer emerging or beginning today. They are here with ours already. We are living in a new era that the economic paradigm and structures are changed remarkably, namely the digital economy era. Tourism policy is crucial to tourism industry competitiveness by triggering changes in the digital economy. Better tourism policy in the digital economy should satisfy the tourist needs as well as create additional value for the tourism industry.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.491-494
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• 1999

Introduction of digital communication network such as Integrated Services Digital Networks(ISDN) and digital storage media have rapidly developed. Due to a large amount of image data, compression is the key techniques in still image and video using digital signal processing for transmitting and storing. Digital image compression provides solutions for various image applications that represent digital image requiring a large amount of data. In this paper, the proposed DWT(Discrete Wavelet Transform) filter bank is consisted of simple architecture, but it is efficiently designed that a user obtain a wanted compression rate as only input parameter. If it is implemented by FPGA chip, the designed encoder operates in 12MHz.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1983.10a
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• pp.56-60
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• 1983

There has been a great amount of interest in the design of digital filters with low sensitivity to coefficient variations. Especiaily the wave digital filter modeled after analog IC ladder filter has been studied to have low-cocfficient-sensitivity properties. This paper examined the design of the wave digital filter and how the sensitivity and roundoff noise porperty arises. As a result of computer simulation the implementation of the digital filter was possible with a lower coefficient word length comparing with the conventional cascade structure.