• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.5
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• pp.417-424
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• 2006

Despite of many researches related to create 3D digital maps, it is still time-consuming and costly because a large part of 3D digital mapping is conducted manually. To circumvent this limitation, we proposed methodologies to create 3D digital maps with 3D symbols automatically. For this purpose, firstly, the 3D symbol library to represent 3D objects as 3D symbols was constructed. In this library, we stored the attribute and geometry information of 3D objects which define types and shapes of symbols respectively. These information were used to match 3D objects with 3D symbols and extracted from 2D digital maps and LiDAR(Light Detection and Ranging) data. Then, to locate 3D symbols into a base map automatically, we used predefined parameters such as the size, the height, the rotation angle and the center of gravity of 3D objects which are extracted from LiDAR data. Finally, the 3D digital map in urban area was constructed and the results were tested. Through this research, we can identify that the developed algorithms can be used as effective techniques for 3D digital mapping.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.9 no.3
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• pp.103-107
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• 1984

According to rapid developments in data communication, we have being used every infromation with ease. In receiving and transmitting the infromation acquired, it is being needed to transmit it with minimizing bits if possible. Therefore this paper suggests the efficient coding system, that is, OCM(Octal-Compact Mapping) technique. In case of average-case, it has 3.5bytes in entropy with 8 symbols. This means it is compressed more than at least 1 byte as compared with another coding techniques. It decreases the redundancy of data and is superior to another data compression techniques.

• Journal of the Korean association of regional geographers
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• v.20 no.3
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• pp.245-255
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• 2014

There is limitation to represent forms and internal process of topography if using simple symbols for geomorphic landscape in the cartography. One of the alternative method to find a solution to these problems is to use association symbol to imagine real landscapes through map reading. This study suggested making method of association symbols to describe geomorphic landscapes effectively. Landforms are not static objects but dynamic pedogenesis and morphogenesis one. It should be consider form, process, and material to make landform mapping, and also, make landform symbols by considering scalable changeability for point-polygon, line-polygon, point-line by scale. As a results, this study expected to help applications for geomorphology as well as environments, ecology, archaeology, and civil engineering etc.

• Journal of Advanced Navigation Technology
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• v.10 no.1
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• pp.20-25
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• 2006

In these days, OFDM(Orthogonal Frequency Division Multiplexing) is adopted to support high-speed data communication based on multi-path RF channel, but it has some weak point. One of those is that it has a higher PAR(peak-to-average power ratio) compared with single-carrier method. If some PAR of the transmitted signal is high, nonlinear amplitude distortion has occurred when it pass through the HPA(high power amplifier). There is a solution to prevent nonlinear distortion using higher peak power HPA, but it makes inefficiency and a cost problem. In this paper, we choose the SLM(Selected Mapping) scheme, which transmit the lowest PAR signal after OFDM symbol mapping, in various schemes reducing PAR for OFDM system. And we derived the performances of SLM method in fading channel through computer simulations.

• ETRI Journal
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• v.31 no.6
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• pp.795-802
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• 2009

This paper presents the design of an advanced terrestrial digital multimedia broadcasting (AT-DMB) baseband receiver SoC. The AT-DMB baseband is incorporated into a hierarchical modulation scheme consisting of high priority (HP) and low priority (LP) stream decoders. The advantages of the hierarchical modulation scheme are backward compatibility and an enhanced data rate. The structure of the HP stream is the same as that of the conventional T-DMB system; therefore, a conventional T-DMB service is possible by decoding multimedia data in an HP stream. An enhanced data rate can be achieved by using both HP and LP streams. In this paper, we also discuss a time deinterleaver that can deinterleave data for a time duration of 384 ms or 768 ms. The interleaving time duration is chosen using the LP symbol mapping scheme. Furthermore, instead of a Viterbi decoder, a turbo decoder is adopted as an inner error correction system to mitigate the performance degradation due to a smaller symbol distance in a hierarchically modulated LP symbol. The AT-DMB baseband receiver SoC is fabricated using 0.13 ${\mu}m$ technology and shows successful operation with a 50 mW power dissipation.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1169-1174
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• 1991

In conventional geographic mapping system, it is needed to input many already existing geographic map into computer system for secure and efficient maintence. Because of large map data, it is required to construct layers from map image for easy display, fast retreval and efficient storage. Thus this paper represents a method of the extracting features from contour map and constructing three layers. The layers are symbol, building, contour line. Experimental results are presented confirming the method's high extraction.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.35-43
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• 2022

The 2020 Gwangju Media Art Festival (2020 GMAF) was held in the area of the National Asian Cultural Center. Under the slogan "The entire Gwangju shines under the theme of "Aesthetics of Light and Coexistence," the media festival demonstrated projection mapping to Jeonnam (former) Provincial Office at the DATA+ Research Institute of Chung-Ang University's Graduate School of Advanced Video. This paper focuses on explaining the overall production process and content development of projection mapping demonstrated in the Jeollanam-do Provincial Government, which is a symbol of Korean democratization and is located in the center of Gwangju, Jeolla-do. It was intended to faithfully express the history of the 2020 GMAF and Jeonnam (former) provincial government, Gwangju's history, and democratization records. It was intended to show images, background sounds, sound effects, and visual effects using various special effects and high-power laser devices using unique characteristics of projection mapping. To this end, about 5 minutes and 30 seconds of content were planned, and it was divided into parts and topics, and one individual story was developed for each chapter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6C
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• pp.565-571
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• 2007

In order to improve PAPR (Peak-to-Average Power Ratio) reduction performance of the conventional SLM (Selective Mapping) for OFDM (Orthogonal Frequency Division Multiplexing) signals, we propose an effective SLM-PRSC (PAPR Reduction Sub-Carrier) hybrid scheme. In the proposed scheme, after performing the SLM for the frequency domain OFDM symbol excluding pre-determined PRSC positions, the SLM-PRSC hybrid sequence with the lowest PAPR generated by adding the time domain PRSC sequence to the results of the SLM, is selected as the transmitted OFDM signal. Since the identical PRSC sequences generated a priori are repeatedly used for every OFDM symbol, excessive IFFT (inverse Fast Fourier Transform) calculation is avoided. Simulation results show that the proposed scheme significantly improves the PAPR reduction performance of the conventional SLM, while avoiding excessive increase of IFFT calculation and the overhead for the SLM.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.10
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• pp.1020-1023
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• 2011

In this paper, we present a symbol remapping method of BRGC M-ary QAM signal by using LLR soft bit decision information which is obtained after iterative decoding process. In order to reconstruct estimated transmitted signal constellation, we have to use exponential or hyperbolic tangent(tanh) function resulting in high implementation complexity. The BRGC mapping rule enables us to use a recursive operation. In addtion, we reduce the implementing complexity by using a curve fitting algorithm.

• Journal of Digital Contents Society
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• v.5 no.2
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• pp.143-150
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• 2004

In this paper, we propose and analyze a new scheme which uses the same scramble codes to each group after symbol grouping to reduce the PAPR (peak-to-avenge power ratio) problem in OFDM system. The conventional SLM scheme randomizes OFDM symbols entered into IFFT block by several scramble codes and then transmits the lowest one among PAPRs. Therefore, the SLM scheme can reduce the additional information as many as the number of grouped OFDM symbols by using same scramble codes after M grouping of sub-carriers. It can also improve PAPR performance more than conventional SLM scheme when we use scramble codes as same as those numbers of SLM scheme.