• Title/Summary/Keyword: 지상

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Analysis of the GPS-derived Control Point Errors for Quality Assurance of 3D Digital Maps (3차원 수치지도 정확도 검증을 위한 GPS 기반 기준점 오차의 영향 분석)

  • Bae, Tae-Suk;Lee, Dong-Cheon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.28 no.1
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    • pp.153-160
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    • 2010
  • It is necessary to determine accurate 3-dimensional coordinates of the building corner points that could be control or check points in order to verify the accuracy of 3D digital maps in the near future. The usual process of obtaining the coordinates of the building corner points is to set up the ground control points with a GPS and then to practice terrestrial survey such as distance or angle measurements. However, since an error in the ground control points can be propagated through the terrestrial survey into the final coordinates of the buildings, accurately should be considered as much as possible. The actual effect of the GPS-derived ground control point error on the estimates of the unknowns through the terrestrial survey is mathematically analyzed, and the simulation data is tested numerically. The error of the ground control points is tested in the cases of 1-4 cm for the horizontal components and 2-8 cm for the vertical component. The vertical component error is assigned twice the horizontal ones because of the characteristics of the GPS survey. The distance measurement is assumed for convenience and the precision of the estimated coordinates of the building corner points is almost linearly increased according to the errors of the ground control points. In addition, the final estimates themselves can vary by the simulated random errors depending on the precision of the survey instrument, but the precision of the estimates is almost independent of survey accuracy.

Utilization of Ground Control Points using LiDAR Intensity and DSM (LiDAR 반사강도와 DSM을 이용한 지상기준점 활용방안)

  • Lim, Sae-Bom;Kim, Jong-Mun;Shin, Sang-Cheol;Kwon, Chan-O
    • Spatial Information Research
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    • v.18 no.5
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    • pp.37-45
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    • 2010
  • AT(Aerial Triangulation) is the essential procedure for creating orthophoto and transforming coordinates on the photographs into the real world coordinates utilizing GCPs (Ground Control Point) which is obtained by field survey and the external orientation factors from GPS/INS as a reference coordinates. In this procedure, all of the GCPs can be collected from field survey using GPS and Total Station, or obtained from digital maps. Collecting GCPs by field survey is accurate than GCPs from digital maps; however, lots of manpower should be put into the collecting procedure, and time and cost as well. On the other hand, in the case of obtaining GCPs from digital maps, it is very difficult to secure the required accuracy because almost things at each stage in the collecting procedure should rely on the subjective judgement of the performer. In this study, the results from three methods have been compared for the accuracy assessment in order to know if the results of each case is within the allowance error: for the perceivable objects such as road boarder, speed bumps, constructions etc., 1) GCPs selection utilizing the unique LiDAR intensity value reflected from such objects, 2) using LiDAR DSM and 3) GCPs from field survey. And also, AT and error analysis have been carried out w ith GCPs obtained by each case.

Development of BIFS Contents Authoring System for T-DMB Interactive Data Service (지상파 DMB 대화형 서비스를 위한 BIFS 콘텐츠 저작 시스템 구현)

  • Ah Sang-Woo;Cha Ji-Hun;Moon Kyung-Ae;Cheong Won-Sik
    • Journal of Broadcast Engineering
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    • v.11 no.3 s.32
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    • pp.263-275
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    • 2006
  • This paper introduces an interactive contents authoring system which can easily and conveniently produce interactive contents for the Terrestrial Digital Multimedia Broadcasting (T-DMB). For interactive broadcasting service, T-DMB adopted MPEG-4 BIFS technology. In order to the interactive service becomes flourishing on the market, various types of interactive contents should be well provided prior to the service. In MPEG-4 BIFS, broadcasting contents are described by the combination of a large number of nodes, routes and descriptors. In order to provide interactive data services through the T-DMB network, it is essential to have an interactive contents authoring system which allows contents authors to compose interactive contents easily and conveniently even if they lack any background on MPEG-4 BIFS technology. The introduced authoring system provides powerful graphical user Interface and produces interactive broadcasting contents in the forms of binary and textual format. Therefore, the BIFS contents authoring system presented in this paper would vastly contribute to the flourishing interactive service.

Analysis of the General Components of Syneilesis palmata Maxim (우산나물(Syneilesis palmata)의 성분 분석)

  • Lee, Yang-Suk;Seo, Soo-Jung;Kim, Nam-Woo
    • Food Science and Preservation
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    • v.16 no.3
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    • pp.412-418
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    • 2009
  • We measured the levels of soluble protein, sugar, free amino acids, minerals, total polyphenols, and flavonoid compounds in Syneilesis palmata as part of a study on nutritional and functional materials for development of valuable foods. The content of soluble protein in the aerial and root portions were 210.36 mg% and 870.42 mg%, respectively. The amount of reducing sugar was 848.12 mg% (aerial parts) and 1,420.91 mg% (roots), and that of free sugar was 14.85 mg% in aerial parts and 355.00 mg% in roots. The free amino acid level in aerial parts was 1,613.10 mg% and that in roots was 3,282.96 mg%. The mineral content of aerial parts was 3,531.53 mg% and that of roots was 1,878.34 mg%. The K, Ca, and Mg levels were greater than those of other minerals, with K comprising more than 75% of the total mineral content. The levels of polyphenol and flavonoid compounds in aerial parts were 1,920.00 mg% and 843.95 mg%, respectively, and those in roots were 487.56 mg% and 91.07 mg%, respectively.

3D Indoor Modeling Based on Terrestrial Laser Scanning (지상레이저스캐닝 기반 3차원 실내 모델링)

  • Hong, Seung Hwan;Cho, Hyoung Sig;Kim, Nam Hoon;Sohn, Hong Gyoo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.2
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    • pp.525-531
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    • 2015
  • According to the increasing demand for 3D indoor spatial information, the utilization of a terrestrial laser scanner comes to the fore. However, the research for the comparison between a terrestrial laser scanning method and a traditional surveying method is insufficient. The paper evaluated the time-efficiency and the locational accuracy of an AMCW type and a direct TOF type of terrestrial laser scanning methods in comparison with the observation using a total station. As a result, an AMCW type showed higher time-efficiency than a direct TOF type and the RMSE between the two types of data was ${\pm}1mm$. Moreover, the terrestrial laser scanning method showed twice higher time-efficiency than the observation using a total station and the RMSE between the two data was ${\pm}3.4cm$. The results indicate that the terrestrial laser scanning method has better profitability and performance for 3D indoor modeling than the traditional survey using a total station. In the future, a terrestrial laser scanner can be efficiently utilized in the construction of 3D indoor spatial information.

8-VSB Remodulator for Retransmitting the Terrestrial Digital Broadcasting (지상파 디지털방송 재전송을 위한 8-VSB 재변조기)

  • Kim, Yoo-Won;Jo, Geun-Sik
    • Journal of Korea Multimedia Society
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    • v.13 no.10
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    • pp.1525-1533
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    • 2010
  • With the digital terrestrial television broadcasting transition, terrestrial television broadcasting have required the replacement of retransmission facilities for the analog broadcasting installed in the existing apartment, building, cable TV station, MATV system and so on. In addition, new standards have been enacted for retransmission of the digital television broadcasting in MATV system. To deal with this issue, in this paper, we propose a new 8-VSB remodulator that can retransmit signals of the terrestrial digital television broadcasting. Moreover, we present a standard and the process composition of the 8-VSB remodulator, and an experimental environment configuration for performance evaluation. To achieve this, we have implemented the 8-VSB remodulator with the sequential process components comprised of the RF signal retransmission, the TS stream modulator, the RF signal reception and demodulation. Through the simulation, we analyze the performance standard from the measured data such as spurious and phase noise. And then, we measure SNR and EVM of each attenuation step of the signal obtained by the signal processor and the 8-VSB remodulator with the same retransmission environment and conditions. Experimental results show that both the 8-VSB remodulator and the signal processor can be used as equipment for the retransmission of the terrestrial digital television broadcasting. In addition, the 8-VSB remodulator performed well to improve the transmission efficiency for the digital broadcasting signal, compare to the existing signal processor.

SIMULTANEOUS OBSERVATIONS OF PI 2 PULSATIONS ON THE SATELLITE AND GROUND-BASED MEASUREMENTS (위성 및 지상자력계에서의 PI 2 파동 동시 관측)

  • 이성환;이동훈;김관혁
    • Journal of Astronomy and Space Sciences
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    • v.14 no.2
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    • pp.275-285
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    • 1997
  • We have investigated Pi 2 pulsations which were observed both on ground magnetometer array and by satellites. On November 9th in 1994, Pi 2 pulsations appeared globally on the 190/210 magnetometer chain and Hermanus station when two satellites(EXOS-D and ETS-VI) were located near the magnetic meridian of the 210 array. The local time of measurements covers from morning(LT=8.47hr) to afternoon(LT=20.3hr) and the bandwidth of peak frequency is found relatively small. The signals of the electric field are highly coherent with ground-based observations with the out of phase oscillations. However, the magnetic field measurement on the ETS-VI in the outer magnetosphere(L=6.60) shows no signature of Pi 2 pulsations over the same time interval and the correlation with any of the ground-based stations is found to be very weak, even through both satellites and magnetometer chain are located close to each other in local time. We suggest that this event may be a direct evidence of Pi 2 pulsations as virtual resonant modes which are localized in the plasmasphere(Lee 1996). The results show that the cavity mode oscillations can occur in the inner magnetosphere with less spectral noise compared to the outer magnetospheric case.

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