• Journal of Korean Society for Geospatial Information Science
• /
• v.20 no.2
• /
• pp.55-61
• /
• 2012

The primary factors of the LOS(Line-of-Sight) analysis process are terrain height, camera capacity, and canopy cover. The canopy cover rate differs depending on the changing season, and its value is influenced by the tree density, tree height, and etc. This study generated the canopy cover value based on relationship between NDVI(Normalized Difference Vegetation Index) and DMT(Density Measure % of Tree/Canopy Cover), which is a digital map attribute, and then performed the LOS analysis on six station of test sites. As results, It was found that NDVI and DMT are correlated with each other through the experiments. Based on this finding, new DMT map can be generated using NDVI. Also, There is a difference between the result of visibility analysis using the present DMT and one using a new DMT. Especially, the spatial distributions of the detected visible areas are significantly different between the two visibility analysis results.

• Journal of Korean Society for Geospatial Information Science
• /
• v.18 no.2
• /
• pp.55-61
• /
• 2010

Using 3D point data implemented from terrestrial LiDAR, this research has modelled geospatial data in 2 categories(gridded & un-gridded) and conducted LOS analysis experiment using outcome from the modeling exercise. To compare LOS analysis results from each of the 2 models in the above, maximum LOS (line of sight) range in the experimental area was specified as 30m in Area A, 40m in Area B and 50m in Area C and the time taken by LOS analysis and the number of visible points were measured. As for the LOS analysis experiment results, in comparison with the gridded model, the un-gridded model took about 3.9 times more time in Area A, 5.4 times in Area B and 6.5 times in Area C. In addition, about 0.97 times fewer points were measured in Area A, 0.93 times in Area B and 0.94 times in Area C. The difference between gridded model and un-gridded model in terms of the time taken by LOS analysis increased, as the maximum LOS range extended. On the other hand, the number visible points did not vary significantly in reference to the size of visible range.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.27 no.3
• /
• pp.357-365
• /
• 2009

RTLS(Real-Time location system) for Location tracking of personnel and equipment of a construction site is now in development, among these techniques the wireless LAN-based techniques are being considered. To introduce these techniques to the construction site, the 3-dimensional visibility analysis prior to the installation location of AP must be simulated. At this time, three-dimensional visibility analysis considering the propagation distance of RTLS signal of AP(Access Point) should be performed. In this research, two processing methods LOS boundary are tested to various grid size of gridded terrestrial LiDAR data, and the results were compared. In evaluations of visible area, the Scanline Fill-Method shows approximately 7.4% more visible area than the Shadow Clipping-Method, but the Shadow Clipping-Method shows stable results for the grid size. About the processing time, the Scanline Fill-Method is about 2 times faster compared to the Shadow Clipping-Method.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.6
• /
• pp.1414-1418
• /
• 2013

In this paper, analyzed of UAVs operation altitude and range from the point of view of the data link. UAVs operation altitude is determined by the specification of the mission equipment and operational purposes. The link-of-sight analysis of data link equipment before deciding the unmanned aircraft operation altitude conditions should be considered. If GDT=0m installation then 32dBi antenna apply 15,779 meter is operation altitude. 44dBi antenna 7,927 meters. Operating altitude perspective, high-gain antenna is recommended of the long range communication.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.05a
• /
• pp.783-785
• /
• 2013

In this paper, analyzed of UAVs operation altitude and range from the point of view of the data link. UAVs operation altitude is determined by the specification of the mission equipment and operational purposes. The link-of-sight analysis of data link equipment before deciding the unmanned aircraft operation altitude conditions should be considered. If GDT=0m installation then 32dBi antenna apply 13,724 meter is operation altitude. 44dBi antenna 6,657 meters. Operating altitude perspective, high-gain antenna is recommended of the long range communication.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.11a
• /
• pp.429-433
• /
• 2004

기존 가시권 분석에 있어서는 주거지 개발, 도로, 송전선 설치 등에 따른 시각적 영향을 분석하는 연구가 많이 이뤄졌다. 이들은 개발에 따른 시각적 영향을 분석하고 부정적 영향을 최소화시킴을 목표로 하고 있다. 경관이 안공요소의 침입을 수용할 수 있는 정도를 고려하여 각 경관의 수용능력에 따른 개발을 유도함으로써 시각적 환경의 질을 높이고자 하는 것이다. 또한 도심지의 개발로 인하여 중요 문화ㆍ관광자원의 훼손으로 오랫동안 잘 보존되어야할 관광자원에 대한 시각적 영향을 분석하고자 하였다. 본 논문에서는 많은 문화ㆍ관광자원을 보유하고 있는 경주시 지역에 대하여 가시권역을 시각화하고 분석하여 보았다. 우선 경주시 지역에 대한 1:25,000 수치지형도 9장을 중첩하여 Arcview 프로그램을 이용하여 등고선만을 추출하였으며, 추출된 등고선도를 가지고 DEM을 생성한 후 Arc/GIS의 Workstation Arc/Info를 이용하여 가시권역을 나타내어 보았다. 이렇게 나타난 가시권역과 문화ㆍ관광지역과의 중첩을 통하여 가시지역의 범위를 분석하여 본 결과 관측점에서의 가시범위가 약 70%정도로 나타났다.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.4
• /
• pp.642-649
• /
• 2010

LOS analysis is used for optimal deployment of mid-range guided weapon system or system engagement effectiveness simulation. Comparing to real-world, LOS analysis includes error sources such as coarse terrain data resolution, refraction of radio waves, and several ideal assumptions. In this research, exact LOS algorithm under assumption of constant earth curvature and error analysis of that is investigated. It proved that LOS algorithm under assumption of constant earth curvature has negligible error in mid-range guidance weapon system's scope.

• The Bulletin of The Korean Astronomical Society
• /
• v.35 no.1
• /
• pp.90.1-90.1
• /
• 2010

우리는 Machholz 혜성(C/2004Q2)의 가시광선 영역 스펙트럼 (황성원 외, 2009, JASS, v. 26, p. 279)과 기존의 연구 문헌에 나오는 Austin, Swift-Tuttle, Brorsen-Metcalf 및 de Vico 혜성의 가시광선 영역 고분산 분광 자료와 비교 분석해 방출선의 파장 및 그 원인이 되는 물질을 확인했다. 그 결과 Machholz 혜성의 방출선은 대부분 $C_2,\;NH_2,\;CN,\;H_2O^+$에 의한 것으로 나타났으며, 기존의 혜성 자료에서 알려지지 않은 미확인 방출선도 발견됐다. 또한, 주로 장파장 영역에서 나타나는 OH 방출선을 지구대기의 OH 방출선 자료와 비교 분석한 결과, Maccholz 혜성 고유의 OH일 가능성이 있는 방출선도 확인됐다. 본 연구에서 정리한 Machholz 혜성 및 다른 혜성들과의 비교 자료는 데이터베이스화하여 공개한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.29 no.2
• /
• pp.165-173
• /
• 2011

Generally, A acquisition of the target is affected by the detector performance and whether it is covered with features or not. This paper represented the comparative analysis of the detection probability for DEM and DSM, when we used by the infrared surveillance device. In the first place, we c1assified as the visible area and invisible area for DEM and DSM, and obtained the acquisition probability values using the ACQUIRE mode. We have known that The Detection Probability of the DSM is very lower than the DEM and is rising when elevates the height value of the detection point.

• Bulletin of the Korean Space Science Society
• /
• 1992.10a
• /
• pp.20-20
• /
• 1992

격변 변광성의 일종인 DQ Her형 별(Intermediate Polar Star; IP)이 자기장에서 방출하는 가시광선은 자전주기에 따라 그 강도가 변한다. 이러한 쌍성계에서 백색 왜성인 주성의 주번에 자기력 선을 따라 정도의 물질이 주계열성인 반성으로부터 accretion 된다. 이 물질은 주성 표면에서 충격파로 생긴 X-선원에 의해 reemission 되는 데, 이런 현상적인 모델을 만들어 관측적으로 나타나는 자전주기에 따른 가시광선의 강도 변화를 설명하였다. 이런 결과가 IP 에서 방출되는 가시광선 관측의 분석과 이런 종류의 쌍성계가 가지는 궤도기울기, accretion rate, 공전축에 대한 자전축의 기울기, interaction radius 등의 물리적 상수를 결정하는 데 응용될 수 있음을 보이려고 한다.