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Shayan Nikoohemat Abdoulaye A. Diakit Ville Lehtola Sisi Zlatanova George Vosselman 《Transactions in GIS》2021,25(1):189-212
Indoor 3D models are digital representations of building interiors reconstructed from scanned data acquired by laser scanners, digital depth (RGBD) cameras, and CAD drawings. Consequently, there is noise in the source data and a notable variety in the methods used to treat the noise and to process these data into reconstructed models. Alas, the correctness of these reconstructions and thus their suitability for a given application are uncertain. There is a lack of a robust base logic that would allow for controlling the consistency of these (automatically) generated models. Fortunately, correctness criteria are well‐defined through existing international standards. Hence, we propose a conceptual framework based on formal grammars to check the semantic, geometric, and topological consistency of a reconstructed 3D model. The proposed method proceeds in three steps to validate the model: (1) correctness checking of individual components; (2) consistency verification of instances’ interactions; and (3) model consistency check for targeted applications. Our method identifies the components in the model that violate the given rules derived from the current standards and expert knowledge. Ultimately, we propose a quantified formulation of our method that may be straightforwardly integrated into industrial‐level model checkers. The approach is independent of level of details and reconstruction method. 相似文献
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An Introduction to MODISI and SCMOD Methods for Correction of the MODIS Snow Assessment Algorithm 总被引:1,自引:0,他引:1
Mohammad Reza Mobasheri Hossein Shafizadeh Moghadam Siavosh Shayan 《Journal of the Indian Society of Remote Sensing》2010,38(4):674-685
Detection, monitoring and precise assessment of the snow covered regions is an important issue. Snow cover area and consequently
the amount of runoff generated from snowmelt have a significant effect on water supply management. To precisely detect and
monitor the snow covered area we need satellite images with suitable spatial and temporal resolutions where we usually lose
one for the other. In this study, products of two sensors MODIS and ASTER both on board of TERRA platform having low and high
spatial resolution respectively were used. The objective of the study was to modify the snow products of MODIS by using simultaneous
images of ASTER. For this, MODIS snow index image with high temporal resolution were compared with that of ASTER, using regression
and correlation analysis. To improve NDSI index two methods were developed. The first method generated from direct comparison
of ASTER averaged NDSI with those of MODIS (MODISI). The second method generated by dividing MODIS NDSI index into 10 codes
according to their percentage of surface cover and then compared the results with the difference between ASTER averaged and
MODIS snow indices (SCMOD). Both methods were tested against some 16 MODIS pixels. It is found that the precision of the MODISI
method was more than 96%. This for SCMOD was about 98%. The RMSE of both methods were as good as 0.02. 相似文献
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Zahra Bagheri Pantea Davoudifar Gohar Rastegarzadeh Milad Shayan 《Journal of Astrophysics and Astronomy》2017,38(1):4
In this paper, we used CORSIKA code to understand the characteristics of cosmic ray induced showers at extremely high energy as a function of energy, detector distance to shower axis, number, and density of secondary charged particles and the nature particle producing the shower. Based on the standard properties of the atmosphere, lateral and longitudinal development of the shower for photons and electrons has been investigated. Fluorescent light has been collected by the detector for protons, helium, oxygen, silicon, calcium and iron primary cosmic rays in different energies. So we have obtained a number of electrons per unit area, distance to the shower axis, shape function of particles density, percentage of fluorescent light, lateral distribution of energy dissipated in the atmosphere and visual field angle of detector as well as size of the shower image. We have also shown that location of highest percentage of fluorescence light is directly proportional to atomic number of elements. Also we have shown when the distance from shower axis increases and the shape function of particles density decreases severely. At the first stages of development, shower axis distance from detector is high and visual field angle is small; then with shower moving toward the Earth, angle increases. Overall, in higher energies, the fluorescent light method has more efficiency. The paper provides standard calibration lines for high energy showers which can be used to determine the nature of the particles. 相似文献
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