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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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Abstract A class of exact solutions to the steady, two-dimensional magnetohydrodynamic equations ina cylindrical geometry is presented. These may model both closed and open magnetic structures found in the solar atmosphere. For closed structures, it is found that increasing the flow speed causes the summit of the arcade of closed magnetic fieldlines to rise. Parameter ranges also exist where the solution has regions of open and closed field, and so the solutions may be relevant for modelling flows in solar magnetic structures such as coronal streamers, X-ray bright points coronal plumes and coronal holes. 相似文献
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Stephen David Johnson Stephen Flint David Hinds & H. De Ville Wickens 《Sedimentology》2001,48(5):987-1023
The Tanqua area of the Karoo basin, South Africa, contains five Permian deep-water turbidite fan systems, almost completely exposed over some 640 km2 . Reconstruction of the basin-fill and fan distributions indicates a progradational trend in the 450 m+ thick succession, from distal basin floor (fan 1) through basin-floor subenvironments (fans 2, 3 and 4) to a slope setting (fan 5). Fans are up to 65 m thick with gradational to sharp bases and tops. Facies associations include basin plain claystone and distal turbidite siltstone/claystone and a range of fine-grained sandstone associations, including low- and high-density turbidite current deposits and proportionally minor debris/slurry flows. Architectural elements include sheets of amalgamated and layered styles and channels of five types. Each fan is interpreted as a low-frequency lowstand systems tract with the shaly interfan intervals representing transgressive and highstand systems tracts. All fans show complex internal facies distributions but exhibit a high-frequency internal stratigraphy based on fan-wide zones of relative sediment starvation. These zones are interpreted as transgressive and highstand systems tracts of higher order sequences. Sandy packages between these fine-grained intervals are interpreted as high-frequency lowstand systems tracts and exhibit dominantly progradational stacking patterns, resulting in subtle downdip clinoform geometries. Bases of fans and intrafan packages are interpreted as low- and high-frequency sequence boundaries respectively. Facies juxtapositions across these sequence boundaries are variable and may be gradational, sharp or erosive. In all cases, criteria for a basinward shift of facies are met, but there is no standard 'motif' for sequence boundaries in this system. High-frequency sequences represent the dominant mechanism of active fan growth in the Tanqua deep-water system. 相似文献
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H. M. Tuihedur Rahman June Y. T. Po Arlette S. Saint Ville Nicolas D. Brunet Stephen M. Clare Samantha Darling 《社会与自然资源》2019,32(12):1344-1363
AbstractThis study expands the Inter-Institutional Gaps (IIGs) framework to conceptualize the legitimacy associated with different types of ecological knowledge (e.g., scientific, traditional and local) used in natural resource governance. We draw on primary qualitative data, and document analysis to examine a case of inland fisheries management in the north-eastern floodplain of Bangladesh. We posit that the pragmatic, moral, cognitive, and regulative legitimacy for different types of ecological knowledge are repeatedly reevaluated by rule-makers and resource users in the process of rule-devising. Results show that inter-institutional gaps may be perpetuated when formal rules do not sufficiently consider traditional and local ecological knowledge. While it is widely proposed that systematically incorporating different knowledge types can better address local-national policy problems, this study underscores that the source of legitimacies for different knowledge types often differs across formal and informal institutional actors. Recognizing the differences is critical to fishers’ resource management. 相似文献
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Andrew D. Venter Pieter G. van Zyl Johan P. Beukes Jan-Stefan Swartz Miroslav Josipovic Ville Vakkari Lauri Laakso Markku Kulmala 《Journal of Atmospheric Chemistry》2018,75(3):285-304
Aerosols consist of organic and inorganic species, and the composition and concentration of these species depends on their sources, chemical transformation and sinks. In this study an assessment of major inorganic ions determined in three aerosol particle size ranges collected for 1 year at Welgegund in South Africa was conducted. SO42? and ammonium (NH4+) dominated the PM1 size fraction, while SO42? and nitrate (NO3) dominated the PM1–2.5 and PM2.5–10 size fractions. SO42? had the highest contribution in the two smaller size fractions, while NO3? had the highest contribution in the PM2.5–10 size fraction. SO42? and NO3? levels were attributed to the impacts of aged air masses passing over major anthropogenic source regions. Comparison of inorganic ion concentrations to levels thereof within a source region influencing Welgegund, indicated higher levels of most species within the source region. However, the comparative ratio of SO42? was significantly lower due to SO42? being formed distant from SO2 emissions and submicron SO42? having longer atmospheric residencies. The PM at Welgegund was determined to be acidic, mainly due to high concentrations of SO42?. PM1 and PM1–2.5 fractions revealed a seasonal pattern, with higher inorganic ion concentrations measured from May to September. Higher concentrations were attributed to decreased wet removal, more pronounced inversion layers trapping pollutants, and increases in household combustion and wild fires during winter. Back trajectory analysis also revealed higher concentrations of inorganic ionic species corresponding to air mass movements over anthropogenic source regions. 相似文献
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Ville Mäkinen Juha Oksanen Tapani Sarjakoski 《International journal of geographical information science》2019,33(2):291-313
Determining stream networks automatically from digital elevation models is an issue that is actively being studied. The quality of elevation models has increased over time, but many hydrologically critical features, such as culverts, are often missing from the elevation data. To analyze the surficial water flow, one must either prepare a special elevation model or post-process an already-existing model.
This study builds on the traditional, well-established method of determining the stream network from digital elevation models. We have extended the traditional method by locating culverts automatically, using road network data as an input. We show, by comparison to the reference data, that the culverts being most relevant for the stream network can be found with good accuracy. We demonstrate that by including the automatically located culverts in the automatic stream network determination, the quality of the generated network can be noticeably improved. 相似文献
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