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Wyszukujesz frazę "alpha shape" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Verification and updating of the Database of Topographic Objects with geometric information about buildings by means of airborne laser scanning data
Autorzy:
Mendela-Anzlik, M.
Borkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1396875.pdf
Data publikacji:
2017
Wydawca:
Politechnika Warszawska. Wydział Geodezji i Kartografii
Tematy:
airborne laser scanning
Database of Topographic Objects
alpha shape
lotnicze skanowanie laserowe
baza danych obiektów topograficznych
kształt alfa
Opis:
Airborne laser scanning data (ALS) are used mainly for creation of precise digital elevation models. However, it appears that the informative potential stored in ALS data can be also used for updating spatial databases, including the Database of Topographic Objects (BDOT10k). Typically, geometric representations of buildings in the BDOT10k are equal to their entities in the Land and Property Register (EGiB). In this study ALS is considered as supporting data source. The thresholding method of original ALS data with the use of the alpha shape algorithm, proposed in this paper, allows for extraction of points that represent horizontal cross section of building walls, leading to creation of vector, geometric models of buildings that can be then used for updating the BDOT10k. This method gives also the possibility of an easy verification of up-to-dateness of both the BDOT10k and the district EGiB databases within geometric information about buildings. For verification of the proposed methodology there have been used the classified ALS data acquired with a density of 4 points/m2. The accuracy assessment of the identified building outlines has been carried out by their comparison to the corresponding EGiB objects. The RMSE values for 78 buildings are from a few to tens of centimeters and the average value is about 0,5 m. At the same time for several objects there have been revealed huge geometric discrepancies. Further analyses have shown that these discrepancies could be resulted from incorrect representations of buildings in the EGiB database.
Źródło:
Reports on Geodesy and Geoinformatics; 2017, 103; 22-37
2391-8365
2391-8152
Pojawia się w:
Reports on Geodesy and Geoinformatics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An application of LSC method for the measurement of gross alpha and beta activities in spiked water and drinking water samples
Autorzy:
Çakal, G. Ö.
Güven, R.
Yücel, H.
Powiązania:
https://bibliotekanauki.pl/articles/146427.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
alpha activity
beta activity
drinking water
liquid scintillation counting (LSC)
pulse shape analysis (PSA) calibration
quench
Opis:
In this study, after the pulse shape calibration of a liquid scintillation counting (LSC) spectrometer (Quantulus 1220), the efficiency was determined depending on sample quenching parameters. Then, gross alpha and beta activities in two spiked water samples obtained from International Atomic Energy Agency (IAEA) were used for the validation of the ASTM D7283-06 method, which is a standard test method for alpha and beta activity in water by LSC. Later, the drinking water samples (35 tap water and 9 bottled water) obtained from different districts of Ankara, Turkey, were measured. The maximum gross alpha activities are measured to be 0.08 Bq/L for tap waters and 0.13 Bq/L for bottled waters, whereas the maximum gross beta activities are found to be 0.18 Bq/L for tap waters and 0.16 Bq/L for bottled waters. These results indicate that these drinking water samples are below the required limits, which are 0.1 Bq/L for alpha emitting radionuclides and 1 Bq/L for beta emitting radionuclides. As a result, gross alpha and beta activities in drinking water of Ankara were determined accurately by this validated LSC method. It is also worth noting that LSC is a rapid and accurate method for the determination of gross alpha and beta activities without requiring a tedious sample preparation.
Źródło:
Nukleonika; 2015, 60, No. 3, part 2; 637-642
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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