Browsing by Subject "SOM"

Now showing 1 - 4 of 4

Access status: Restricted ,
Klasyfikacja dokumentów przy użyciu sieci Kohonena i redukcja wymiarowości przestrzeni wektorowej z wykorzystaniem algorytmu scatter
(Data obrony: 2019-09-19) Domański, Karol
Wydział Inżynierii Metali i Informatyki Przemysłowej
Access status: Open Access ,
Multiscale evaluation of a thin-bed reservoir
(Wydawnictwa AGH, 2021) Lis-Śledziona, Anita
A thin-bed laminated shaly-sand reservoir of the Miocene formation was evaluated using two methods: high resolution microresistivity data from the XRMI tool and conventional well logs. Based on high resolution data, the Earth model of the reservoir was defined in a way that allowed the analyzed interval to be subdivided into thin layers of sandstones, mudstones, and claystones. Theoretical logs of gamma ray, bulk density, horizontal and vertical resistivity were calculated based on the forward modeling method to describe the petrophysical properties of individual beds and calculate the clay volume, porosity, and water saturation. The relationships amongst the contents of minerals were established based on the XRD data from the neighboring wells, hence, the high-resolution lithological model was evaluated. Predicted curves and estimated volumes of minerals were used as an input in multimineral solver and based on the assumed petrophysical model the input data were recalculated, reconstructed and compared with the predicted curves. The volumes of minerals and input curves were adjusted during several runs to minimalize the error between predicted and recalculated variables. Another approach was based on electrofacies modeling using unsupervised self-organizing maps. As an input, conventional well logs were used. Then, the evaluated facies model was used during forward modeling of the effective porosity, horizontal resistivity and water saturation. The obtained results were compared and, finally, the effective thickness of the reservoir was established based on the results from the two methods.
Access status: Open Access ,
Wykorzystanie sieci Kohonena do selekcji podobrazów na potrzeby dopasowania zdjęć lotniczych
(Wydawnictwa AGH, 2007) Czechowicz, Anna; Mikrut, Zbigniew
Automatic relative orientation is one of the key problems in photogrammetric processing. This paper concerns the application of the representation based on the gradient distribution and Kohonen neural networks for the selection of sub-images for aerial photographs matching purposes. The examinations were conducted over 904 sub-images of the aerial photographs of the Krakow's surroundings with different land cover, grouped into three categories: advantageous, nondescript and disadvantageous in respect of searching features for relative orientation. The 2D histogram was acquired for every sub-image and on this basis the representation in form of the vector of maximum values for gradient direction has been determined. This representation was utilized for the classification of areas with Kohonen network. The correctness of the obtained classification, compared to manually done, achieved the Ievel of 68,3%.
Access status: Open Access ,
Wykrywanie krwi na obrazach bronchoskopowych za pomocą sieci neuronowych
(Wydawnictwa AGH, 2009) Mikrut, Zbigniew; Duplaga, Mariusz
In the paper the experiments with using SOM-supervised neural networks for pixel (HSV) classification were presented. Six visually different images were chosen to be the basis for the SOM training. For these images learning sets were created based on the refined masks of the bleeding regions pointed out by the doctor. Next the six learning sets were merged and the ambiguous pixel representations were removed. Two types of SOM-supervised networks (of »normal« and »small« sizes) were created and learned. The classification results were obtained and analyzed both for learning sets and for 14 test images. Several conclusions were stated concerning the learning methodology and the bleeding areas postprocessing.