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1

Multiscale evaluation of a thin-bed reservoir

Lis-Śledziona Anita

Geology, Geophysics and Environment

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2021

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Vol. 47, no. 1

5--20

EN

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.

2

Evaluation of the diference in water quality between urban and suburban rivers based on self organizing map

Jiang Yaqi, Gui Herong, Li Chen, Chen Jiayu, Chen Chen, Wang Chunlei, Zhao Honghai, Guo Yan, Xu Jiying, Li Jun, Qiu Huili

Acta Geophysica

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2021

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Vol. 69, no. 5

1855--1864

EN

Urban rivers play an important role in maintaining the urban aquatic ecological environment, and there are bound to be differences in the water environment quality and pollution sources due to different locations of urban rivers. Therefore, this paper selects the urban river (Tuo River) and the suburban river (Bian River) in Suzhou City, Anhui, China, as the research objects. Based on the understanding of the hydrogeochemical characteristics of these two rivers, the self-organizing map is used to identify the main control factors that affect the water quality of the two rivers. The results showed that both the Bian river and Tuo river were weakly alkaline. The average content of conventional ions in Tuo river is less than that of Bian river (except HCO3 −); the water of Bian river was of Na–SO4–Cl type, and the water of Tuo river was mainly of Na–HCO3 type, with the minority was of Na–SO4–Cl type; Silicate weathering is an important source of conventional ions in the water of these two rivers; agricultural non-point source pollution is the main source of pollutants in Bian river, while Tuo river was mainly affected by natural factors, and human activities had little impact.

3

Response of the rotifer community to human-induced changes in the trophic state of a reservoir

Kim Seong-Ki, Kim Jeong-Cheol, Joo Jeong-Cheol, Choi Jong-Yun

Oceanological and Hydrobiological Studies

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2020

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Vol. 49, No. 4

329--344

EN

Human disturbance and nutrient runoff lead to water pollution, particularly in downstream waters and reservoirs. We hypothesized that increased human activity in summer would affect the trophic state of downstream reservoirs, affecting the interannual species composition of rotifers. We used long-term data for the Unmun Reservoir in South Korea (2009–2015), which is increasingly affected by human activity. The interannual variation of nitrogen and phosphorus levels was higher in summer and autumn, resulting in eutrophication. This led to a change in species composition of rotifers. Anuraeopsis fissa, Brachionus calyciflorus and Trichocerca gracilis were abundant in the most eutrophic state, while high densities of Ascomorpha ovalis and Ploesoma hudsoni were observed when nutrient concentrations were lower. The trophic state changes in the Unmun Reservoir were largely attributed to summer human activity in tributary streams. Our study location is typical of the stream network in South Korea and we assume that similar trophic state changes in reservoirs will be common. Changes in the density and species diversity of rotifers due to eutrophication indicate the need for active management and conservation, including the restriction of human activity around streams.

4

Cluster analysis on the example of work data of the National Power System. Part 1, Comparative study of methods and conditions

Tchórzewski Jerzy, Kania Tomasz

Studia Informatica : systems and information technology

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2019

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Vol. 1-2(23)

25--41

EN

The paper presents the results of the research on the comparative study of the methods of cluster analysis and conditions, which was carried out from the point of view of their use, on the example of data concerning the operation of the National Power System. Two algorithms were used for the clustering analysis, i.e. the Ward algorithm and the algorithm of self-organizing two-dimensional maps. Cluster analysis was preceded by a review of hierarchical and non-hierarchical methods of data analysis and a description of the prepared experiment. The obtained results were interpreted. The work consists of two parts published under the same main title with different subtitles. This part 1 presents the results of the conducted review of selected methods of cluster analysis and the research conditions resulting from the adopted data on the operation of the National Power System. Part 2 presents the cluster analysis process and selected research results and their discussion.

5

Sztuczne sieci neuronowe ANN : sieci Kohonena

Iljaszewicz Paweł

Biuletyn Naukowy Wrocławskiej Wyższej Szkoły Informatyki Stosowanej. Informatyka

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2018

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vol. 8, nr 1

34--39

PL

Artykuł omawia sztuczne sieci neuronowe (ang. ANN- Artificial neural networks). Jedną z odmian są sieci Kohonena zwane Mapą Samoorganizującą (ang. SOM – Self Organizing Map) realizują one proces uczenia się sieci neuronowych samodzielnie tzn. rozpoznają relacje występujące w skupieniach poprzez wykrycie wewnętrznej struktury i kategoryzują je w procesie samouczenia. SOM służy do uformowania odwzorowania z przestrzeni wielowymiarowej do przestrzeni jednowymiarowej lub dwuwymiarowej. Główną cechą SOM jest to, że tworzy on nieliniową projekcję wielowymiarową kolektora danych na regularnej, niskowymiarowej (zwykle 2D) sieci. Na wyświetlaczu klastrowanie przestrzeni danych, jak również relacje metryczno-topologiczne elementów danych, są wyraźnie widoczne. Jeśli elementy danych są wektorami, składniki, których są zmiennymi z określone znaczenie, takie jak deskryptory danych statystycznych lub pomiary, które opisują proces, siatka SOM może być wykorzystana, jako podstawa, na której może znajdować się każda zmienna wyświetlane osobno przy użyciu kodowania na poziomie szarości lub pseudo koloru. Ten rodzaj projekcji został uznany za bardzo przydatny do zrozumienia wzajemnych zależności między zmiennymi, a także strukturami zbioru danych.

EN

The article discusses artificial neural networks (ANN). One of the varieties is the Kohonen network, called the Self Organizing Map (SOM), that perform the learning process of neural networks independently, i.e. they recognize relationships occurring in clusters by detecting an internal structure and categorizing them in the process of self-learning. SOM is used to form mapping from a multidimensional space to a one-dimensional or two-dimensional space. The main feature of SOM is that it creates a non-linear multi-dimensional projection of a data collector on a regular, low-dimensional (usually 2D) network. On the display, data space clustering as well as metric-topological relations of data elements are clearly visible. If the data elements are vectors, the components of which are variables with defined meanings, such as statistical data descriptors or measurements that describe the process, the SOM grid can be used as a basis on which each variable can be displayed separately using gray or pseudo-color coding. This type of projection has been found to be very useful for understanding the interrelationships between variables as well as data set structures.

6

Automated and effective content-based mammogram retrieval using wavelet based CS-LBP feature and self-organizing map

Singh V. P., Srivastava R.

Biocybernetics and Biomedical Engineering

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2018

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Vol. 38, no. 1

90--105

EN

In this paper, automated, fast and effective content based-mammogram image retrieval system is proposed. The proposed pre-processing steps include automatic labelling-scratches suppression, automatic pectoral muscle removal and image enhancement. Further, for segmentation selective thresholds based seeded region growing algorithm is introduced. Furthermore, we apply 2-level discrete wavelet transform (DWT) on the segmented region and wavelet based centre symmetric-local binary pattern (WCS-LBP) features are extracted. Then, extracted features are fed to self-organizing map (SOM) which generates clusters of images, having similar visual content. SOM produces different clusters with their centres and query image features are matched with all cluster representatives to find closest cluster. Finally, images are retrieved from this closest cluster using Euclidean distance similarity measure. So, at the searching time the query image is searched only in small subset depending upon cluster size and is not compared with all the images in the database, reflects a superior response time with good retrieval performances. Descriptive experimental and empirical discussions confirm the effectiveness of this paper.

7

Application of self-organizing maps in visualization of multidimensional pareto fronts

Schlieter T.

Zeszyty Naukowe Wyższej Szkoły Informatyki

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2016

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Vol. 15, Nr 1

75--87

EN

The aim of this study is to show the application of Kohonen’s self-organizing maps for the purpose of visualization. Multi-dimensional sets of solutions of test functions for optimization and real multiobjective optimization problems are presented using self-organizing maps and traditional methods for comparison.

PL

Celem pracy jest przedstawienie zastosowania samoorganizujących map Kohonena do wizualizacji. Wielowymiarowe zbiory niezdominowanych rozwiązań testowych funkcji optymalizacji oraz rzeczywistych problemów optymalizacji wielokryterialnej są przedstawione z wykorzystaniem samoorganizujących map oraz tradycyjnych metod dla porównania.

8

Zastosowanie sieci samoorganizującej do identyﬁkacji struktur odmienionych węgla kamiennego

Skiba M., Młynarczuk M.

Prace Instytutu Mechaniki Górotworu PAN

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2016

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T. 18, nr 3

61--66

PL

Wewnętrzna budowa węgla, możliwa do obserwacji wyłącznie pod mikroskopem, może wykazywać pewne cechy (takie jak: obecność spękań, struktury kataklastyczne czy mylonityczne), które wpływają na zwiększoną pojemność gazową oraz wskazują na pokład szczególnie zagrożony wyrzutami gazów i skał. Problematyka ta była przedmiotem zainteresowania licznych badaczy, którzy dokonali klasyfikacji węgla odmienionego, wyróżniając różne typu strukturalne takiego węgla. W pracy do identyfikacji poszczególnych struktur zastosowano mapę samoorganizującą (SOM). Może ona posłużyć do ujawnienia takich cech w zbiorze danych, które są często niedostrzegalne w wypadku zastosowania sieci neuronowej uczonej z nauczycielem. Badania wykonane zostały na zdjęciach mikroskopowych, a każdą z analizowanych klas opisano za pomocą 7-wymiarowej przestrzeni cech. Zastosowanie sieci samoorganizującej skutkowało klasyfikacją badanych struktur na poziomie 82% skuteczności.

EN

The internal structure of the coal, observable microscopically only, may have certain features (such as the presence of cracks, cataclastic or mylonitic structures) that affect the increased gas capacity and point to the seams particularly endangered by gas and rock outbursts. The issue was the subject of interest for many researchers who have made a classifi cation of structurally altered coal, distinguishing different types of such coal structure. In this paper, individual structures were identified using self-organizing map (SOM). It can be used to reveal such features in the data set, which are often invisible in the case of the use of neural network learning with a teacher. Tests were performed on microscopic photographs, each of the analyzed grades were described using a 7-dimensional feature space. The use of a self-organizing map resulted in the effectiveness of the classification of these structures at the level of 82%.

9

Zastosowanie metod czarnej skrzynki do prognozowania wartości wybranych wskaźników jakości ścieków dopływających do oczyszczalni komunalnej

Szeląg B., Bartkiewicz L., Studziński J.

Ochrona Środowiska

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2016

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Vol. 38, nr 4

39--46

PL

Prognozowanie ilości i jakości ścieków dopływających do oczyszczalni komunalnej z odpowiednim wyprzedzeniem czasowym daje możliwość optymalnego sterowania wieloma parametrami procesów oczyszczania ścieków. Dlatego prowadzi się badania mające na celu opracowanie modeli matematycznych (fizykalnych deterministycznych i operatorowych statystycznych), prognozujących zarówno ilość, jak i jakość ścieków dopływających do oczyszczalni. W artykule zbadano możliwość zastosowania prostszych modeli operatorowych do prognozowania wartości wybranych wskaźników jakości ścieków na dopływie do oczyszczalni (BZT5, zawiesiny ogólne, azot ogólny i amonowy, fosfor ogólny) jedynie na podstawie wyników pomiarów natężenia przepływu ścieków oraz – w celu porównania – na podstawie ich zmierzonych wartości. Do tego celu zastosowano metody czarnej skrzynki typu MARS oraz lasy losowe (RF). Dodatkowo przedstawiono możliwość połączenia metody lasów losowych z modelem klasyfikacyjnym (RF+SOM). Do identyfikacji danych określających zmienność wybranych wskaźników jakości ścieków zastosowano metody drzew wzmacnianych (BT) i analizy składowych głównych (PCA). Modele opracowano na podstawie wyników ciągłych pomiarów dobowych przeprowadzonych w latach 2013–2015 w oczyszczalni ścieków komunalnych w Rzeszowie.

EN

Forecasting the amount and quality of wastewater flowing into a treatment plant sufficiently in advance, enables effective control of numerous treatment process parameters. Therefore, mathematical (physical deterministic and time series statistical) models forecasting both the amount and quality of wastewater inflow into a sewage treatment plant are under development. In this paper, a possibility of simpler time series models application to forecasting values of selected indicators (biochemical oxygen demand (BOD5), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP) and ammonium (NH4+)) of sewage quality in the inflow into a treatment plant was investigated. The research was based solely on sewage flow rate data and – for the purpose of comparison – the actual measured indicator values. For this purpose, MARS type black-box and random forest (RF) methods were used. Also, a possibility of combining the RF method with a classification model (RF+SOM) was investigated. Boosted trees (BT) and principal component analysis (PCA) methods were applied for identification of data that determine variability of the selected sewage quality indicators. The models were developed on the basis of continuous daily measurements performed in the period of 2013–2015 in the municipal sewage treatment plant in Rzeszow.

10

Adaptive modelling of spatial diversification of soil classification units

Urbański K., Gruszczyński S.

Journal of Water and Land Development

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2016

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no. 30

127--139

EN

The article presents the results of attempts to use adaptive algorithms for classification tasks different soils units. The area of study was the Upper Silesian Industrial Region, which physiographic and soils parameters in the form of digitized was used in the calculation. The study used algorithms, self-organizing map (SOM) of Kohonen, and classifiers: deep neural network, and two types of decision trees: Distributed Random Forest and Gradient Boosting Machine. Especially distributed algorithm Random Forest (algorithm DRF) showed a very high degree of generalization capabilities in modeling complex diversity of soil. The obtained results indicate, that the digitization of topographic and thematic maps give you a fairly good basis for creating useful models of soil classification. However, the results also showed that it cannot be concluded that the best algorithm presented in this research can be regarded as a general principle of system design inference.

PL

Wraz z rozwojem technologii informatycznych następuje stopniowa zmiana podejścia do dokumentacji kartograficznej obiektów przyrodniczych, w tym gleb. Podstawowymi cechami dowolnej klasyfikacji, których przedmiotem są gleby, jest wielowymiarowość jednostek (nie ma pojedynczej właściwości, możliwej do wyznaczenia w drodze pomiaru, która wystarczałaby do jednoznacznego przypisania pedonu do określonej klasy w stosowanych skalach klasyfikacyjnych gleb), w związku z czym właściwe wydaje się wykorzystanie do tego celu dostępnych komputerowych metod przetwarzania danych. Modelowanie przestrzennego zróżnicowania gleb na podstawie przesłanek natury fizjograficznej, odtworzonych na podstawie digitalizacji istniejących materiałów kartograficznych, jest podstawą do tworzenia przestrzennych baz danych przechowywanych w wersji cyfrowej. Inaczej niż w typowej kartografii tematycznej zawierającej treści glebowo-siedliskowe, modele te wskazują na prawdopodobieństwo a priori występowania określonej jednostki glebowej w określonym położeniu, nie zaś bezwzględną przynależność terenu do niej. Taka interpretacja wymaga zbudowania stosownego algorytmu wiążącego czynniki natury geologicznej i fizjograficznej z jednostkami glebowymi. Do tego celu często wykorzystuje się tak zwane algorytmy adaptacyjne, umożliwiające elastyczne tworzenie modeli zależności bazujących na danych. W pracy przedstawiono dwa warianty doboru parametrów przetwarzania danych fizjograficzno-glebowych potencjalnie przydatnych do tych celów. Wykorzystano dane pochodzące z bazy danych fizjograficznoglebowych z rejonu GOP (Górnośląski Okręg Przemysłowy) uzyskanych w wyniku digitalizacji materiałów kartograficznych. Analizie poddano wyłącznie tereny użytków rolnych: gruntów ornych (R) i trwałych użytków zielonych (Ł i Ps). Na obszarze o powierzchni 1 km2 wyodrębniono 6,4 mln jednostek tworzących siatkę kwadratów o rozmiarach 20 × 20 m. Wykorzystane zostały algorytmy samoorganizującej mapy (SOM) Kohonena oraz klasyfikatory – głęboka sieć neuronowa, oraz dwa rodzaje drzew decyzyjnych – rozproszony las losowy (ang. Distributed Random Forest) i wzmacniane drzewa losowe (ang. Gradient Boosting Machine). Szczególnie algorytm rozproszonego lasu losowego (algorytm DRF) wykazał bardzo wysoki stopień zdolności generalizacyjnej w modelowaniu zróżnicowania kompleksów glebowych.

11

Tailwater habitat stability after dam removal and return to a natural hydrological regime

Tszydel M., Kruk A.

Oceanological and Hydrobiological Studies

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2015

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Vol. 44, No. 3

410--425

EN

The study was conducted from 2000 to 2003 in the tailwater of the Drzewieckie Lake, an artificial reservoir in Central Poland. Short-term peaks in water flow were generated for the purpose of the operation of a whitewater slalom canoeing track built just downstream of the dam. In 2002, the reservoir was drawn down. The patterns in habitat samples were recognized with a Kohonen’s unsupervised artificial neural network (SOM). The SOM spatial gradient was stronger than the SOM temporal gradient, which shows that the removal of the studied dam did not have a destructive impact on habitats’ features, as shown in other studies, and that the patchy nature of the riverbed has been maintained. The complete emptying of the Drzewieckie Lake took place at the beginning of the vegetation season, which allowed plants to cover the exposed bottom of the reservoir and, consequently, reduce the downstream flow of organic matter accumulated there. Patterns in the displacement of aquatic macrophytes, inorganic substratum and different fractions of particulate organic matter are discussed. The amount of dissolved oxygen decreased because of the lack of intensive water discharge from the reservoir into the river, which would result in high water turbulence. Results of this study are important for planning the ecologically sound dam removals.

12

A class of neuro-computational methods for assamese fricative classification

Patgiri C., Sarma M., Sarma K. K.

Journal of Artificial Intelligence and Soft Computing Research

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2015

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Vol. 5, No. 1

59--70

EN

In this work, a class of neuro-computational classifiers are used for classification of fricative phonemes of Assamese language. Initially, a Recurrent Neural Network (RNN) based classifier is used for classification. Later, another neuro fuzzy classifier is used for classification. We have used two different feature sets for the work, one using the specific acoustic-phonetic characteristics and another temporal attributes using linear prediction cepstral coefficients (LPCC) and a Self Organizing Map (SOM). Here, we present the experimental details and performance difference obtained by replacing the RNN based classifier with an adaptive neuro fuzzy inference system (ANFIS) based block for both the feature sets to recognize Assamese fricative sounds.

13

Music Mood Visualization Using Self-Organizing Maps

Plewa M., Kostek B.

Archives of Acoustics

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2015

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Vol. 40, No. 4

513--525

EN

Due to an increasing amount of music being made available in digital form in the Internet, an automatic organization of music is sought. The paper presents an approach to graphical representation of mood of songs based on Self-Organizing Maps. Parameters describing mood of music are proposed and calculated and then analyzed employing correlation with mood dimensions based on the Multidimensional Scaling. A map is created in which music excerpts with similar mood are organized next to each other on the two-dimensional display.

14

Using Singular Value Decomposition (SVD) as a solution for search result clustering

Abdulla H. D., Abdelrahman A. S., Snasel V.

Poznan University of Technology Academic Journals. Electrical Engineering

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2014

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No. 80

71--78

EN

There are many search engines in the web, but they return a long list of search results, ranked by their relevancies to the given query. Web users have to go through the list and examine the titles and (short) snippets sequentially to identify their required results. In this paper we present how usage of Singular Value Decomposition (SVD) as a very good solution for search results clustering. Results are presented by visualizing neural network. Neural network is responsive for reducing result dimension to two dimensional space and we are able to present result as a picture that we are able to analyze.

15

Towards Assessment of Innovativeness Economy Determinant Correlation: the Double Self-Organizing Feature Map Approach

Czyżewska M., Szkoła J., Pancerz K.

Fundamenta Informaticae

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2014

|

Vol. 129, nr 1/2

37--48

EN

In the paper, we attempt to identify the crucial determinants of innovativeness economy and the correlations between the determinants. We based our research on the Innovativeness Union Scoreboard (IUS) dataset. In order to solve the problem, we propose to use the Double Self-Organizing Feature Map (SOM) approach. In the first step, countries, described by determinants of innovativeness economy, are clustered using SOMs according to five year time series for each determinant separately. In the second step, results of the first step are clustered again using SOM to obtain the final correlation represented in the form of a minimal spanning tree. We propose some modifications of the clustering process using SOMs to improve classification results and efficiency of the learning process.

16

Pulse shape discrimination of neutrons and gamma rays using kohonen artificial neural networks

Tambouratzis T., Chernikova D., Pzsit I.

Journal of Artificial Intelligence and Soft Computing Research

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2013

|

Vol. 3, No. 2

77--88

EN

The potential of two Kohonen artificial neural networks (ANNs) - linear vector quantisation (LVQ) and the self organising map (SOM) - is explored for pulse shape discrimination (PSD), i.e. for distinguishing between neutrons (n’s) and gamma rays (’s). The effect that (a) the energy level, and (b) the relative size of the training and test sets, have on identification accuracy is also evaluated on the given PSD dataset. The two Kohonen ANNs demonstrate complementary discrimination ability on the training and test sets: while the LVQ is consistently more accurate on classifying the training set, the SOM exhibits higher n/ identification rates when classifying new patterns regardless of the proportion of training and test set patterns at the different energy levels; the average time for decision making equals ˜100 μs in the case of the LVQ and ˜450 μs in the case of the SOM.

17

Rozpoznawanie wzorców emisji spalin w pomiarach PEMS za pomocą sieci Kohonena (SOM)

Merkisz J., Barczak A., Pielecha J.

Logistyka

|

2012

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nr 4

PL

Rozwój technik pomiarowych PEMS sprzyja badaniom ekologiczności pojazdów w rzeczywistych warunkach pracy. Interpretacja wyników pomiarów, na przykład emisji zanieczyszczeń, reprezentowanych bardzo licznymi zbiorami różnorodnych danych wymaga przeprowadzenia złożonych analiz numerycznych. Wyrafinowane metody statystyczne są skuteczne, lecz interpretacja wyników wymaga udziału eksperta o bardzo specjalistycznej wiedzy. Stosowanie metod data mining stwarza szerokie perspektywy i zwiększa zdecydowanie możliwości w zakresie analizy i interpretacji wyników eksperymentu. W artykule przeprowadzono badania transformacji wielolicznego zestawu uczącego uzyskanego z pomiarów do mało licznego zestawu neuronów sieci Kohonena. Dla wyuczonej sieci Kohonena przeprowadzono badania dotyczące rozpoznawania zadanych wzorców stanu pojazdu pomierzonych w trakcie eksperymentu drogowego.

EN

The improvement of PEMS enables better estimation of ecological quality of vehicles. However, interpretation of divers sort of data, e.g. exhaust emissions, gathered during on road testing requires complex numerical analyses. Advanced statistical analyses have already proven their applicability in this domain but the interpretation of the results requires the participation of experts with extended knowledge. The usage of the data mining methods brings the perspective in the ease of interpretation of obtained results. In this article, the Self-Organizing Maps were used to transform the multiplicity of data gathered during the on road experiment into the reduced set of representative data. Trained SOM was tested in the recognition of the vehicle states measured during the on road experiment.

18

Modelowanie procesu osiadania terenu górniczego Kopalni Węgla Brunatnego Bełchatów - nowe podejście

Palmąka M.

Przegląd Geologiczny

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2011

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Vol. 59, nr 3

245-245

EN

From the beginning of open-pit mining works (i.e. ground massive dewatering, access excavation, cover dumping) in 1976, which were strictly connected with an exposure a brown coal beds on Bełchatów field it was noticed, that a land surface subsided in the vicinity of Brown Coal Mine Bełchatów. Quantitative land subsidence assessments, which are based on deterministic models (elastic ground model, consolidation model), are not efficient enough to simulate the process – adjusted coefficient of determination amounts R2kor2kor

19

Amplitude-Frequency Monitoring of Power Quality Transients using Higher-Order Statistics and Self-Organizing Neural Networks

Gonzalez de la Rosa J. J., Aguera-Perez A., Palomares-Salas J. C., Moreno-Munoz A.

Przegląd Elektrotechniczny

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2011

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R. 87, nr 8

128-137

EN

In this paper a smart automatic classification of PQ transients is performed attending to their amplitudes and frequencies, and the extreme of higher-order cumulants. Feature extraction stage is double folded. First, these statistical measurements reveal the hidden geometry for a constant amplitude or frequency, conforming the 2D clustering grace to the third and fourth-order features associated to each signal anomaly, coupled to the 50-Hz power line. Precisely the main contribution of the work is the novel finding that the maxima and the minima of the higher-order cumulants distribute according to curves families, each of which associated to the transient's frequency or amplitude. Given a statistical order, each datum in a curve corresponds to the initial amplitude (or constant frequency), and to a couple of extremes (min-max) associated to the statistical estimator. The random grouping along each curve reveals the a priori hidden geometry, linked to the subjacent electrical phenomenon. Secondly, the regular surface grid in the input space (amplitude-frequency) experiments a transformation to the output space which is developed by the higher-order statistics. Once the geometry in the feature space has been found, we show the computational intelligence modulus, based in Self-Organizing Maps, which performs satisfactory learning along each frequency and amplitude curve. Performance of a four-neuron network with different geometries is shown, confirming the curves' patterns.

PL

W artykule opisano automatyczną metodę klasyfikacji jakości energii w stanach przejściowych z uwzględnieniem amplitudy, częstotliwości i wartości ekstremalnych. W pierwszym etapie przeprowadzane są pomiary statystyczne dla stałej amplitudy i częstotliwości uwzględniające klastry 2D i właściwości trzeciego i czwartego rzędu towarzyszące anomaliom. Następnie uwzględniana jest geometria sieci. Po tym etapie włączany jest moduł sztucznej inteligencji bazujący na sieciach neuronowych.

20

Nursing logistics activities in massive services

Simić D.

Journal of Medical Informatics & Technologies

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2011

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Vol. 18

77--84

EN

Hybrid patient classification system in nursing logistics activities is discussed in this paper. Hybrid classification model is based on two of the most used competitive artificial neural network algorithms that use learning vector quantization models (LVQ) and self-organizing maps (SOM). In general, the history of patient classification in nursing dates back to the period of Florence Nightingale. The first and the foremost condition for providing quality nursing care, which is measured by care standards, and determined by number of hours of actual care, is the appropriate number of nurses. It is possible to discus three types of experimental results. First result type could be assessment for risk of falling measured by Mors scale and pressure sores risk measured by Braden scale. Both of them are assessed by LVQ. Hybrid LVQ-SOM model is used for second result type, which presents the time for nursing logistics activities. The third type is possibility to predict appropriate number of nurses for providing quality nursing care. This research was conducted on patients from Institute of Neurology, Clinical Centre of Vojvodina.