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1

Machine learning-based analysis of English lateral allophones

Piotrowska Magdalena, Korvel Gražina, Kostek Bożena, Ciszewski Tomasz, Czyżewski Andrzej

International Journal of Applied Mathematics and Computer Science

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2019

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Vol. 29, no. 2

393--405

EN

Automatic classification methods, such as artificial neural networks (ANNs), the k-nearest neighbor (kNN) and self-organizing maps (SOMs), are applied to allophone analysis based on recorded speech. A list of 650 words was created for that purpose, containing positionally and/or contextually conditioned allophones. For each word, a group of 16 native and non-native speakers were audio-video recorded, from which seven native speakers’ and phonology experts’ speech was selected for analyses. For the purpose of the present study, a sub-list of 103 words containing the English alveolar lateral phoneme /l/ was compiled. The list includes ‘dark’ (velarized) allophonic realizations (which occur before a consonant or at the end of the word before silence) and 52 ‘clear’ allophonic realizations (which occur before a vowel), as well as voicing variants. The recorded signals were segmented into allophones and parametrized using a set of descriptors, originating from the MPEG 7 standard, plus dedicated time-based parameters as well as modified MFCC features proposed by the authors. Classification methods such as ANNs, the kNN and the SOM were employed to automatically detect the two types of allophones. Various sets of features were tested to achieve the best performance of the automatic methods. In the final experiment, a selected set of features was used for automatic evaluation of the pronunciation of dark /l/ by non-native speakers.

2

Pattern layer reduction for a generalized regression neural network by using a self-organizing map

Kartal S., Oral M., Ozyildirim B. M.

International Journal of Applied Mathematics and Computer Science

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2018

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Vol. 28, no. 2

411--424

EN

In a general regression neural network (GRNN), the number of neurons in the pattern layer is proportional to the number of training samples in the dataset. The use of a GRNN in applications that have relatively large datasets becomes troublesome due to the architecture and speed required. The great number of neurons in the pattern layer requires a substantial increase in memory usage and causes a substantial decrease in calculation speed. Therefore, there is a strong need for pattern layer size reduction. In this study, a self-organizing map (SOM) structure is introduced as a pre-processor for the GRNN. First, an SOM is generated for the training dataset. Second, each training record is labelled with the most similar map unit. Lastly, when a new test record is applied to the network, the most similar map units are detected, and the training data that have the same labels as the detected units are fed into the network instead of the entire training dataset. This scheme enables a considerable reduction in the pattern layer size. The proposed hybrid model was evaluated by using fifteen benchmark test functions and eight different UCI datasets. According to the simulation results, the proposed model significantly simplifies the GRNN’s structure without any performance loss.

3

Wykorzystanie sieci neuronowej Kohonena do wizualizacji danych MPG

Oszutowska-Mazurek D. A.

Problemy Nauk Stosowanych

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2016

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T. 4

19--30

PL

Wstęp i cel: Zastosowanie sieci neuronowych Kohonena zapewnia zmniejszenie wielowymiarowości danych. Wizualizacja w postaci map samoorganizujących się (SOM) jest użytecznym narzędziem do wstępnego kastrowania (grupowania) danych. Materiał i metody: Wizualizację przeprowadzona dla rzeczywistych danych, udostępnionych przez uniwersytet w Kalifornii za pomocą oprogramowania SNNS v.4.3. Głównym celem pracy jest zastosowanie sieci neuronowych Kohonena zapewniające zmniejszenie wielowymiarowości danych. Wyniki: Otrzymano wizualizacje danych wskazujące jednoznacznie na dodatnie i ujemne korelacje danych MPG. Wniosek: Mapy samoorganizujące się mogą być dedykowane wizualizacji danych wielowymiarowych jednak wyniki zależą od sposobu mapowania danych wejściowych, zwłaszcza o charakterze jakościowym, nawet jeśli stosowana jest normalizacja każdego z parametrów.

EN

Introduction and aim: The use of Kohonen neural network ensures the decrease of data multidimensionality. Visualisation called Self organized maps is useful tool for preliminary data clustering. Material and methods: The visualisation of real data set was obtained with the use of program SNNS v.4.3 for real dataset from California University. The main aim of this paper is the use of Kohonen neural network to ensure the reduction of multidimensional data. Results: Obtained visualisations of data indicate unambiguously positive and negative correlations for MPG data Conclusion: Self organising maps could be dedicated to multidimensional data visualisation and preliminary quality assessment, but the results depend on the mapping method of input data, especially quantity type, even if normalisation of every parameter is provided.

4

A connectionist computational method for face recognition

Pujol F. A., Mora H., Girona-Selva J. A.

International Journal of Applied Mathematics and Computer Science

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2016

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Vol. 26, no. 2

451--465

EN

In this work, a modified version of the elastic bunch graph matching (EBGM) algorithm for face recognition is introduced. First, faces are detected by using a fuzzy skin detector based on the RGB color space. Then, the fiducial points for the facial graph are extracted automatically by adjusting a grid of points to the result of an edge detector. After that, the position of the nodes, their relation with their neighbors and their Gabor jets are calculated in order to obtain the feature vector defining each face. A self-organizing map (SOM) framework is shown afterwards. Thus, the calculation of the winning neuron and the recognition process are performed by using a similarity function that takes into account both the geometric and texture information of the facial graph. The set of experiments carried out for our SOM-EBGM method shows the accuracy of our proposal when compared with other state-of the-art methods.