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Wyszukujesz frazę "Łęski, J." wg kryterium: Autor


Tytuł:
Improving the Generalization Ability of Neuro-Fuzzy Systems by e-Insensitive Learning
Autorzy:
Łęski, J.
Powiązania:
https://bibliotekanauki.pl/articles/908037.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
informatyka
fuzzy systems
neural networks
tolerant learning
generalization control
robust methods
Opis:
A new learning method tolerant of imprecision is introduced and used in neuro-fuzzy modelling. The proposed method makes it possible to dispose of an intrinsic inconsistency of neuro-fuzzy modelling, where zero-tolerance learning is used to obtain a fuzzy model tolerant of imprecision. This new method can be called e-insensitive learning, where, in order to fit the fuzzy model to real data, the e-insensitive loss function is used. e-insensitive learning leads to a model with minimal Vapnik-Chervonenkis dimension, which results in an improved generalization ability of this system. Another advantage of the proposed method is its robustness against outliers. This paper introduces two approaches to solving e-insensitive learning problem. The first approach leads to a quadratic programming problem with bound constraints and one linear equality constraint. The second approach leads to a problem of solving a system of linear inequalities. Two computationally efficient numerical methods for e-insensitive learning are proposed. Finally, examples are given to demonstrate the validity of the introduced methods.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 3; 437-447
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Iteratively reweighted least squares classifier and its l2- and l1-regularized Kernel versions
Autorzy:
Łęski, J.
Powiązania:
https://bibliotekanauki.pl/articles/199904.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
classifier design
IRLS
conjugate gradient optimization
gradient projection
Kernel matrix
Opis:
This paper introduces a new classifier design method based on regularized iteratively reweighted least squares criterion function. The proposed method uses various approximations of misclassification error, including: linear, sigmoidal, Huber and logarithmic. Using the represented theorem a kernel version of classifier design method is introduced. The conjugate gradient algorithm is used to minimize the proposed criterion function. Furthermore, .1-regularized kernel version of the classifier is introduced. In this case, the gradient projection is used to optimize the criterion function. Finally, an extensive experimental analysis on 14 benchmark datasets is given to demonstrate the validity of the introduced methods.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2010, 58, 1; 171-182
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kernel Ho-Kashyap classifier with generalization control
Autorzy:
Łęski, J.
Powiązania:
https://bibliotekanauki.pl/articles/907269.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
metoda jądrowa
metoda odporna
projekt klasyfikatora
kernel methods
classifier design
Ho-Kashyap classifier
generalization control
robust methods
Opis:
This paper introduces a new classifier design method based on a kernel extension of the classical Ho-Kashyap procedure. The proposed method uses an approximation of the absolute error rather than the squared error to design a classifier, which leads to robustness against outliers and a better approximation of the misclassification error. Additionally, easy control of the generalization ability is obtained using the structural risk minimization induction principle from statistical learning theory. Finally, examples are given to demonstrate the validity of the introduced method.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2004, 14, 1; 53-61
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An ε-Insensitive Approach to Fuzzy Clustering
Autorzy:
Łęski, J.
Powiązania:
https://bibliotekanauki.pl/articles/908067.pdf
Data publikacji:
2001
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
programowanie
metoda grupowania
fuzzy clustering
fuzzy c-means
robust methods
varepsilon-insensitivity
fuzzy c-medians
Opis:
Fuzzy clustering can be helpful in finding natural vague boundaries in data. The fuzzy c-means method is one of the most popular clustering methods based on minimization of a criterion function. However, one of the greatest disadvantages of this method is its sensitivity to the presence of noise and outliers in the data. The present paper introduces a new varepsilon-insensitive Fuzzy C-Means (varepsilonFCM) clustering algorithm. As a special case, this algorithm includes the well-known Fuzzy C-Medians method (FCMED). The performance of the new clustering algorithm is experimentally compared with the Fuzzy C-Means (FCM) method using synthetic data with outliers and heavy-tailed, overlapped groups of the data.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2001, 11, 4; 993-1007
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Fuzzy If-Then Rule-Based Nonlinear Classifier
Autorzy:
Łęski, J.
Powiązania:
https://bibliotekanauki.pl/articles/908190.pdf
Data publikacji:
2003
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
informatyka
classifier design
fuzzy if-then rules
generalization control
mixture of experts
Opis:
This paper introduces a new classifier design method that is based on a modification of the classical Ho-Kashyap procedure. The proposed method uses the absolute error, rather than the squared error, to design a linear classifier. Additionally, easy control of the generalization ability and robustness to outliers are obtained. Next, an extension to a nonlinear classifier by the mixture-of-experts technique is presented. Each expert is represented by a fuzzy if-then rule in the Takagi-Sugeno-Kang form. Finally, examples are given to demonstrate the validity of the introduced method.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2003, 13, 2; 215-223
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Clustering algorithm for classification methods
Autorzy:
Łęski, J.
Jeżewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/333004.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
grupowanie
klasyfikacja
clustering
classification
class boundaries
Opis:
Classification plays an important role in many fields of life, including medical diagnosis support. In the paper, fuzzy clustering algorithm dedicated to classification methods is proposed. Its goal is to find pairs of prototypes located near boundaries of both classes of objects. The minimization procedure of the proposed criterion function is described. The algorithm for determining the value of the clustering parameter is also presented. Presented results (synthetic dataset) confirm correctness of clustering - most of final prototypes, determined based on obtained pairs, are located between boundary of two classes.
Źródło:
Journal of Medical Informatics & Technologies; 2012, 20; 11-18
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalized ordered linear regression with regularization
Autorzy:
Łęski, J.
Henzel, N.
Powiązania:
https://bibliotekanauki.pl/articles/201591.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
linear regression
IRLS
OWA
conjugate gradient optimization
robust methods
Opis:
Linear regression analysis has become a fundamental tool in experimental sciences. We propose a new method for parameter estimation in linear models. The 'Generalized Ordered Linear Regression with Regularization' (GOLRR) uses various loss functions (including the o-insensitive ones), ordered weighted averaging of the residuals, and regularization. The algorithm consists in solving a sequence of weighted quadratic minimization problems where the weights used for the next iteration depend not only on the values but also on the order of the model residuals obtained for the current iteration. Such regression problem may be transformed into the iterative reweighted least squares scenario. The conjugate gradient algorithm is used to minimize the proposed criterion function. Finally, numerical examples are given to demonstrate the validity of the method proposed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 3; 481-489
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Neuro-Fuzzy System Based on Logical Interpretation of If-then Rules
Autorzy:
Łęski, J.
Henzel, N.
Powiązania:
https://bibliotekanauki.pl/articles/911145.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
system rozmyty
implikacja rozmyta
fuzzy implications
approximate reasoning
neuro-fuzzy systems
soft computing
Opis:
Several important fuzzy implications and their properties are described on the basis of an axiomatic approach to the definition of the fuzzy implications. Then the idea of approximate reasoning using the generalized modus ponens and fuzzy implications is considered. The elimination of the non-informative part of the final fuzzy set before defuzzification plays the key role in this paper. After reviewing well-known fuzzy systems, a new artificial neural network based on logical interpretation of if-then rules (ANBLIR) is introduced. Moreover, this system automatically generates rules from numerical data. Applications of ANBLIR to pattern recognition on numerical examples using benchmark databases are indicated.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2000, 10, 4; 703-722
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Fuzzy System with ε-insensitive Learning of Premises and Consequences of if-then Rules
Autorzy:
Łęski, J. M.
Czogała, T.
Powiązania:
https://bibliotekanauki.pl/articles/908547.pdf
Data publikacji:
2005
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
system rozmyty
zdolność uogólnienia
modelowanie rozmyte
fuzzy system
generalization ability
extraction of fuzzy if-then rules
global ε-insensitive learning
local ε-insensitive learning
Opis:
First, a fuzzy system based on if-then rules and with parametric consequences is recalled. Then, it is shown that the global and local ε-insensitive learning of the above fuzzy system may be presented as a combination of both an ε-insensitive gradient method and solving a system of linear inequalities. Examples are given of using the introduced method to design fuzzy models of real-life data. Simulation results show an improvement in the generalization ability of a fuzzy system trained by the new method compared with the traditional and other ε-insensitive learning methods.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2005, 15, 2; 257-273
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Linguistically defined clustering of data
Autorzy:
Leski, J. M.
Kotas, M. P.
Powiązania:
https://bibliotekanauki.pl/articles/329995.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
data clustering
possibility theory
linguistic rules
data analysis
grupowanie danych
teoria możliwości
analiza danych
Opis:
This paper introduces a method of data clustering that is based on linguistically specified rules, similar to those applied by a human visually fulfilling a task. The method endeavors to follow these remarkable capabilities of intelligent beings. Even for most complicated data patterns a human is capable of accomplishing the clustering process using relatively simple rules. His/her way of clustering is a sequential search for new structures in the data and new prototypes with the use of the following linguistic rule: search for prototypes in regions of extremely high data densities and immensely far from the previously found ones. Then, after this search has been completed, the respective data have to be assigned to any of the clusters whose nuclei (prototypes) have been found. A human again uses a simple linguistic rule: data from regions with similar densities, which are located exceedingly close to each other, should belong to the same cluster. The goal of this work is to prove experimentally that such simple linguistic rules can result in a clustering method that is competitive with the most effective methods known from the literature on the subject. A linguistic formulation of a validity index for determination of the number of clusters is also presented. Finally, an extensive experimental analysis of benchmark datasets is performed to demonstrate the validity of the clustering approach introduced. Its competitiveness with the state-of-the-art solutions is also shown.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2018, 28, 3; 545-557
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Szereg czasowy zbiorów rozmytych w opisie i analizie sygnałów elektrokardiograficznych
Time series of fuzzy sets in the description and analysis of electrocardiographic signals
Autorzy:
Henzel, N.
Gacek, A.
Łęski, J.
Powiązania:
https://bibliotekanauki.pl/articles/261567.pdf
Data publikacji:
2011
Wydawca:
Politechnika Wrocławska. Wydział Podstawowych Problemów Techniki. Katedra Inżynierii Biomedycznej
Tematy:
zbiory rozmyte
ziarna informacji
analiza sygnałów biomedycznych
elektrokardiografia
fuzzy sets
information granules
analysis of biomedical signals
electrocardiography
Opis:
W pracy przedstawiono ujednolicenie metod opisu sygnałów elektrokardiograficznych za pomocą koncepcji szeregu czasowego zbiorów rozmytych. Sygnał elektrokardiograficzny jest przetwarzany w "ruchomym oknie" czasowym i przekształcany na szereg czasowy funkcji przynależności zbiorów rozmytych. Jako szczególne przypadki wprowadzonej metody można rozważać koncepcję sygnału rozmytego oraz ciąg ziaren informacyjnych.
The unification of the electrocardiography signals description methods by means of time series of fuzzy sets, is presented. The electrocardiographic signal is processed in a “moving window” and transformed into a time series of fuzzy sets membership functions. The idea of fuzzy signal and the sequence of information granules can be considered as special case of the presented method.
Źródło:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna; 2011, 17, 4; 313-316
1234-5563
Pojawia się w:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of cardiotocogram signal feature selection method on fetal state assessment efficacy
Autorzy:
Jeżewski, M.
Czabański, R.
Łęski, J.
Powiązania:
https://bibliotekanauki.pl/articles/333440.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
cardiotocography
classification
feature selection
kardiotokografia
klasyfikacja
selekcja cech
Opis:
Cardiotocographic (CTG) monitoring is a method of assessing fetal state. Since visual analysis of CTG signal is difficult, methods of automated qualitative fetal state evaluation on the basis of the quantitative description of the signal are applied. The appropriate selection of learning data influences the quality of the fetal state assessment with computational intelligence methods. In the presented work we examined three different feature selection procedures based on: principal components analysis, receiver operating characteristics and guidelines of International Federation of Gynecology and Obstetrics. To investigate their influence on the fetal state assessment quality the benchmark SisPorto® dataset and the Lagrangian support vector machine were used.
Źródło:
Journal of Medical Informatics & Technologies; 2014, 23; 51-58
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Empirical Bayesian averaging method and its application to noise reduction in ECG signal
Autorzy:
Momot, A.
Momot, M.
Łęski, J.
Powiązania:
https://bibliotekanauki.pl/articles/333575.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
sygnał EKG
średnia ważona
wnioskowanie bayesowskie
ECG signal
weighted averaging
Bayesian inference
Opis:
An electrocardiogram (ECG) is the prime tool in non-invasive cardiac electrophysiology and has a prime function in the screening and diagnosis of cardiovascular diseases. However one of the greatest problems is that usually recording an electrical activity of the heart is performed in the presence of noise. The paper presents empirical Bayesian approach to problem of signal averaging which is commonly used to extract a useful signal distorted by a noise. The averaging is especially useful for biomedical signal such as ECG signal, where the spectra of the signal and noise significantly overlap. In reality the variability of noise can be observed, with power from cycle to cycle, which is motivation for weighted averaging methods usage. It is demonstrated that by exploiting a probabilistic Bayesian learning framework, it can be derived accurate prediction models offering significant additional advantage, namely automatic estimation of 'nuisance' parameters. Performance of the new method is experimentally compared to the traditional averaging by using arithmetic mean and weighted averaging method based on criterion function minimization.
Źródło:
Journal of Medical Informatics & Technologies; 2006, 10; 93-101
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Fuzzy Relevance Vector Machine and its application to noise reduction in ECG signal
Autorzy:
Momot, A.
Momot, M.
Łęski, J.
Powiązania:
https://bibliotekanauki.pl/articles/333828.pdf
Data publikacji:
2005
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
systemy rozmyte
wnioskowanie bayesowskie
sygnał EKG
fuzzy systems
Bayesian inference
ECG signal
Opis:
The paper presents new method called the Fuzzy Relevance Vector Machine (FRVM), a modification of the relevance vector machine, introduced by M. Tipping, applied to learning Takagi-Sugeno-Kang (TSK) fuzzy system. Moreover it describes application of the FRVM to noise reduction in ECG signal. The results of the process are compared to those obtained using both Least Squares method for learning output functions in TSK rules and commonly used method using a low-pass moving average filter.
Źródło:
Journal of Medical Informatics & Technologies; 2005, 9; 99-105
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Weighted averaging of ECG signals based on partition of input set in time domain
Autorzy:
Momot, A.
Momot, M.
Łęski, J.
Powiązania:
https://bibliotekanauki.pl/articles/333836.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
sygnał EKG
ważone uśrednianie
redukcja hałasu
ECG signal
weighted averaging
noise reduction
Opis:
The paper presents new approach to problem of signal averaging which is commonly used to extract a useful signal distorted by a noise. The averaging is especially useful for biomedical signal such as ECG signal, where the spectra of the signal and noise significantly overlap. In reality can be observed variability of noise power from cycle to cycle which is motivation for using methods of weighted averaging. Performance of the new method, based on partition of input set in time domain and criterion function minimization, is experimentally compared with the traditional averaging by using arithmetic mean, weighted averaging method based on empirical Bayesian approach and weighted averaging method based on criterion function minimization.
Źródło:
Journal of Medical Informatics & Technologies; 2007, 11; 165-170
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł

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