Autor: Jeżewski, R. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: GaAlAs Allox/Pseudoalloy Type II Structures
Autorzy:: Jeżewski, M.
Teissier, R.
Planel, R.
Powiązania:: https://bibliotekanauki.pl/articles/1879871.pdf
Data publikacji:: 1991-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.65.Fa
Opis:: The existence of type-II structures made from the combination of Ga$\text{}_{1-x}$AI$\text{}_{x}$As alloy and a short period GaAs/AlAs type-I superlattice is presented. Such three material structures are of type-II having at the same time electrons and holes of Γ-symmetry. This contrasts with the usual situation in type-II two material GaAs/AlAs structure where the ground state of electrons is of X-symmetry. The mechanism allowing creation of three material type-II structures is based on the difference of effective masses of electrons and holes. It should be valid for all similar semiconductor systems. Experimental results of photoluminescence and photoluminescence excitation studies of such structures made by Molecular Beam Epitaxy are presented. We determine the mutual positions of the electron and hole ground levels in the alloy and pseudoalloy and confirm that the studied structure is of type-II.
Źródło:: Acta Physica Polonica A; 1991, 79, 2-3; 195-198
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Fuzzy system for evaluation of fetal heart rate signals using FIGO criteria
Autorzy:: Czabański, R.
Jeżewski, M.
Wróbel, J.
Jeżewski, J.
Horoba, K.
Powiązania:: https://bibliotekanauki.pl/articles/333142.pdf
Data publikacji:: 2009
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: monitoring płodu
tętno płodu
kryteria FIGO
fetal monitoring
fetal heart rate
signal classification
fuzzy systems
Opis:: Cardiotocography is a biophysical method of fetal monitoring during pregnancy and labour. It is mainly based on recording and analysis of fetal heart activity. The computerized fetal monitoring systems provide the quantitative description of the recorded signals but the effective methods supporting the conclusion generation are still needed. The evaluation of the signal can be made using criteria recommended by FIGO. Nevertheless, the quantitative description of the traces is inconsistent with qualitative nature of the obstetric knowledge. Therefore, we applied the fuzzy system based on Takagi-Sugeno-Kang model to evaluate and classify signals. FIGO guidelines were used for developing a set of fuzzy conditional rules defining the system performance. The proposed system was evaluated using data collected with computerized fetal surveillance system – MONAKO. The classification results confirm the improvement of the fetal state evaluation quality while using the proposed fuzzy system support.
Źródło:: Journal of Medical Informatics & Technologies; 2009, 13; 189-194
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Fuzzy prediction of fetal acidemia
Autorzy:: Czabański, R.
Roj, D.
Jeżewski, J.
Horoba, K.
Jeżewski, M.
Powiązania:: https://bibliotekanauki.pl/articles/333483.pdf
Data publikacji:: 2011
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: monitorowanie płodu
tętno płodu
klasyfikacja sygnału
systemy rozmyte
fetal monitoring
fetal heart rate
signal classification
fuzzy systems
Opis:: Cardiotocography is the primary method for biophysical assessment of a fetal state. It is based mainly on the recording and analysis of fetal heart rate signal (FHR). Computer systems for fetal monitoring provide a quantitative description of FHR signals, however the effective methods for their qualitative assessment are still needed. The measurements of hydronium ions concentration (pH) in newborn cord blood is considered as the objective indicator of the fetal state. Improper pH level is a symptom of acidemia being the result of fetal hypoxia. The paper proposes a twostep analysis of signals allowing for effective prediction of the acidemia risk. The first step consists in the fuzzy classification of FHR signals. The task of fuzzy inference is to indicate signals that according to the FIGO guidelines represent the fetal wellbeing. These recordings are eliminated from the further classification with Lagrangian Support Vector Machines. The proposed procedure was evaluated using data collected with computerized fetal surveillance system. The classification results confirmed the high quality of the proposed fuzzy method of fetal state evaluation.
Źródło:: Journal of Medical Informatics & Technologies; 2011, 17; 81-87
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

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

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Skocz do pozycji: 5.

Tytuł:: The prediction of the low fetal birth weight based on quantitative description of cardiotocographic signals
Autorzy:: Czabański, R.
Jeżewski, M.
Wróbel, J.
Kupka, T.
Łęski, J.
Jeżewski, J.
Powiązania:: https://bibliotekanauki.pl/articles/333495.pdf
Data publikacji:: 2008
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: weryfikacja podpisu online
programowanie dynamiczne
online signature verification
feature context
dynamic programming
Opis:: Cardiotocography (CTG) is a routine method of fetal condition assessment used in modern obstetrics. It is a biophysical method based on simultaneous recording and analysis of activity of fetal heart, fetal movements and maternal uterine contractions. The fetal condition is diagnosed on the basis of printed CTG trace evaluation. The correct interpretation of CTG traces from a bedside monitor is very difficult even for experienced clinicians. Therefore, computerized fetal monitoring systems are used to yield the quantitative description of the signal. However, the effective methods, aiming to support the conclusion generation, are still being searched. One of the most important features defining the state of fetal outcome is the weight of the newborn. The presented work describes an application of the Artificial Neural Network Based on Logical Interpretation of fuzzy if-then Rules (ANBLIR) to evaluate the risk of the low birth weight using a set of parameters quantitatively describing the CTG traces. The obtained results confirm that the neuro-fuzzy based CTG classification methods are very efficient for the prediction of the fetal outcome.
Źródło:: Journal of Medical Informatics & Technologies; 2008, 12; 97-102
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Influence of gestational age on neural networks interpretation of fetal monitoring signals
Autorzy:: Jeżewski, M.
Czabański, R.
Horoba, K.
Wróbel, J.
Łęski, J.
Jeżewski, J.
Powiązania:: https://bibliotekanauki.pl/articles/333505.pdf
Data publikacji:: 2008
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: monitoring płodu
kardiotokografia
klasyfikacja
sieci neuronowe
fetal monitoring
cardiotocography
classification
neural networks (NN)
Opis:: Cardiotocographic monitoring (CTG) is a primary biophysical monitoring method for assessment of the fetal state and is based on analysis of fetal heart rate, uterine contraction activity and fetal movement signals. Visual analysis of CTG traces is very difficult so computer-aided fetal monitoring systems have become a standard in clinical centres. We proposed the application of neural networks for the prediction of fetal outcome using the parameters of quantitative description of acquired signals as inputs. We focused on the influence of the gestational age (during trace recording) on the fetal outcome classification quality. We designed MLP and RBF neural networks with changing the number of neurons in the hidden layer to find the best structure. Networks were trained and tested fifty times, with random cases assignment to training, validating and testing subset. We obtained the value of sensitivity index above 0.7, what may be regarded as good result. However additional trace grouping within similar gestational age, increased classification quality in the case of MLP networks.
Źródło:: Journal of Medical Informatics & Technologies; 2008, 12; 137-142
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Photovoltaic Effect with a Spectrally Dependent Sign in Type-II GaAlAs Heterostructure
Autorzy:: Jeżewski, M.
Teissier, R.
Mollot, F.
Planel, R.
Powiązania:: https://bibliotekanauki.pl/articles/1923840.pdf
Data publikacji:: 1992-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.55.Cr
72.40.+w
72.20.Jv
Opis:: An asymmetric n-i-n like-II GaAs/GaAlAs/AlAs quantum heterostructure was designed and fabricated in order to observe a static photovoltage with a spectrally dependent sign. This photovoltage is associated with a light induced spatial separation of electrons and holes within selected regions of the structure. The observed photovoltage spectrum is compared with luminescence and luminescence excitation results.
Źródło:: Acta Physica Polonica A; 1992, 82, 5; 833-836
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Evaluation of predictive capabilities of quantitative cardiotocographic signal features
Autorzy:: Czabański, R.
Jeżewski, M.
Roj, D.
Szaszkowski, Z.
Kupka, T.
Wróbel, J.
Powiązania:: https://bibliotekanauki.pl/articles/332937.pdf
Data publikacji:: 2010
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: monitorowanie płodu
tętno płodu
klasyfikacja sygnału
fetal monitoring
fetal heart rate
signal classification
ROC analysis
Opis:: Cardiotocography (CTG) is the main method of assessment of the fetal state during pregnancy and labour used in clinical practice. It is based on quantitative analysis of fetal heart rate, fetal movements and uterine contractions signals. The evaluation of the CTG signals can be made using criteria recommended by International Federation of Obstetrics and Gynecology. Nevertheless, the diagnosis verification is possible only after the delivery on the basis of newborn assessment. In the proposed work we evaluated the capacity of quantitative analysis of CTG traces in predicting fetal outcome. The relationship between CTG signal features and attributes of fetal outcome was assessed on the basis of ROC curves analysis. The obtained results indicate the adequate predictive capabilities of the selected CTG features especially for fetal outcome assessed with Apgar score and suggest the necessity of applying the criteria for the CTG traces evaluation that are related to the gestational age. Our study also shows the value of the CTG monitoring as a screening procedure providing appropriate confirmation of fetal wellbeing.
Źródło:: Journal of Medical Informatics & Technologies; 2010, 16; 11-17
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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