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Institution

Wrocław University of Technology

EducationWrocław, Poland
About: Wrocław University of Technology is a education organization based out in Wrocław, Poland. It is known for research contribution in the topics: Laser & Fuzzy logic. The organization has 13115 authors who have published 31279 publications receiving 338694 citations.


Papers
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Journal ArticleDOI
TL;DR: A theoretical and experimental study of GaNPAs with ~40% phosphorus and up to 2% nitrogen was conducted by as mentioned in this paper, who found that this HMA has an electronic band structure well suited for IBSC applications.
Abstract: Semiconductors known as highly mismatched alloys (HMAs) have unique properties that make them useful in the fabrication of intermediate band solar cells (IBSCs). Now a theoretical and experimental study of GaNPAs with ~40% phosphorus and up to 2% nitrogen finds that this HMA has an electronic band structure well suited for IBSC applications.

69 citations

Journal ArticleDOI
TL;DR: In this article, the fundamental frequency component amplitude and the decaying DC component in each period were estimated for each period, and the accuracy of the estimation was shown to be excellent for the case of the CT primary current.
Abstract: If a current transformer (CT) saturates while transforming the heavy primary current, in each period, there are sections when the magnetic core is unsaturated and transformation is correct, and when it is saturated, it causes enormous errors. The key to correct the errors is to detect instants of saturation and moments when the saturation ends. This paper presents simple and efficient methods of doing that. In addition, it shows the way how to predict up to three samples after saturation with the acceptable degree of accuracy, thus artificially expanding the unsaturated section. It may substantially facilitate operation of protective devices. The ultimate solution of the problem is to estimate the values of the fundamental frequency component amplitude and the decaying DC component in each period. This paper presents the method of doing that on the ground of four consecutive samples taken during the unsaturated section. If the primary current consists of the fundamental and DC exponential components only, the accuracy of the method is excellent. Neglecting contamination of the current signal with harmonics and noise, it is possible to reconstruct the CT primary current based on the measured values of fundamental and DC components.

69 citations

Journal ArticleDOI
TL;DR: A novel method for constructing comprehensible scoring model by applying Classification Restricted Boltzmann Machines (ClassRBM) is proposed and its performance is evaluated by comparing its performance with the results gained by other methods using four datasets from the credit scoring domain.
Abstract: We propose a comprehensible model for credit risk assessment using a scoring table.We use Restricted Boltzmann Machine to determine scoring points in a scoring table.We deal with the imbalanced data by applying the geometric mean criterion.The quality of the presented method is evaluated on four credit scoring datasets. Credit scoring is the assessment of the risk associated with a consumer (an organization or an individual) that apply for the credit. Therefore, the problem of credit scoring can be stated as a discrimination between those applicants whom the lender is confident will repay credit and those applicants who are considered by the lender as insufficiently reliable. In this work we propose a novel method for constructing comprehensible scoring model by applying Classification Restricted Boltzmann Machines (ClassRBM). In the first step we train the ClassRBM as a standalone classifier that has ability to predict credit status but does not contain interpretable structure. In order to obtain comprehensible model, first we evaluate the relevancy of each of binary features using ClassRBM and further we use these values to create the scoring table (scorecard). Additionally, we deal with the imbalanced data issue by proposing a procedure for determining the cutting point using the geometric mean of specificity and sensitivity. We evaluate our approach by comparing its performance with the results gained by other methods using four datasets from the credit scoring domain.

69 citations

Journal ArticleDOI
TL;DR: In this paper, a short introductory review of the properties of the codifference is given, and it is shown that for Gaussian processes the covariance is equivalent to codifference.
Abstract: Correlation and spectral analysis represent the standard tools to study interdependence in statistical data. However, for the stochastic processes with heavy-tailed distributions such that the variance diverges, these tools are inadequate. The heavy-tailed processes are ubiquitous in nature and finance. We here discuss codifference as a convenient measure to study statistical interdependence, and we aim to give a short introductory review of its properties. By taking different known stochastic processes as generic examples, we present explicit formulas for their codifferences. We show that for the Gaussian processes codifference is equivalent to covariance. For processes with finite variance these two measures behave similarly with time. For the processes with infinite variance the covariance does not exist, however, the codifference is relevant. We demonstrate the practical importance of the codifference by extracting this function from simulated as well as real data taken from turbulent plasma of fusion device and financial market. We conclude that the codifference serves as a convenient practical tool to study interdependence for stochastic processes with both infinite and finite variances as well.

68 citations

Journal ArticleDOI
TL;DR: Probable sources of PM2.5 were: power plants, soil, and roads in Zabrze and in Katowice an industrial source, probably a non-ferrous smelter or/and a steelwork, and power plants.
Abstract: The paper discusses ambient concentrations of PM(25) (ambient fine particles) and of 29 PM(25)-related elements in Zabrze and Katowice, Poland, in 2007 The elemental composition of PM(25) was determined using energy dispersive X-ray fluorescence (EDXRF) The mobility (cumulative percentage of the water-soluble and exchangeable fractions of an element in its total concentration) of 18 PM(25)-related elements in Zabrze and Katowice was computed by using sequential extraction and EDXRF combined into a simple method The samples were extracted twice: in deionized water and in ammonium acetate In general, the mobility and the concentrations of the majority of the elements were the same in both cities S, Cl, K, Ca, Zn, Br, Ba, and Pb in both cities, Ti and Se in Katowice, and Sr in Zabrze had the mobility greater than 70% Mobility of typical crustal elements, Al, Si, and Ti, because of high proportion of their exchangeable fractions in PM, was from 40 to 66% Mobility of Fe and Cu was lower than 30% Probable sources of PM(25) were determined by applying principal component analysis and multiple regression analysis and computing enrichment factors Great part of PM(25) (78% in Katowice and 36% in Zabrze) originated from combustion of fuels in domestic furnaces (fossil fuels, biomass and wastes, etc) and liquid fuels in car engines Other identified sources were: power plants, soil, and roads in Zabrze and in Katowice an industrial source, probably a non-ferrous smelter or/and a steelwork, and power plants

68 citations


Authors

Showing all 13239 results

NameH-indexPapersCitations
Krzysztof Palczewski11463146909
Claude B. Sirlin9847533456
Marek Czosnyka8874729117
Alfred Forchel85135834771
Jerzy Leszczynski7899327231
Kim R. Dunbar7447020262
Massimo Olivucci6729214880
Nitesh V. Chawla6138841365
Edward R. T. Tiekink60196721052
Bobby G. Sumpter6061923583
Wieslaw Krolikowski5950412836
Pappannan Thiyagarajan5924510650
Marek Samoc5840111171
Lutz Mädler5823227800
Rafał Weron5828512058
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202372
2022231
20211,579
20201,769
20191,753
20181,963