Angelos T. Vouldis

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This paper uses dynamic panel data methods to examine the determinants of non-performing loans (NPLs) in the Greek banking sector, separately for each type of loan (consumer, business and mortgage loans). The study is motivated by the hypothesis that both macroeconomic and bank-specific variables have an effect on loan quality and that these effects vary(More)
The three dimensional (3-D) extension of the two well-known diffraction tomography algorithms, namely, direct Fourier interpolation (DFI) and filtered backpropagation (FBP), are presented and the problem of the data needed for a full 3-D reconstruction is investigated. These algorithms can be used efficiently to solve the inverse scattering problem for weak(More)
In 2013 all ECB publications feature a motif taken from the €5 banknote. note: This Working Paper should not be reported as representing the views of the European Central Bank (ECB). The views expressed are those of the authors and do not necessarily reflect those of the ECB. Any reproduction, publication and reprint in the form of a different publication,(More)
A new algorithm for solving the three-dimensional inverse scattering problem using time-domain data is presented. The algorithm is intended for application in cases where linearization using the Born or Rytov approximations is not possible. A functional is defined accounting for the error of the object and data equations and the unknown coefficients of the(More)
— Most business decisions depend on accurate approximations to the cost and production functions. Traditionally, the estimation of cost and production functions in economics relies on standard specifications which are less than satisfactory in numerous situations. However, instead of fitting the data with a pre-specified model, Artificial Neural Networks(More)