Author

Alex Karagrigoriou

Lab of Statistics and Data Analysis, Greece

2 articles in our journals

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Research ArticleOpen accessAdjusted Transformation Methods for Reproduction Quality ControlEmmanouil-Nektarios Kalligeris, Alex Karagrigoriou, Kostantinos Ladopoulos, Christina Parpoulan this paper we introduce adjusted transformation methods for off-line quality control. The proposed methods result in proper performance measures for the determination of the controllable factors that affect the mean and variability of the response variable of interest. The details of the proposed adjusted transformations are provided and compared with the well-known Box and Coxtransformation and the safeguard method … …Journal of Mathematics and Statistics, Vol. 15, Issue 1 · 22 Oct 2019 · 6,874 accessesView PDF Cite

Research ArticleOpen accessEstimation and Reliability for a Special Type of Semi-Markov ProcessVlad Stefan Barbu, Alex Karagrigoriou, Andreas MakridesThis work deals with multi-state systems modelled by means of semi-Markov processes. The sojourn times are seen to be independent not identically distributed random variables and assumed to belong to one of two different general classes of distributions so that the first class is closed under maxima and the second one is closed under minima. We obtain maximum likelihood estimators … …Journal of Mathematics and Statistics, Vol. 15, Issue 1 · 20 Oct 2019 · 7,049 accessesView PDF Cite