

Georgios (George) Othon Glentis was born in Athens, Greece. He received the B.Sc. degree in Physics in 1987 and the Ph.D degree in Informatics in 1991, both from the University of Athens. Since 2015 he serves as a Professor in the Department of Informatics and Telecommunications, University of Peloponnese, Tripolis, Greece. His research interests include signal and image processing, and telecommunication applications. He has published over 100 papers in major journals and conferences.  
 Structured matrices are encountered in various signal and image processing, control, telecommunications and optimization theory, methods and applications. Structured matrices are usually dense and could be of very large size. The introduction of the concept of displacement structure allows for a low rank representation of structured matrices. Given the displacement structure of a matrix, computationally intensive operations such as matrix vector products, products of matrices, linear system solution, matrix inversion etc., can be computed efficiently. We review the fundamental concept, theory and properties of the displacement structure of Toeplitz matrices, in particular, and the recent advances on the exploitation of the Toeplitz structure of matrices involved into pertinent spectral analysis techniques. We demonstrate the use of the displacement structure concept on the development of fast algorithms for high resolution nonparametric grid based spectral analysis and coherence spectrum estimation, for the complete data as well as for the missing data case, for stationary as well for time varying signals.  