**About the Editors**

**J. A. Tenreiro Machado** was born in 1957, graduated with 'Licenciatura' (1980), PhD (1989) and 'Habilitation' (1995) degrees in Electrical and Computer Engineering at the University of Porto. From 1980 to 1998, he worked as a professor at the Department of Electrical and Computer Engineering, University of Porto. Since 1998, he has been a coordinator professor at the Institute of Engineering of the Polytechnic Institute of Porto, Department of Electrical Engineering. His main research interests are: nonlinear dynamics, modeling, fractional calculus, evolutionary computing, control, and robotics. He is the author of more than 680 papers and his Scopus h-index is 54.

**Antonio ´ M. Lopes** obtained his PhD and 'Habilitation' in Mechanical Engineering in 2000 and 2018, respectively, both at the Faculty of Engineering of the University of Porto (FEUP), Portugal. Currently, he works at the Department of Mechanical Engineering (DEMec) and the Associated Laboratory for Energy, Transports and Aeronautics (LAETA/INEGI). Antonio ´ M. Lopes has been involved in teaching activities for the master's degree in Mechanical Engineering, the master's degree in Industrial Engineering and Management, and the doctoral program in Mechanical Engineering, all at FEUP. He participated in several research projects in the area of Mechanical Engineering and Automation. His research interests include: complex systems, fractional calculus, nonlinear dynamics, automation, robotics, control, systems modelling, and simulation. Antonio ´ M. Lopes has published about 130 papers in international journals with high impact factors, and nearly 100 book chapters, plus conference papers. His Scopus h-index is 23. He currently participates on the Editorial Board of eight international journals, and has been a gues<sup>t</sup> editor of several journal Special Issues.
