Bacem Ben Nasser is a postdoctoral researcher fellow in the Electrical Engineering department within the CEMSE division. He obtained his Ph.D. degree in Sciences and Technology-Mathematics from the University of Sfax, Faculty of Sciences of Sfax, Tunisia, where he worked in Lyapunov and control theories, nonlinear integral inequalities and time scale calculus. In January 2017, he was affiliated with the University of Kairouan, Tunisia, at the Higher Institute of Applied Sciences and Technology of Kairouan as assistant professor of applied mathematics. Dr. Ben Nasser joined the research group EMAN at King Abdullah University of Science and Technology (KAUST) in October 2017. His current research interests concerns the analysis and control design for nonlinear and hybrid dynamical systems including time scales theory, modeling on non-uniform time domains, wireless communications, renewable energy and biomedical research.

Bacem's expertise is on time scale theory and control design. The time scale calculus is a new mathematical approach used to depict the engineering systems relating to the continuous and the discrete analysis. In addition, it can be employed in various domains such as economic modeling, mechanical systems, population modeling, dynamic programming, robotics, and other scientific fields. Since its appearance in 1988, several mathematicians played an initial role in the development of this theory. Such approach helps to confer more credibility and diversity for the prospective findings evolving on non-uniform time-domains. It intercepts various fields including wireless communications where the natural temporal evolution of the system is characterised by some random time-interruptions. Such temporal aspect can not be covered by the mathematical classical approaches.

The time scale theory improves new investigations on optical wireless communication (OWC) systems. For achieving an energy-efficient and secure communication link, the narrow-beam-based line-of-sight (LOS) configuration is usually employed in the OWC system, requiring strict alignment between the transmitter and the receiver. To address the alignment problem for the OWC system, various control strategies have been proposed before, such as the extremum seeking control and $\mathcal{H}_{\infty}$ pointing error control. Among them, the state estimation is a common technique in alignment control. This state estimation is, however, not trivial because the receiver would lose the optical signals sporadically, when the OWC system suffers from disturbances. This results in the intermittent received signals, professionally known as the intermittent measurements or non-uniform measurements.