This book constitutes the refereed proceedings of the 7th International Symposium on Ubiquitous Networking, UNet 2021, held in May 2021. Due to COVID-19 pandemic the conference was held virtually. The 16 revised full papers presented together with 6 invited papers and 3 special sessions were carefully reviewed and selected from 38 submissions. The papers are organized in topical sections: ubiquitous communication technologies and networking; tactile internet and internet of things; mobile edge networking and fog-cloud computing; artificial intelligence-driven communications; and data engineering, cyber security and pervasive services.

The present book includes extended and revised versions of a set of selected papers presented at the 17th International Joint Conference on e-Business and Telecommunications, ICETE 2020, held as an online web-based event (due to the COVID-19 pandemic) in July 2020.ICETE 2020 is a joint conference aimed at bringing together researchers, engineers and practitioners interested in information and communication technologies, including data communication networking, e-business, optical communication systems, security and cryptography, signal processing and multimedia applications, and wireless networks and mobile systems.The 10 full papers included in the volume were carefully selected from the 30 submissions accepted to participate in the conference.

This book constitutes selected papers of the Second International Conference on Advanced Communication Systems and Information Security, ACOSIS 2019, held in Marrakesh, Morocco, in November 2019. The 10 full papers and 10 short papers were thoroughly reviewed and selected from 94 submissions. The papers are organized accroding to the following topical sections: wireless communications and services; vehicular communications; channel coding; construction of error correcting codes; intrusion detection techniques; wireless and mobile network security; applied cryptography.