Editorships Editor for IEEE Transactions on Green Communications and Networking from March 2023. Editor for IEEE Transactions on Communications from July 2022. Editor for IEEE Wireless Communications Letters from July 2021. Editor for IEEE Transactions on Wireless Communications from June 2016 till June 2021. Editor for IEEE Communications Letters from June 2016 till August 2021. Editor for Elsevier Computer Networks from January 2019. Review Editor for Frontiers in Communications and Networks from May 2020. Editor for ITU Journal on Future and Evolving Technologies from August 2020. Associate Editor for IET Electronics Letters from October 2015 till October 2017. Guest Editor for the special issue on "Reconfigurable Intelligent Surfaces for Smart Radio Environments: Theory, Hardware Design, and Experimentation" by the Radio Science in 2022. Guest Editor for the special issue on "Reconfigurable Holographic MIMO Surfaces for 6G Wireless" by the IEEE Open Journal of the Communications Society in 2022. Guest Editor for the special issue on "5G Advanced" by the IEEE Communications Standards Magazine in 2022. Guest Editor for the special issue on "Full Duplex and its Applications" by the IEEE Journal on Selected Areas in Communications in 2022. Guest Editor for the special issue on "Applications of Wireless Sensor Networks and Its Security" by the Routledge and CRC Press in 2022. Guest Editor for the special issue on "Antennas and Propagation for 6G Wireless Communications" by the HINDAWI International Journal of Antennas and Propagation in 2022. Guest Editor for the special issue on "Aerial Access Networks for 6G" by the IEEE/KICS Journal of Communications and Networks in 2021. Guest Editor for the special issue on "UAV Control and Communications in 5G and Beyond Networks" by the MDPI Sensors in 2021. Guest Editor for the special issue on "Intelligent Surfaces for 6G Cellular Networks: A Holistic View" by the MDPI Applied Sciences in 2021. Guest Editor for the special issue on "Communications and Computing for Green Industrial IoT and Smart Grids" by the IEEE Transactions on Green Communications and Networking in 2020. Feature topic Editor for the TCCN Newsletter Issue June 2020 on "Reconfigurable Intelligent Surfaces." Guest Editor for the special issue on "Optimization of Cross-layer Collaborative Resource Allocation for Mobile Edge Computing, Caching and Communication" by Elsevier Computer Networks in 2020. Guest Editor for the special issue on "Full-Duplex Wireless Communication" by MDPI Sensors in 2020. Guest Editor for the special issue on "Intelligent Surfaces for Smart Wireless Communications" by IEEE Transactions on Cognitive Communications and Networking in 2020. Guest Editor for the special issue on "Non-Orthogonal Multiple Access for 5G and Beyond Wireless Networks" by IEEE Open Journal of the Communications Society in 2020. Guest Editor for the special issue on "Energy and Spectrum-Efficient Wireless Sensor Networks" by HINDAWI International Journal of Distributed Sensor Networks in 2015. Member of the Editorial Board for KSII Transactions on Internet and Information Systems, Korean Society for Internet Information from 2013 till 2016. Member of the Editorial Advisory Board for Recent Advances in Communications and Networking Technology, Bentham Science Publishers from 2011 till 2015. Reviewing Journals: IEEE Transactions on Signal Processing, IEEE Transactions on Wireless Communications, IEEE Transactions on Communications, IEEE Transactions on Information Theory, IEEE Communications Magazine, IEEE Wireless Communications Magazine, IEEE Transactions on Vehicular Technology, IEEE Transactions on Mobile Computing, IEEE Communications Letters, IEEE Wireless Communications Letters, IEEE Signal Processing Letters, IET Communications, Elsevier Signal Processing, EURASIP Journal on Wireless Communications and Networking, and several other international journals. Conferences: IEEE International Conference on Communications (ICC), IEEE Global Communications Conference (GLOBECOM), IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), IEEE Vehicular Technology Conference (VTC), IEEE International Workshop on Signal Processing Advances for Wireless Communications (SPAWC), IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), IEEE Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP), IEEE Information Theory Workshop (ITW), and several other international conferences. Memberships in Scientific Communities IEEE Senior Member from 2015 (Student Member from 2007 – 2010 and Member from 2010 – 2015). IEEE Vehicular Technology Society Member from 2022. IEEE Information Theory Society Member from 2020. IEEE Signal Processing Society Member from 2012. Involved with the Integrated Sensing and Communication Technical Working Group from 2023 and the Signal Processing for Communications and Networking Technical Committee from 2024. IEEE Communications Society Member from 2012. Involved with the Radio Communications, Communication Theory, and Signal Processing and Computing for Communications Technical Committees; served as Standards Liaison for the latter two committees. Involved with the Green Communications and Computing Technical Committee and served as vice chair of the special interest group entitled "Green Smart Grid Communications." Founding member serving as online content officer for the Emerging Technology Initiative (ETI) on Reconfigurable Intelligent Surfaces, and serving as Workshops, Tutorials, and Symposia Officer for the ETI on Machine Learning for Communications (2021–present). Founding member of the Special Interest Group (SIG) on beyond diagonal reconfigurable intelligent surfaces. Founding member of the ETSI Industry Specification Group (ISG) on Reconfigurable Intelligent Surfaces from 2021. Founding member of the ETSI ISG on THz from 2022. Founding member of the ETSI ISG on Integrated Sensing and Communications from 2023. Member of the RIS TECH Alliance (RISTA), which is a global technology alliance to promote technology research, standardization, and industrialization of reconfigurable intelligent surfaces from 2022. Member of the Expert Advisory Group of ETP NetWorld 2020 from 2015. Member of the EURASIP Technical Area Committee on Signal Processing for Communications and Networking from 2021; serving as vice-chair from 2022. Member of the Technical Program Committee for several international conferences (IEEE GLOBECOM, ICC, ICASSP, ISIT, PIMRC, SPAWC, VTC, WCNC etc. and EUSIPCO) from 2009. Registered Engineer of the Technical Chamber of Greece from 2005.