Invited Talks / Seminars / Tutorials 81. Keynote talk at the IEEE International Symposium on Intelligent Signal Processing and Communication Systems, Kaohsiung, Taiwan on 11 December 2024 with title: Hybrid reconfigurable intelligent surfaces: From programmable signal reflections to distributed intelligent sensing. 80. Invited talk in the framework of the IEM Distinguished Lectureships Seminar at the Institute of Electrical and Micro Engineering, EPFL, Lausanne, Switzerland on 12 November 2024 with title: Reconfigurable intelligent surfaces for extending the limits of wireless communications. 79. Tutorial at the IEEE International Conference on Communications, Denver, USA on 9 June 2024 with title: Full-duplex MIMO for simultaneous communications and sensing. (tutorial given together with B. Smida) 78. Tutorial at the IEEE Wireless Communications and Networking Conference, Dubai, UAE on 21 April 2024 with title: Integrated sensing and communications: Fundamental limits, signal design, and emerging PHY technologies. (tutorial given together with F. Liu and Y. Xiong) 77. Invited talk at the Department of Information Engineering, Electronics, and Telecommunications, Sapienza University of Rome, Rome, Italy on 17 April 2024 with title: Multi-RIS-empowered smart wireless networks: Capacity characterization and environment learning potential. 76. Keynote talk at the 5GItaly conference, Rome, Italy, sponsored by the Italian National Inter-University Consortium for Telecommunications (CNIT), on 17 April 2024 with title: The RIS technology for beyond 5G wireless: Modeling, optimization, and applications. 75. Research seminar at the Department of Electronics Engineering, Chungnam National University, Daejeon, South Korea on 11 April 2024 with title: Localization and sensing with multi-functional reconfigurable intelligent surfaces. 74. Tutorial at the International Symposium on Joint Communications and Sensing, Leuven, Belgium on 19 March 2024 with title: Integrated sensing and communications: Fundamental limits, signal design, and emerging PHY technologies. (tutorial given together with F. Liu and Y. Xiong) 73. Research seminar at the Department of Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden on 6 March 2024 with title: Hybrid reconfigurable intelligent surfaces: From efficient optimization to integrated sensing and communications. 72. Invited talk at the Hexa-X II Workshop on 6G on 26 January 2024 with title: The RIS potential for THz wireless applications: Feasibility study and open challenges. 71. Research seminar at the Interdisciplinary Centre for Security, Reliability and Trust, University of Luxembourg, Luxembourg City, Luxembourg on 17 January 2024 with title: Simultaneous sensing and communications with full duplex MIMO and reconfigurable intelligent surfaces. 70. Research seminar at the online Expert Seminar on 6G: New PHY-layer solutions and spectrum on 14 December 2023 with title: Multi-functional RISs, holographic MIMO, integrated sensing and communications, cell-free smart wireless environments. 69. Tutorial at the RISE-6G online training workshop on 12 December 2023 with title: The RIS technology: Today's key pillars and open challenges. 68. IEEE ComSoc Distinguished Lectureship at the Institute of Radiocommunications, Faculty of Computing and Telecommunications, Poznan University of Technology, Poznan, Poland on 16 November 2023 with title: Joint sensing and communications with full duplex radios and reconfigurable metasurfaces. 67. IEEE ComSoc Distinguished Lectureship at the School of Physics, Engineering, and Computer Science, University of Hertfordshire, Hatfield, UK on 14 September 2023 with title: Hybrid reconfigurable intelligent surfaces: From conventional optimization to autonomous learning. 66. IEEE ComSoc Distinguished Lectureship at the Department of Computer Science and Technology, Cambridge University, Cambridge, UK on 13 September 2023 with title: Reconfigurable intelligent surfaces: From programmable wireless propagation to holographic MIMO. 65. Keynote talk at the IEEE PIMRC Workshop (virtual) "6G Envisioned Reconfigurable Intelligent and Holographic Surfaces" on 5 September 2023 with title: RIS-empowered smart wireless environments: Capacity characterization and optimization. 64. Research seminar at the Lake Como School of Advanced Studies, Lake Como, Italy on 4 July 2023 with title: Reconfigurable intelligent surfaces: From programmable wireless propagation to holographic MIMO. 63. Research seminar at the Summer School on Integrated Sensing and Communication, Baiona, Spain on 28 June 2023 with title: Beamforming for joint radar and communication with self-interference cancellation constraints. The school was sponsored by the IEEE Signal Processing Society, IEEE Aerospace and Electronic Systems Society, and EURASIP. 62. Research seminar at the Summer School on Integrated Sensing and Communication, Baiona, Spain on 28 June 2023 with title: RIS-aided joint radar and communication. The school was sponsored by the IEEE Signal Processing Society, IEEE Aerospace and Electronic Systems Society, and EURASIP. 61. Tutorial at the IEEE International Conference on Communications, Rome, Italy on 28 May 2023 with title: Leveraging smart wireless environments for beyond 5G localization and sensing. (tutorial given together with H. Wymeersch) 60. Invited talk at the UK-Taiwan Joint Webinar on Next Generation Multiple Access and AI for 6G on 1 May 2023 with title: Integrated sensing and communications with multi-functional reconfigurable metasurfaces. 59. IEEE ComSoc Distinguished Lectureship at the University of Glasgow, Glasgow, Scotland on 30 March 2023 with title: Reconfigurable metasurfaces for 6G wireless: Hardware architectures, modeling, optimization, and applications. 58. Tutorial at the IEEE Wireless Communications and Networking Conference, Glasgow, Scotland on 26 March 2023 with title: Leveraging full-duplex MIMO systems for beyond 5G simultaneous transmit and receive applications. (tutorial given together with K. Kolodziej) 57. IEEE ComSoc Distinguished Lectureship at the Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, USA on 10 March 2023 with title: Hybrid reconfigurable intelligent Surfaces: From channel estimation improvement to self-optimization. 56. Tutorial at the National Conference on Communications, Indian Institute of Technology Guwahati, India on 23 February 2023 with title: Reconfigurable intelligent surfaces and holographic MIMO transceivers: Current status and future directions. 55. IEEE ComSoc Distinguished Lectureship at EURECOM, Campus Sophia Antipolis, Nice, France on 9 February 2023 with title: Integrated sensing and communications with multi-functional reconfigurable metasurfaces. 54. Invited talk at the session "Radio and sensing for 6G" of the ICT-52 and Hexa-X Workshop on 6G on 18 January 2023 with title: Localization, sensing, and their integration with reconfigurable intelligent surfaces. 53. IEEE ComSoc Distinguished Lectureship at the IEEE ComSoc Greece Chapter, Computer Engineering and Informatics Department, University of Patras, Greece on 16 December 2022 with title: Reconfigurable intelligent surfaces: An enabling technology for smart radio propagation and its beyond 5G applications. 52. IEEE ComSoc Distinguished Lectureship at the IEEE Spanish Signal Processing and Communications Joint Chapter and IEEE United Kingdom and Ireland Section on 14 December 2022 with title: Reconfigurable intelligent surfaces: Communications, sensing, and their integration. 51. IEEE ComSoc Distinguished Lectureship at the IEEE Atlanta Chapter, USA on 8 December 2022 with title: Reconfigurable intelligent surfaces: Communications, sensing, and their integration. 50. Invited talk at the Round Table "mmWaves and sub-THz Ranges in Wireless Communication: Promising Applications and Coverage Problems" at the Moscow Institute of Physics and Technology, Moscow, Russia on 23 November 2022 with title: Metasurface-based holographic MIMO: Communications, localization, and sensing. 49. Invited seminar at the Zhejiang University Graduate International Workshop "Toward 6G with Intelligent Communications, Sensing, and Computing" on 27 October 2022 with title: Hybrid reconfigurable intelligent surfaces: Hardware architectures, orchestration, and open challenges. 48. Invited talk at the RIS Tech Alliance (RISTA) on 12 October 2022 with title: Hybrid reconfigurable intelligent surfaces: Current hardware architectures, orchestration, and future directions. 47. IEEE ComSoc Distinguished Lectureship at the IEEE Baltimore Chapter, USA on 4 October 2022 with title: Reconfigurable intelligent surfaces and smart radio propagation environments. 46. Invited talk at the 5GPPP Workshop on "6G KPIs and How to Measure Them" on 28 September 2022 with title: RISE-6G’s KPIs and two challenges with RISs: Area and bandwidth of influence. 45. Tutorial at the IEEE Vehicular Technology Conference Fall, London/Beijing, UK/China on 26 September 2022 with title: Leveraging full-duplex MIMO systems for beyond 5G simultaneous transmit and receive applications. (tutorial given together with H. A. Suraweera and K. Kolodziej) 44. Keynote talk at the Workshop "Reconfigurable Holographic and Intelligent Surfaces for Green 6G Sensing, Communication and Networking" in the framework of the IEEE International Conference on Sensing, Communication, and Networking (virtual) on 23 September 2022 with title: Smart reflectors and holographic MIMO: Metasurface-based architectures and challenges. 43. Tutorial at the IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (virtual) on 12 September 2022 with title: Smart wireless environments for beyond 5G localization and sensing. (tutorial given together with H. Wymeersch and K. Keykhosravi) 42. Keynote talk at the IEEE PIMRC Workshop (virtual) "Reconfigurable Intelligent Surfaces for Sensing, Localization, Computing, and Communications" on 12 September 2022 with title: Capacity optimization in RIS-empowered smart wireless environments: A large system analysis. 41. Invited talk at the 86th Thessaloniki International Fair, Greece on 11 September 2022 with title: Information and communications technologies: The role of the digital policy analyst. 40. IEEE ComSoc Distinguished Lectureship at the Department of Electrical and Computer Engineering, North Carolina State University, North Carolina, USA on 9 September 2022 with title: Reconfigurable intelligent surfaces: Communications, sensing, and their integration. 39. Keynote talk at the IEEE International Mediterranean Conference on Communications and Networking in Athens, Greece on 8 September 2022 with title: Full duplex MIMO radios: From efficient spectrum usage to integrated communications and sensing. 38. Invited talk at the IEEE International Conference on Signal Processing and Communication in Bangalore, India on 13 July 2022 with title: Integrated communications and sensing with hybrid reconfigurable intelligent surfaces. 37. IEEE ComSoc Distinguished Lectureship at the IEEE Information Theory Society Bangalore Chapter, India on 12 July 2022 with title: Smart wireless environments: From programmable passive reflectors to autonomous reconfigurable metasurfaces. 36. IEEE ComSoc Distinguished Lectureship at the IEEE Singapore ComSoc Chapter and the Singapore University of Technology and Design, Singapore on 6 July 2022 with title: Environmental AI: From programmable metamaterials to autonomous reconfigurable metasurfaces. 35. IEEE ComSoc Distinguished Lectureship at the IEEE Kolkata ComSoc Chapter and the Indian Institute of Technology, Patna, India on 20 June 2022 with title: Reconfigurable intelligent surfaces: Communications, localization, and sensing. 34. Invited talk at the 1st Open Annual Workshop on Future ICT in Athens, Greece on 25 May 2022 with title: Programmable radio propagation environments: The RISE-6G perspective. The talk was part of the 5G/6G future ICT area. 33. Research seminar on 9 May 2022 with title: Reconfigurable intelligent surfaces for 6G wireless communications, localization, and sensing. The seminar was organized by PAINLESS, the H2020 Marie Sklodowska-Curie Innovative Training Network with grant number 812991, in the framework of School 4. 32. Virtual research seminar on 28 January 2022 with title: Full duplex MIMO systems: From efficient spectrum usage to joint communications and sensing. The seminar was organized by SEMANTIC, the H2020 Marie Sklodowska-Curie Innovative Training Network with grant number 861165, in the framework of School 3: "PHY layer techniques and design principles in 5G New Radio." 31. Invited talk at the track on Internet of Things in Chicago, USA on 12 October 2021 with title: Smart wireless connectivity for IoT applications enabled by reconfigurable intelligent surfaces. The track was part of the IEEE Real Time Communications Conference. 30. Tutorial at the IEEE GLOBECOM in Madrid, Spain on 7 December 2021 with title: Reconfigurable intelligent surfaces for 6G: Communications, localization, and sensing. (tutorial given together with L. Song, H. Wymeersch, Z. Han, B. Di, and H. Zhang) 29. Research seminar at the Lake Como School of Advanced Studies, Lake Como, Italy on 7 July 2021 with title: Cell-free communications and reconfigurable intelligent surfaces: Two candidate 6G technologies and their joint potential. 28. Invited talk at the special session on recent progress in antennas and metasurfaces for 6G in Porto, Portugal on 9 June 2021 with title: Simultaneous reflecting and sensing metasurfaces for 6G wireless communications. The special session was part of the 2021 Joint EuCNC & 6G Summit (virtual). 27. Invited talk at the Hexa-X The European 6G initiative workshop in Porto, Portugal on 8 June 2021 with title: The RISE-6G project: Wireless environment as a service enabled by reconfigurable intelligent surface. The workshop was part of the 2021 Joint EuCNC & 6G Summit (virtual). (talk given by E. Calvanese Strinati in collaboration with V. Sciancalepore and G. C. Alexandropoulos) 26. Tutorial at the 2021 Joint EuCNC & 6G Summit (virtual) in Porto, Portugal on 8 June 2021 with title: Reconfigurable intelligent surfaces: Localization and communication convergence. (tutorial given together with H. Wymeersch) 25. Tutorial at the IEEE Global Communications Conference (virtual) in Taipei, Taiwan on 7 December 2020 with title: Reconfigurable metasurfaces for intelligent 6G wireless networking. (tutorial given together with C. Liaskos and I. F. Akyildiz) 24. Keynote talk at the 5th South-East Europe Design Automation, Computer Engineering, Computer Networks and Social Media Conference, co-sponsored by the IEEE Computational Intelligence Society, on 25 September 2020 with title: Beyond 5G smart wireless connectivity: Radio wave propagation control via reconfigurable metasurfaces. 23. Tutorial at the IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (virtual) in London, UK on 31 August 2020 with title: Reconfigurable metasurfaces for intelligent 6G wireless networking. (tutorial given together with C. Liaskos and I. F. Akyildiz) 22. Research seminar at the Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, USA on 16 November 2018 with title: Transceiver design for beyond 5G communications: Emerging architectures and signal processing. 21. Research seminar at EURECOM, Campus Sophia Antipolis, Nice, France on 5 July 2018 with title: Millimeter wave communication systems: Current status and future challenges. The seminar was organized by SPOTLIGHT, the H2020 Marie Sklodowska-Curie Innovative Training Network with grant number 722788. 20. Invited talk at the Department of Informatics and Telecommunications, National and Kapodistrian University of Athens, Athens, Greece on 8 May 2017 with title: The role of multi-antenna signal processing techniques in 5G mobile networks and beyond. 19. Invited talk at the Institute of Mobile Communications, Southwest Jiaotong University, Chengdu, China on 22 June 2016 with title: Some recent results in candidate physical-layer technologies for 5G mobile networks. 18. Invited talk at the Microwave Branch, Huawei Technologies Co. Ltd., Chengdu, China on 20 June 2016 with title: Robust beamforming for multi-antenna communications: Beam tracking and antenna calibration. 17. Research seminar at the Communications and Information Systems Research Group, Department of Electronic and Electrical Engineering, University College of London, London, England on 22 January 2016 with title: Interference management techniques for emerging and future wireless networks. 16. Invited talk at the Communications Theory Lab, Huawei Technologies Co. Ltd., Shanghai, China on 6 November 2015 with title: Millimeter wave communication systems: Signal processing techniques and performance analysis. 15. Research seminar at the Mathematical and Algorithmic Sciences Lab, Paris Research Center, Huawei Technologies France SASU, Boulogne–Billancourt, France on 3 June 2015 with title: Signal processing techniques for multi-user MIMO communication systems. 14. Invited talk at the Interdisciplinary Centre for Security, Reliability and Trust, University of Luxembourg, Luxembourg City, Luxembourg on 13 January 2015 with title: Signal processing techniques for the K-user MIMO interference channel. 13. Invited talk at the Computer Engineering and Informatics Department (CEID), School of Engineering (SE), University of Patras (UoP), Rio-Patras, Greece on 26 June 2014 with title: Transceiver techniques for multi-user multi-antenna systems. The talk was coorganized by CEID's Signal Processing and Communications Laboratory (SPCL), IEEE Greece Signal Processing Chapter and UoP's Network on Research and Applications of Wireless Communication and Sensor Networks. 12. Invited talk at the Institute of Computer Science, Foundation for Research and Technology-Hellas (FORTH), Heraklion, Crete, Greece on 10 June 2014 with title: Some recent results in signal processing techniques for multi-user wireless systems. 11. Invited talk at the Communications Systems Group, Darmstadt University of Technology, Darmstadt, Germany on 26 May 2014 with title: Cooperative techniques for cognitive radios: Design and performance analysis. 10. Invited talk at the Scandinavian workshop on testbed based wireless research, Stockholm, Sweden on 27 November 2013 with title: Design of parasitic antenna arrays & experimentation at AIT’s B-WiSE Lab. (talk given by C. B. Papadias in collaboration with G. C. Alexandropoulos, V. I. Barousis and E. I. Roumpakias) 9. Invited talk at the Beijing University of Posts and Telecommunications, Wireless Signal Processing and Network Laboratory, Beijing, China on 30 May 2011 with title: Performance analysis of cooperative techniques over generalized fading channels. 8. Invited talk at the Athens Information Technology (AIT) Center for Research and Education, Broadband Wireless and Sensor Networks Group, Athens, Greece on 27 April 2011 with title: Analyzing the performance of multi-antenna systems over non-ideal conditions. 7. Research seminar at the Institute of Informatics and Telecommunications (IIT), National Center for Scientific Research (NCSR)–"Demokritos," Athens, Greece on 29 October 2009 with title: Low complexity diversity techniques in correlated fading channels. 6. Invited talk at the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Palea Penteli, Greece on 4 December 2008 with title: Diversity systems in correlated generalized fading channels. 5. Research seminar at IIT, NCSR–"Demokritos," Athens, Greece on 16 July 2008 with title: Diversity systems in correlated fading channels. 4. Invited talk at SPCL, CEID, SE, UoP, Rio-Patras, Greece on 14 April 2008 with title: Performance analysis of multi-channel receivers over correlated fading channels. 3. Research seminar at IIT, NCSR–"Demokritos," Athens, Greece on 5 April 2008 with title: Performance analysis of diversity receivers over correlated fading channels. 2. Research seminar at IIT, NCSR–"Demokritos," Athens, Greece on 20 June 2007 with title: Performance analysis of multiple-input multiple-output (MIMO) systems. 1. Research seminar at IIT, NCSR–"Demokritos," Athens, Greece on 1 November 2006 with title: Performance analysis of diversity receivers over correlated Weibull fading channels.