This book features selected papers from the 9th International Conference in Advanced Engineering-Theory Applications (AETA 2024), during 7-8 November, in Brno, Czech Republic. The topics of the papers cover three main topics: energy (energy saving power electronics, electrical machines and drive systems, green-energy IT, nontrivial dynamics of electronic devices); control engineering (robotics, automatic control, biosensor IT); communication and security (broadcasting IT, communications, cyber security). Its content caters to researchers, scientist, and engineers who are interested in scientific achievements and advanced technologies of electrical, electronic-telecommunication, computer science, and mechanical-mechatronics engineering.