This book contains papers on mathematical modeling and simulation of processes in various areas: in ecology and the environment, manufacturing and energetics, information technology, samples of special purpose equipment and cyber-physical systems. In the context of comprehensive digitalization, computer modeling becomes a direct component of creating and operating modern complex multi-domain systems.The outcomes presented in the book will be useful to specialists involved in the modeling of real-world and cyber-physical systems, physical processes simulation, management and decision-making models, functioning and cybersecurity models, modeling software and tools. Scientists have the opportunity to familiarize themselves with the latest research in a variety of solutions proposed by leading scientists and to determine promising directions for solving complex scientific and practical tasks. Chapters of this book contain papers presented at the 19th MODS International Conference, November 11–13, 2024, Chernihiv, Ukraine.