Ubiquitous computing is a scientific field that studies the communication of a highly interconnected network of heterogeneous computing devices and services that autonomously or collaboratively capture and process data and information in order to apply it through appropriate services according to the context and specific activity of the user. They are thus adapted to the user in private and business environments and in public places to ensure security, privacy and fraud prevention. This is therefore an area where, on the one hand, good knowledge of mathematics and logic (combinatorial optimisation, multi-valued logic), hardware (recently, especially sensors and actuators), and, on the other hand, knowledge of communication technologies (Internet, wireless communications, sensor networks) is needed at the service and information level (methodologies for developing information systems and service-oriented architectures), where knowledge of modelling the user and of user-tailored interactions is needed. The key theoretical (internationally relevant) elements of the Ubiquitous computing research programme are new paradigms for efficient processing, including customised hardware solutions, new algorithms for computationally challenging problems, new paradigms for efficient communication, data integration, heterogeneous devices and new services, provision of (cyber)security, new types of solutions contextually tailored to users and organisations, and finally - new paradigms for user modelling with tight integration of humans and computer, incorporating a systemic approach and with sustainability considerations.