Cyber-Physical Systems (CPS) and Socio-Technical Systems (STS) are well-known paradigms in engineered systems. The former emphases the integration between software, hardware and cyberware components, the latter on the interaction between humans and technology infrastructure in workplaces and society at large studying, for instance, human-machine interactions. CPS and STS have very different focuses at the general level, yet nowadays their integration is necessary to model, design and control complex systems where several heterogeneous agents need to interact. This integration pushes for a change in perspective leading to the development of a new approach that we call Agent-based Cyber-Physical Social System (ACPSS). The emergence of ACPSS can be effective only if we develop a conceptual framework in which the differences and similarities across CPS and STS can be modelled and merged. Since the core of ACPSS is the focus on agentivity and interaction, in this paper we provide an initial characterization of these via ontological analysis. Given this general aim, here we concentrate on ACPSS structural articulation (types of agentive components) and the functional and social relations that can hold across their elements (types of interactions).
