The authors investigate an integrated model of Cyber-Physical-Social Systems (CPSS) that combines computing, control, networking and human decision making with physical systems to better understand the interdependencies between different aspects of complex systems. The objective of this investigation is to develop a holistic framework to support policy decision making in large-scale dynamical systems such as smart-grids, considering socio-technical objectives and constraints for different interacting agents. So far, the authors have developed the framework for separately integrating a) cyber and physical aspects using the theory of Decentralized Networked Control Systems (DNCS), and b) physical and social aspects embedding power-flow analysis within complementarity-based approaches for modeling Nash equilibria of decisions. The ongoing work is focused on integrating the three aspects. The development of this framework will enhance our understanding of how entities interact in complex systems and thus build better strategies and protocols to improve the systems resilience, security and welfare. Specific applications of the framework include demand response modeling by considering decisions made by consumers, GENCOs, and ISOs.