Antonis Papachristodoulou

The SYSOS (System of Systems) Group develops tools and algorithms based on modern control theory for the robust analysis and design of biological and technological systems and applies them in a range of areas, from Synthetic Biology to fluid mechanics. In particular, they have been developing theory to understand how nonlinear networked systems operate and how to design control laws for them, using computational tools based on the Sum of Squares decomposition and Semidefinite Programming. They have been applying this theory to understand and (re)design biological systems (Systems and Synthetic Biology) but also to analyse and design control laws for fluid flows, robust synchronization, multi-agent system consensus, smart power networks and congestion control for the Internet. Their areas of research include: - Nonlinear systems analysis, Sum of Squares optimization and Lyapunov techniques/LMIs. In this spirit, they have developed methods for stability analysis of systems described by Ordinary, Delay and Partial Differential Equations, as well as switched/hybrid systems. - Systems and Synthetic Biology. The team collaborates closely with groups in Engineering Science (Professor Wei Huang) Oxford Biochemistry (Dr George Wadhams and Professor Judith Armitage) and other institutions for understanding biological pathways through mathematical modelling using experimental data and designing new experiments for model invalidation (Systems Biology), as well as proposing and implementing redesigns for existing biological systems for improved performance (Synthetic Biology). - Software Development (SOSTOOLS and CDCS). - Large-scale Networked Systems analysis with communication and structural constraints. Examples in this field come from synchronization phenomena in oscillator networks, Network Congestion Control for the Internet and Power System analysis/Smart grid. They are also looking at multi-agent systems consensus under communication and structural constraints such as the effect of time delays and switching topologies. - Fluid mechanics. The group takes a control engineering approach to understand questions in Hydrodynamic Stability and mechanisms for background noise energy amplification and subsequent reduction. We are also using a Sum of Squares approach for the stability analysis and control design of systems described by Partial Differential Equations.

A Prototyping Framework for Distributed Control of Multi-Robot Systems Prolyl hydroxylase-dependent proteolysis enables the orthogonal hypoxia responses in plants. A Distributed SOS Program For Local Stability Analysis of Polynomial PDEs in the PIE Representation A synthetic ERFVII-dependent circuit in yeast sheds light on the regulation of early hypoxic responses of plants. Host-Aware Control of Gene Expression using Data-Enabled Predictive Control