Welcome to SYSOS


A group researching complex networked control systems, biological and technological

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Our group develops tools and algorithms for the analysis and design of biological and technological systems and applies them in a range of areas, from Synthetic Biology to fluid mechanics. In particular, we have been developing theory to understand how nonlinear networked systems (System of Systems) operate how to design control laws for them, using computational tools based on the Sum of Squares decomposition and Semidefinite Programming. We 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. Here is a short summary of the areas we work on - please follow the links below for more details.

  • Nonlinear systems analysis, Sum of Squares optimization and Lyapunov techniques. In this spirit, we have developed methods for stability analysis of systems described by Ordinary, Delay and Partial Differential Equations, as well as switched/hybrid systems. Of current interest is how to scale these tools to handle much more complicated and richer system descriptions, of higher dimension.
  • Systems and Synthetic Biology. We collaborate closely with groups in Engineering Science (Professor Wei Huang), Oxford Biochemistry (Professor Judith Armitage) and Plant Sciences (Professors Steve Kelly and Philip Poole) 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). This can be found here.
  • 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. We 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 and Heat transfer, from a control perspective. We are taking 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.
  • Complexity reduction of networked systems. We are investigating methods based on model decomposition and reduction to facilitate computational analysis and identification of large-scale and nonlinear systems. Systems of interest include biochemical reaction networks, power systems and consensus networks.
  • Scaling Sum of Squares and Semidefinite Programming. We are using sparsity- and symmetry-exploiting algorithms for improving the scalability of semidefinite programming, including the development of software (such as CDCS) to implement relevant operator-splitting algorithms.

Current Members

  • Mr Licio Romao - DPhil Candidate, October 2017-. Co-supervised with Professor Kostas Margellos.
  • Ms Carolin Schulte - DPhil Candidate, July 2018-. Co-supervised with Professor Philip Poole.
  • Mr Boon Lim - DPhil candidate, October 2018-. Co-supervised with Professor Wei Huang.
  • Mr Patrick Green - Probationary Research Student, July 2019-. Co-supervised with Professor Philip Poole.
  • Mr Emmanouil Alexis - DPhil Candidate, October 2019 -. Co-supervised with Professor Luca Cardelli.
  • Mr Han Wang - Probationary Research Student, October 2020 -. Co-supervised with Professor Kostas Margellos.

Current Externally Funded Projects



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  • Workshop on `New Vistas in computational systems and synthetic biology', May 2019, Vigo, Spain.
  • Antonis Papachristodoulou is elevated to IEEE Fellow for his fundamental contributions to theory and applications of Sum of Squares Programming and networked control systems.

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Joining SySOS

  • There are several other routes for joining SySOS, mainly through fellowships.

Previous Members

  • Dr Aivar Sootla - Post-Doctoral Research Associate, September 2016-June 2019.
  • Dr Axel Nyström - DPhil Student, October 2013-2018. Co-supervised with Dr Andrew Angel.
  • Dr Thomas Folliard - DPhil student, 2013-2017. Co-supervised with Professor Judith Armitage.
  • Dr Dhruva Raman - DPhil student, 2013-2017. Co-supervised with Dr James Anderson
  • Dr James Anderson DPhil student, 2008 - 2011, Post-Doctoral Research Associate 2011-2012, Junior Research Fellow, 2012-2016.
  • Dr Bing Chu - Postdoctoral Research Assistant, June 2010-March 2012
  • Dr Yo-Cheng (Mark) Chang DPhil, co-supervised with Professor Judith Armitage, Department of Biochemistry, January 2007-January 2011.
  • Dr Bence Mélykúti, DPhil, co-supervised with Professor Alison Etheridge, Department of Statistics, January 2008-February 2011.
  • Miss Nassia Inglessis, September 2009 - October 2009
  • Mr Christoph Maier, April 2009 - July 2009

Completed Projects

  • European Space Agency project with GMV (Spain), NGC (Canada) and the University of Leicester, "Worst-Case and Safety Analysis Tools for Autonomous Rendezvous Systems".

Useful Links