Welcome to SYSOS


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Welcome to SySOS

A group researching complex networked control systems, biological and technological

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Research Interests

Our group develops tools and algorithms for the analysis and design of feedback control in 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 (SOS) decomposition and Semidefinite Programming (SDP). 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, the robustness of (deep) neural network controllers 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 (see also point below, on scaling SDP/SOS methods).
  • Systems and Synthetic Biology. We collaborate closely with groups in Engineering Science (Professor Wei Huang) and Plant Sciences (Professor 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.
  • Robust analysis and design of (deep) neural network controllers. We are using tools from traditional and modern control theory for the analysis and design of (deep) neural network controllers used in (deep) reinforcement learning.

Current Members

  • Mr Patrick Green - DPhil candidate, July 2019-. Co-supervised with Professor Philip Poole.
  • Mr Emmanouil Alexis - DPhil Candidate, October 2019 -. Co-supervised with Professor Luca Cardelli.
  • Mr Miroslav Gasparek - DPhil Candidate, October 2019 -. Co-supervised with Professor Harrison Steel.
  • Mr Han Wang - DPhil Candidate, October 2020 -. Co-supervised with Professor Kostas Margellos.
  • Mr Scott Stacey - Probationary Research Student, July 2021 -. Co-supervised with Professor Harrison Steel.
  • Mr Bergthor Traustason - Probationary Research Student, July 2021 -. Co-supervised with Professor Philip Poole.
  • Mr Liqun Zhao - Probationary Research Student, October 2021 -. Co-supervised with Dr Konstantinos Gatsis.

Current and Previous Externally Funded 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".



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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

  • If you are an Oxford undergraduate interested in doing a summer internship on any of the above research directions (or anything else) get in touch.
  • There are several other routes for joining SySOS, mainly through fellowships. Please contact us to discuss.

Previous Members

  • Ms Carolin Schulte - DPhil student, July 2018- November 2021. Co-supervised with Professor Philip Poole.
  • Mr Boon Lim - DPhil student, October 2018- November 2021. Co-supervised with Professor Wei Huang.
  • Mr Licio Romao - DPhil student, October 2017 - September 2021. Co-supervised with Professor Kostas Margellos.
  • Dr Harrison Steel - DPhil student, October 2016-June 2019. PDRA, June 2019- September 2020.
  • 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

Useful Links