Control-theoretic tools for the structural analysis of biological systems
Biological systems can be modelled as dynamical networks resulting from the interaction of myriads of dynamic subsystems, arranged in several concurrent control loops; interactions occur according to a given topology, which can be visually represented as a graph, or a hyper-graph. Control-theoretic methods allow us to reveal and explain the complexity of interlaced feedback loops in biological systems (systems biology), and to design feedback loops in the cell to induce the desired behaviours (synthetic biology). Biological phenomena are characterised by astounding robustness despite huge uncertainties and environmental fluctuations.
In this seminar, Prof. Giordano will present a "structural" approach to understanding the robustness of biological systems, which exhibit fundamental life-preserving properties exclusively due to their inherent structure (graph topology), regardless of the system parameters. The "BDC-decomposition" is presented as a local and global tool for the structural analysis of biological systems. Based on this decomposition, she will propose criteria to structurally assess stability and the sign of steady-state input-output influences. Prof. Giordano will also illustrate a structural classification of the transitions to instability (either oscillatory or multi-stationary) that can occur in systems having a sign-definite Jacobian or consisting of the sign-definite interaction of stable monotone subsystems.