PhD defence

Dynamics of complex systems inferred from multivariate time series

PhD candidate Els E (Els) Weinans MSc
Promotor prof.dr. M (Marten) Scheffer
Co-promotor EH (Egbert) van Nes
External copromotor dr IA van de Leemput
Organisation Wageningen University, Aquatic Ecology and Water Quality Management

Mon 18 October 2021 16:00 to 17:30



In my PhD I explored how time series analysis can be used to understand the behaviour of complex systems. My focus was two-fold. Firstly, some systems encounter ‘tipping points’ where they suddenly change their behavior. Examples include species extinction or the disappearance of ice sheets. I demonstrated how time series of the system may contain information about the weak spots in the system, i.e. which species is most likely to initiate the extinction or which location of the ice sheet will melt the quickest. Secondly, some systems are chaotic, meaning that they are highly unpredictable. I used statistical methods specifically designed for chaotic systems to quantify complexity in physiological data and to detect causal links in the carbon cycle during the glacial-interglacial cycles of the past 800,000 years.