Julien Flaig

Modelling and Simulation

Ongoing Projects

Epidemic Spread and Vaccination Behaviour

Getting vaccinated comes at a cost. Whether monetary, psychological, logistical, or a matter of ideology, this cost is weighted by individuals against the benefits of vaccination when it comes to deciding whether or not to vaccinate. Now, the benefits of vaccination depend on the future spread of the disease, which in turn depends on how many people did indeed vaccinate.

So we end up with a complex dynamical system, which we can expect to give rise to such phenomena as free-riding behaviour or epidemic recurrence. That is, individuals may have little incentive to vaccinate if the disease prevalence is low, but if too few individuals are vaccinated, further outbreaks may occur.

These questions have been widely publicized in the press until quite recently. There is also a rich and still growing body of academic research on vaccination behaviour, both in the field of biology and of economics. Nicolas Houy, Philippe Michel, and I, are developing general models of infectious diseases featuring individual anticipatory and strategic vaccination behaviour. We aim at producing numerical benchmarks, and investigate anti-vaccination behaviour.

Smart Thermostats and the Energy Paradox

Why are energy efficient technologies not more widely implemented, even when they are cost efficient? The slow diffusion of such technologies is called the "energy paradox" and has been studied at least since the 90's. Authors discussed market failures and non market failures explanations of the energy paradox, and advisable public policy interventions.

The energy sector changed a lot since the 90's, most notably through the implementation of smart grid technologies. Smart thermostats are among these. They allow households to optimize their energy consumption for heating (and cooling). Examples of smart thermostats include this one, this one, and that one (French).

Yet the energy paradox remains an issue. As part of the Smart Electric Lyon (French) smart grid pilot project, St├ęphane Robin and I investigated prospective adoption paths for smart thermostats and similar add-ons.

Rather than focusing on using available adoption data, we first developed a simulation model, so as to explore a range of regulatory and energy price scenarios. Since smart thermostats are complements of heating systems, we had to model the evolution of the entire French heating system market.