Speaker
Description
I will speak basically on two topics.
[1] Coupled social and ecological dynamics:
I will discuss the issue of replicator dynamics versus best response dynamics. First I will speak two models related to illegall logging in tropical forests. One model discusses the action of profit sharing by the Indonesian government, which was effective in suppressing illegal logging of teak forests. In this model, we adopted the stochastic best response dynamics.
The second model is on the corruption — rule enforcer might receive bribe and neglect the illegal logging case. The work was in collaboration with Karl Sigmund and Ulf Dieckmann, and certainly it is based on replicator dynamics. The main conclusion was that the resurgence of illegal logging and corruption persists.
Then I ask what are the major differences between the two dynamics. Which is more appropriate? Are there any empirical evidence supporting one over the other? etc. These are just questions, and I do not have definite answers myself.
[2] Coupled behavioral and epidemilogical dynamics:
In 2020-2021, we have COVID-19 infection that exhibited several waves of infection, but the total number of infected stayed rather low (the cumulated number of infected was less than 1.5%). I think this was caused by the coupling of people’s behavioral responses and epidemiology.
There are many papers written on epidemiology models incorporating people’s behavioral responses, which are all quite high dimensional and were analyzed only numerically.
We constructed a very simples model of just two dimensions, and we can prove many bifurcations (homoclinic bifurcation, Hopf bifurcation, transcritical etc.). We concluded that both risk avoidance and conformity are needed to explain the observation.
