  In this paper, we propose a model for simulating search operators whose
behaviour often changes continuously during the search. In these scenarios, the
performance of the operators decreases when they are applied. This is motivated
by the fact that operators for optimization problems are often roughly
classified into exploitation operators and exploration operators. Our
simulation model is used to compare the different performances of operator
selection policies and clearly identify their ability to adapt to such specific
operators behaviours. The experimental study provides interesting results on
the respective behaviours of operator selection policies when faced to such non
stationary search scenarios.
