Vega Collision Rates - What's the Trend?

There was an explosion of research around the 19 sixties, all throughoutt the 19 eighties. But recently there's moving away from that, because they quite often determine tat there's a fixed variation structure in the collision rates. So my latest attempt to use is stacastic volatility - which doesn't assume this kind of fixed structure of variation. And we have to find modelling techniques tho kind of adapt that too.