A new concept of local metric entropy for finite-time nonautonomous   dynamical systems
  We introduce a new concept of finite-time entropy which is a local version of the classical concept of metric entropy. Based on that, a finite-time version of Pesin's entropy formula and also an explicit formula of finite-time entropy for $2$-D systems are derived. We also discuss about how to apply the finite-time entropy field to detect special dynamical structures such as Lagrangian coherent structures. 
Luu Hoang Duc, Stefan Siegmund
math.DS