The analysis of models specified with formalisms like Markovian process algebras or stochastic automata can be based on equivalence relations among the states. In this paper we introduce a relation called exact equivalence that, differently from most aggegation approaches, induces an exact lumping on the underlying Markov chain instead of a strong lumping. We prove that this relation is a congr...

We study a simple mechanical model whose aim is to reproduce basic physical mechanisms behind reversible surface attachment-detachment under quasi-static loading. At the micro level the adhesive layer is modeled as an elastic chain of particles interacting with a rigid foundation through breakable springs. This model can be viewed as prototypical for the description of a wide range of phenomena...

A phenomenological two-fluid model of the (time-reversible) spectrally-truncated 3D Euler equation is proposed. The thermalized small scales are first shown to be quasi-normal. The effective viscosity and thermal diffusion are then determined, using EDQNM closure and Monte-Carlo numerical computations. Finally, the model is validated by comparing its dynamics with that of the original truncated...