  Redistribution systems iteratively redistribute mass between groups under the
control of rules. PRAM is a framework for building redistribution systems. We
discuss the relationships between redistribution systems, agent-based systems,
compartmental models and Bayesian models. PRAM puts agent-based models on a
sound probabilistic footing by reformulating them as redistribution systems.
This provides a basis for integrating agent-based and probabilistic models.
\pram/ extends the themes of probabilistic relational models and lifted
inference to incorporate dynamical models and simulation. We illustrate PRAM
with an epidemiological example.
