Requirements for modeling and simulation of self-adaptive systems: A hierarchical and modular approach

Complex systems exhibiting structural changes should be represented by models that mimic these transformations. This direct representation of the reconfigurations occurring in real systems produces more intuitive models that are easier to build and test. The Heterogeneous Flow System Specification (HFSS) is a comprehensive formalism that can describe a large variety of models using a unifying representation for both continuous and discrete event systems. The HFSS formalism represents models in a hierarchical and modular form. This explicit representation of structure makes possible to describe self-adaptive systems. As an application of the HFSS formalism, we introduce a representation of a self-adaptive communication network based on fluid queues.