A graph model and grammar for multi-scale modelling using XL

A graph formalism and grammar suitable for multi-scale modelling is introduced in this paper. Existing rule-based rewriting mechanisms related to L-systems do not take scales into account or rely on string-based mechanisms. This poses difficulties to develop multi-scale models using rule-based graph approaches. Using a type graph to capture scale relationships and accounting for scales using an additional edge type, we introduce a technique to overcome these problems. Syntax for expressing multi-scale graphs allows the construction of models in the language XL coupled with existing rule-based functionality.