Enhancing Model Reuse via Component-Centered Modeling Frameworks: the Vision and Example Realizations

Model frameworks have represented a substantial step forward with respect to monolithic implementations of biophysical models. However, the diffusion of such frameworks, as model development environment, beyond the groups developing them has been very modest. The reusability of models has also proved to be modest. The reason for the latter was attributed also to the lack of standardization toward few frameworks. Emphasis has been placed on the framework and even new implementations of models have been made targeting a specific framework, likely assuming that the reusability of the model unit would have been directly proportional to the quality of the framework. In any case, the goal of several projects has been to make available the framework. Developers in the operational arena, but even in research, have reacted by developing their own framework. Still, the problem of model reuse has been largely unsolved; estimating that increasing the flexibility for reuse would have added a costly overhead, in terms of both complexity and possibly as lack of efficiency in the operational use. The focus on frameworks has made software architects overlooking on the requirements of reusability per se of model units. The component oriented programming paradigm allows targeting intrinsic reusability of discrete model units, and makes room for enabling advances functionalities in simulation systems. This paper firstly present the abstract architecture of a component oriented framework articulated in independent layers: Model, Composition, and Configuration. The Application layer may link to any of these, to develop from simple console applications to sophisticated MVC applications. Proofs of concept are presented for each layer, including the BioMA framework of the European Commission used for agriculture and climate change studies.