Dr. Robert Muetzelfeldt
University of Edinburgh

The Simile visual modelling environment

Simile (http://simulistics.com) is a visual modelling environment for continuous systems modelling. It has been developed for ecological and environmental research, though it is generic and can be used in a wide range of disciplines. It is based on the familiar System Dynamics (stock-and-flow) notation, like Stella and Vensim, but, unlike other products, is also strongly object-based. The modeller can define the behaviour of an object (such as a tree or a patch of land) in System Dynamics terms, then specify that there are many instances of this object, including terms for creating and destroying instances, all through a diagramming interface.

Simile also:

- supports strong modularity (plug-and-play, unplug-and-play);

- enables users to develop their own visualistaion tools;

- generates highly efficient simulations in C++; and

- is committed to an open standard for model representation, enabling models to be shared with other tools.

Simile is available for free download for research and education.

Simile is one element in what will eventually become a suite of tools for supporting the integration of data and models over the internet, in an e-science Grid. This will include formal methods for annotating the 'meaning' of models, model quantities, data sets and research results, including the development of ontologies, thesauri and metadata standards.

Characterising the flow of data and information through the research process is an important requirement of this vision. An example of the sort of notation that might be developed is the Data Destiny Diagram (http://homepages.ed.ac.uk/ebfr28/datadestiny/), which uses notation very similar to that of Simile for showing the structure and processing of data.