"A probable scenario for ecological modelling is that standardized objects for at least some components of ecosystems will be developed and widely distributed in a form that can be used in many different models." - Silvert W (1993), Ecological Modelling 68: 91-118.
"What modellers need is a standardized set of tools that will enable them to collaborate and share model components, pieces of well-defined software objects that can be interchanged and combined freely: Download the annual life cycle models of species A and B, combine them with soil model C and weather generator D, and set it all in the context of cropping system model E. We need a way out of modeling as a purely personal, or in the best case, small-team exercise." - Holst N (2010), Weed Science 58: 497-502.
Universal Simulator is a software package for collaborative ecological modelling. It is composed of a GUI main module which is used to open and execute model specifications read from XML files. The XML files specify the components constituting a model. The functionality of these components are defined in plug-in libraries. This makes UniSim extendible and open for re-use. It is programmed in standard C++ but relies on the Qt library. Universal Simulater is open source (GPL).
Universal Simulator is currently being extended with a better syntax than XML for model specification. Moreover, this coming version will integrate smoothly with both R and MatLab, and, hopefully, will run on Linux and Mac OS, in addition to Windows.
I thank the first four batches of students for their perseverance during the autumn online courses. Without their participation I would never have realised the imperfections of Universal Simulator, thus showing me the way for improvement.