Interactive Modelling und Simulation of Environmental Systems on Workstations

Many systems dealt with in environmental sciences such as ecology or environmental biology could be easily modelled and efficiently simulated on personal computers or on workstations. Thanks to their graphical capabilities such computers make it possible to model systems interactively, e.g. supported by graphical structure editors. or allow for interactive simulation featuring s0phisticated graphical output of the simulation results. However, in practice this potential remains often underexploited, since traditional, simulation software is mostly batch oriented, largely ignores computer science research, and offers rarely the functionality needed for a sensible interactive use. Instead of porting simulation software from main-frames onto workstations we propose new concepts based on Wymore and Zeigler's modeling theory, enhanced by some new interactive user oriented task concepts. This paper presents a scheme called RAMSES for the architecture of a modeling and simulation environment on a workstation particularly suited for the working with environmental systems. Furthennore it reports on some results which have been obtained by implementing portions of the RAMSES architecture, in particular an open and extensible modeling and simulation environment for the two classical model formalisms SM (Sequential Machine), DESS (Differential Equation System Specification) featuring modular modeling. Fmally the modeling and simulation of a system from population ecology is presented as an example to illustrate and evaluate some of the concepts of RAMSES in ecological research.