Interactive software tools, BGS-II and BGS-III, for ecological simulation

Abstract

Interactive processing is vital to software for constructing ecological models. Two versions of interactive software have been developed, and named biological growth simulators BGS-II and BGS-III. BGS-II is portable (machine-independently accessible) as it is written in Fortran; BGS-III embodies high-quality graphical output. These are both designed for constructing models which are described by simultaneous ordinary differential equations. In BGS-II, a model is written as a Fortran subroutine which follows a particular pattern. Parameters of the model, initial conditions for state variables and some additional information to control simulation are requested in terms of menu and/or prompting messages on an interactive terminal. Five integration methods (Euler, modified Euler, Runge-Kutta, Runge-Kutta-Gill and Milne methods) are prepared. Integration methods and step size can be changed at any stage of the simulation process. The outputs generated from the simulation are obtained in table and/or graph (printed and/or plotted). Five results are saved in disk files to be compared with one another or with experimental data. BGS-III is interactive simulation programs running on a local computer network. Although BGS-II runs on a host computer including character display unit, BGS-III operates on a system which is composed of host computer and intelligent graphic terminal (TOSBAC UX-300). Host computer supports the same simulation functions as run in BGS-II. The terminal has a data transmission program (UX-NET) which assigns input and output functions of the simulation. The screen of the graphic display controlled by UX-NET is divisible into four sections. Three sections display simulation states, prompting messages and output information. Commands are entered in the other section. A model and equations necessary to the model definition are entered by request of prompting messages in this version. BGS-III has lost portability in input and output functions, but has gained more effective man-machine communication.