Aachen, Germany: Shaker Verlag, 312 pages, January 1998. In German; ISBN 3-8265-3291-0.
Abstract: Computer based systems modeling and simulation is a commonly used method in research, development, and application. This method has spread rapidly because of the tremendous technical advances of the computational power of todays computers and due to the permanent improvement of modeling approaches and simulation tools.
In the past, systems modeling was mainly done by either purely discrete or purely continuous approaches. Although, systems of real world applications are often characterized by discrete and continuous components influencing each other. Examples for such systems can be found in industrial production plants, ecological systems, or process control systems. For modeling these kinds of systems the use of hybrid (or combined) modeling methods is recommended, today.
This thesis presents a new modeling method for modeling and simulation of hybrid systems which is called Hybrid High-level Nets (HyNets). The basic formal framework of this approach is represented by a special class of high-level Petri nets, which showed good suitability especially for modeling discrete systems. By the integration of differential and algebraic equations into this approach it is also possible to describe continuous systems behavior in a convenient manner. The main advantages of the new modeling method are a graphical representation of models, a well-defined semantics, and a high expressiveness. Therefore, complex hybrid systems can be described in a compact and clear way.
After a general introduction to systems modeling and simulation and a comparative survey of some known hybrid modeling approaches the new method is presented informally as well as formally. The second part of this thesis starts with an overview of some fundamental techniques of hybrid systems simulation, especially the approximation of continuous systems behavior and the exact determination of discontinuities is considered in more detail. From these investigations and the previously defined operational semantics a simulation concept for hybrid high-level nets is derived, which serves as a basis for a prototypic implementation of a tool for editing, simulation, and evaluation of HyNet-models. Finally, the suitability of the new method is illustrated with some case studies related to different application areas.
Keywords: Modeling; Simulation; Hybrid; Petri nets; object-oriented.