In this paper, we discuss the model of an environment for a geographically based simulation system. The environment is structured as a graph in which nodes represent locations and edges represent paths between locations. The space is decomposed into a network of cells which are managed by cell controllers. In order to visualize location information at various levels of abstraction, we define the environment as a cell hierarchy.

We present a framework for the automatic generation of layouts of statechart diagrams. Statecharts [] are widely used for the requirements specification of reactive systems. Our framework is based on several techniques that include hierarchical drawing, labeling, and floorplanning, designed to work in a cooperative environment. Therefore, the resulting drawings enjoy several important properties: they emphasize the natural hierarchical decomposition of states into substates; they have a low number of edge crossings; they have good aspect ratio; and require a small area. We also present techniques for interactive operations. We have implemented our framework and obtained drawings for several statechart examples.

Software engineers have long needed a way to understand complex software systems during all phases of the lifecycle. This need is driven by the fact that, in Software Engineering, there is ample evidence that a clear and visual representation of a software product can significantly enhance its understandability and reduce the lifecycle cost. For instance, when large volumes of data or text are to be understood or analyzed, it is often the case that a simple visual representation of the information allows the user to quickly and accurately detect discrepancies caused by confusing software documents. This early understanding reduces the person-months needed to take the project through successful system implementation.

In this paper we present an approach that facilitates the validation of high consequence system requirements. This approach consists of automatically generating a graphical representation from an informal document. Our choice of a graphical notation is statecharts. We proceed in two steps: we first extract a hierarchical decomposition tree from a textual description, then we draw a graph that models the statechart in a hierarchical fashion. The resulting drawing is an effective requirements assessment tool that allows the end user to easily pinpoint inconsistencies and incompleteness.