A Characterization of Inter-Object Behavior for High Reliability Systems

Object-oriented methodologies are often used for developing highly reliable systems. In object-oriented methodologies, state transition diagrams and event trace diagrams are used to describe the system behavior. The state transition diagram describes the behavior of each object while the event trace diagrams describes inter-object behavior. Event trace diagrams may include the timing order of object's output events which are not important when considering the inter-object behavior model. This leads to a higher system complexity and increases the risk of errors. We propose the Event Dependency Graph(EDG) to describe inter-object essential behavior. Using EDG, we can characterize and specify communication and interaction among objects. In this paper, we characterize a certain communication model, called Statechart-type communication model(SCM), using EDG. We also compare two communication models, The SCM model and an Asynchronous communication model.