The authors have successfully applied formal specification techniques to the construction of medical products. The approach is characterized by concentrating on the use of HP-SL to construct clear and precise specifications of behavior. In a number of collaborative product developments, the effectiveness of the software development process has been improved significantly without getting involved in the 'difficult' formal methods areas of refinement and program proof.>

A notation called Objectcharts for specifying object classes is introduced. An Objectchart diagram is an extended form of a Statechart, which characterizes the behavior of a class as a state machine. The Objectchart transitions correspond to the state-changing methods that the class provides and those that it requires of other classes. Object attributes and observer methods annotate Objectchart states. Firing and postconditions are used to specify the effect of transitions on class attributes. The Objectchart notions is described through the development of an alarm clock application. How Objectcharts can be used to find subtyping inheritance relationships between classes and a systematic approach for evolving Objectchart specifications are shown.>