Jyhjong Lin

Object-oriented specification and formal verification of real-time systems

An object-oriented approach for specification and verification of real-time systems is described in this paper. It is motivated by taking advantage of object-oriented techniques to produce real-time software that is easy to understand, maintain, and reuse. The approach specifies the structural, behavioral, and control aspects of objects in one model with a textual representation as well as a graphical representation. For ease to comprehend and use, the model encapsulates object states and allows an analyst to focus on specifying object operations one at a time. System behavior from individual objects can be deduced and analyzed. For safety considerations, the approach supports specification of failures to object behavior and their resultant faults. The approach also supports modeling of timed temporal constraints for specifying and verifying desirable real-time properties. An object timed temporal logic OTTL is defined for expressing the syntax and semantics of these constraints. Decision procedures for their verification are also presented.

An object-oriented real time systems modeling and verification methodology

An object-oriented real time systems conceptual modeling approach is described. In this approach, each object is specified by an object type, consisting of supertypes (inheritance), component types (aggregation), attributes, operations, static constraints, and temporal constraints. That is, an object type specification defines a theory of a type of objects. An object-oriented real time conceptual model using the object types can be translated into an augmented Petri net with timing and temporal constraints. A reachability tree of permissible system states is generated for the augmented Petri nets for verifying whether the conceptual model satisfies desired temporal constraints.

Toward an object-oriented modeling approach with representation of temporal knowledge

Object-oriented conceptual modeling captures real world entities as close as possible. Data and functions on encapsulated in an object. This allows software to be easily adapted to changes in the application. We present an object-oriented approach for modeling and analysis of time dependent systems. It describes the structural aspect and the time critical behavioral aspect of objects in one model and from which formal analysis can be conducted to verify desirable properties. In particular, the main concern of behavioral modeling is to present the specification of temporal knowledge about object activities such as their chronological ordering, durations, and time limits.<<ETX>>

Top-down development of real-time software specification

Top down development has been well known to manage the complexity of characterizing large systems. The paper presents a top down object oriented approach to formal specification of real time software which is often large and complex for modern real time applications. The method creates an abstract object interaction model to describe objects in the application domain and their structure and behavior. An object specification model is then derived from the object interaction model to formally specify the objects. The method is applied to a simple illustrative example, the specification of a real time house heating system.