A formal specification of the look manager of a dialog system is presented. The look manager deals with the presentation of visual aspects of objects and the editing of those visual aspects. A formal model for specifying the look of objects based on the notion of texturing objects is presented. The texturing model is built from the observed real-life use of overlays of slides. The specification takes as a given hypothesis an invariant relation between the logical display of objects and their layout on the physical screen. The look on the screen is characterized as an invariant ideal show relation. The formalization achieves modularity for the look manager. The specifications are written using the Z notation. The experiment is an integral part of a larger effort in the formal design of a dialog system. It shows that the state-based specification methodology Z is very well suited for description of graphical interface software. Further, the formal specification yields insight into the inherent complexity of building graphical interfaces and their associated displays.>

A real-time variant of temporal interval logic is proposed for the specification and reasoning of real-time systems. In the framework of the logic, it is possible to specify qualitative and quantitative aspects of temporal behaviors of systems. The formalism provides capabilities for quantitative specification of time behavior. The harmonization of temporal interval logic with real-time features leads to a very-high-level notation for the specification of real-time systems. Temporal interval logic, being event-based, also facilitates the specification of quantitative aspects of temporal behavior relative to the occurrence of events in a given context. The use of the formalism is shown for three examples of real-time system specification: a packet network with rerouting, a traffic-light controller, and a time-constrained broadcast bus protocol.>

Abstract CCNPASCAL is a language derived from Pascal and Concurrent Pascal which has been used in the development of an operating system for a multiprocessor. This paper introduces some of the important features of the language and illustrates them with examples. The language provides mechanisms for interfacing separately compiled modules, for building abstractions of collections of resources and for efficient asynchronous communication.