. In this paper, we present two logics that allow for specifying distributed information systems, emphasizing communication among sites. The low-level logic D 0 offers features that are easy to implement but awkward to use for specification, while the high-level logic D 1 offers convenient specification features that are not easy to implement. We show that D 1 specifications may be automatically translated to D 0 in a sound and complete way. In order to prove soundness and completeness, we define our translation as a simple map of institutions. Our result may be useful for making implementation platforms like Corba easier accessible by providing high-level planning and specification methods for communication. 1 Introduction Two logics are presented that allow for specifying distributed information systems, emphasizing communication among sites. The low-level logic D 0 offers features that are easy to implement but awkward to use for specification, while the high-level logic D 1 offers...

From an arbitrary temporal logic institution we show how to set up the corresponding institution of objects. The main properties of the resulting institution are studied and used in establishing a categorial, denotational semantics of several basic constructs of object specification, namely aggregation (parallel composition), interconnection, abstraction (interfacing) and monotonic specialization. A duality is established between the category of theories and the category of objects, as a corollary of the Galois correspondence between these concrete categories. The special case of linear temporal logic is analysed in detail in order to show that categorial products do reflect interleaving and reducts may lead to internal nondeterminism. Key words: object-orientation, system specification, temporal logic, institution, denotational semantics, duality. 1 Introduction The advantages of object-orientation in software engineering in general and system specification in particular...

During the last years, a number of formal specification languages for knowledge-based systems has been developed. Characteristic for knowledge-based systems are a complex knowledge base and an inference engine which uses this knowledge to solve a given problem. Specification languages for knowledge-based systems have to cover both aspects. They have to provide means to specify a complex and large amount of knowledge and they have to provide means to specify the dynamic reasoning behaviour of a knowledge-based system. This paper focuses on the second aspect. For this purpose, we survey existing approaches for specifying dynamic behaviour in related areas of research. In fact, we have taken approaches for the specification of information systems (Language for Conceptual Modelling and TROLL), approaches for the specification of database updates and logic programming (Transaction Logic and Dynamic Database Logic), and the generic specification framework of Abstract State Machines. Keywords...

Numerous proposals for applying temporal logic to the specification and verification of object-oriented systems have appeared in the past several years. Although various temporal models have been proposed for the requirements analysis of object-oriented distributed systems, there is no similar body of work for the design phase. We present a formal model for the design stage which reflects practical requirements and yet is sufficiently general to be applied to a wide range of systems. In our model, which relies on event-based behavioral abstraction, we use linear-time temporal logic as the underlying formalism for the specification of behavioral constraints. We show that although temporal logic is a powerful tool for behavior specifications, its basic formulation does not have the expressive power required for non-trivial object systems. Specifically, in an object-system it is often essential to express procedural dependencies rather than simple temporal relationships for which we intro...