We study linear time temporal logics of multiple agents, where the temporal modalities are local. These modalities not only refer to local next-instants and local eventuality, but also global views of agents at any local instant, which are updated due to communication from other agents. Thus agentsalso reason about the future, present and past of other agents in the system. The models for these logics are simple : runs of networks of synchronizing automata. Problems like gossipping in interconnection networks are naturally described in the logics proposed here. We present solutions to the satisfiability and model checking problems for these logics. Further, since formulas are insensitive to different interleavings of runs, partial order based verification methods become applicable for properties described in these logics. 1. Introduction 1 The Propositional Temporal Logic of Linear Time (PTL) has proved to be a successful logical tool for specifying and reasoning about the behaviou...

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Introduction From an object-oriented point of view, software systems are considered to be dynamic collections of autonomous objects that interact with each other. Autonomy means that each object encapsulates all features needed to act as an independent computing agent: individual attributes (data), methods (operations) , behavior (process), and communication facilities. And each object has a unique identity that is immutable throughout lifetime. Coincidentally, objectorientation comes with an elaborate system of classes and types, facilitating structuring and reuse of software. The object approach is widely accepted in software technology, and there are object-oriented programming languages, database systems, and software development methods. The basic idea is not new, because essential features were already present in the programming language Simula [DMN67]. Wider acceptance came with Smalltalk [KG76, GR83]. While the object approach is success

. 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...

Information systems are open, reactive, and often distributed systems that maintain persistent data. The Troll and omTroll languages aim at specifying information systems on a high level of abstraction, supported by tools integrated in the Tbench. The development is rooted in abstract data types, conceptual modeling, behavior modeling, specification of reactive systems, and concurrency theory.

In this paper, we present the use of Troll for the conceptual modelling of distributed information systems. Troll offers both textual and graphical notations. Troll has been used in practice to model an industrial information system. We use an extract of this case study to describe briey the syntax and underlying semantics of the language. We also show a set of software tools that are being developed to support the modelling with Troll. These tools include editors, checkers as well as an animator for validating Troll specifications. We report on the experiences we gained by applying the language to the industrial project. Finally, a short description on further work is given.

We present fundamentals of an approach to object-oriented specification of distributed information systems. We do not assume global time for concurrent object systems. For specifying those systems we propose Dtl, a distributed temporal logic. The main contribution is that Dtl is capable of specifying complex constraints about the behavior of distributed systems and communication between concurrent objects. For instance, we distinguish different kinds of synchronous communication such as immediate calling vs. deferred calling. The ideas are illustrated by examples given in Troll, a formal object-oriented specification language. We introduce notations for formally specifying object-based distributed systems. Finally, we briefly explain how Dtl is semantically explained in terms of a true concurrent model, i.e., labelled event structures, and which concepts for in-the-large specification are covered by our approach. Keywords Object orientation, specification language, distributed system...

The aim of our work is the modelling and design of information systems in the object-oriented setting. An object-oriented specification covers structural as well as behavioural aspects of the system.

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...

. Our concern is the high level specification of reactive software systems such as information systems. We adopt an object oriented, temporal logic based approach to specification. The notion of transaction incorporates various application domains, for instance transactions as abstractions from processes as known from refinement theory, transactions as abstractions from business processes as known in business process modelling or database transactions. In this paper we investigate object specifications with transactions. We illustrate the use of transactions by examples given in an object oriented style and introduce a linear temporal logic with transactions (Tosl) which serves as denotional model for such object specifications with transactions. We explain how Tosl is semantically defined in terms of life cycles and illustrate by example the translation of object specifications to Tosl. Using Tosl for system specification results in sets of formulae which are independent from the lev...