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. 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.

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 general aim of our work is the specification of distributed information systems, that means reactive systems consisting of one or more databases and application programs. In this context the formal object oriented specification language Troll was developed and is now going to be extended by module concepts. In this paper we give a short introduction in Troll and a survey over related work done not only in the object oriented setting but also in the fields of specification languages in general, theory of abstract data types and parameterized programming. When presenting our own module concepts we explicitly distinguish between providing the possibility to structure a large system on one hand and supporting the reuse of (parts of) specifications on the other hand.

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...

. 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...

In this paper we propose a language-independent model for concurrent distributed object systems where objects interact with each other by asynchronous message passing. Objects are modeled by sequential labelled event structures. These event structures are combined into an asynchronous system model by means of a new relation, the so called communication arrow, that expresses directed asynchronous object interaction. We give an inductive construction of a specific asynchronous system model, and prove that it is sound. This paper is a first step towards denotational semantics of and reasoning about asynchronously communicating object societies. 1 Introduction One of the main principles of the object-oriented framework is the idea of encapsulation. Objects are self-contained units concurrently put together to global systems in which they interact with each other by message passing. Thus, objects constitute modular units which can be accessed according to their interfaces. The int...

The validation of conceptual models is an important task with the aim of checking whether the model correctly and adequately expresses the requirements informally stated by the users. Different techniques and tools have been developed to support this task. In this paper and as part of a doctoral work, we propose an animation tool for an object oriented modelling language. This tool generates executable specifications from conceptual model specifications on the same level of abstraction. In this way, the model behaviour can be observed and checked against the intended requirements. We introduce the modelling language, the functionalities of the animation system and its architecture. 1 Introduction The process of modelling information systems is becoming more and more important in systems development as the size and complexity of systems are growing. The result of this process is a conceptual model or system specification which describes the functional requirements that the desired info...

Abstract. When defining the requirements of a system, specification units typically are partial or incomplete descriptions of a system component. In this context, providing a complete description of a component means integrating all the existing partial views for that component. However, in many cases defining the semantics of this integration operation is not an easy task. In particular, this is the case when the framework used at the specification level is, in some sense, an “operational ” one (e.g. a Petri net or a statechart). Moreover, this problem may also apply to the definition of compositional semantics for modular constructs for this kind of frameworks. In this paper, we study this problem, at a general level. First, we define a general notion of framework whose semantics is defined in terms of transformations over states represented as algebras and characterize axiomatically the standard tight semantics. Then, inspired in the double-pullback approach defined for graph transformation, we axiomatically present a loose semantics for this class of transformation systems, exploring their compositional properties. In addition, we see how this approach may be applied to a number of formalisms. 1