Abstract not found

The UML meta model [3] captures the abstract syntax...

The notion of refactoring —transforming the source-code of an objectoriented program without changing its external behaviour — has increased the need for a precise definition of refactorings and their properties. This paper introduces a graph representation of those aspects of the source code that should be preserved by a refactoring, and graph rewriting rules as a formal specification for the refactoring transformations themselves. To this aim, we use type graphs, forbidden subgraphs, embedding mechansims, negative application conditions and controlled graph rewriting. We show that it is feasible to reason about the effect of refactorings on object-oriented programs independently of the programming language being used. This is crucial for the next generation of refactoring tools.

The issue of confluence is of major importance for the successful application of attributed graph transformation, such as automated translation of UML models into semantic domains. Whereas termination is undecidable in general and must be established by carefully designing the rules, local confluence can be shown for term rewriting and graph rewriting using the concept of critical pairs. In this paper, we discuss typed attributed graph transformation using a new simplified notion of attribution. For this kind of attributed graph transformation systems we establish a definition of critical pairs and prove a critical pair lemma, stating that local confluence follows from confluence of all critical pairs.

We propose an unfolding semantics for graph transformation systems in the double-pushout (DPO) approach. Mimicking Winskel’s construction for Petri nets, a graph grammar is unfolded into an acyclic branching structure, that is itself a (nondeterministic occurrence) graph grammar describing all the possible computations of the original grammar. The unfolding can be abstracted naturally to a prime algebraic domain and then to an event structure semantics. We show that such event structure coincides both with the one defined by Corradini et al. [3] via a

UML Statecharts are well-known visual means to capture the dynamic behavior of reactive systems in the object-oriented design methodology. Since the UML standard only contains an informal description on how to execute such statemachines various semantic frameworks have already been proposed to provide a precise formalization, which is indispensable for implementing automated analysis tools for statecharts. However, none of this approaches have been accepted as a standard formal semantics, mainly because the huge abstraction gap lying between engineering and formal mathematical practice. The current paper aims at to bridge this gap by providing a formal semantics that is (i) simultaneously visual and precise, (ii) built on metamodeling techniques, and (iii) that provides direct access to simulation and verification tools.

Abstract not found

Graph transformation has recently become more and more popular as a general, rule-based visual specification paradigm to formally capture (i) requirements or behavior of user models (on the model-level), and (ii) the operational semantics of modeling languages (on the meta-level) as demonstrated by benchmark applications around the Unified Modeling Language (UML). In the paper, we present a meta-level transformation technique to enable model checking-based symbolic verification for arbitrary well-formed models and modeling languages (with formal semantics defined by graph transformation systems) by projecting them into state transitions systems that serve as the underlying mathematical specification formalism of various model checker tools. The feasibility of our approach is demonstrated by modeling and analyzing a well-known verification benchmark both on the model and metamodel level.

We use the double-pushout graph transformation approach for the specication of run-time reconguration of software architectures.

View merging, also called view integration, is a key problem in conceptual modeling. Large models are often constructed and accessed by manipulating individual views, but it is important to be able to consolidate a set of views to gain a unified perspective, to understand interactions between views, or to perform various types of analysis. View merging is complicated by incompleteness and inconsistency: Stakeholders often have varying degrees of confidence about their statements. Their views capture different but overlapping aspects of a problem, and may have discrepancies over the terminology being used, the concepts being modeled, or how these concepts should be structured. Once views are merged, it is important to be able to trace the elements of the merged view back to their sources and to the merge assumptions related to them. In this paper, we present a framework for merging incomplete and inconsistent graph-based views. We introduce a formalism, called annotated graphs, with a built-in annotation scheme for modeling incompleteness and inconsistency. We show how structure-preserving maps can be employed to express the relationships between disparate views modeled as annotated graphs, and provide a general algorithm for merging views with arbitrary interconnections. We provide a systematic way to generate and represent the traceability information required for tracing the merged view elements back to their sources, and to the merge assumptions giving rise to the elements.