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.

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This paper presents a formal approach for managing unanticipated software evolution. Labelled typed nested graphs are used to represent arbitrarily complex software artifacts, and conditional graph rewriting is used for managing evolution of these artifacts. More specifically, we detect structural and behavioural inconsistencies when merging parallel evolutions of the same software artifact. The approach is domain-independent, in the sense that it can be customised to many different domains, such as software architectures, UML analysis and design models, and software code.

Designing and managing a companies specific landscape and business processes has been identified as a great challenge for several years. Business processes are highly dynamic and distributed and can only rarely be planned, modeled and analyzed completely. To offer a computer aided business process system, which supports the designing and managing process, first a powerful uniform formalism is necessary, where all necessary knowledge concerning companies and business processes can be represented. In this paper we will concentrate on the introduction of such a formal methodology to describe business processes, company organization structures and information technology structures in one uniform formalism. The ideas we use are based mainly on methods from graph grammars, workflow management, CASE, Artificial Intelligence and business process (re-)engineering. February 22, 1996 -- 09 : 44 DRAFT 3 1 Motivation & Goal The term Business Process Re-engineering (BPR) degenerates towards an e...

We propose LMNtal, a simple language model based on the rewriting of hierarchical graphs that use logical variables to represent links. The two major goals of the model are (i) to unify various computational models based on multiset rewriting and (ii) to serve as the basis of a truly general-purpose language covering various platforms ranging from wide-area to embedded computation. Another important contribution of the model is it greatly facilitates programming with dynamic data structures.

Spatial and temporal refinement relations between typed graph transformation systems have been introduced in [6, 7]. In a spatial refinement each rule is refined by an amalgamation of rules while in a temporal refinement it is refined by a sequence of rules: in both cases, the refinement relation supports the modeling of implementation. In the first part of this paper, we further investigate the properties of spatial and temporal refinements while, in the second part, we employ them for the development of a module concept for Typed Graph Transformation Systems (TGTS). Finally, as a first step towards an algebra of modules of TGTS, we introduce the operations of union and composition of modules. 1

This document was originally meant as a proposal for one master thesis. Since the resulting proposal was oversized as a master thesis, it has been split into several proposals/research topics, most of which concentrate on a specific topic, and are ordered according to their dependences (if any exist).

This paper addresses the simulation of the dynamics of complex systems by using hierarchical graph and multi-agent system. A complex system is composed of numerous interacting parts that can be described recursively. First we summarize the hierarchical aspect of the complex system. We then present a description of hierarchical graph as a data structure for structural modeling in parallel with dynamics simulation by agents. This method can be used by physiological modelers, ecological modelers, etc as well as in other domains that are considered as complex systems. An example issued from physiology will illustrate this approach.