Electronic Communications of the EASST (European Association of Software Science and Technology)
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Graph Modelling and Transformation: Theory meets Practice
Get PDFIn this paper, we focus on the role of graphs and graph transformation for four practical application areas from software system development. We present the typical problems in these areas and investigate how the respective systems are
modelled by graphs and graph transformation. In particular, we are interested in the usefulness of theoretical graph transformation results and graph transformation tools in order to solve these problems. Finally, we characterize concepts and tool features
which are still missing in practice to solve the presented and related problems even better.
Keywords: graph modelling, graph transformation, graph transformation tool
Verified Visualisation of Textual Modelling Languages
Get PDFMany modelling languages have both a textual and a graphical form. The relationship between these two forms ought to be clear and concrete, but is instead commonly underspecified, weak, and informal. Further, processes and tool support for modelling often do not treat both forms as first-class citizens, instead choosing to favour one as the “real” representation and the other as a derivable representation.
As textual and graphical forms have their individual strengths and weaknesses, ideally one should be able to view and edit a model in whichever form is most desirable at the moment. Furthermore, we should be able to do so without having to worry about semantic differences between what is seen in a graphical view versus what is seen in a textual view. If we are to develop tools that allow dual-editing—simultaneous editing of both the textual and graphical forms—then it is essential that their relationship is clearly and precisely defined.
This paper details a formal relationship between the textual and graphical forms of a high-level modelling language called the Business Object Notation (BON). We describe the semantics of the graphical and textual representations and the relationship that holds between them. We also formally define a view on an underlying model as an extraction function, and model diffs as a means of tracking changes as a model evolves. This theoretical foundation provides a means by which tools guarantee consistency between textual and graphical notations, as well shows how to efficiently perform model updates, reason about model views, and interpret properties between modelling perspectives
Training the Behaviour Preferences on Context Changes
Get PDFPersonalized ambient intelligent systems should meet changes in user’s needs, which evolve over time. Our objective is to create an adaptive system that learns the user behaviour preferences. We propose *BAM – * Behaviour Adaptation Mechanism, a neural-network based control system that is trained, supervised by user’s (affective) feedback in real-time. The system deduces the preferred behaviour, based on the detection of affective state’s valence (negative, neutral and positive) from facial features analysis. The neural network is retrained periodically with the updated training set, obtained from the interpretation of the user’s reaction to the system’s decisions. We investigated how many training examples, rendered from user’s behaviour, are required in order to train the neural network so that it reaches an accuracy of at least 75%. We present the evolution of behaviour preference learning parameters when the number of context elements increases
What Algebraic Graph Transformations Can Do For Model Transformations
Get PDFModel transformations are key activities in model-driven development (MDD). A number of model transformation approaches have emerged for different purposes and with different backgrounds.
This paper focusses on the use of algebraic graph transformation concepts to specify and verify model transformations in MDD
Defining Models - Meta Models versus Graph Grammars
Get PDFThe precise specification of software models is a major concern in model-driven design of object-oriented software. Metamodelling and graph grammars are apparent choices for such specifications. Metamodelling has several advantages: it is easy to use, and provides procedures that check automatically whether a model is valid or not. However, it is less suited for proving properties of models, or for generating large sets of example models. Graph grammars, in contrast, offer a natural procedure - the derivation process - for generating example models, and they support proofs because they define a graph language inductively. However, not all graph grammars that allow to specify practically relevant models are easily parseable. In this paper, we propose contextual star grammars as a graph grammar approach that allows for simple parsing and that is powerful enough for specifying non-trivial software models. This is demonstrated by defining program graphs, a language-independent model of object-oriented programs, with a focus on shape (static structure) rather than behavior
Categorical Framework for the Transformation of Object-Oriented Systems: Operations and Methods
Get PDFRefactoring of information systems is hard, for two reasons. On the one hand, large databases exist which have to be adjusted. On the other hand, many programs access that data. These programs all have to be migrated in a consistent manner such that their semantics does not change. It cannot be relied upon, however, that no running processes exist during such a migration. Consequently, a refactoring of an information system needs to take care of the migration of data, programs, and processes. This paper extends the model described in [SLK10] by operations, messages, and methods, which allows to model complete object-oriented systems. Methods are expressed by special double-pushout graph transformations. Homomorphisms are used for the typing of the instance level as well as for the description of refactorings which specify the addition, folding, and unfolding of schema elements. Finally, a categorical framework is presented which allows to derive instance migrations from schema transformations in such a way that programs and processes to the old schema are correctly migrated into programs and processes to the new schema
A Middleware for Self-Organising Distributed Ambient Assisted Living Applications
Get PDFThis paper presents a middleware approach for self-organising distributed applications in the area of Ambient Assisted Living (AAL) as part of a home service platform. The middleware uses real time data processing techniques to identify complex events based on sensor input and service logs. This low-level and high-level information represents the platform’s context model, which forms the basis for self-organisation properties: Controllers use context information to manage running services while adhering to strategies defined by users or inferred by the system itself
Conditional Adaptive Star Grammars
Get PDFThe precise specification of software models is a major concern in
the model-driven design of object-oriented software. Models are commonly given as graph-like diagrams so that graph grammars are a natural candidate for specifying them. However, context-free graph grammars are not powerful enough to specify all static properties of a model. Even the recently proposed adaptive star grammars cannot capture all properties of object-oriented models. So we extend adaptive star rules by positive and negative application conditions to overcome these deficiencies without sacrificing parsing algorithms. It turns out that conditional adaptive star grammars are powerful enough to generate program graphs, a software model with rather complicated contextual properties
Design Pattern Modeling with Constraint Relaxation
Get PDFMetamodeling is a widely applied technique in the field of graphical language engineering. Environments supporting metamodeling aid rapid and flexible domain-specific modeling language (DSML) definition and utilization. In software engineering, design patterns are efficient solutions for recurring problems. With the proliferation of DSMLs, there is a need for domain-specific design patterns to offer solutions to problems recurring in different domains. The aim of this paper is to illustrate a concept that integrates modeling patterns into a metamodeling environment. The introduced approach utilizes the modeling functionalities of the environment; a visual design pattern metamodel, a system architectural metamodel extended with textual constraints are introduced. Furthermore, design patterns are validated against relaxed constraints defined in the metamodel to only allow the creation of patterns that can be extended to valid instance models
Integrating Data from Multiple Repositories to Analyze Patterns of Contribution in FOSS Projects
Get PDFThe majority of Free and Open Source Software (FOSS) developers are mobile and often use different identities in the projects or communities they participate in. These characteristics not only poses challenges for researchers studying the presence (where) and contributions (how much) of developers across multiple repositories, but may also require special attention when formulating appropriate metrics or indicators for the certification of both the FOSS product and process. In this paper, we present a methodology to study the patterns of contribution of 502 developers in both SVN and mailing lists in 20 GNOME projects. Our findings shows that only a small percentage of developers are contributing to both repositories and this cohort are making more commits than they are posting messages to mailing lists. The implications of these findings for our understanding of the patterns of contribution in FOSS projects and on the quality of the final product are discussed