Arne Lindow

Model transformations? transformation models!

Much of the current work on model transformations seems essentially operational and executable in nature. Executable descriptions are necessary from the point of view of implementation. But from a conceptual point of view, transformations can also be viewed as descriptive models by stating only the properties a transformation has to fulfill and by omitting execution details. This contribution discusses the view that model transformations can be abstracted as being transformation models. As a simple example for a transformation model, the well-known transformation from the Entity-Relationship model to the Relational model is shown. A transformation model in this contribution is nothing more than an ordinary, simple model, i.e., a UML/MOF class diagram together with OCL constraints. A transformation model may transport syntax and semantics of the described domain. The contribution thus covers two views on transformations: An operational model transformation view and a descriptive transformation model view.

MultiMedia Instruction in Safe and Secure Systems

The aim of the MMiSS project is the construction of a multi-media Internet-based adaptive educational system. Its content will initially cover a curriculum in the area of Safe and Secure Systems. Traditional teaching materials (slides, handouts, annotated course material, assignments, and so on) are to be converted into a new hypermedia format, integrated with tool interactions for formally developing correct software; they will be suitable for learning on campus and distance learning, as well as interactive, supervised, or co-operative self-study. To ensure ”sustainable development”, i.e. continuous long-term usability of the contents, coherence and consistency are especially emphasised, through extensive semantic linking of teaching elements and a particular version and configuration management, based on experience in formal software development and associated support tools.

On better understanding OCL collections or an OCL ordered set is not an OCL set

Modeling languages like UML or EMF support textual constraints written in OCL. OCL allows the developer to use various collection kinds for objects and values. OCL 1.4 knows sequences, sets, and bags, while OCL 2.0 adds ordered sets. We argue that this addition in the OCL standard was not carried out in a careful way and worsened conceptional problems that were already present previously. We discuss a new way of establishing the connection between the various collection kinds on the basis of explicitly highlighting and characterizing fundamental collection properties.