Non-functional properties of software should be specified early in the development process. In a distributed process of software development, this means that quality requirements must be made explicit in the specification, and the developing party of a commissioned component needs to deliver not only the implemented component, but also a description of its non-functional properties. Based on these artefacts, a conformance check guarantees that the implemented component fulfills the performance requirements. We extend the notion of model refinement to non-functional properties of software and propose a refinement calculus for conformance checking between abstract performance descriptions of components. The calculus is based on a refinement notion that covers the performance-relevant aspects of components. The approach is applied to the Palladio Component Model as a description language for performance properties of components.

Software certification as it is practised today guarantees that certainstandards are kept in the process of software development. However, thisdoes not make any statements about the actual quality of implemented code.We propose an approach to certify the non-functional properties of component-based software which is based on a formal refinement calculus, using the performance abstractions of the Palladio Component Model.The certification process guarantees the conformance of a component implementationto its specification regarding performance properties, without having toexpose the source code of the product to a certification authority. Instead,the provable refinement of an abstract performance specification to the performance description of the implementation, together with evidence that the performance description reflects the propertiesof the component implementation, yields the certification seal.The refinement steps are described as Prolog rules so that the validity ofrefinement between two performance descriptions can be checked automatically.

The evolution of software systems often produces incompatibilities with existing data and applications. To prevent incompatibilities, changes have to be well-planned, and developers should know the impact of changes on a software system. This consideration also applies to the field of model-driven development, where changes occur with the modification of the underlying metamodels. Models that are instantiated from an earlier metamodel version may not be valid instances of the new version of a metamodel. In contrast to other metamodeling standards like the Eclipse Modeling Framework (EMF), no classification of metamodel changes has been performed yet for the Meta Object Facility (MOF).The contribution of this paper is the evaluation of the impact of metamodel changes on models. For the formalisation of changes to MOF-based metamodels, a ChangeMetamodel is introduced to describe the transformation of one version of a metamodel to another. The changes are then classifed by their impact on the compatibility to existing model data. The classification is formalised using OCL constraints. The ChangeMetamodel and the change classifications presented in this paper lay the foundation for the implemention of a mechanism that allows metamodel editors to estimate the impact of metamodel changes semi-automatically.

This report introduces the Palladio Component Model (PCM), a novel software component model for business information systems, which is specifically tuned to enable model-driven quality-of-service (QoS, i.e., performance and reliability) predictions. The PCMs goal is to assess the expected response times, throughput, and resource utilization of component-based software architectures during early development stages. This shall avoid costly redesigns, which might occur after a poorly designed architecture has been implemented. Software architects should be enabled to analyse different architectural design alternatives and to support their design decisions with quantitative results from performance or reliability analysis tools.

In der Welt der komponentenbasierten Software-Entwicklung werden Komponentenmodelle unter Anderem dazu eingesetzt, Software-Systeme mit vorhersagbaren Eigenschaften zu erstellen. Die Bandbreite reicht von Forschungs- bis zu Industrie-Modellen. In Abhängigkeit von den Zielen der Modelle werden unterschiedliche Aspekte von Software in ein Komponentenmodell abgebildet. In diesem technischen Bericht wird ein überblick über die heute verfügbaren Software-Komponentenmodelle vermittelt.

The evolution of software systems can produce incompatibilities with existing data and applications. For this reason, changes have to be well-planned, and developers should know the impact of changes on a software system. This also affects the branch of model-driven development, where changes occur as modification of the metamodels that the system is based on. Models that are instantiated from an earlier metamodel version may not be valid instances if the new version of a metamodel. Also, changes in the interface definition may require adaptations to the modeling tools. In this thesis, the impact of meta-model changes is evaluated for the modeling standards Meta Object Facility (MOF) and the interface definition Java Metadata Interface (JMI), based on the Modeling Infrastructure (MOIN) project at SAP, which includes a MOF- based repository and implements the JMI standard. For the formalisation of changes to MOF-bases metamodels, a Change Metamodel is introduced to describe the transformation of one version of a metamodel to another by the means of modeling itself. The changes are then classifed by their impact on the compatibility of existing model data and the generated JMI interfaces. The description techniques and change classifications presented in this thesis can be used to implement a mechanism that allows metamodel editors to estimate the impact of metamodel changes with the help of modeling tools that can adapt existing data semi-automatically.