Gunnar Brataas

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Product lines need decision models that guide the derivation of product variants satisfying specific requirements. In dynamic product lines, whose requirements vary during runtime, these decision models are also required to support automatic product reconfigurations in response to changing requirements. However, because of the combinatorial explosion of(More)
We describe a structured, hierarchic approach to exploring the scalability of IT systems architectures. An architecture is considered to be scalable over a particular set of requirements if the physical resource usage per unit of capacity remains roughly constant. For completeness, both requirements and capacity must be defined in the three dimensions of(More)
Many software engineering courses include all-term projects to convey principles relating to large-scale multi-person development. But even such projects will easily be too small and simple, unless a sufficient amount of study time is allocated to them. This time may be hard to find, especially in strictly programmed profession studies where a lot of(More)
A performance property prediction (PPP) method for component-based self-adaptive applications is presented. Such performance properties are required by an adaptation middleware for reasoning about adaptation activities. Our PPP method is based on the Structure and Performance (SP) framework, a conceptually simple, yet powerful performance modelling(More)
This work-in-progress paper introduces the EU FP7 STREP CloudScale. The contribution of this paper is an overall description of CloudScale's engineering approach for the design and evolution of scalable cloud applications and services. An Electronic Health Record (EHR) system serves as a motivation scenario. The overall CloudScale method describes how(More)
An integrated approach to performance analysis ofworkflows in terms of throughput and response time to satisfy customer requirements is investigated. Integration of performance is particularly important for workflow systems where human and computerised processes are intertwined. The proposed modelling framework encompasses both human and computer resources(More)
Utility-based adaptation approaches permit to determine the "best" suited variant of an application at run-time. Utility policies are usually specified in terms of resources and QoS dimensions. Although utility policies provide a precise formulation for adaptation decision, they are difficult to specify. The developer especially needs assistance in the(More)