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The ability to adapt to different computing environments or external changes is an important requirement for both stationary and mobile computing. Without this ability, all requirements have to be foreseen, which is often not possible in practice. Classical software engineering approaches often lead to redeployment or even software migration. Therefore loosely coupled software design and a dynamic adaptation model are required. Dynamic aspect-oriented programming (d-AOP) in conjunction with service oriented programming is well suited to face this demand. One well known approach providing a service-oriented component model is the OSGi Service Platform. This paper introduces our approach to combine an OSGi Framework with d-AOP to establish dynamic adaptation of core concerns as well as crosscutting concerns. Seamless integration of current d-AOP frameworks is managed by mapping aspect deployment and undeployment to OSGi bundle lifecycle operations without affecting the deployment model. Unlike former proposals, this approach retains the strict separation of bundles as mandated by OSGi.

Database Management Systems (DBMSs) that can be tailored to specific requirements offer the potential to improve reliability and maintainability and simultaneously the ability to reduce the footprint of the code base. If the requirements of an application change during runtime the DBMS should be adapted without a shutdown. Runtimeadaptation is a new and promising research direction to dynamically change the behavior of a DBMS. Especially the adaptation of the Transaction Manager (TM) states a challenge.In this paper, we present the session semantics of a runtimeadaptable TM. We define preliminaries and assumptions to activate the TM during sessions from a conceptual point of view. The advantages and disadvanteges of different approaches are discussed, especially regarding the occurence of ANSI SQL phenomena. From a technical point of view, we define requirements for the architecture of the TM and the DBMS that arose in our prototype.

Abstract. Nowadays maintenance of database management systems (DBMSs) often requires offline operations for enhancement of functionality or security updates. This hampers the availability of the provided services and can cause undesirable implications. Therefore it is essential to minimize the downtime of DBMSs. We present the CoBRA DB (Component Based Runtime Adaptable DataBase) project that allows the adaptation and extension of a modular DBMS at runtime. In this paper we focus on the definition of an adaptation model describing the semantics of adaptation processes.