Eike Steffen Reetz

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. Abstract—In the scope of ubiquitous computing, one of the key issues is the awareness of context, which includes diverse aspects of the user’s situation including his activities, physical surroundings, location, emotions and social relations, device and network characteristics and their interaction with each other. This contextual knowledge is typically(More)
The integration of Wireless Sensor Networks at a global scale is a crucial step on the road to a tighter coupling between the virtual and real world. In a context-aware system with thousands or even millions of data items describing the current situation, it is obvious that this data needs to be filtered and aggregated in order to distribute the detection(More)
Semantic modeling for the Internet of Things has become fundamental to resolve the problem of interoperability given the distributed and heterogeneous nature of the "Things". Most of the current research has primarily focused on devices and resources modeling while paid less attention on access and utilisation of the information generated by the things. The(More)
The information generated from the Internet of Things (IoT) potentially enables a better understanding of the physical world for humans and supports creation of ambient intelligence for a wide range of applications in different domains. A semantics-enabled service layer is a promising approach to facilitate seamless access and management of the information(More)
To date implementations of Internet of Things (IoT) architectures are confined to particular application areas and tailored to meet only the limited requirements of their narrow applications. To overcome technology and sector boundaries this paper proposes a dynamic service creation environment that employs i) orchestration of business services based on(More)
Concepts for Internet of Things (IoT) are currently limited to particular domains and are tailored to meet only limited requirements of their narrow applications. To overcome current silo architectures, we propose a business oriented service composition of IoT enabled services with (semi-) automated model based testing capabilities. Explicit description of(More)
Efficient testing of Internet of Things (IoT)-based services suffers from the underlying heterogeneous nature of IoT resources and hinders the process of rapid service creation and deployment. Real world effects, based on the behaviour of IoT-based services, tend to prevent the straight forward execution within the productive environment. Current solutions(More)
The evaluation of context middleware systems is a challenging endeavour. On the one hand, testbed investigations suffer from an unrealistic environment in terms of number of users, high implementation effort for changes and questionable portability of results. On the other hand simulation of middleware systems is complex due to the high abstraction of(More)