Medical Cyber Physical Systems of Systems (MCPSoS) refer to a set of systems that flexibly collaborate at runtime in order to render higher level functionality. Most systems in a MCPSoS offer a generic piece of functionality so that they can contribute to many totally different collaboration scenarios. Consequently, it is unknown at design time which systems will how collaborate at runtime. This unpredictability leads to new challenges for the assurance of safety, because established approaches always build on the assumption that systems and their environments are completely known. We believe that the safety research community has to pull together in order to tackle the challenge of unpredictability and that this requires an appropriate taxonomy in order to establish a common understanding of the challenge and related solutions. To this end, we propose enhancements based on a widely accepted taxonomy for dependable computing with respect to the system-of-systems aspect. Further, we will use the taxonomy to reflect on the new challenge of unpredictability and related solutions from the state-of-the-art, namely, safety contracts and dynamic risk assessment. Finally, we motivate an integration of the safety contracts and dynamic risk assessment and present some ideas on this integration. Throughout the paper, we use a real-world example to exemplify our proposed taxonomy and our thoughts
Nowadays, Spatial Data Infrastructures (SDIs) play an important role in government agencies, at different levels: global, national, and local. They aim to improve the management and sharing of geospatial data. Nonetheless, these SDIs have been developed as information islands, in which a user's query is compared to metadata described only in their own catalog services. The lack of interaction among SDIs limits the potential of these infrastructures in providing geospatial data to a larger audience. This article presents a distributed architecture, based on a federation of SDIs which interact among themselves, using query propagation. This propagation facilitates data discovery and sharing. We also describe a distributed query processing service used to enable the resource discovery in distributed infrastructures.
The volume of spatial data available on the Web has been increasing rapidly. Currently, the Web has been used not only for document searching but also for the provision and use of services, known as Web services, which are published in a directory and may be automatically discovered by software agents. Particularly in the spatial domain, the possibility of accessing these large spatial datasets via Web services has motivated research into the new field of Spatial Data Infrastructure (SDI) implemented using service-oriented architecture. In this paper, we propose WS-GIS which is a SDI using Web services. WS-GIS enables spatial search on distributed catalogs that form a federation of spatial databases.
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