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...aightforward measure of physical sensor accuracy as supplied by the sensor manufacturer. However, it may also incorporate additional sources of error such as errors in using a sensor, as described in =-=[9]-=-. 1 Ubisense is a networked location system: www.ubisense.net156 S. McKeever et al. Evidence Transfer. Evidence propagation through layers of the hierarchy from context value upwards is achieved usin...

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... from sensor data cannot be treated as fact, but simply evidence of fact. Users’ actions can contribute to degradation ofsinformation quality, such as the failure of users to carry their locator tags =-=[2]-=-. Uncertainty of sensor information should be tracked and preserved to determine uncertaintysat higher levels of context.sFurthermore, the process of interpretation of sensed context is also subject t...

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...ntext.sOther types of imperfections aresambiguity, imprecision, error. Thesnotion of QoC (Quality of Context) aimssto measure the imperfection of sensedsinformation. A good example of QoCsmodeling is =-=[10]-=-. The authors propose ansextendable UML-based model forscontext quality. They define threescontext levels (sensor, abstracted contextsand situation). For each level a set ofsquality parameters is defi...

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...bove. This is however of no particular surprise as ς0(6) = {n, f} violates the Dempster-Shafer assumption of working with exclusive hypotheses. A possible solution would either be to focus on basic sensor functions that map to singleton contexts only, or to integrate the modified theory of Dempster-Shafer (DSmt, see [6]) where the assumption of exclusive hypotheses is removed. Technically, this requires to go from powersets to hyperpowersets in order to represent disjunctive versus conjunctive hypotheses. 4 Related Work Context-awareness [13,1], context reasoning [16,1] and Quality of Context [9,10] have been studied as general concepts and methods for pervasive computing applications. Without a good “understanding” of their working context, such devices cannot realise the vision of smart and ubiquitous computing. As soon as smart devices start to act autonomously in a heterogeneous environment, a new “quality of quality” has to be considered as wrong context information can lead to severe hazards. This problem has in particular been recognised for autonomous vehicles [18,12,8], however no widely accepted formal framework for a thorough investigation of safety-critical context informatio...

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... reasoning-approach bases on probabilisticsnetworks where we distinct between two different uncertaintymetrics (confidence and probability), similar to other existingsreasoning approaches (e.g. [19], =-=[20]-=-).sBeside the adaption of these metrics, we furthermoresassume that a human expert initially designs the situationstemplate and so we have to cope with ontology and designserrors. In our previous work...