Situation awareness for networked systems

Modern technology offers the possibility to construct networked monitoring systems from autonomous computing nodes equipped with appropriate sensors. Complementing such a system with actuators yields a cyber-physical system that must be able to cope with uncertainties arising from feedback loops via the physical world. The common property of such systems lies in the high degree of uncertainty in the varying configuration of the system and also in the potentially high amounts of (unstructured) data that can be generated by such a system. In order to tackle these problems and make the distributed monitoring systems more usable the concepts of situational information and hierarchies of situations can be applied in this domain. The problem of high amounts of data can be partially solved by arriving at a higher level of abstraction lower in the processing chain, communicating only data fused into an ontological structure to information consumers. The fusion templates are called situation parameters and values of the fused data items are called situational parameter values in the context of the current article. Situation parameter values must be tagged with situational and temporal validity information in order to cope with the delays and spatial uncertainties that can occur in a distributed monitoring system. The lower level situation parameters can be fused to even higher level situation parameters, projecting the temporal and spatial validity information from the lower level parameters up to the higher level parameters. The article presents the concepts of forming situational information templates and hierarchies based on data available from a distributed monitoring system where the temporal and spatial properties of situational information are taken into account. A case study is presented that shows the feasibility of the concepts in a real world monitoring scenario.