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Transitions for Increased Flexibility in Fog Computing: A Case Study on Complex Event Processing

Manisha Luthra; Boris Koldehofe; Ralf Steinmetz
In: Informatik Spektrum, Vol. 42, No. 4, Pages 244-255, Springer, 2019.


Fog computing is envisioned to enable profound applications in the Internet of Things (IoT). A key characteristic of such applications is the need to exchange vital information between distinct IoT devices in the form of event notifications, e. g., traffic conditions when performing traffic monitoring. Complex event processing (CEP) is a powerful paradigm to overcome the information gap from observing primary sensor data by IoT devices to delivering event notifications to the IoT application users. However, to perform CEP in a highly dynamic IoT environment, e. g., involving mobile and heterogeneous devices, require an extremely flexible design of a CEP system to adaptively meet the changing requirements and conditions in which the CEP system is executed. In this article, we show on the use case of CEP, “how to increase flexibility in a fog-cloud computing environment building on a methodology known as mechanism transitions”. In particular, we state and analyze two exemplary IoT use cases to show the potential of mechanism transitions. We identify and discuss possible promising mechanism transitions in the context of CEP. We perform an experimental study for operator placement and show how transitions help to adapt to conflicting performance objectives.