A seal arrangement in a fuel cell device seals against leaks in a mechanical joint between two components which convey a liquid andor a gaseous process medium 3 in a media chamber of the fuel cell device. The method comprises capturing a plurality of patterned images from a plurality of locations, correlating the plurality of patterned images to generate sets of linear differences, and using the sets of linear differences to generate the rotation information. The input stage provides a temporary store for data and thus hides the latency of the storage device. The system memory includes code configured to generate one or more decision graphs for predicting events with event labels chosen from a number of event labels based on the events within the event stream, wherein the decision graph includes decision nodes and leaf nodes, and wherein each of the decision nodes includes a question. A mobile phone is also described and claimed.