Wednesday, February 27, 2013

Event tree analysis in hybrid system simulation

Last week Walid, Michal, Jan and Adam finished a revised specification for an event detection and handling procedure for hybrid systems based on explicit tracking of event sequences. The sequences are gathered into a structure encoded as a tree, analogous to the event trees used in to analyze causal relations between events in hazard analysis. Along with an event, each node in the tree also encodes an approximation of the states that are reachable from the states approximated in the preceding node. The information encoded in the event tree makes it possible for the procedure to sometimes detect that all reachable states have been accounted for, even when the event tree contains an infinite branch.