Clearing models for M/G/1 queues

We consider M/G/1-type queueing systems with 'disasters', occurring at cert ain random times and causing an instantaneous removal of the entire residua l workload from the system. After such a clearing, the system is assumed to be ready to start working again immediately. We consider clearings at dete rministic equidistant times, at random times and at crossings of some presp ecified level, and derive the stationary distribution of the workload proce ss for these clearing times and some of their combinations.