On The Optimality Of Lept And c|ì Rules For Machines In Parallel

We consider scheduling problems with m machines in parallel and n jobs. The machinesare subject to breakdown and repair. Jobs have exponentially distributed processing timesand possibly random release dates. For cost functions that only depend on the set ofuncompleted jobs at time t we provide necessary and sucient conditions for the LEPTrule to minimize the expected cost at all t within the class of preemptive policies. Thisencompasses results that are known for makespan, and provides new ...