A survey on approximation algorithms for scheduling with machine unavailability

Abstract

In this chapter we present recent contributions in the field of sequential job scheduling on network machines which work in parallel; these are subject to temporary unavailability. This unavailability can be either unforeseeable (online models) or known a priori (offline models). For the online models we are mainly interested in preemptive schedules for problem formulations where the machine unavailability is given by a probabilistic model; objectives of interest here are the sum of completion times and the makespan. Here, the non-preemptive case is essentially intractable. For the offline models we are interested in non-preemptive schedules where we consider the makespan objective; we present approximation algorithms which are complemented by suitable inapproximability results. Here, the preemptive model is polynomial-time solvable for large classes of settings. © 2009 Springer Berlin Heidelberg.