The concept of electronic money is no longer a hypothesis but a realisation. Advanced smart card technology and the ability to replace physical cash with an electronic alternative is a reality with mass market utilisation being a matter of time, rather than just supposition.Mondex is an...

We study a two-machine open shop scheduling problem, in which the machines are not continuously available for processing. No preemption is allowed in the processing of any operation. The objective is to minimize the makespan. We consider approximability issues of the problem with more than one...