In this paper we consider a basic scheduling problem called the busy time scheduling problem given n jobs, with release times rj , deadlines dj and processing times pj , and m machines, where each machine can run up to g jobs concurrently, our goal is to find a schedule to minimize the sum of the “on” times for the machines. We develop the first correct constant factor online competitive algori...

In this talk, we discuss semi-online scheduling on two uniform machines under a grade of service (GoS) provision, where one machine with speed one can process all jobs, and the other machine with speed s (s>0) can only process some jobs. The objective is to minimize the makespan. We consider two variants, where the total size of jobs or the optimal makespan is known in advance. For both variant...

In this paper we consider a basic scheduling problem called the busy time scheduling problem given n jobs, with release times rj , deadlines dj and processing times pj , and m machines, where each machine can run up to g jobs concurrently, our goal is to find a schedule to minimize the sum of the “on” times for the machines. We develop the first correct constant factor online competitive algori...

this paper considers the problem of scheduling hybrid flowshops with machine availability constraints (mac) to minimize makespan. the paper deals with a specific case of mac caused by preventive maintenance (pm) operations. contrary to previous papers considering fixed or/and conservative policies, we explore a case in which pm activities might be postponed or expedited while necessary. regardi...

This paper focuses on a two-machine re-entrant flowshop scheduling problem with the objective of minimizing makespan. In the re-entrant flowshop considered here, all jobs must be processed twice on each machine, that is, each job should be processed on machine 1, machine 2 and then machine 1 and machine 2. We develop dominance properties, lower bounds and heuristic algorithms for the problem, a...

This paper investigates the semi-online machine covering problems on m ≥ 3 parallel identical machines. Three different semi-online versions are studied and optimal algorithms are proposed. We prove that if the total processing time of all jobs or the largest processing time of all jobs is known in advance, the competitive ratios of the optimal algorithms are both m − 1. If the total processing...

Motivated by problems in distributed computing, this thesis presents the first nontrivial polynomial time approximation algorithms for an important class of machine scheduling problems. We study the family of preemptive minimum makespan scheduling problems where jobs have stochastic processing requirements and provide the first approximation algorithms for these problems when machines have unre...