We introduce a novel global constraint for the total weighted completion time of activities on a single unary capacity resource. For propagating the constraint, an O(n) algorithm is proposed, which makes use of the preemptive mean busy time relaxation of the scheduling problem. The solution to this problem is used to test if an activity can start at each start time in its domain in solutions th...

RACT : We consider the two-machine flowshop scheduling problem where jobs have random processing times are bounded within certain intervals. The objective is to minimize total completion time of all jobs. The decision of a solution for the problem has to be made based on the lower and upper bounds on job processing times since this only information available. The problem is NP-hard since the sp...

The need for calculating actions has been emerged everywhere and in any time, by advancing of information technology. Cloud computing is the latest response to such needs. Prominent popularity has recently been created for Cloud computing systems. Increasing cloud efficiency is an important subject of consideration. Heterogeneity and diversity among different resources and requests of users in ...

The need for calculating actions has been emerged everywhere and in any time, by advancing of information technology. Cloud computing is the latest response to such needs. Prominent popularity has recently been created for Cloud computing systems. Increasing cloud efficiency is an important subject of consideration. Heterogeneity and diversity among different resources and requests of users in ...

We show that minimizing the average job completion time on unrelated machines isAPX -hard if preemption of jobs is allowed. This provides one of the last missing pieces in the complexity classification of machine scheduling with (weighted) sum of completion times objective. The proof is based on a mixed integer linear program. This means that verification of the reduction is partly done by an I...

We consider the problem of reconstructing a rank-k n × n matrix M from a sampling of its entries. Under a certain incoherence assumption on M and for the case when both the rank and the condition number of M are bounded, it was shown in [CR09, CT10, KMO10, Rec11, JNS12, Mor14] that M can be recovered exactly or approximately (depending on some trade-off between accuracy and computational comple...

Task allocation is one of the biggest issues in the area of parallel and distributed computing. Given a parallel program composed of M communicating modules (tasks) and a multicomputer system of N processors with a specific interconnection network, the problem is how to assign the program modules onto the available processors in the system so as to minimize the entire program completion time. T...

We propose an exact branch-and-bound algorithm for the problem of maximizing the minimum machine completion time on identical parallel machines. The proposed algorithm is based on tight lower and upper bounds aswell as an effective symmetry-breaking branching strategy. Computational results performed on a large set of randomly generated instances attest to the efficacy of the proposed algorithm.

⎯We consider the problem of scheduling a set of simultaneously available jobs on a single machine. The objective is to determine a schedule that minimizes the class-based completion time variance (CB-CTV) of the jobs while reducing the overall CTV is taken as the secondary objective. This non-regular performance measure is closely related to service stability and of practical significance in ma...