This paper addresses a large-scale power plant maintenance scheduling and production planning problem, which has been proposed by the ROADEF/EURO Challenge 2010. We develop two lower bounds for the problem: a greedy heuristic and a flow network for which a minimum cost flow problem has to be solved. Furthermore, we present a solution approach that combines a constraint programming formulation o...

Cost-optimal planning, in which the aim is to minimize the sum of costs of actions, is a challenging problem due to its computational complexity. A linear program derived from a relaxation which ignores the constraints on the ordering of actions can be used to obtain a lower bound on the cost of a solution-plan. We show that the dual of this linear program provides a transformation of the probl...

Cost-optimal planning, in which the aim is to minimize the sum of costs of actions, is a challenging problem due to its computational complexity. A linear program derived from a relaxation which ignores the constraints on the ordering of actions can be used to obtain a lower bound on the cost of a solution-plan. We show that the dual of this linear program provides a transformation of the probl...

The progression of technology in this up-to-the-minute era keeps on booming rapidly from time to time (Aljabre, 2012). Cloud computing is the today’s latest trend which offers unlimited and flexible shared storage server in a computer system. It can be used by any organizations and institutions. It provides services anytime anywhere. It gives user satisfaction because it enhances efficiency, pr...

In this paper, we provide a Genetic Algorithm (GA) based approach for change management in Enterprise IT systems which minimizes change delay and improves change capacity. Change management evolves the implementation of change queues on the set of applications which are running on one or more servers. To implement these changes there are some constraints involved: atomic nature of changes; when...

In this research, a model for optimal PM planning based on reliability is developed and solved for multi-component systems. In the proposed model, the type of PM actions for each inspection period is determined in such manner that the total weighted related costs are minimized while a minimum required system reliability is maintained. The planning horizon is divided into some inspections interv...

We propose a way to define the logic computation cost of operations to be used in evaluations of scalability and efficiency for simulated distributed constraint reasoning (DCR) algorithms. We also report experiments showing that the cost associated with a constraint check, even within the same algorithm, depends on the problem size. The DCR research has seen heated debate regarding the correct ...

Earlier virtual machine (VM) migration techniques consisted of stop-and-copy: the VM was stopped, its address space was copied to a different physical machine, and the VM was restarted at that machine. Recent VM hypervisors support live VM migration, which allows pages to be copied while the VM is running. If any copied page is dirtied (i.e., modified), it has to be copied again. The process st...

Abstract The gas booster station of a steel works has experienced excessive bearing failures since commissioning over two decades ago. This was designed with redundancy, allowing for automatic switch-over between fans. Bearing were observed, on average once every 15.7 days, instances where both fans simultaneous downtime. Booster resulted in regular downtime, preventing Coke Oven Gas (COG) tran...

Load balancing is one of the main challenges in a Virtual Machine (VM) Environment in order to ensure equal utilization of all the available resources while avoiding overloading a subset of machines. In this paper, we propose an efficient load balancing strategy based on VM live migration. Unlike previous work, our strategy records the history of mappings to inform future placement decisions. W...