Energy-efficient resource allocation within computing systems is important because of the growing demand for, and cost of, energy. In this paper, we study the problem of energy-constrained static resource allocation of a collection of communicating tasks to a heterogeneous computing environment. Our goal is to maximize the probability (calculated via Monte Carlo method) that our collection of t...

We consider the NP-hard problem of scheduling parallel jobs with release dates on identical parallel machines to minimize the makespan. A parallel job requires simultaneously a prespecified, job-dependent number of machines when being processed. We prove that the makespan of any nonpreemptive list-schedule is within a factor of 2 of the optimal preemptive makespan. This gives the best-known app...

We consider the fuzzy job shop problem, where uncertain durations are modelled as fuzzy numbers and the objective is to minimise the expected makespan. A recent local search method from the literature has proved to be very competitive when used in combination with a genetic algorithm, but at the expense of a high computational cost. Our aim is to improve its efficiency with an alternative resch...

The paper is devoted to some single-machine scheduling problems with variable job processing times. The objectives are to minimize the makespan (i.e., the maximum completion time of all jobs), and to minimize the total completion time. For some special cases, we show that these problems can be solved in polynomial time. For some another special cases of the makespan and the total completion tim...

A hybrid genetic algorithm is proposed in this paper to minimize the makespan and the total flowtime in the no-wait flowshop scheduling problem, which is known to be NP-hard for more than two machines. The Variable Neighborhood Search is used as an improvement procedure in the last step of the genetic algorithm. First, comparisons are provided with respect to several techniques that are represe...

In a fundamental paper on workload balancing on m identical parallel machines, Ho et al. (2009) proved that a schedule which minimizes the normalized sum of squares is necessarily a makespan-optimal one. Based on their theoretical result, they proposed a heuristic algorithm to solve the workload balancing problem. In this note we provide a counter-example for the above-mentioned result and expl...

Grid computing is gaining ground in academia and commerce moving from scientific-based applications to service oriented problem solving environments. Grid is a distributed large-scale computing infrastructure providing dependable, secure, transparent, pervasive, inexpensive, and coordinated resource sharing. Resource selection and use are necessary to enhance application performance. Grid task ...

We consider the following special case of minimizing makespan. A set of jobs J and a set of machines M are given. Each job j ∈ J can be scheduled on a machine from a subset Mj of M . The processing time of j is the same on all machines in Mj . The jobs are of two sizes, namely b (big) and s (small). We present a polynomial-time algorithm that approximates the value of the optimal makespan withi...

This paper discusses the scheduling of precedence-related jobs non-preemptively in a job shop environment with an objective of minimizing the makespan. Due to the NP-hard nature of the scheduling problems, it is usually difficult to find an exact optimal schedule and hence one should rely on finding a near to optimal solution. This paper proposes a computationally effective powers-of-two heuris...

In this paper we deal with the two-stage hybrid flow shop with dedicated machines. The objective is to minimize the makespan. We first provide some basic properties, a set of lower bounds and two polynomial cases. We then propose a new heuristic based on the established properties. The heuristic tries to sequence jobs in such a way that the obtained makespan corresponds to the lower bound. In t...