Search results for " scheduling"

Checkpointing Workflows for Fail-Stop Errors

2017

International audience; We consider the problem of orchestrating the exe- cution of workflow applications structured as Directed Acyclic Graphs (DAGs) on parallel computing platforms that are subject to fail-stop failures. The objective is to minimize expected overall execution time, or makespan. A solution to this problem consists of a schedule of the workflow tasks on the available processors and of a decision of which application data to checkpoint to stable storage, so as to mitigate the impact of processor failures. For general DAGs this problem is hopelessly intractable. In fact, given a solution, computing its expected makespan is still a difficult problem. To address this challenge,…

A hybrid genetic algorithm for the resource-constrained project scheduling problem

2008

Abstract In this paper we propose a Hybrid Genetic Algorithm (HGA) for the Resource-Constrained Project Scheduling Problem (RCPSP). HGA introduces several changes in the GA paradigm: a crossover operator specific for the RCPSP; a local improvement operator that is applied to all generated schedules; a new way to select the parents to be combined; and a two-phase strategy by which the second phase re-starts the evolution from a neighbour’s population of the best schedule found in the first phase. The computational results show that HGA is a fast and high quality algorithm that outperforms all state-of-the-art algorithms for the RCPSP known by the authors of this paper for the instance sets j…

Vehicle scheduling for rental-with-driver services

2021

Abstract In this paper, we introduce a new vehicle scheduling problem (VSP) with driver consistency faced by rental-with-driver companies. A weekly time-horizon is considered and a set of potential customers, each one associated with a list of required tasks, is assumed. The company can choose to accept or reject a customer, but if accepted, all required tasks must be performed by the same driver. A profit is associated with each customer. The goal is to maximize the company’s total profit, by respecting a list of daily and the weekly drivers’ workload limitations imposed by drivers’ contracts. We propose a mathematical formulation of the problem and design an exact solution method based on…

Implementing a cyber-physical system to monitor soil water status and environmental variables for irrigation scheduling

2018

The most advanced research on irrigation at farm scale, following the paradigm “more crop per drop”, has been aimed at the definition of strategies of precision irrigation, in order to optimize crop water productivity and to maximize the economic benefits without affecting environmental quality.Water saving management strategies, such as regulated deficit irrigation (RDI), can be effectively applied if supported by the real time control of soil/plant water status allowing the identification of appropriate irrigation scheduling parameters (irrigation timing and doses). This challenge can be achieved by integrating sensing technologies, internet of things and cloud computing supported with co…

Agro-hydrological models to schedule irrigation of Mediterranean tree crops

2010

In this paper a comparison between two agro-hydrological models, used to schedule irrigation of typical Mediterranean tree crops, is assessed. In particular the comparison between the model proposed by FAO, using a black box processes schematization, and the SWAP model based on the numerical analysis of Richards’ equation is initially presented for two irrigation seasons, 2005 and 2006, and two Mediterranean tree crops, i.e. grapevine (Vitis vinifera, L.) and olive oil (Olea europea, L.). The comparison mainly focuses on hydrological balance components and on soil water contents. After investigating and setting the scheduling parameters ordinarily practiced by the framers in the area (i.e o…

Assessing agro-hydrological models to schedule irrigation for crops of Mediterranean Environment

2008

A Non-Parametric Parallel Harris-Affine Detector

2009

This paper describes a parallel version of a new automatic Harris-based corner detector. A simple but effective client-server based scheduler has been implemented in order to dynamically distribute the workload on heterogeneous parallel architectures such as Grid systems. Results obtained on the COMETA Grid show the effectiveness and the robustness of the proposed approach.

A Harris-based Region Detector on a Computational Grid

2007

This paper introduces a new Harris-based feature detector algorithm, characterized by no parameters tuning to detect region of interest. Preliminary results show that the proposed methodology returns good results with respect to standard detectors which need a set of parameters. An uncommon parallel implementation of the proposed algorithm is presented to support the high computational workload which is required to avoid the approximation of the results. Our parallel approach differs from the conventional one because an internal scheduler, based on the expected running time, is used to balance the data distribution on a client-server model. The aim of this paper is also to underline the adv…

Maintenance Planning For The Reliability Maximization In A Large System With Vagueness In The Reliability Values Of Some Components

2015

This paper tackles the problem to single out the maintenance actions to be executed on a production system during the planned stop of given length. In detail, from a reliability viewpoint the system is assimilated as a series-parallel multi-component system and the maintenance actions need to maximize the system reliability up to the next planned stop. Moreover, it is assumed that some components reliability values are affected by vagueness within a given range. To solve the considered problem, an exact dynamic programming algorithm suitable to quickly point out the maintenance scheduling is developed and, moreover, it is formulated a proper parameter able to express the robustness of the o…

Implementazione di funzioni aggiuntive per la rappresentazione e la gestione ottimizzata di risorse energetiche distribuite in un distretto energetic…

2013

Il presente Rapporto descrive le attività svolte dal personale del DEIM dell’Università degli Studi Palermo nell’ambito della prima fase delle attività di ricerca dal titolo: “Implementazione di funzioni aggiuntive per la rappresentazione e la gestione ottimizzata di risorse energetiche distribuite in un distretto energetico. Simulazione di scenari in ambiente integrato”, oggetto dell’Accordo di Collaborazione tra ENEA e DEIM sottoscritto in data 25 marzo 2013. Scopo del presente accordo di collaborazione è la definizione di funzioni aggiuntive per i vari componenti del distretto energetico già descritti e modellati in un apposito software nella scorsa annualità. Le simulazioni sono state s…