Search results for "Scheduling"
showing 10 items of 275 documents
Determinants of elimination decisions in the activity scheduling process
2016
[EN] This paper presents an analysis on the determinants related to a particular rescheduling decision in the activity-travel scheduling process: elimination decisions, which consist in the non-execution of pre-planned activity-travel episodes. Data used come from an in-depth computer-assisted telephone interview (CATI) follow up survey carried out during the implementation of the first wave of an activity scheduling process panel survey. Open-ended answers related to the reasons associated to changes between pre-planned and executed agenda are studied. First, an interpretative qualitative method based on analytic induction (AI) is used to cope with the complex nature of the rescheduling de…
Changes in the Scheduling Process According to Observed Activity-travel Flexibility
2014
Abstract In this work we analyze the reasons for changing pre-planned activities and travels episodes considering the type of modification observed during the scheduling process. Specifically we selected a small sample from those pre-planned episodes that are no executed at all as a pilot study. The data analyzed was collected in the first wave of a weekly activity-travel panel survey carried out in Valencia (Spain) in 2010. Each survey wave consisted on a face-to-face interview to generate a pre-planned activity agenda for the following week, an activity-travel diary implemented on mobile phones to collect activities and travels as they are executed, and in-depth telephone interviews to in…
Minimizing weighted earliness-tardiness on parallel machines using hybrid metaheuristics
2015
We consider the problem of scheduling a set of jobs on a set of identical parallel machines where the objective is to minimize the total weighted earliness and tardiness penalties with respect to a common due date. We propose a hybrid heuristic algorithm for constructing good solutions, combining priority rules for assigning jobs to machines and a local search with exact procedures for solving the one-machine subproblems. These solutions are then used in two metaheuristic frameworks, Path Relinking and Scatter Search, to obtain high quality solutions for the problem. The algorithms are tested on a large number of test instances to assess the efficiency of the proposed strategies. The result…
Identification for a general class of LPV Models
2000
Abstract In this paper we consider the problem of identifying discrete-time Linear Parameter Varying (LPV) models of non-linear or time-varying systems. LPV models are considered for their connection with the industrial practice of gain-scheduling. We assume that inputs, outputs and the scheduling parameters are measured, and a form of the functional dependence of the coefficients on the parameters is known. We show how the identification problem can be reduced to a linear regression so that a Least Mean Square identification algorithm can be reformulated. Conditions on the persistency of excitation in terms of the inputs and parameter trajectories are given to ensure the consistency of the…
Identification of linear parameter varying models
2003
We consider the problem of identifying discrete-time linear parameter varying models of nonlinear or time-varying systems. We assume that inputs, outputs and the scheduling parameters are measured, and a form of the functional dependence of the coefficients on the parameters. We show how the identification problem can be reduced to a linear regression, and we give conditions on persistency of excitation in terms of the inputs and parameter trajectories.
Simultaneous optimization of harvest schedule and data quality
2015
In many recent studies, the value of forest inventory information in harvest scheduling has been examined. In a previous paper, we demonstrated that making measurement decisions for stands for which the harvest decision is uncertain simultaneously with the harvest decisions may be highly profitable. In that study, the quality of additional measurements was not a decision variable, and the only options were between making no measurements or measuring perfect information. In this study, we introduce data quality into the decision problem, i.e., the decisionmaker can select between making imperfect or perfect measurements. The imperfect information is obtained with a specific scenario tree fo…
Two Simple Constructive algorithms for the Distributed Assembly Permutation Flowshop Scheduling Problem
2014
Nowadays, it is necessary to improve the management of complex supply chains which are often composed of multi-plant facilities. This paper proposes a Distributed Assembly Permutation Flowshop Scheduling Problem (DAPFSP). This problem is a generalization of the Distributed Permutation Flowshop Scheduling Problem (DPFSP) presented by Naderi and Ruiz (Comput Oper Res, 37(4):754–768, 2010). The first stage of the DAPFSP is composed of f identical production factories. Each center is a flowshop that produces jobs that have to be assembled into final products in a second assembly stage. The objective is to minimize the makespan. Two simple constructive algorithms are proposed to solve the proble…
The effects of using participatory working time scheduling software on sickness absence: A difference-in-differences study.
2020
Abstract Background Participatory working time scheduling is a collaborative approach to scheduling shift work. As a potential way of improving work time control, it may provide a means to reducing sickness absence in shift work. So far, experimental and quasi-experimental studies on the effects of increased work time control on sickness absence are lacking. Objective To investigate the effects of using digital participatory working time scheduling software on ward-level sickness absence among Finnish hospital employees. Participants and methods This quasi-experimental study compared the amount of sickness absence in hospital wards using a participatory working time scheduling software (n=1…
Verifica dell’applicabilità del metodo irriguo sub-superficiale su colture agrumicole e ottimizzazione dell’uso della risorsa idrica
2020
Gli impianti di subirrigazione (SDI), in relazione alla posizione interrata dei gocciolatori permettono la riduzione dei consumi irrigui, garantendo la possibilità di utilizzo di risorse altrimenti non utilizzabili. Tuttavia, i costi di investimento iniziali risultano maggiori di quelli relativi ai tradizionali impianti di microirrigazione e pertanto, diventano economicamente vantaggiosi, se l'efficienza del sistema viene garantita per periodi di almeno 15-20 anni. La SDI, inoltre, permette di ottenere valori elevati di efficienza d’uso dell’acqua, spesso superiori al 90%, se associata ad un monitoraggio continuo dello stato idrico del suolo e della pianta e ad una corretta stima delle esig…
Smart grid-aware scheduling in data centres
2015
In several countries the expansion and establishment of renewable energies result in widely scattered and often weather-dependent energy production, decoupled from energy demand. Large, fossil-fuelled power plants are gradually replaced by many small power stations that transform wind, solar and water power into electrical power. This leads to changes in the historically evolved power grid that favours top-down energy distribution from a backbone of large power plants to widespread consumers. Now, with the increase of energy production in lower layers of the grid, there is also a bottom-up flow of the grid infrastructure compromising its stability. In order to locally adapt the energy deman…