Search results for " Scheduling"

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…

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…

A cost model for the selection of a maintenance activity in a series system

2012

Economic lot scheduling on multiple production lines with resource constraints

2003

Abstract This paper deals with the multiple production line economic lot scheduling problem, where some items cannot be produced concurrently since they compete for some discrete resources. In particular, cyclic schedules are sought for a problem where identical production lines are present, lost sales are allowed, and minimization of the long-range production, setup, inventory, and shortage penalty costs are required. A heuristic procedure for this problem is introduced, a numerical example is worked out and some computational experiments are presented.

Justification technique generalizations

2006

The justification technique was introduced various decades ago for the resource-constrained project scheduling problem, although it has rarely been used with the problem. Justification is a simple and quick technique which when applied to schedules produces a new schedule that is, at most, as long as the original schedule — and often shorter. A recent article (Valls et al, 2005), showed that incorporating justification in heuristic algorithms can produce a substancial improvement in the results obtained. These results have motivated us to generalise this technique in order to study it in greater depth. This paper proposes distinct forms and generalisations for the justification technique an…

Sleep apnoea management in Europe during the COVID-19 pandemic: data from the European Sleep Apnoea Database (ESADA)

2020

Sleep disordered breathing (SDB) is highly prevalent with a male to female predominance of two to one, and is more common in middle-aged and elderly subjects [1]. Affected patients often present with comorbidities such as obesity, cardiovascular disease (systemic hypertension, heart failure, atrial fibrillation), and diabetes mellitus Type II [2]. The strong overlap between the profile for SDB patients and the identified risk factors for adverse outcomes of COVID-19 infection that include age, male gender, and cardio-metabolic comorbidity [3] suggest that SDB patients may benefit from effective therapy if confronted with COVID-19 infection [4].

Multi-stage Linear Programming Optimization for Pump Scheduling

2014

This study presents a methodology based on Linear Programming for determining the optimal pump schedule on a 24-hour basis, considering as decision variables the continuous pump flow rates which are subsequently transformed into a discrete schedule. The methodology was applied on a case study derived from the benchmark Anytown network. To evaluate the LP reliability, a comparison was made with solutions generated by a Hybrid Discrete Dynamically Dimensioned Search (HD-DDS) algorithm. The cost associated with the result derived from the LP initial solution was shown to be lower than that obtained with repeated HD-DDS runs with differing random seeds. (C) 2013 The Authors. Published by Elsevi…

Pilot Prototype of Autonomous Pallets and Employing Little’s Law for Routing

2015

Application of autonomous control for shop-floor scheduling by considering real-time control of material flows is advantageous to those assembly lines with dynamic and uncertain circumstances. Among several potential processors with computing and communication capabilities—for representing autonomous material carriers—wireless sensor nodes seem as promising objects to be applied in practice. For realizing autonomy in making scheduling and routing-control decisions some methodologies need to be embedded in the nodes. Among several experimented methodologies, e.g., artificial intelligence, genetic algorithm, etc., in the context of a doctoral research, in this current special case of assembly…