67 research outputs found
A reclaimer scheduling problem arising in coal stockyard management
We study a number of variants of an abstract scheduling problem inspired by
the scheduling of reclaimers in the stockyard of a coal export terminal. We
analyze the complexity of each of the variants, providing complexity proofs for
some and polynomial algorithms for others. For one, especially interesting
variant, we also develop a constant factor approximation algorithm.Comment: 26 page
A simulation framework for the design of a station-based bike sharing system
Many cities and towns offer nowadays to citizens a bike sharing system (BSS).
When a company starts the service, several decisions have to be taken on the
location and size of the rental stations, and the number of vehicles to use to
re-balance the bikes in the stations, in addition to the cost and policies for
the payment of the service. Also, when the service is in place, it is often
necessary to modify it, in many cases to expand it. In this paper, starting
from the experience gained in a real-case application, we present a simulation
framework to support the tactical decisions in the design or revision of a BSS.
We will also present the application of the framework to the case of Bicimia in
Brescia, Italy
Sleepiness, Neuropsychological Skills, and Scholastic Learning in Children
Abstract: Excessive daytime sleepiness is a frequent condition among children and adolescents that may lead to several and significant daytime consequences, including impaired neurocognitive skills and scholastic performance. Here, we evaluated in one hundred and ninety-one unselected primary school children, the relationship between sleepiness and a wide range of cognitive and academic skills through a standardized neuropsychological test battery. In order to assess the statistical relationship, we performed a partial least squares path modelling, a non-parametrical approach which combined a model of paths between latent variables and the coefficients between indicators and dimensions. Results were validated through the bootstrap approach and suggest that sleepiness is not associated with all cognitive and scholastic abilities, but only with those relying on verbal abilities and complex cognitive functions (i.e., reading comprehension, oral/syntactic comprehension, spelling, and mathematic skills). Our data suggest the idea that sleepiness in children is associated mostly with “higher” (mainly verbal) cognitive function(s), while the visuospatial domain was not affected
Complexity and approximation for Traveling Salesman Problems with profits
International audience; In TSP with profits we have to find an optimal tour and a set of customers satisfying a specific constraint. In this paper we analyze three different variants of TSP with profits that are NP-hard in general. We study their computational complexity on special structures of the underlying graph, both in the case with and without service times to the customers. We present polynomial algorithms for the polynomially solvable cases and fully polynomial time approximation schemes (FPTAS) for some NP-hard cases
Polygraphic findings in simplified Barbed Reposition Pharyngoplasty (BRP) as a treatment for OSA patients
This study aims to compare polygraphic data in patients with OSA treated with Barbed Reposition Pharyngoplasty (BRP) performed with a simplified technique compared to the standard method. Variations of technique were performed and tested with the purpose of promoting tolerability and diffusion of this simplified technique. To evaluate the efficacy of the simplified BRP method, a sample of 99 patients was divided into two groups: Group A was treated with BRP (BRP group) and Group B was treated with simplified BRP (sBRP group). The results obtained on the two groups were compared with the two sample Bootstrap t-tests method, showing a substantial overlap in polygraphic results recorded 6 months after surgery
Analisi di algoritmi per problemi di scheduling e routing
Dottorato di ricerca in metodi computazionali per le decisioni economiche e finanziarie. A.a. 199 - 9. Tutore Maria Grazia SperanzaConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal
American and European Portfolio Selection Strategies: The Markovian Approach
Technical Report n. 309, Department of Quantitative Methods, University of Bresci
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