Non-stationary wave relaxation methods for general linear systems of Volterra equations: convergence and parallel GPU implementation

Producción CientíficaIn the present paper, a parallel-in-time discretization of linear systems of Volterra equations of type u¯(t)=u¯0+∫t0K(t−s)u¯(s) d s+f¯(t),0<t≤T, is addressed. Related to the analytical solution, a general enough functional setting is firstly stated. Related to the numerical solution, a parallel numerical scheme based on the Non-Stationary Wave Relaxation (NSWR) method for the time discretization is proposed, and its convergence is studied as well. A CUDA parallel implementation of the method is carried out in order to exploit Graphics Processing Units (GPUs), which are nowadays widely employed for reducing the computational time of several general purpose applications. The performance of these methods is compared to some sequential implementation. It is revealed throughout several experiments of special interest in practical applications the good performance of the parallel approach.Ministerio de Universidades e Investigación de Italia (MUR), a través del proyecto PRIN 2017 (No. 2017JYCLSF) “Aproximación preservadora de estructuras de problemas evolutivos”Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

Recommender systems: a novel approach based on singular value decomposition

Due to modern information and communication technologies (ICT), it is increasingly easier to exchange data and have new services available through the internet. However, the amount of data and services available increases the difficulty of finding what one needs. In this context, recommender systems represent the most promising solutions to overcome the problem of the so-called information overload, analyzing users' needs and preferences. Recommender systems (RS) are applied in different sectors with the same goal: to help people make choices based on an analysis of their behavior or users' similar characteristics or interests. This work presents a different approach for predicting ratings within the model-based collaborative filtering, which exploits singular value factorization. In particular, rating forecasts were generated through the characteristics related to users and items without the support of available ratings. The proposed method is evaluated through the MovieLens100K dataset performing an accuracy of 0.766 and 0.951 in terms of mean absolute error and root-mean-square error

Ile587Val Polymorphism of the eIF2B5 Gene as Susceptibility Factor for Multiple Sclerosis

ABSTRAC

Sporadic ALS is not associated with VAPB gene mutations in Southern Italy

Mutations in the Cu/Zn superoxide dismutase (Sod1) gene have been reported to cause adult-onset autosomal dominant Amyotrophic Lateral Sclerosis (FALS). In sporadic cases (SALS) de novo mutations in the Sod1 gene have occasionally been observed. The recent finding of a mutation in the VAMP/synaptobrevin-associated membrane protein B (VAPB) gene as the cause of amyotrophic lateral sclerosis (ALS8), prompted us to investigate the entire coding region of this gene in SALS patients. One hundred twenty-five unrelated patients with adult-onset ALS and 150 healthy sex-age-matched subjects with the same genetic background were analyzed. Genetic analysis for all exons of the VAPB gene by DHPLC revealed 5 variant profiles in 83 out of 125 SALS patients. Direct sequencing of these PCR products revealed 3 nucleotide substitutions. Two of these were found within intron 3 of the gene, harbouring 4 variant DHPLC profiles. The third nucleotide variation (Asp130Glu) was the only substitution present in the coding region of the VAPB gene, and it occurred within exon 4. It was found in three patients out of 125. The frequency of the detected exon variation in the VAPB gene was not significantly different between patients and controls. In conclusion, our study suggests that VAPB mutations are not a common cause of adult-onset SALS

Amnestic Mild Cognitive Impairment Is Associated With Frequency-Specific Brain Network Alterations in Temporal Poles

There is general agreement that the neuropathological processes leading to Alzheimer’s disease (AD) begin decades before the clinical onset. In order to detect early topological changes, we applied functional connectivity and network analysis to magnetoencephalographic (MEG) data obtained from 16 patients with amnestic Mild Cognitive Impairment (aMCI), a prodromal stage of AD, and 16 matched healthy control (HCs). Significant differences between the two groups were found in the theta band, which is associated with memory processes, in both temporal poles (TPs). In aMCI, the degree and betweenness centrality (BC) were lower in the left superior TP, whereas in the right middle TP the BC was higher. A statistically significant negative linear correlation was found between the BC of the left superior TP and a delayed recall score, a sensitive marker of the “hippocampal memory” deficit in early AD. Our results suggest that the TPs, which are involved early in AD pathology and belong to the memory circuitry, have an altered role in the functional network in aMCI

Non-stationary wave relaxation methods for general linear systems of Volterra equations: convergence and parallel GPU implementation

Producción CientíficaIn the present paper a parallel--in--time discretization of linear systems of Volterra equations of type \baru(t) = \baru_0 + \int_0^t \bK(t-s) \baru(s)\dd s + \barf(t),\qquad 0 is addressed. Related to the analytical solution a general enough functional setting is firstly stated. Related to the numerical solution a parallel numerical scheme based on the Non Stationary Wave Relaxation (NSWR) method for the time discretization is proposed, and its convergence is studied as well. A CUDA parallel implementation of the method is carried out in order to exploit Graphics Processing Units (GPUs), which are nowadays widely employed for reducing the computational time of several general purpose applications. The performance of these methods is compared to some sequential implementation. It is revealed throughout several experiments of special interest in practical applications the good performance of the parallel approach

L’implementazione di un Piano del Cibo: il caso di Castel del Giudice

To leave or to stay? This is the most frequent question people who live in the inner areas ask themselves. The inhabitants of Castel del Giudice, together with the municipal administration, have decided to get involvedand practice new ways of re-inhabiting places, leveraging the potential of the local agri-food system. The article explores the evolution of the local food policy of Castel del Giudice with the aim of assessing its consistencywith the Food Plan adopted in 2019 after a bottom-up policy design process.Partire o restare? È questa la domanda più frequente che si pongono le persone che vivono al margine. Gli abitanti di Castel del Giudice, insieme all’Amministrazione comunale, hanno deciso di mettersi in gioco e praticare nuove forme del riabitare i luoghi, facendo leva sulle potenzialità del sistema agroalimentare locale. L’articolo esplora l’evoluzione della politica locale del cibo di Castel del Giudice con l’obiettivo di valutarne la coerenza rispetto al Piano del Cibo adottato nel 2019 dopo un percorso di costruzione dal basso

A Content-Based Recommender System for Hidden Cultural Heritage Sites Enhancing

The enhancement of Italian artistic and cultural heritage is a big challenge for modern technologies. Modern systems are capable of producing an information flood that, however, keeps users away from what they need. There are fascinating places that often remain hidden due to the overload of information. In this scenario, it would be interesting to introduce a recommendation methodology that brings the right information to the user according to their profile, ensuring a unique and tailored experience. This paper aims to propose a Content-Based Recommender System able to exploit Singular Value Decomposition proprieties. The Recommender System will be used to recommend hidden cultural sites through the support of the Digital Storytelling and Context-Aware approach. Numerical tests return promising results compared with some Collaborative Filtering RS methodologies