Preconditioned fully implicit PDE solvers for monument conservation

Mathematical models for the description, in a quantitative way, of the damages induced on the monuments by the action of specific pollutants are often systems of nonlinear, possibly degenerate, parabolic equations. Although some the asymptotic properties of the solutions are known, for a short window of time, one needs a numerical approximation scheme in order to have a quantitative forecast at any time of interest. In this paper a fully implicit numerical method is proposed, analyzed and numerically tested for parabolic equations of porous media type and on a systems of two PDEs that models the sulfation of marble in monuments. Due to the nonlinear nature of the underlying mathematical model, the use of a fixed point scheme is required and every step implies the solution of large, locally structured, linear systems. A special effort is devoted to the spectral analysis of the relevant matrices and to the design of appropriate iterative or multi-iterative solvers, with special attention to preconditioned Krylov methods and to multigrid procedures. Numerical experiments for the validation of the analysis complement this contribution.Comment: 26 pages, 13 figure

Monitoring Fetal Heart Rate during Pregnancy: Contributions from Advanced Signal Processing and Wearable Technology

Monitoring procedures are the basis to evaluate the clinical state of patients and to assess changes in their conditions, thus providing necessary interventions in time. Both these two objectives can be achieved by integrating technological development with methodological tools, thus allowing accurate classification and extraction of useful diagnostic information. The paper is focused on monitoring procedures applied to fetal heart rate variability (FHRV) signals, collected during pregnancy, in order to assess fetal well-being. The use of linear time and frequency techniques as well as the computation of non linear indices can contribute to enhancing the diagnostic power and reliability of fetal monitoring. The paper shows how advanced signal processing approaches can contribute to developing new diagnostic and classification indices. Their usefulness is evaluated by comparing two selected populations: normal fetuses and intra uterine growth restricted (IUGR) fetuses. Results show that the computation of different indices on FHRV signals, either linear and nonlinear, gives helpful indications to describe pathophysiological mechanisms involved in the cardiovascular and neural system controlling the fetal heart. As a further contribution, the paper briefly describes how the introduction of wearable systems for fetal ECG recording could provide new technological solutions improving the quality and usability of prenatal monitoring. © 2014 Maria G. Signorini et al

Dynamic Modification and Damage Propagation of a Two-Storey Full-Scale Masonry Building

The progressive change of modal characteristics due to accumulated damage on an unreinforced masonry (URM) building is investigated. The stone URM building, submitted to five consecutive shakings, has been experimentally studied on the shaking table of EUCENTRE laboratory (Pavia, Italy). The dynamic characteristics of the test specimen are analytically estimated using frequency and state-space modal identification from ambient vibration stationary tests carried out before the strong motion transient tests at various levels of damage. A singular value (SV) decomposition of the cross-correlation matrix of the acceleration response in the frequency domain is applied to determine the modal characteristics. In the time domain, the subspace state-space system identification is performed. Modal characteristics evolve from the initial linear state up to the ultimate collapse state in correlation with accumulated damage. Modal frequencies shorten with increasing intensity, whereas modal damping ratios are enhanced. Modal shapes also change with increasing level of accumulated damage. Comparing the evolution of modal characteristics, it is concluded that modal damping ratio shift can be better correlated with the system's actual performance giving a better representation of damage than that of natural frequency shift ratio or the modes difference

Model of murine ventricular cardiac tissue for in vitro kinematic-dynamic studies of electromagnetic and beta2-adrenergic stimulation

In a model of murine ventricular cardiac tissue in vitro, we have studied the inotropic effects of electromagnetic stimulation (frequency, 75 Hz), isoproterenol administration (10 μM), and their combination. In particular, we have performed an image processing analysis to evaluate the kinematics and the dynamics of beating cardiac syncytia starting from the video registration of their contraction movement. We have found that the electromagnetic stimulation is able to counteract the β-adrenergic effect of isoproterenol and to elicit an antihypertrophic response

Simplified methodologies for assessing the out-of-plane two-way bending seismic response of unreinforced brick masonry walls: lessons from recent experimental studies

This paper describes a simplified methodology for the assessment of unreinforced masonry (URM) walls under out-of-plane two-way bending seismic action. The methodology involves a force-based check derived from the principle of virtual work. This check is proposed based on experimental observations of significant cracking resistance associated with two-way spanning URM walls, indicating methodologies considering such walls to be pre-cracked or to be non-laterally supported as overly conservative. The methodology incorporates several findings and developments from recent experimental campaigns: ranging from novel characterization tests on masonry couplets to incremental dynamic tests on full-scale buildings. Such incorporations include new formulation to calculate the torsional shear strength of a bed joint and accounting for possible changes in the boundary conditions of an OOP wall during dynamic loading. Testing standards as well as recommendations in several international guidelines for masonry structures addressing the input properties required to implement the proposed methodology are enlisted and reviewed. The methodology requires the definition of the period of vibration of the assessed URM walls, to calculate which plate theory based formulation is provided. Open research questions and potential avenues for further development of the methodology are ultimately highlighted

LA RELAZIONE TRA ESPERIENZA DI BENESSERE E APPRENDIMENTO NEGLI STUDENTI CON DISTURBI SPECIFICI DELL'APPRENDIMENTO (DSA)

Il presente progetto di ricerca si articola in tre studi e ha l’obiettivo di indagare l’esperienza di benessere nell’adolescenza secondo i principi della Psicologia Positiva. Più precisamente, il primo studio si pone l’obiettivo di adattare e valutare le caratteristiche psicometriche di uno strumento che valuta il benessere, il Comprehensive Inventory of Thriving (CIT) in età adolescenziale (14-19 anni), misura già validata per le fasce di età inferiori. Il secondo studio del presente progetto di ricerca restringe il suo raggio di azione ed intervento su un contesto specifico e fondamentale per gli studenti: la scuola. Proprio per questo motivo, l’obiettivo è di indagare la relazione tra il benessere, il vissuto emotivo, lo student engagement e il clima scolastico percepito dagli studenti della scuola secondaria di primo grado e di secondo grado, con una particolare attenzione agli studenti con Disturbi Specifici dell’Apprendimento (DSA). Infine, il terzo studio si è posto l’obiettivo di indagare e valutare i vissuti emotivi negli studenti con un Disturbo Specifico di Apprendimento, la Dislessia Evolutiva (DE), in relazione all’apprendimento di una lingua straniera, come l’inglese. A questo proposito, verrà presentato il processo di costruzione e validazione del KIT Includi. Questo intervento educativo nasce all’interno di un ampio progetto finanziato (Interreg-Italia Svizzera) e si pone l’obiettivo di sostenere l’inclusione sociale e il miglioramento dell’esperienza scolastica degli studenti con DE nella scuola secondaria di I e II grado. Il progetto è stato finalizzato a promuovere l’apprendimento della lingua inglese con metodologie didattiche ideate in funzione del modello MIND, un approccio che evidenzia le attitudini e i punti di forza degli studenti con dislessia.The present research project consists of three studies and aims to investigate the experience of well-being in adolescence, according to the principles of Positive Psychology. More specifically, the first study aims to adapt and evaluate the psychometric characteristics of an instrument that assesses well-being, the Comprehensive Inventory of Thriving (CIT), in adolescence (14-19 years). Such measure has already been validated for younger children. The second study of the present research project narrows its scope and intervention to a specific and fundamental context for students, i.e. the school. In detail, the aim of this study is to investigate the relationship between well-being, emotional experience, student engagement and perceived school climate among high school students, with a special focus on students with Specific Learning Disorders (SLD). Finally, the third study is aimed to investigate and assess emotional experiences in students with a SLD, in particular Developmental Dyslexia (DD), in relation to learning a foreign language, such as English. In this regard, the Includi KIT has been created thanks to a funded project (Interreg-Italy Switzerland), aimed to support the social inclusion and improvement of the quality of life of students with DD in secondary school. The project was aimed at promoting the learning of the English language with teaching methodologies designed according to the MIND model, an approach that highlights the attitudes and strengths of students with dyslexia

Effects of vertical ground motions on the dynamic response of URM structures: Comparative shake-table tests

This paper discusses the results of an experimental study aimed at evaluating the influence of the vertical ground motion component on the seismic performance of unreinforced brick-masonry buildings. The research was motivated by post-earthquake observations of significant structural damage in the vicinity of the fault, where horizontal and vertical ground motions are often strong and synchronized. Vertical accelerations can fluctuate gravity loads, which control the in-plane lateral load capacity of masonry piers and affect the out-of-plane overturning stability of thin walls. Such phenomena seem not to be sufficiently explained in existing literature, while experimental evidence is undoubtedly missing. Here, the damage potential of vertical accelerations was investigated through a series of multidirectional shake-table tests on full-scale structures under simulated near-source ground motions of increasing intensity. The experiments comprised three nominally identical building specimens subjected to the principal horizontal component alone, the horizontal component combined with the vertical one, and the full three-component ground motion. The buildings included structural/nonstructural elements (e.g., gables, chimneys, and parapets) sensitive to gravity load variations due to their low axial loads. Two different sets of three-component earthquake records were employed to assess the effects of both tectonic and induced seismicity scenarios. Overall, the vertical earthquake motion did not cause appreciable differences in the behavior of the buildings. Any influence on the strength and peak response of structural/nonstructural walls was marginal and non-systematic. Data and observations from these experiments add substantially to our understanding of the vertical acceleration effects on masonry structures

A deep learning mixed-data type approach for the classification of FHR signals

The Cardiotocography (CTG) is a widely diffused monitoring practice, used in Ob-Gyn Clinic to assess the fetal well-being through the analysis of the Fetal Heart Rate (FHR) and the Uterine contraction signals. Due to the complex dynamics regulating the Fetal Heart Rate, a reliable visual interpretation of the signal is almost impossible and results in significant subjective inter and intra-observer variability. Also, the introduction of few parameters obtained from computer analysis did not solve the problem of a robust antenatal diagnosis. Hence, during the last decade, computer aided diagnosis systems, based on artificial intelligence (AI) machine learning techniques have been developed to assist medical decisions. The present work proposes a hybrid approach based on a neural architecture that receives heterogeneous data in input (a set of quantitative parameters and images) for classifying healthy and pathological fetuses. The quantitative regressors, which are known to represent different aspects of the correct development of the fetus, and thus are related to the fetal healthy status, are combined with features implicitly extracted from various representations of the FHR signal (images), in order to improve the classification performance. This is achieved by setting a neural model with two connected branches, consisting respectively of a Multi-Layer Perceptron (MLP) and a Convolutional Neural Network (CNN). The neural architecture was trained on a huge and balanced set of clinical data (14.000 CTG tracings, 7000 healthy and 7000 pathological) recorded during ambulatory non stress tests at the University Hospital Federico II, Napoli, Italy. After hyperparameters tuning and training, the neural network proposed has reached an overall accuracy of 80.1%, which is a promising result, as it has been obtained on a huge dataset