Methods and good practice guidelines for human joint kinematics estimation through magnetic and inertial wearable sensors

According to the World Health Organization, the ability to move is recognized as a key factor for the human well-being. From the wearable Magnetic and Inertial Measurement Units (MIMUs) signals it is possible to extract several digital mobility outcomes including the joint kinematics. To this end, it is first required to estimate the orientation of the MIMUs by means of a sensor fusion algorithm (SFA). After that, the relative orientation is computed and then decomposed to obtain the joint angles. However, the MIMUs do not provide a direct output of the physical quantity of interest which can be only determined after an ad hoc processing of their signals. It follows that the joint angle accuracy mostly depends on multiple factors. The first one is the magnitude of the MIMU measurements errors and up to date there is still a lack of methods for their characterization. A second crucial factor is the choice of the SFA to use. Despite the abundance of formulations in the literature, no-well established conclusions about their accuracy have been reached yet. The last factor is the biomechanical model used to compute the joint angles. In this context, unconstrained methods offer a simple way to decompose the relative orientation using the Euler angles but suffer from the inherent issues related to the SFA. In contrast, constrained approaches aim at increasing the robustness of the estimates by adopting models in which an objective function is minimized through the definition of physiological constraints. This thesis proposed the methods to accurately estimate the human joint kinematics starting from the MIMU signals. Three main contributions were provided. The first consisted in the design of a comprehensive battery of tests to completely characterize the sources of errors affecting the quality of the measurements. These tests rely on simple hypotheses based on the sensor working principles and do not require expensive equipment. Nine parameters were defined to quantify the signal accuracy improvements (if any) of 24 MIMUs before and after the refinement of their calibration coefficients. The second contribution was focused on the SFAs. Ten among the most popular SFAs were compared under different experimental conditions including different MIMU models and rotation rate magnitudes. To perform a “fair” comparison it was necessary to set the optimal parameter values for each SFA. The most important finding was that all the errors fall within a range from 3.8 deg to 7.1 deg thus making it impossible to draw any conclusions about the best performing SFA since no statistically significant differences were found. In addition, the orientation accuracy was heavily influenced by the experimental variables. After that, a novel method was designed to estimate the suboptimal parameter values of a given SFA without relying on any orientation reference. The maximum difference between the errors obtained using optimal and suboptimal parameter values amounted to 3.7 deg and to 0.6 deg on average. The last contribution consisted in the design of an unconstrained and a constrained methods for estimating the joint kinematics without considering the magnetometer to avoid the ferromagnetic disturbances. The unconstrained method was employed in a telerehabilitation platform in which the joint angles were estimated in real time. Errors collected during the execution of a full-body protocol were lower than 5 deg (considered the acceptability threshold). However, this method may be inaccurate after few minutes since no solutions can be taken to mitigate the drift error. To overcome this limitation a constrained method was developed based on a robotic model of the upper limb to set appropriate constraints. Errors relative to a continuous robot motion for twenty minutes were lower than 3 deg at most suggesting the feasibility of employing these solutions in the rehabilitation programs to properly plan the treatment and to accurately evaluate the outcomes

Real time investigation of solvent swelling induced β phase formation in poly(9-9-dioctyl fluorene)

The physical processes leading to solvent swelling induced glassy- to beta-phase transition in poly(9,9-dioctylfluorene) thin films are investigated in real time by photoluminescence and confocal spectroscopy. We show that the vapor solvent swelling induced beta-phase formation takes place in much shorter times (few minutes) than the one usually employed in literature (several hours). Moreover, we show that the swelling is faster if the solvent mainly interacts with the PF8 aromatic rings (toluene) than with the octyl chains (isooctane). On the contrary, no swelling is caused by nonsolvents such as n-butylic alcohol. Finally, we demonstrate that the beta-phase formation is due to athermal (simultaneous) nucleation followed by diffusion controlled one dimensional crystallization

MODELLAZIONE FISICA DEL FENOMENO DI EROSIONE INTERNA

Fra le cause di collasso di pendii e rilevati in terra soggetti a filtrazione vi è l’erosione interna di particelle, fenomeno evolutivo che può manifestarsi inizialmente in modo diffuso, per poi localizzarsi in canali di flusso, oppure innescarsi lungo discontinuità preesistenti. Questo contributo presenta lo sviluppo di un’attrezzatura di laboratorio per l’osservazione e la misura del fenomeno di erosione interna e formazione di canali di flusso alla piccola e media scala. Consente di analizzare l’influenza del percorso di flusso e di una pressione di confinamento, di condurre prove in regime di filtrazione confinata o non confinata, e di ricostruire modelli fisici in scala ridotta di pendii e rilevati, per strati di qualunque inclinazione

Computationally Efficient Innovative Techniques for the Design-Oriented Simulation of Free-Running and Driven Microwave Oscillators

Analysis techniques for injection-locked oscillators/amplifiers (ILO) can be broadly divided into two classes. To the first class belong methods with a strong and rigorous theoretical basis, that can be applied to rather general circuits/systems but which are very cumbersome and/or time-consuming to apply. To the second class belong methods which are very simple and fast to apply, but either lack of validity/accuracy or are applicable only to very simple or particular cases. In this thesis, a novel method is proposed which aims at combining the rigorousness and broad applicability characterizing the first class of analysis techniques above cited with the simplicity and computational efficiency of the second class. The method relies in the combination of perturbation-refined techniques with a fundamental frequency system approach in the dynamical complex envelope domain. This permits to derive an approximate, but first-order exact, differential model of the phase-locked system useable for the steady-state, transient and stability analysis of ILOs belonging to the rather broad (and rigorously identified) class of nonlinear oscillators considered. The hybrid (analytical-numerical) nature of the formulation developed is suited for coping with all ILO design steps, from initial dimensioning (exploiting, e.g., the simplified semi-analytical expressions stemming from a low-level injection operation assumption) to accurate prediction (and fine-tuning, if required) of critical performances under high-injection signal operation. The proposed application examples, covering realistically modeled low- and high-order ILOs of both reflection and transmission type, illustrate the importance of having at one's disposal a simulation/design tool fully accounting for the deviation observed, appreciable for instance in the locking bandwidth of high-frequency circuits with respect to the simplified treatments usually applied, for a quick arrangement, in ILO design optimization procedures.Analysis techniques for injection-locked oscillators/amplifiers (ILO) can be broadly divided into two classes. To the first class belong methods with a strong and rigorous theoretical basis, that can be applied to rather general circuits/systems but which are very cumbersome and/or time-consuming to apply. To the second class belong methods which are very simple and fast to apply, but either lack of validity/accuracy or are applicable only to very simple or particular cases. In this thesis, a novel method is proposed which aims at combining the rigorousness and broad applicability characterizing the first class of analysis techniques above cited with the simplicity and computational efficiency of the second class. The method relies in the combination of perturbation-refined techniques with a fundamental frequency system approach in the dynamical complex envelope domain. This permits to derive an approximate, but first-order exact, differential model of the phase-locked system useable for the steady-state, transient and stability analysis of ILOs belonging to the rather broad (and rigorously identified) class of nonlinear oscillators considered. The hybrid (analytical-numerical) nature of the formulation developed is suited for coping with all ILO design steps, from initial dimensioning (exploiting, e.g., the simplified semi-analytical expressions stemming from a low-level injection operation assumption) to accurate prediction (and fine-tuning, if required) of critical performances under high-injection signal operation. The proposed application examples, covering realistically modeled low- and high-order ILOs of both reflection and transmission type, illustrate the importance of having at one's disposal a simulation/design tool fully accounting for the deviation observed, appreciable for instance in the locking bandwidth of high-frequency circuits with respect to the simplified treatments usually applied, for a quick arrangement, in ILO design optimization procedures

L'azienda siderurgica. Profili gestionali e di bilancio. "Il caso Lucchini s.p.a."

Fin dai tempi più remoti l’uomo ha sempre utilizzato e studiato nuove tecniche per lo sfruttamento dei metalli come il ferro, l’oro, il rame e l’argento. Ciò detto, occorre precisare che, a causa delle proprie caratteristiche, il ferro puro, non ha alcun uso pratico. Per essere utilizzato tecnologicamente, questo necessita di essere messo in lega con il carbonio, al fine di produrre acciaio o ghisa, oppure, laddove si aggiungano anche altri metalli, è possibile ottenere una serie infinita di leghe ferrose. Nel corso degli anni si sono apprese ed affinate soprattutto tecniche attinenti alla lavorazione del ferro ed alla creazione di proprie leghe, fra i quali l’acciaio, che costituiscono la componente primaria di oltre il 60% di ciò che comunemente ogni giorno utilizziamo. Su questi propositi, possiamo apprezzare l’importanza della siderurgia per lo sviluppo economico e sociale dell'umanità. In effetti tale sviluppo è stato sempre condizionato dal livello di avanzamento delle industrie metallurgiche di produzione e di elaborazione. Si pensi a tal proposito che la potenza militare degli Ittiti si fondò sull'utilizzazione di armi in materiale ferroso; i Romani conoscevano l'acciaio e svilupparono miniere e industrie metallurgiche; gli Inglesi, nel periodo del loro maggiore splendore economico, avevano a Swansea le industrie metallurgiche più progredite. A pensarci bene, l’importanza della siderurgia, per alcuni aspetti, può apparire anche banale: i metalli come il ferro sono sempre stati utilizzati dall’uomo per molteplici impieghi (nelle produzioni industriali, nelle lavorazioni artigianali, nell’oggettistica ecc..) ma, in realtà, senza la siderurgia il ferro non potrebbe essere impiegato in alcun tipo di produzione. Per queste ragioni, la siderurgia è ancora oggi, come fu nel passato, alla base di qualsiasi sviluppo industriale. Uno solo è il materiale di base per molteplici applicazioni: il ferro, la cui scelta è dettata principalmente da ragioni economiche e le cui proprietà possono essere variate entro ampi limiti con aggiunte di elementi di lega e con particolari lavorazioni. Si tende però a modificare la struttura delle industrie siderurgiche, con conseguenti sconvolgimenti economici e sociali. La necessità di approvvigionamento di materie prime che aveva imposto l'ubicazione di queste industrie vicino alle miniere, ora ne consiglia lo spostamento in località di facile accesso via mare. Il progresso tecnologico porta, inoltre, all'integrazione del processo produttivo, anche se per ora solamente a settori. Si sta arrivando ad un’organizzazione razionale del ciclo completo, anche per limitare i danni ecologici provocati dagli scarti, cercando d'impostarlo sull'esempio dei grandi cicli naturali. L'industria metallurgica basata sul recupero da rottami dev'essere considerata oggi parte integrante del ciclo completo di produzione-elaborazione-utilizzazione-recupero. Nonostante l’importanza di questo settore, oggi si assiste ad una grave crisi della siderurgia italiana ma, prima ancora, della siderurgia europea. Si avverte la necessità di imminenti e rilevanti interventi, in grado di rilanciare un compartimento di estrema importanza per l’economia generale e ciò, sia per il volume degli investimenti che è capace di attrarre sia per gli interessi sociali coinvolti. Il presente lavoro ha per oggetto lo studio del comparto siderurgico partendo dalle sue origini, per arrivare ad analizzare le caratteristiche, le criticità e l’andamento dell’attuale produzione di acciaio. Al termine di tale analisi, il lavoro si focalizzerà sul caso pratico relativo alla crisi economica della società “Lucchini s.p.a. in Amministrazione Straordinaria”, importante acciaieria locale che coinvolge il futuro di un’intera città e di quasi 4 mila famiglie

Applicability of the Sustainable Structural Design (SSD) method at urban/regional/national level

The alarming data on world climatic change, resources impoverishment and increasing human diseases caused by environmental pollution has encouraged the modern society to feel committed in reducing the environmental issues and to adopt a sustainable approach to every human activity. Sustainability is an ambitious challenge for Europe development and European policy is addressed in investing massive resources for achieving sustainable goals. Construction is one of the most impactful industrial sector because of the high consequences it generates on the society, the environment and the economy. Indeed, building constructions involve social aspects, as safety and comfort, economic aspects, as construction investments and maintenance, and environmental aspects, as energy consumption and emissions. The present study derives from the development of a building design method, called Sustainable Structural Design (SSD) Methodology. This methodology is based on a multi-performance and life cycle-oriented approach, which includes the environmental aspects, related to energy consumption and CO2 emissions, in structural design, performed with a simplified Performance Based Assessment (sPBA) methodology, in order to obtain a global assessment parameter in monetary terms. Moreover, the study derives from the awareness about the structural condition of the European building stock, which is old and, in some cases, far from the structural safety required by the European codes. Thus, a simply applicable methodology, allowing the identification of the territorial areas which need a more urgent intervention is necessary. The application of the SSD methodology at territorial level could allow the inclusion of the main aspects of sustainability, identifying the areas which an intervention could reduce the energy consumptions, the CO2 emissions and the structural losses of the included buildings. Thus, this report aims at studying the applicability of the SSD methodology at territorial level, considering three different area dimensions, as countries, regions and cities, and identifying the right approach for each of them. Consequently, an SSD methodology at territorial level is developed and illustrated.JRC.E.4-Safety and Security of Building

Orientation Estimation Through Magneto-Inertial Sensor Fusion: A Heuristic Approach for Suboptimal Parameters Tuning

Magneto-Inertial Measurement Units (MIMUs) are a valid alternative tool to optical stereophotogrammetry in human motion analysis. The orientation of a MIMU may be estimated by using sensor fusion algorithms. Such algorithms require input parameters that are usually set using a trial-and-error (or grid-search ) approach to find the optimal values. However, using trial-and-error requires a known reference orientation, a circumstance rarely occurring in real-life applications. In this article, we present a way to suboptimally set input parameters, by exploiting the assumption that two MIMUs rigidly connected are expected to show no orientation difference during motion. This approach was validated by applying it to the popular complementary filter by Madgwick et al. and tested on 18 experimental conditions including three commercial products, three angular rates, and two dimensionality motion conditions. Two main findings were observed: i) the selection of the optimal parameter value strongly depends on the specific experimental conditions considered, ii) in 15 out of 18 conditions the errors obtained using the proposed approach and the trial-and-error were coincident, while in the other cases the maximum discrepancy amounted to 2.5 deg and less than 1.5 deg on average

Hic Sunt Leones! The role of national identity on aggressiveness between national football teams

This paper examines the role of national identity in explaining on field aggression during soccer competitions between national teams. In particular, this paper empirically investigates whether differences in macro identity markers such as: the economy, religion, education, governance and power between nation-states influence football players’ aggressiveness across a range of international FIFA competitions. We analyse the finals of the FIFA World, Confederations and Under 20’s World Cups as well as the Olympic tournaments from 1994 to 2012, resulting in 1088 individual matches. Our aggression focus is derived from both the (i) weighted measure of penalties (red and yellow cards) and; (ii) the count of sanctions (fouls) issued during a game as a proxy measure for on field aggression. We generate national identity factors from a set of macro level variables in order to estimate the size of national differences, from which we determine the impact that national identity has on the emergence of on field aggression between rival countries. Our results show that these national identity factors are significant predictors of aggression, while the match specific variables seem to be of less importance. Interestingly, our results also show that these aggression factors disappear once we include referee fixed effects, indicating that while national differences are played out on the football pitch the referees are effective at controlling the aggression

Innovative approach for the in vitro research on biomedical scaffolds designed and customized with CAD-CAM technology

Studies on biomaterials involve assays aimed to assess the interactions between the biomaterial and the cells seeded on its surface. However, the morphology of biomaterials is heterogeneous and it could be tricky to standardize the results among different biomaterials and the classic plastic plates. In this light, we decided to create, by means of computer-aided design (CAD) technology, a standardized sample model, with equal shape and sizes, able to fit into a classic shape of a 96-wells tissue culture plate (TCP)