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Saturation and exceedance: the problem of space in schellingian aesthetics and naturphilosophie
Get PDFLa presente tesi vuole analizzare il problema dello spazio all'interno della produzione del filosofo tedesco Friedrich Wilhelm Joseph von Schelling, con una particolare attenzione al ruolo giocato da questo elemento nel rapporto tra estetica e Naturphilosophie. Lo spazio risulta essere una reazione nella riflessione schellinghiana all'impossibilità di fondare su base trascendentale una filosofia della storia. Pertanto, gli elementi che abbiamo analizzato sono la figura della rovina e del paesaggio nella prima produzione del filosofo; il problema delle cose in sé in rapporto all'eredità di Immanuel Kant, relativamente al realismo, alla cosmogenesi e alla libertà di Dio; l'evoluzione del concetto di χώρα in tutta la produzione di Schelling, in relazione al problema del male; la figura del Weltbaumeister, origine metaforica della concezione dell'architettura come musica congelata nella Filosofia dell'arteThis thesis aims to analyse the problem of space within the production of the German philosopher Friedrich Wilhelm Joseph von Schelling, with a particular focus on the role played by this element in the relationship between aesthetics and Naturphilosophie. Space turns out to be a reaction in Schellingian reflection to the impossibility of founding a philosophy of history on a transcendental basis. Thus, the elements we have analysed are the element of ruin and landscape in the philosopher's early production; the problem of things in themselves in relation to Immanuel Kant's legacy, in respect to cosmogenesis and the freedom of God; the evolution of the concept of χώρα throughout Schelling's production, in relation to the problem of evil; the figure of the Weltbaumeister, the metaphorical origin of the conception of architecture as frozen music in the Philosophy of Ar
Application of acoustic metamaterials in biomedical and audio fields
Get PDFIn recent decades, noise has become increasingly present in people’s daily lives. Acoustic absorption is a fundamental concept when addressing noise control and is defined as the dissipation of acoustic energy associated with an emission. Nowadays, traditional porous and fibrous materials are the most used sound-absorbing materials, thanks to their cost-effectiveness and ease of manufacture. However, they do not provide good sound absorption at low frequencies, require maintenance, and may, in some cases, pose a risk due to deterioration, making them unsuitable in critical contexts.
In recent years, acoustic metamaterials (AMM) entered the discussion of sound absorption. AMM are innovative structures whose acoustic properties depend on the geometry rather than the materials they are made. This allows them to overcome the limitations of traditional materials and achieve optimal performance at low frequencies through compact structures.
This thesis aims to develop a robust method through analytical models, numerical simulations, 3D prototyping, and experimental measurements for the design of a specific class of AMM consisting of resonant elements: Quarter-Wavelength Resonator (QWR) and Helmholtz resonator (HR) have been used to design innovative solutions in two different contexts. The first involves the development of a passive sound absorber to reduce reverberation time and sound pressure levels within a hospital room. The second entails using AMM for unwanted noise control in loudspeakers and resonance reduction in audio systems. The results demonstrate how the application of acoustic metamaterials may serve as a solid alternative to traditional materials in various fields, adapting to stringent requirements. The thesis serves as a starting point for designing AMMs, providing theoretical insights and practical considerations for their physical realization.Negli ultimi decenni, il rumore è diventato sempre più presente nella vita quotidiana delle persone.
L'assorbimento acustico è un concetto fondamentale quando si affronta il tema del controllo del rumore, ed è definito come la dissipazione dell'energia acustica associata ad un'emissione.
Ad oggi, i materiali fonoassorbenti tradizionali sono i più largamente utilizzati per il loro basso costo e la facilità di realizzazione. Tuttavia, risultano carenti nell'assorbimento in bassa frequenza, richiedono manutenzione, possono, in alcuni casi, comportare rischi dovuti al deterioramento, rendendoli inadatti in contesti critici.
Negli ultimi anni, i metamateriali acustici (AMM) sono entrati al centro del dibattito dell’assorbimento, grazie alle loro proprietà acustiche che dipendono dalla geometria e non dal materiale da cui sono costituti. Questa caratteristica consente di superare le limitazioni dei materiali tradizionali, e ottenere performance in bassa frequenza attraverso strutture compatte.
Questa tesi ha come obiettivo lo sviluppo di un metodo solido attraverso lo studio dei modelli analitici, la modellazione numerica, la prototipazione 3D e le misure sperimentali per il design e la progettazione di una specifica classe di metamateriali formati da elementi risonanti: risonatori a quarto di lunghezza d'onda (QWR) e risonatori di Helmholtz (HR) sono utilizzati al fine di progettare soluzioni innovative in due contesti differenti. Il primo è lo sviluppo di un fonoassorbente passivo per la riduzione del tempo di riverberazione e dei livelli di pressione sonora all’interno di una stanza ospedaliera. Il secondo coinvolge l'uso di metamateriali acustici per il controllo del rumore indesiderato negli altoparlanti e la riduzione delle risonanze nei sistemi audio.
I risultati presentati dimostrano come l'applicazione di AMM possa rappresentare una valida alternativa ai materiali tradizionali negli ambiti più disparati, adattandosi a requisiti stringenti.
La tesi rappresenta un punto di partenza per il design di metamateriali acustici, fornendo approfondimenti teorici e considerazioni pratiche per la loro realizzazione fisica
Neglected genomic elements in overlooked taxonomic groups: diversity, evolution, and genomic impact of transposable elements in bivalve molluscs
Get PDFTransposable elements (TEs) are intriguing features found in all eukaryotic genomes, capable of replicating independently within the host cell and spreading throughout the genome. They exhibit high diversity across various eukaryotic clades and even among closely related species. While traditionally overlooked, advancements in long-read sequencing technologies have revitalized their study. However, their distribution, evolutionary trajectories, and biological consequences remain still poorly understood in non-model species. Bivalves (Class: Bivalvia), an ancient and diversified clade of filter-feeding molluscs, represent one of such overlooked taxonomic group. This dissertation makes a first attempt to addresses this gap by exploring the distribution, evolution, and genomic impacts of TEs across the clade. After generating a novel long reads-based genome assembly for the Manila clam Ruditapes philippinarum, I utilized a wide sampling of bivalve genomes to study the distribution and evolution of LINEs, SINEs, and DDE/D DNA transposons across their diversity. Bivalves were found to host a highly diversified TE complement compared to other molluscs, with multiple bivalve-specific amplifications likely associated with their diversification. Then I characterized the genomic impacts of TEs and related Structural Variants (SVs) among the economically important oysters. Here, I found that up to 14% of the oyster genome exhibits structural differences between haplotypes in terms of insertions and deletions. TEs and SVs were also found to be significant contributors to population differentiation in the Estuarine oyster Crassostrea ariakensis, potentially providing substrates for local adaptations to varying ocean salinity and temperatures. As a secondary outcome of these projects, I significantly increased the availability of high-quality TE resources for bivalves by depositing hundreds of novel sequences in freely available databases. The post-genomics era presents an unparalleled opportunity for scientists to understand genome composition and evolution and this dissertation might help further research into characterizing transposons and their effects in other non-model species
Attitude and trajectory control system design for the emergency maneuver of a unmanned helicopter
Get PDFThe constant growth in the Unmanned Aerial Systems industrial sector, and the perspective of new applications in various, operational scenarios pose a challenge in the development of more performing and safe systems. In this context, crucial importance will be the development of systems with higher emergency management capabilities and enhanced control performance. The main objectives of this thesis are 1) the development of the automatic autorotation maneuver for a small-scale helicopter, and 2) the implementation of a nonlinear dynamic controller, allowing precise reference attitude and velocity trackiing. The design of a suitable maneuver has been conducted by dividing the maneuver into its two fundamental phases and analyzing the key variables to be considered and controlled. In particular, all the possible steady descent conditions were calculated with a trim algorithm, and a suitable flare profile was adopted and optimized. A PID-based control architecture has been adopted to follow the nominal autorotation maneuver in a closed loop. Several simulations have been considered to test the maneuver for a wide range of different initial conditions. Also, a nonlinear dynamic inversion controller made of an inner loop for attitude stabilization and an outer loop for velocity control has been designed. The attitude control systems has been derived by inverting a medium-order helicopter rotational dynamics model, while for the velocity controller, a simpler translational dynamics system has been developed. To ensure adequate control performance, an extended Kalman filter allowing the estimation of the inflow ratio, has been developed and implemented. An extensive simulation campaign has been conducted in order to validate the controller in different flight maneuvers, including the autorotation
Anatomical biomarkers of body composition in oncological population: application and development of artificial intelligences
Get PDFIn the Era of precision medicine and big medical data sharing, it is necessary to solve the work-flow of digital radiological big data in a productive and effective way. In particular, nowadays, it is possible to extract information “hidden” in digital images, in order to create diagnostic algorithms helping clinicians to set up more personalized therapies, which are in particular targets of modern oncological medicine. Digital images generated by the patient have a “texture” structure that is not visible but encrypted; it is “hidden” because it cannot be recognized by sight alone. Thanks to artificial intelligence, pre- and post-processing software and generation of mathematical calculation algorithms, we could perform a classification based on non-visible data contained in radiological images. Being able to calculate the volume of tissue body composition could lead to creating clasterized classes of patients inserted in standard morphological reference tables, based on human anatomy distinguished by gender and age, and maybe in future also by race. Furthermore, the branch of “morpho-radiology" is a useful modality to solve problems regarding personalized therapies, which is particularly needed in the oncological field. Actually oncological therapies are no longer based on generic drugs but on target personalized therapy. The lack of gender and age therapies table could be filled thanks to morpho-radiology data analysis application
Meaningful insights: explainability techniques for black-box models on tabular data
Get PDFArtificial Intelligence (AI) and Machine Learning (ML) are novel data analysis techniques providing very accurate prediction results. They are widely adopted in a variety of industries to improve efficiency and decision-making, but they are also being used to develop intelligent systems. Their success grounds upon complex mathematical models, whose decisions and rationale are usually difficult to comprehend for human users to the point of being dubbed as black-boxes. This is particularly relevant in sensitive and highly regulated domains.
To mitigate and possibly solve this issue, the Explainable AI (XAI) field became prominent in recent years. XAI consists of models and techniques to enable understanding of the intricated patterns discovered by black-box models.
In this thesis, we consider model-agnostic XAI techniques, which can be applied to Tabular data, with a particular focus on the Credit Scoring domain. Special attention is dedicated to the LIME framework, for which we propose several modifications to the vanilla algorithm, in particular: a pair of complementary Stability Indices that accurately measure LIME stability, and the OptiLIME policy which helps the practitioner finding the proper balance among explanations' stability and reliability. We subsequently put forward GLEAMS a model-agnostic surrogate interpretable model which requires to be trained only once, while providing both Local and Global explanations of the black-box model. GLEAMS produces feature attributions and what-if scenarios, from both dataset and model perspective. Eventually, we argue that synthetic data are an emerging trend in AI, being more and more used to train complex models instead of original data. To be able to explain the outcomes of such models, we must guarantee that synthetic data are reliable enough to be able to translate their explanations to real-world individuals. To this end we propose DAISYnt, a suite of tests to measure synthetic tabular data quality and privacy
MR in vivo tractography for the reconstruction of cranial nerves course
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The aim of my Ph.D. was to implement a diffusion tensor tractography (DTT) pipeline to reconstruct cranial nerve I (olfactory) to study COVID-19 patients, and anterior optic pathway (AOP, including optic nerve, chiasm, and optic tract) to study patients with sellar/parasellar tumors, and with Leber’s Hereditary Optic Neuropathy (LHON).
Methods
We recruited 23 patients with olfactory dysfunction after COVID-19 infection (mean age 37±14 years, 12 females); 27 patients with sellar/parasellar tumors displacing the optic chiasm eligible for endonasal endoscopic surgery (mean age 53. ±16.4 years, 13 female) and 6 LHON patients (mutation 11778/MT-ND4, mean age 24.9±15.7 years). Sex- and age-matched healthy control were also recruited.
In LHON patients, optical coherence tomography (OCT) was performed. Acquisitions were performed on a clinical high field 3-T MRI scanner, using a multi-shell HARDI (High Angular Resolution Diffusion Imaging) sequence (b-values 0-300-1000-2000 s/mm2, 64 maximum gradient directions, 2mm3 isotropic voxel). DTT was performed with a multi-tissue spherical deconvolution approach and mean diffusivity (MD) DTT metrics were compared with healthy controls using an unpaired t-test. Correlations of DTT metrics with clinical data were sought by regression analysis.
Results
In all 23 hypo/anosmic patients with previous COVID-19 infection the CN I was successfully reconstructed with no DTT metrics alterations, thus suggesting the pathogenetic role of central olfactory cortical system dysfunction.
In all 27 patients with sellar/parasellar tumors the AOP was reconstructed, and in 11/13 (84.7%) undergoing endonasal endoscopic surgery the anatomical fidelity of the reconstruction was confirmed; a significant decrease in MD within the chiasma (p<0.0001) was also found.
In LHON patients a reduction of MD in the AOP was significantly associated with OCT parameters (p=0.036).
Conclusions
Multi-shell HARDI diffusion-weighted MRI followed by multi-tissue spherical deconvolution for the DTT reconstruction of the CN I and AOP has been implemented, and its utility demonstrated in clinical practice
Nanocellulose films activated with essential oils for active packaging applications
Get PDFThe study focused on the analysis of the state of the art of active packaging and on the development of an innovative active packaging system for food application based on the use of nanocellulose matrix embedded with essential oils. The solubility and diffusivity of thyme, cinnamon and oregano essential oils in three nanocellulose films, endowed with different carboxymethylation degree, were analysed. The antimicrobial and antioxidant activity of those films was also analyzed. Firstly, the activity against model pathogenic bacteria was tested and the minimum inhibitory concentration of each oil was determined (0.37 – 0.68 mg/mg of matrix). This initial validation was then followed by experimental settings aimed at testing the system directly on clamshell type packed raspberries. It was observed that thyme and oregano essential oils were more effective in maintaining firmness and reduce weight loss than cinnamon essential oil or controls, through 12 days storage at 1ºC. From the results obtained, it is possible to conclude that the dispersion of thyme and oregano essential oils in nanocellulose matrix is a promising technology to improve shelf-life of raspberries or other fresh fruits
New perspectives on A.I. in sentencing. Human decision-making between risk assessment tools and protection of humans rights.
Get PDFThe aim of this thesis is to investigate a field that until a few years ago was foreign to and distant from the penal system. The purpose of this undertaking is to account for the role that technology could plays in the Italian Criminal Law system. More specifically, this thesis attempts to scrutinize a very intricate phase of adjudication. After deciding on the type of an individual's liability, a judge must decide on the severity of the penalty. This type of decision implies a prognostic assessment that looks to the future. It is precisely in this field and in prognostic assessments that, as has already been anticipated in the United, instruments and processes are inserted in the pre-trial but also in the decision-making phase. In this contribution, we attempt to describe the current state of this field, trying, as a matter of method, to select the most relevant or most used tools. Using comparative and qualitative methods, the uses of some of these instruments in the supranational legal system are analyzed.
Focusing attention on the Italian system, an attempt was made to investigate the nature of the element of an individual's ‘social dangerousness’ (pericolosità sociale) and capacity to commit offences, types of assessments that are fundamental in our system because they are part of various types of decisions, including the choice of the best sanctioning treatment. It was decided to turn our attention to this latter field because it is believed that the judge does not always have the time, the means and the ability to assess all the elements of a subject and identify the best 'individualizing' treatment in order to fully realize the function of Article 27, paragraph 3 of the Constitution
Numerical modeling and experimental validation of the recrystallization behaviour in the extrusion of 6XXX aluminum alloys
Get PDFThe microstructure of 6XXX aluminum alloys deeply affects mechanical, crash, corrosion and aesthetic properties of extruded profiles. Unfortunately, grain structure evolution during manufacturing processes is a complex phenomenon because several process and material parameters such as alloy chemical composition, temperature, extrusion speed, tools geometries, quenching and thermal treatment parameters affect the grain evolution during the manufacturing process. The aim of the present PhD thesis was the analysis of the recrystallization kinetics during the hot extrusion of 6XXX aluminum alloys and the development of reliable recrystallization models to be used in FEM codes for the microstructure prediction at a die design stage. Experimental activities have been carried out in order to acquire data for the recrystallization models development, validation and also to investigate the effect of process parameters and die design on the microstructure of the final component. The experimental campaign reported in this thesis involved the extrusion of AA6063, AA6060 and AA6082 profiles with different process parameters in order to provide a reliable amount of data for the models validation. A particular focus was made to investigate the PCG defect evolution during the extrusion of medium-strength alloys such as AA6082. Several die designs and process conditions were analysed in order to understand the influence of each of them on the recrystallization behaviour of the investigated alloy. From the numerical point of view, innovative models for the microstructure prediction were developed and validated over the extrusion of industrial-scale profiles with complex geometries, showing a good matching in terms of the grain size and surface recrystallization prediction. The achieved results suggest the reliability of the developed models and their application in the industrial field for process and material properties optimization at a die-design stage