Tesi di Dottorato
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Item Studio delle tecnologie di localizzazione acustica subacquea e sviluppo di tecniche per la riduzione dell'errore di posizione(Università della Calabria, 2023-02-08) Aiello, Rosario; Conte, Enrico; Bruno, FabioItem Innovative Techniques to Support the Surveying and the Exploration of Underwater Sites by Scientific and Recreational Divers(Università della Calabria, 2021-05-14) Mangeruga, Marino; Crupi, Felice; Casavola, Alessandro; Bruno, Fabio; Pupo, FrancescoIn the submerged environment divers often suffer from low visibility conditions that make difficult the orientation within an underwater site. At present, there is a lack of technologies and tools supporting the divers to better orientate themselves in the underwater environment and to simplify their comprehension of the context. The research aims to design and develop innovative solutions to support divers, both recreative and technical/scientific ones, through a novel system for underwater navigation and exploration, providing them with underwater geo-localization, contextualized information, augmented reality (AR) contents and recommendation about the optimal path to follow during the dive. A first aspect on which the research work focused is the Underwater Image Enhancement. This study has led to the development of a software tool to enhance underwater images with well-known methods at the SoA. A benchmark of these well-known methods has been produced and some guidelines to evaluate the underwater image enhancement methods have been formulated. The effort of this part of the research has been to guide the community towards the definition of a more effective and objective methodology for the evaluation of underwater image enhancement methods. Another aspect of the research concerned the Underwater Navigation and Underwater AR (UWAR). A software for underwater tablets, namely Divy, has been designed and developed to support divers’ navigation and exploration. It enables the divers to access different features such as the visualization of a map of the underwater site that allows them to know their position within the submerged site, the possibility to acquire geo-localized data, the visualization of additional information about specific points of interest and the communication with the surface operators through an underwater messaging system. On this basis, the UWAR concept applied in Underwater Cultural Heritage sites has been designed and developed as well, consisting of an augmented visualization representing a hypothetical 3D reconstruction of the archaeological remains as they appeared in the past. The geo-localization is provided by an acoustic localization system, but this kind of technology suffers from a low update rate, and cannot be employed alone for the AR purpose. To improve the performance of the UWAR and provide the users with a smooth AR visualization, a hybrid technique that merges data from an acoustic localization system with data coming from a visual inertial-odometry framework has been conceived and developed to deliver positioning information with a higher update rate with respect to the acoustic system alone. In particular, given the low update rate of the acoustic system, a strategy has been implemented aimed to fill the gaps between two consecutive acoustic positioning data. User testing has been conducted to assess the effectiveness and potential of the developed UWAR technologies. Finally, an innovative approach to dive planning based on an original underwater pathfinding algorithm has been conceived. It computes the best 3D path to follow during the dive in order to maximise the number of Points of Interest (POIs) visited, while taking into account the safety limitations strictly related to scuba diving. This approach considers the morphology of the 3D space in which the dive takes place to compute the best path, taking into account the diving decompression limits and avoiding the obstacles through the analysis of a 3D map of the site.Item Development of new bio-materials and technologies for the green regeneration of RAP(Università della Calabria, 2021) Loise, Valeria; Cerra, Maria Carmela; Oliverio Rossi, CesareIl presente lavoro di ricerca ha avuto come scopo lo sviluppo di nuovi rigeneranti green per il fresato d’asfalto, noto anche come reclaimed asphalt pavement (RAP). Questa ricerca nasce dalla necessità di aumentare l’uso del RAP nelle pavimentazioni stradali. L’uso del RAP ha sia un impatto economico positivo, infatti non è necessario usare inerti e bitume fresco, ma soprattutto ha un alto un impatto in termini di ecosostenibilità, il RAP da rifiuto da smaltire diventa di fatto materia prima, implementando l’economia circolare e l’end waste. Infatti il riuso del fresato d’asfalto consentirebbe di non trattare più questo materiale come uno scarto, con tutti le relative problematiche ambientali derivabili, ma bensì come una risorsa. Inoltre sono state sviluppate ed implementate tecniche di indagine chimico-fisiche e nuove metodologie per determinare i meccanismi di azione di un rigenerante sulla struttura del bitume e distinguere in modo univoco un rigenerante da un semplice flussante. Tale tesi è stata la base scientifica che ha permesso di definire una norma europea e nazionale da seguire per le aziende che commercializzano rigeneranti bituminosi. Spesso infatti il fresato d’asfalto viene trattato con agenti che non modificano la struttura colloidale del bitume riportandola alla loro struttura originaria, ma che semplicemente hanno una mera attività flussante (abbassare la viscosità del sistema). Le “classiche” metodologie di indagine generalmente basate su parametri fisici-meccanici ed ingegneristici, non sono sufficienti per discriminare l’azione di un rigenerante da quella di un flussante. Tale approccio finora comunemente usato ha avuto un forte impatto sulla durata e qualità delle pavimentazioni stradali, effetto devastante dal punto di vista economico, sociale e soprattutto ambientale. The present research aimed to develop a procedure and methodologies that could uniquely distinguish between a fluxing agent and a rejuvenating agent. Recently, it has been realized that the reclaimed asphalt pavement (RAP) was a resource of considerable importance. In fact, it contains an appreciable amount of binder, which under certain conditions can be recycled for the construction of new pavements, thus reducing not only costs but also the use of raw materials. Therefore, this allows to consider the RAP more as a resource than a waste. Most of the time, the bitumen obtained from the RAP is treated with agents that have a mere flux function (lowering the viscosity of the system). These agents do not modify the colloidal structure of the bitumen. Therefore, they are not able to restore the structure of the aged bitumen to that of the neat bitumen. Furthermore, the investigation methodologies generally used to counter the regenerating effect of an additive are based on physical-mechanical and engineering parameters. These parameters are almost always insufficient to discriminate the action of a regenerant from that of a flux. For this reason, chemical-physical investigation techniques have been developed and implemented to determine the action mechanisms of a rejuvenator on the inner structure of the bitumen. In this way, it was possible to uniquely discriminate between a real rejuvenator and a fluxing agent. Finally, this thesis was the scientific basis that allowed the definition of a new European and National standard to be followed for companies that market bituminous regenerants.Item Approximate Query Answering over Incomplete and Inconsistent Databases(Università della Calabria, 2021-09-14) Fiorentino, Nicola; Molinaro, Cristian; Trubitsyna, IrinaItem Use of seismic metamaterials as innovative concept for the design of earthquake-resistant structures(Università della Calabria, 2022-04-01) Fiore, Stefania; Cipparrone, Gabriella; Garcea, Giovanni; Carbone, VincenzoLa progettazione di edi ci sismo-resistenti è nalizzata a proteggere gli edi ci dall'impatto dei terremoti che rappresentano ancora oggi uno degli eventi più pericolosi in quanto causano ingenti danni e perdita di vita umane. Le attuali strategie di protezione sismica si basano o su un dimensionamento strutturale tale da permettere all'edi cio di danneggiarsi durante il terremoto evitando in ogni caso il meccanismo di collasso oppure nella riduzione degli e etti del sisma mediante sistemi di isolamento alla base o ai dissipatori sismici. Una nuova opportunità per migliorare le prestazioni anti-sismiche degli edi ci è l'impiego di metamateriali sismici che permettano di ottenere un e etto di scudo alla propagazione delle onde sismiche. Questo e etto può essere ottenuto grazie a una architettura periodica che tipicamente caratterizza i metamateriali e anche grazie alla presenza di elementi localmente risonanti. In questo lavoro sono studiate le performance di una metafondazione, chiamata METACOMF, progettata per mitigare gli e etti del sisma alle frequenze più basse. In primo luogo è stato studiato lo stato dell'arte nel campo dei metamateriali sismici e gli strumenti teorici per la modellazione di essi. Sono state implementate procedure numeriche per lo studio della propagazione delle onde in sistemi periodici armonici e anarmonici. Sono state inoltre implementate analisi di risposta sismica locale del terreno in presenza di metamateriale e, in ne, è stata condotta una campagna di simulazioni di edi ci a telaio multipiano isolati con la metafondazione al ne di evidenziarne il funzionamento. Inoltre, per quanto concerne il rischio sismico per gli edi ci esistenti, è stata proposta una metodologia basata su approccio meccanico a nalizzata alla costruzione di curve di fragilità per la valutazione di vulnerabilità sismica degli edi ci in muratura Abstract The design of earthquake-resistant buildings is aimed to protect buildings from the impact of earthquakes which represent one of the most dangerous events and still cause signi cant damage and loss of human life today. The current seismic protection strategies are based either on structural sizing that allows damages in the building when an earthquake occurs, avoiding in any case, collapse mechanism yet or in reducing the e ects of the earthquake through base isolation systems or seismic dissipators. A new opportunity for increasing the anti-seismic performance of the buildings is represented by the use of seismic metamaterials which introduce a shield e ect against the seismic waves propagation. This is achieved through a periodic architecture, which is typical in metamaterials, and locally resonances elements. In this work, the performance of a metafondation, called METACOMF, designed to mitigate the e ects of the system at lower frequencies, is studied. Firstly, the state of the art in seismic metamaterials is given. Furthermore, the theoretical tools for modelling them are described. Then, numerical procedures developed to study wave propagation in harmonic and anharmonic periodic systems are described. The local seismic response analysis of the soil in the presence of a metamaterial is also studied. Then, an extensive campaign of simulations of multi-storey frame buildings isolated with metafondation is carried out in order to highlight their operating. Finally, regarding the seismic risk for existing buildings, a methodology is proposed to assess the seismic vulnerability of masonry buildings. This is based on a mechanical approach and aims to obtains fragility curves.Item Progettazione di circuiti a bassissima potenza e tensione per System on Chip energicamente autonomi(Università della Calabria, 2021-05-15) Fassio, Luigi; Crupi, Felice; Lanuzza, MarcoUltra-low power/voltage (ULP/ULV) circuits (both analog and digital blocks) have been gaining considerable interest from the scientific community in the last few years. The advent of the Internet of Things (IoT) era has also increased the interest of the market in ULP/ULV circuits addressed to energy-autonomous and extremely small-sized Systems-on-Chip (SoCs). Wireless sensor networks, biomedical implantable devices, wearable computing, ambient control intelligence, air quality monitoring, warehouse, and agriculture monitoring are just some of the fields that can benefit from ULP/ULV circuits. The design of ULP/ULV circuit blocks for energy-autonomous SoCs is a wide topic and needs some knowledge on several elements that can compose these SoCs. In this regard, this thesis first provides a general overview on energy-autonomous SoCs with a focus on available energy harvesting sources and energy storage solutions. The availability of on-chip energy harvesting/storage opens the route for the development of battery-less IoT sensor nodes and moves the challenge towards the design of ULP/ULV circuits that make the node working even with a small amount of available energy from harvesting. Among various key building blocks of SoCs, this thesis presents the design of voltage/current reference circuits to provide a precise and stable DC bias under a wide range of environmental conditions, a level shifter to interface blocks between different voltage domains, and comparators to interface the analog world with the digital one. More specifically, a low-area voltage reference circuit able to operate at supply voltage as low as 250 mV and 5.4 pW of power consumption at room temperature is first presented. The proposed circuit exploits a body biasing scheme to deal with the effect of voltage/temperature fluctuations and hence to ensure good accuracy of the generated output voltage, as demonstrated through measurements on a test chip fabricated in 180-nm CMOS technology. The design of a current reference circuit based on a voltage generator exploiting the structure used for the voltage reference is also presented and validated by means of silicon measurements on a 180-nm prototype. The proposed circuit properly works down to 0.6 V to generate a current in the nA range with only 4,000-μm2 area occupancy, while reaching high power efficiency as guaranteed by the pW-power consumption of the voltage generator sub-block. Then, the design of a global variation-aware voltage reference based on an on-chip process sensor is proposed with the aim of achieving low sensitivity to process variations and overall good accuracy against process-voltage-temperature (PVT) variations, while also ensuring ULP/ULV operation, i.e., minimum supply voltage of 200 mV and power consumption of only 3.2 pW at room temperature. Experimental results in 180-nm CMOS technology across corner wafers demonstrate the effectiveness of the proposed solution. In addition, the design of a robust level shifter able to convert input voltages from the subthreshold regime (around 100 mV) up to the nominal supply voltage (1.8 V) is presented. The proposed circuit is based on a self-biased low-voltage cascode current mirror topology that features diode-connected PMOS and NMOS transistors to drive the split-input inverting buffer used as output stage with high energy efficiency. Obtained measurement results in 180-nm CMOS technology and across corner wafers demonstrate good robustness and performance of the proposed level shifter as compared to prior art. Finally, the design of an ULP/ULV comparator is proposed by using the dynamic leakage suppression (DLS) logic family. In particular, two different topologies, i.e., a single-stage structure and a dual-stage architecture based on the combination of two single-stage comparator are presented and validated through silicon measurements on 180-nm test chips, which demonstrate a power consumption of few tens of pW. My research activity during PhD concerned the design of innovative ULP/ULV circuits and their validation through silicon measurements. First, a low-area voltage reference circuit able to operate at supply voltage as low as 250 mV and 5.4 pW of power consumption at room temperature was designed and fabricated in 180-nm CMOS technology. The proposed circuit exploits a body biasing scheme to deal with the effect of voltage/temperature fluctuations and hence to ensure good accuracy of the generated output voltage. A current reference circuit based on a voltage generator exploiting the structure used for the voltage reference was also designed and validated by means of silicon measurements on a 180-nm prototype. The proposed current reference properly works down to 0.6 V to generate a current in the nA range with only 4,000-μm2 area occupancy, while reaching high power efficiency as guaranteed by the pW-power consumption of the voltage generator sub-block. Then, the design of a global variation-aware voltage reference based on an on-chip process sensor was realized with the aim of achieving competitive sensitivity to process variations and and overall accuracy against process-voltage-temperature (PVT) variations, while also ensuring ULP/ULV operation (minimum supply voltage of 200 mV and power consumption of only 3.2pW at room temperature). Experimental results in 180-nm CMOS technology across corner wafers demonstrate the effectiveness of the proposed solution. The research activity was also addressed to interfacing blocks between different voltage domains in multiple-voltage systems. In this regard, a robust level shifter able to convert input voltages from the subthreshold regime (around 100 mV) up to the nominal supply voltage (1.8 V) was designed. The proposed circuit is based on a self-biased low-voltage cascode current mirror topology that features diode-connected PMOS and NMOS transistors to drive the split-input inverting buffer used as output stage with high energy efficiency. Obtained measurement results in 180-nm CMOS technology and across corner wafers demonstrate good robustness and performance of the proposed level shifter as compared to prior art. Finally, to interface the analog world with the digital one, an ULP/ULV comparator was designed by using the dynamic leakage suppression (DLS) logic family. Two different topologies, i.e., a single-stage structure and a dual-stage architecture based on the combination of two single-stage comparator were fabricated and validated through silicon measurements on 180-nm test chips, which demonstrated a power consumption of few tens of pW.Item Study characterization of modern 4h-sic power mosfetsF(Università della Calabria, 2021-05-05) Cosentino, Giuseppe; Crupi, FeliceItem Emering problems in influence propagation and maximization(Università della Calabria, 2021-05-10) Caliò, Antonio; Crupi, Felice; Tagarelli, AndreaIn the last two decades we witnessed the advent and the rapid growth of online social networks (OSNs). The impact of their pervasive diffusion on everyday life has been dramatic. In fact, social networks changed the way we interact with each other, the way we access information and the way companies engage with their audience or customers. A major consequence of the broad adoption and diffusion of social networks is the availability of an unprecedented amount of user data, which enables the opportunity for social and network scientists to investigate and observe many facets of human behaviors. Arguably, one of the most interesting facet is related to the notion of social influence. Following this observation, this research project is mainly centered around the concept of social influence, specifically its propagation and maximization. Therefore, the goal of this thesis is twofold. To begin with, we investigate the complexity of influence propagation in real-world contexts. This leads to the definition of a novel class of diffusion models. Such models represent an attempt to unify, under a well-defined framework, all the aspects that contribute to the inherent complexity of any influence propagation phenomena. Afterwards, we devote our attention to the influence maximization problem. To this purpose, we first provide a detailed characterization of social influence from a topological perspective. Specifically, we want to understand if and to what extent being a good spreader depends on being located into strategic regions of a network. Finally, we focus on the application of the influence maximization problem. In particular, we address a variant of the original problem, which is especially suitable for viral marketing scenarios. To this end, we propose two different diversity-sensitive targeted influence maximization problems. Both proposals share a common intent, which is assessing the benefit of embedding a notion of diversity into the process of the seeds identification. Nonetheless, diversity is considered from two different perspectives: (i) as a function of the topological properties of the nodes; (ii) as a function of some categorical data available on the node level.Item Drinking water supply modelling for advanced metering Infrastructures(Università della Calabria, 2021-09-27) Bonora, Marco Amos; Critelli, Salvatore; Maiolo, Mario; De Oliveira Sousa, Joaquim Josè; ;L’evoluzione della società umana e dei processi produttivi sta accrescendo il fabbisogno idrico mondiale. La risorsa idrica è distribuita in maniera disomogenea e sta subendo una progressiva riduzione a causa dei cambiamenti climatici in atto. La necessità di gestire con maggiore attenzione e di ottimizzare il Sistema idrico integrato rende necessario l’utilizzo di strumenti messi a disposizione da nuove tecnologie che devono collaborare in una gestione multidisciplinare ed integrata. Le attuali normative italiane ed europee sanciscono tale necessità, prescrivendo l’utilizzo di strumenti elettronici specifici per la progettazione e la creazione di database territoriali standardizzati e di facile accesso. L’obbiettivo del progetto di dottorato è lo sviluppo di modellistica idraulica a supporto dei processi gestionali delle reti di distribuzione idropotabile. La modellistica va ad integrarsi nel framework gestionale origAMI, che supporta la gestione operativa, economica e della Workflow Management, attraverso l’integrazione di software idraulico, strumenti previsionali e di Anomaly Detection. In questo lavoro sono state approfondite le azioni ed i criteri necessari alla costruzione dei modelli digitali delle reti di distribuzione, presentando diversi casi applicativi che hanno raggiunto diversi livelli di dettaglio e maturità. Sono approfondite le procedure di stima delle prestazioni mediante indici sintetici e misure surrogate, approfondendo concetti come l’affidabilità e la resilienza delle reti. È inoltre presentato un approccio metodologico che si integra nei modelli di progettazione ed ottimizzazione delle infrastrutture di trasporto della risorsa idrica. Tale approccio permette una modellazione più realistica dell’orografia reale introducendo la possibilità di imporre vincoli territoriali ed idraulici nella ricerca degli schemi progettuali. The human society and production processes evolution is increasing the world's water needs. The water resource is unevenly distributed and is undergoing a progressive reduction due to the ongoing climate changes. The need to more carefully manage and optimize the integrated water system makes it necessary to use tools made available by new technologies, which must collaborate in multidisciplinary and integrated management. Current Italian and European regulations underline this need, prescribing the use of specific electronic tools for the design and creation of standardized and easy-to-access territorial databases. The goal of the PhD project is the development of hydraulic modelling to support the management processes of drinking water distribution networks. The modelling is integrated into the origAMI management framework, which supports operational, economic and workflow management, through the integration of hydraulic software, forecasting and anomaly detection tools. In this work, the actions and criteria necessary for the construction of digital models of distribution networks have been studied in-depth, presenting various application cases that have reached different levels of detail and maturity. Performance estimation procedures are explored using synthetic indexes and surrogate measures, deepening concepts such as network reliability and resilience. The thesis presents a methodological approach integrated into the design and optimization models of water resource transport infrastructures. This approach allows more realistic modelling of the real orography by introducing the possibility of imposing territorial and hydraulic constraints in the search for design schemes.Item The quality of air transport service(Università della Calabria, 2021-03-25) Bellizzi, Maria Grazia; Conte, Enrico; Eboli, LauraThe socioeconomic development of a country necessarily relies on the improvement of all transport services. With the introduction of new technologies, transport industry has developed considerably in recent years, and as a consequence people habits and travel choices changed as well. In this context, air transport has a significant role, and it could be considered one of the most significant contributors to the advancement of modern society. Evaluating air transport service quality is important as it is for the other public transport systems. Airport facilities and services are the first experiences that a passenger receives upon arrival. For this reason, providing airport services characterized by high levels of quality is very important to make the travel more pleasant for the passengers, with the final objective to attract more users. Therefore, measuring the levels of airport services by evaluating passengers’ satisfaction with them is essential to understand the needs of customers. In the same way, with the airlines’ deregulation the number of airlines entered into the air transport industry significantly increased, causing a stronger competition. In this context, it is evident that provided service quality, as well as passengers’ satisfaction, play an important role also in the airlines marketing strategies. While literature regarding the evaluation of road and rail public transport service quality is well established from many years, literature concerning air transport service quality is relatively recent. A first substantial issue that emerges from the air transport related literature concerns the complexity of the various characteristics of the services, which can relate to the airport managing companies and to the airlines. For this reason, the major part of the studies treats separately these two groups of service. Specifically, the researchers analysed air transport services by distinguishing the concerning the services offered in the airports from the ones provided by the airlines. The aim of this thesis work is to give a contribution to the existing literature, by applying various techniques and models for analysing both airport and airlines’ service quality. As suggested by the literature, also in this work the airport services have been treated separately by the airlines’ services. In fact, two different data samples were analysed. Specifically, the International airport of Lamezia Terme (Italy) has been considered as case study for the airport services. Otherwise, data collected by an online survey conducted at the University of Calabria (Italy) became object of study for the airlines’ services analyses. Several tools have been tested and proposed. The obtained results could be considered not only as a research contribution, but also as starting point to help air transport managers and providers in choosing the effective strategy for providing services characterized by adequate levels of quality.