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Essays in Empirical Political Economics
Get PDFThis thesis takes two perspectives on political institutions. From the one side, it examines the long-run effects of institutions on cultural values. From the other side, I study strategic communication, and its determinants, of politicians, a pivotal actor inside those institutions.
The first chapter provides evidence for the legacy of feudalism - a set of labor coercion and migration restrictions -, on interpersonal distrust. I combining administrative data on the feudal system in the Prussian Empire (1816 – 1849) with the geo-localized survey data from the German Socio-Economic Panel (1980 – 2020). I show that areas with strong historical exposure to feudalism have lower levels of inter-personal trust today, by means of OLS- and mover specifications.
The second chapter builds a novel dataset that includes the Twitter handles of 18,000+ politicians and 61+ million tweets from 2008 – 2021 from all levels of government. I find substantial partisan differences in Twitter adoption, Twitter activity and audience engagement. I use established tools to measure ideological polarization to provide evidence that online-polarization follows similar trends to offline-polarization, at comparable magnitude and reaches unprecedented heights in 2018 and 2021. I develop a new tool to demonstrate a marked increase in affective polarization.
The third chapter tests whether politicians disseminate distortive messages when exposed to bad news. Specifically, I study the diffusion of misleading communication from pro-gun politicians in the aftermath of mass shootings. I exploit the random timing of mass shootings and analyze half a million tweets between 2010 – 2020 in an event-study design. I develop and apply state-of-the-art text analysis tools to show that pro- gun politicians seek to decrease the salience of the mass shooting through distraction and try to alter voters’ belief formation through misrepresenting the causes of the mass shootings
Learning from errors: Psychological, relational, and cultural aspects
Get PDFAlthough errors might foster learning, they can also be perceived as something to avoid if they are associated with negative consequences (e.g., receiving a bad grade or being mocked by classmates). Such adverse perceptions may trigger negative emotions and error-avoidance attitudes, limiting the possibility to use errors for learning. These students’ reactions may be influenced by relational and cultural aspects of errors that characterise the learning environment. Accordingly, the main aim of this research was to investigate whether relational and cultural characteristics associated with errors affect psychological mechanisms triggered by making mistakes. In the theoretical part, we described the role of errors in learning using an integrated multilevel (i.e., psychological, relational, and cultural levels of analysis) approach. Then, we presented three studies that analysed how cultural and relational error-related variables affect psychological aspects. The studies adopted a specific empirical methodology (i.e., qualitative, experimental, and correlational) and investigated different samples (i.e., teachers, primary school pupils and middle school students). Findings of study one (cultural level) highlighted errors acquire different meanings that are associated with different teachers’ error-handling strategies (e.g., supporting or penalising errors). Study two (relational level) demonstrated that teachers’ supportive error-handling strategies promote students’ perceptions of being in a positive error climate. Findings of study three (relational and psychological level) showed that positive error climate foster students’ adaptive reactions towards errors and learning outcomes. Overall, our findings indicated that different variables influence students’ learning from errors process and teachers play an important role in conveying specific meanings of errors during learning activities, dealing with students’ mistakes supportively, and establishing an error-friendly classroom environment
Evaluation of seismic losses of RC buildings: the case of the industrial areas after the 2012 Emilia Earthquake
Get PDFThe topic of seismic loss assessment not only incorporates many aspects of the earthquake engineering, but also entails social factors, public policies and business interests. Because of its multidisciplinary character, this process may be complex to challenge, and sound discouraging to neophytes. In this context, there is an increasing need of deriving simplified methodologies to streamline the process and provide tools for decision-makers and practitioners.
This dissertation investigates different possible applications both in the area of modelling of seismic losses, both in the analysis of observational seismic data.
Regarding the first topic, the PRESSAFE-disp method is proposed for the fast evaluation of the fragility curves of precast reinforced-concrete (RC) structures. Hence, a direct application of the method to the productive area of San Felice is studied to assess the number of collapses under a specific seismic scenario. In particular, with reference to the 2012 events, two large-scale stochastic models are outlined. The outcomes of the framework are promising, in good agreement with the observed damage scenario.
Furthermore, a simplified displacement-based methodology is outlined to estimate different loss performance metrics for the decision-making phase of the seismic retrofit of a single RC building. The aim is to evaluate the seismic performance of different retrofit options, for a comparative analysis of their effectiveness and the convenience.
Finally, a contribution to the analysis of the observational data is presented in the last part of the dissertation. A specific database of losses of precast RC buildings damaged by the 2012 Earthquake is created. A statistical analysis is performed, allowing deriving several consequence functions. The outcomes presented may be implemented in probabilistic seismic risk assessments to forecast the losses at the large scale. Furthermore, these may be adopted to establish retrofit policies to prevent and reduce the consequences of future earthquakes in industrial areas
Functional characterization of the gonococcal polyphosphate pseudo-capsule
Get PDFNeisseria gonorrhoeae is an exclusively human pathogen able to evade the host immune system through multiple mechanisms. Gonococci accumulate a large portion of phosphate moieties as polyphosphate (polyP) on the exterior of their cells, however its function has not been yet clarified. Although its polyanionic nature has suggested that it may form a protective shield on the cell surface, its role has remained controversial.
Taking advantage of a recombinant His-tagged polyP-binding protein, the presence of a polyP pseudo-capsule in gonococcus was demonstrated. Interestingly, the polyP shield was found to be strain specific. To investigate its functional role in host immune evasion, such as resistance to serum bactericidal activity, phagocytosis and antimicrobial peptides, the enzymes involved in polyP metabolism were genetically deleted, generating mutants with altered polyP external production. To this regard, mutants not expressing polyP on their surface, became sensitive to complement-mediated killing in presence of normal human serum. Conversely, naturally serum sensitive strains did not display polyP pseudo-capsule and could reverse their phenotype in the presence of exogenous polyP. Resistance to phagocytic killing was assessed by using differentiated HL60, a validated cell model for gonococcus-neutrophils interaction. Results exhibited a significant increase in viability of strains shielded with polyP in comparison to those lacking it on their surface. Interestingly, the addition of exogenous polyP restored bacterial survival. Finally, the presence of polyP pseudo-capsule was critical also in the protection from antibacterial activity of cationic antimicrobial peptide, like the cathelicidin LL-37. Indeed, results evidenced that the minimum bactericidal concentration was significantly lower in strains lacking polyP than in those harboring the pseudo-capsule, a condition that overturned after the complementation with exogenous polyP.
Taken together, data presented have suggested an essential role of polyP pseudo-capsule in the gonococcal pathogenesis, paving the way to a new perspective on gonococcal biology and new treatments
Framing Active Labour Market Policy
Get PDFContrary to passive benefits, ALMPs are intended to reskill individuals and require their ‘active’ participation to facilitate reinstatement into the labour market. In this thesis, I investigate how ALMPs do not remain a mere symbolic political message but become something which significantly helps individuals and benefits society. In particular, the thesis tries to raise the understanding of the economic and social effects of the law reflected in: i) the promotion of targeted reforms, ii) the evolution of labour market instruments embraced or disregarded by lawmakers, and iii) the existence of an identity in the labour market which has a social dynamic.
First, I study the effect of participating in a European active labour market policy aimed at fighting youth inactivity; namely, the recent Youth Guarantee. Then, I use text analysis to illustrate how the progressive emergence of an ALMP approach in the law corresponds, over time, to the rising success of policymakers in fighting unemployment and preventing the NEET emergency. Finally, I exploit experimental methods to demonstrate that occupationally inactive individuals may deviate from standard social norms, such as working, and therefore may avoid participating in job training, due to negative peer pressure from their sub-cultural group of reference.
In conclusion, this thesis sheds new light on the economic, institutional, and social implications of an active labour market policy approach by showing that measures to fight occupational inactivity can be effective insofar as we consider their framing; namely, their target, their institutional framework, and their societal role
Guidelines for the Management of Cultural Heritage using 3D models for the insertion of heterogeneous data
Get PDFThe Management of Cultural Heritage (MCH) is a very complex operation aimed at protecting the physical integrity of CH assets, while promoting their historical value and development of tourism industry. In recent years, the use of digital technologies has become an essential part of the MCH delicate process, but the use of 3D models is still limited to few academic research to date. Furthermore, very few supra-national standard guidelines regulating their use are available to date and the operator who decides to use a 3D model as a basis for management is faced with the scarcity and fragmentation of standards and guidelines.
The aim of the PhD research is to develop guidelines to produce 3D models for MCH, with the purpose to efficiently entry, store and manage digital data. The here provided guidelines investigate every aspect of the process leading from data acquisition to cataloguing and archiving, processing and creation of a simplified information system for the management. In order to elaborate guidelines that could be suitable for as many typologies of CH as possible an international approach was chosen, developing the thesis in joint supervision under the University of Bologna and the Universitat Politècnica de València, and by applying the state-of-the-art technologies of acquisition, processing and use of 3D models to a variety of case studies.
The investigation, by highlighting the problems inherent to the MCH, made it possible to identify the main open issues that need to be explored in future lines of research, such as the application of standards to a large number of cultural assets; the automatic classification of raw data; the processing of collected data for the creation of relations, strategies and methods for the classification, integration and optimisation of heterogeneous data.La Gestione del Patrimonio Culturale (GPC) è un’operazione molto complessa mirata alla conservazione dell’integrità fisica dei Beni Culturali e alla contemporanea divulgazione dei valori storici e fruizione del Patrimonio. Nel corso degli ultimi anni l’applicazione delle tecnologie digitali ai Beni Culturali è diventata una parte imprescindibile nella GPC, ma l’uso dei modelli 3D per la gestione è finora limitato ad alcune ricerche e applicazioni accademiche. Inoltre, ad oggi sono pochi gli standard con carattere sovranazionale che guidano gli Enti nel procedimento di creazione e uso dei modelli tridimensionali per la GPC. Il gestore che decide di utilizzare un modello 3D come base per la gestione si scontra con la scarsezza e la frammentarietà di standard e indicazioni in tale ambito.
L’obiettivo della tesi è quello di elaborare linee guida per la produzione di modelli 3D per un’efficace gestione, inserimento e conservazione dei dati. Tali linee guida indagano ogni aspetto del processo che porta dall’acquisizione del dato, alla sua catalogazione e archiviazione, al suo processamento e alla creazione di un sistema informativo semplificato per la gestione. Per arrivare all’elaborazione di linee guida che si adattino a più tipologie possibili di Beni Culturali è stato scelto un approccio interdisciplinare e internazionale, sviluppando la tesi in regime di cotutela tra l’Università di Bologna e l’Universitat Politècnica de València, e applicando lo stato dell'arte delle tecnologie di acquisizione, elaborazione e utilizzo dei modelli 3D ad una varietà di casi studio.
Il percorso di ricerca ha permesso di individuare le principali questioni aperte che devono essere approfondite in futuro, come l’applicazione di standard a un alto numero di Beni Culturali; la ricerca di sistemi per la classificazione automatica dei dati grezzi; l’elaborazione dei dati raccolti per la creazione di relazioni, strategie e metodi per la classificazione, l’integrazione e l’ottimizzazione di dati eterogenei.La Gestión del Patrimonio Cultural (GPC) es una operación muy compleja cuyo objetivo es la conservación de la integridad física del Patrimonio y la difusión de los valores históricos. En los últimos años, la aplicación de las tecnologías digitales se ha convertido en una parte indispensable de la GPC, pero el uso de modelos 3D para la gestión se limita a algunas investigaciones y aplicaciones académicas. Además, hasta la fecha existen pocas normas y directrices de carácter supranacional que guíen a las instituciones en el proceso de creación y uso de modelos 3D para la GPC.
El objetivo de la tesis es desarrollar directrices para la producción de modelos 3D del Patrimonio Cultural con el fin de gestionar, introducir y preservar eficazmente los datos. Estas directrices investigan todos los aspectos del proceso que va desde la adquisición de datos, pasando por su catalogación y archivo, hasta su tratamiento y la creación de un sistema de información simplificado para su gestión. Se ha optado por un enfoque interdisciplinar e internacional con el fin de elaborar directrices que se adapten al mayor número posible de tipos de Bienes Culturales, desarrollando la tesis en el marco de un acuerdo de cotutela entre la Universidad de Bolonia y la Universitat Politècnica de València, y aplicando las tecnologías más avanzadas para la adquisición, procesamiento y uso de modelos 3D a una variedad de casos de estudio.
La investigación ha permitido identificar las principales cuestiones abiertas que se deben explorar en futuras líneas de investigación, como la aplicación de estándares a un gran número de Bienes Culturales; la búsqueda de sistemas para la clasificación automática de los datos brutos; el tratamiento de los datos recogidos para la creación de relaciones, estrategias y métodos de clasificación, integración y optimización de datos heterogéneos
Innovative Hybrid Approaches for Vehicle Routing Problems
Get PDFThis thesis deals with the efficient resolution of Vehicle Routing Problems (VRPs).
The first chapter faces the archetype of all VRPs: the Capacitated Vehicle Routing Problem (CVRP). Despite having being introduced more than 60 years ago, it still remains an extremely challenging problem. In this chapter I design a Fast Iterated-Local-Search Localized Optimization algorithm for the CVRP, shortened to FILO. The simplicity of the CVRP definition allowed me to experiment with advanced local search acceleration and pruning techniques that have eventually became the core optimization engine of FILO. FILO experimentally shown to be extremely scalable and able to solve very large scale instances of the CVRP in a fraction of the computing time compared to existing state-of-the-art methods, still obtaining competitive solutions in terms of their quality.
The second chapter deals with an extension of the CVRP called the Extended Single Truck and Trailer Vehicle Routing Problem, or simply XSTTRP. The XSTTRP models a broad class of VRPs in which a single vehicle, composed of a truck and a detachable trailer, has to serve a set of customers with accessibility constraints making some of them not reachable by using the entire vehicle. This problem moves towards VRPs including more realistic constraints and it models scenarios such as parcel deliveries in crowded city centers or rural areas, where maneuvering a large vehicle is forbidden or dangerous. The XSTTRP generalizes several well known VRPs such as the Multiple Depot VRP and the Location Routing Problem. For its solution I developed an hybrid metaheuristic which combines a fast heuristic optimization with a polishing phase based on the resolution of a limited set partitioning problem. Finally, the thesis includes a final chapter aimed at guiding the computational evaluation of new approaches to VRPs proposed by the machine learning community
Algorithms and Systems for IoT and Edge Computing
Get PDFThe idea of distributing the signal processing along the path that starts with the acquisition and ends with the final application has given light to the Internet of Things and Edge Computing, which have demonstrated several advantages in terms of scalability, costs, and reliability. In this dissertation, we focus on designing and implementing algorithms and systems that allow performing a complex task on devices with limited resources.
Firstly, we assess the trade-off between compression and anomaly detection from both a theoretical and a practical point of view. Information theory provides the rate-distortion analysis that is extended to consider how information content is processed for detection purposes. Considering an actual Structural Health Monitoring application, two corner cases are analysed: detection in high distortion based on a feature extraction method and detection with low distortion based on Principal Component Analysis.
Secondly, we focus on streaming methods for Subspace Analysis. In this context, we revise and study state-of-the-art methods to target devices with limited computational resources. We also consider a real case of deployment of an algorithm for streaming Principal Component Analysis for signal compression in a Structural Health Monitoring application, discussing the trade-off between the possible implementation strategies.
Finally, we focus on an alternative compression framework suited for low-end devices that is Compressed Sensing. We propose a different decoding approach that splits the recovery problem into two stages and effectively adopts a deep neural network and basic linear algebra to reconstruct biomedical signals. This novel approach outperforms the state-of-the-art in terms of quality of reconstruction and requires lower computational resources
Participation of wind power plants in power system stability
Get PDFThe integration of large amounts of wind power in power systems coupled with the increasing replacement of large conventional synchronous generators by wind power plants (WPPs) presents a considerable impact on power system stability. This is partly because most WPPs, particularly variable speed wind turbine (VSWT) types, are connected to the network via power converters which decouples their output power from the grid frequency, and this results in considerable loss of system inertia. Also, VSWTs are in general operated at the maximum power point tracking, which makes them unable to increase their output power beyond the maximum power level for long-term frequency support. For this reason, it is important to develop control techniques that enable WPPs to participate in power system stability improvement. In literature, several studies have been reported on the frequency control provision of a wind turbines (WT), mainly classified into two categories: inertial response (IR) and primary frequency response (PFR).
This work investigates the IR and PFR capabilities of VSWTs; the control schemes are presented in detail and the required energy buffers also discussed. For the IR, the electrostatic energy stored in the dc-link capacitors and the kinetic energy reserve of the WT rotors are utilised. The PFR service is guaranteed by a deloading scheme that reserves a portion of the maximum available power of the WT. Also, the possibility of providing both IR and PFR using external energy storage systems, in this work supercapacitors and battery energy storage system, has been considered. For each support scheme analysed, this work provides a comprehensive survey.
This dissertation further proposes two coordinated control strategies that exploits the full potential of VSWTs to participate in power system frequency response enhancement and small-signal stability support.
All the control schemes are developed and simulation studies performed on DIgSILENT PowerFactory simulation environment
Joints and innovative components for automotive applications
Get PDFThe research activities described in this thesis were focused on two main topics: the study of shaft-hub joint performance, with particular regard to interference-fitted and adhesively bonded connection, and the fatigue characterization of additively processed metal alloys. The research on interference-fitted shaft-hub joints dealt with some studies in the field of fretting fatigue. Rotating bending fatigue tests were performed on different materials by not conventional specimens to determine the fatigue properties of interference-fitted joints and to investigate the fretting fatigue phenomenon, which led to novel and original results. In adhesively bonded and interference-fitted shaft-hub connections (called hybrid joints) the synergic effect of anaerobic adhesive and interference has the capability of improving the joint strength. However, the adhesive contribution depends on several factors. Therefore, its behavior was investigated for different coupling pressure, coupling procedure, operating temperature and joint design. The study on additively manufactured metal alloy deals with rotating banding fatigue tests. AlSi10Mg and Maraging Stainless Steel CX were involved in the campaign for their wide applicability in Automotive. Build direction, heat and surface treatments were considered as input parameters. Fatigue results were interpreted by statistical method and microscopy analyses in order to determine the effectiveness and the beneficial or detrimental effects of the considered factors. Fracture mode and microstructure were investigated by fractographic and micrographic analyse