1731 research outputs found
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Quantifying Urban Social Well-Being using Mobile Phone Data
No full textToday, more than half of the world population is living in cities, which has been doubled in the last 50 years. The reason for that attraction is not only economical, but also security, education, and health. While people migrate to cities to reach improved life conditions, several issues raised by the increasing population. Recent studies have shown the importance of ethnic and cultural diversity of urban population to encourage tolerance, and to foster creativity and economic growth. Facing the urban growth challenges, we search for the key formulas to obtain healthy societies under the light of new type of data sources, such as mobile phone usage datasets. To this end, first we build up a tool to identify security related incidents from a country, which unstable political conditions held. Then we trace the formulas of healthy societies with examples from both developing and developed countries. We check the individual interaction and communication pattern effects (bridging and bonding) for the existence of social capital. Then we analyze aggregated ethnic diversity, and associate segregation scores with census data, and different ethnic groups preferences to move in the city, existence of any pattern for specific nation. The current studies are mainly hypothetical, with the absence of large scale real life data sources. This thesis aims to provide an insight to policy makers for building healthy societies, for the benefit of urban well-being
Automatic Creation of Evocative Witty Expressions
No full textIn linguistic creativity, the pragmatic effects of the message are often as important as its aesthetic properties. The productions of creative humans are often based both on a generic intent (such as amusing) and a specific one, for example to attract the attention of the audience, to provoke thoughts, to get the message home, to influence other people and change their attitudes and beliefs. In computational linguistic creativity, however, these pragmatic effects are rarely accounted for. Most works in automated linguistic creativity are limited to the production of a syntactically and semantically correct output that is also pleasing, but in applied scenarios it would be important to validate also the effectiveness of the output. This thesis aims at demonstrating that automatic systems can create productions that are attractive, pleasant and memorable, based on variations of well-known expressions, using the optimal innovation hypothesis as a frame of reference.
In particular, these witty expressions can be used for evoking a given concept, improving its memorability, or for other pragmatic goals
Penetration Mechanics of Plant Roots and Related Inspired Robots
Full text linkThe ability of plant roots to penetrate soils is affected by several stimuli from the surrounding medium such as mechanical stresses and chemical changes. Therefore, roots have developed multiple responses to the several outer stimuli. Since plant roots have to face very complex problems to grow deeply into the ground, they are remarkable examples of problem-solving behaviour and adaptation to the outer constraints. The adaptation strategies of a natural root are not yet completely known and understood with exhaustive explanations. For this reason, mathematical models and experimental techniques applied to biological phenomena can perform a key role in translating the Nature adaptive solutions into engineering applications. The aim of this thesis is to provide further insights in understanding biological phenomena for the development of new technologies inspired by the adaptive ability of plant roots. Accordingly, both theoretical and experimental explanations to the adaptive behaviour of plant roots are proposed. The mathematical modelling is based on a modified version of the extended West, Brown and Enquist universal law, considering the root growth as an inclusion problem. The proposed equation has as a particular case a growth equation exploiting an approach similar to Lockhart taking into account the soil impedance. The influence of mechanical stresses and nutrient availability on the root growth are studied. The solutions of the analytical models are compared with experimental data collected in real and artificial soils. In addition, the theories and hypotheses of the root ability to grow in the apical region through nanoindentation, wettability, and photoelasticity are investigated. The first technique provided insights for the possible role and function at both different tissues levels and distances from the tip in the root movement and penetration during the growth. The investigation of root tissue properties revealed that the penetration and adaptation strategies adopted by plant roots could be enhanced by a combination of soft and stiff tissues. The second technique aimed to highlight the wettability of the apical zone and root hairs for the acquisition of water and nutrients. Finally, photoelastic experiments provided a non-invasive and in situ observation of plant roots growth and, by exploiting the fringe multiplication, a set up for the study of plant roots growing in edible gelatine is proposed
Theoretical analysis and experimental investigation of contact fatigue and surface damage in prealloyed and diffusion bonded sintered steels
Full text linkThe contact fatigue and surface damage of prealloyed (Fe-0.85Mo, Fe-1.5Mo) and diffusion bonded (Ni-free, low-Ni, high-Ni) powder metallurgy (PM) steels were investigated. Materials subjected to contact stress fail due to the nucleation of subsurface cracks (contact fatigue cracks), nucleation of brittle surface cracks, and surface plastic deformation. The occurrence of these contact damage mechanisms was predicted using theoretical models, which were developed by assuming that crack nucleation is preceded either by local plastic deformation (contact fatigue and surface plastic deformation) or local brittleness (brittle surface cracks ) of the metallic matrix. With reference to the mean yield strength of the matrix (mean approach) or the yield strength of soft constituents (local approach), the models predict the theoretical resistance of materials to the formation of damage mechanisms. The models were then verified using experimental evidence from lubricated rolling-sliding contact tests.
In addition, the effect of compact density and microstructures of materials on the resistance to contact damage mechanisms was investigated. Density and microstructure were modified by varying green density, alloying elements, sintering temperature and time, and applying strengthening treatments: carburizing and shot peening on prealloyed (homogenous microstructure) and carburizing, sinterhardening and through hardening on diffusion bonded (heterogeneous microstructure) steels.
The theoretical resistance to subsurface and surface crack nucleation in prealloyed materials was predicted using the mean approach since the microstructure is homogeneous. But the local approach is applied for diffusion bonded materials (Ni-free and low-Ni); exceptionally, the mean approach was applied for some homogeneous microstructure of Ni-free material sintered at a prolonged time. However, the models have a limitation in predicting the contact damage mechanisms in a high-Ni material. This issue may require further investigation to modify the model.
Shot peening provides higher resistance to the nucleation of surface cracks. High compact density, high sintering temperature and time, and sinterhardening improve the resistance to contact damage mechanisms for Ni-free and low-Ni materials
Understanding human behavior from personal mobile and online data: personal data disclosure, mobility in public-health, recommendations of social links
No full textPersonal data, generated and continuously collected by modern devices and online services, open new perspectives in human behavior understanding. They can characterize human behavior at a very fine and precise resolution, covering a huge variety of daily life, from communication and individual mobility to complex social phenomena and economic behaviors. While from the research point of view the collection of behavioral data has never been so cost-effective and unobtrusive, at the same time, from the applicative point of view, numerous applications supporting users’ needs have leveraged on the massive availability of personal data and the insights produced by human behavior comprehension. Nevertheless, this scenario also raises unprecedented risks affecting users’ privacy.
The high relevance and effectiveness of digital footprints in capturing and describing human behaviors establishes the basis of this work. In this thesis, we use behavioral personal data, collected online or from mobile phones, to understand human behavior with the aim to support users in their everyday lives, investigating aspects that can be turned into personal or societal value in real application scenarios. In our work, we approached our research problems in a comprehensive way by leveraging on real personal data continuously observed in daily-life.
In particular, in this dissertation we investigate three main problems. Firstly, we understand the attitudes of individuals towards personal mobile data disclosure by using both individual characteristics and dynamic behaviors related to communication and mobility, captured from mobile phones. Secondly, we predict the future health status of individuals, in terms of flu-like and cold symptoms, on the basis of a systematic characterization of their mobility behaviors derived from their mobile phones. Finally, we infer the formation of future links in individuals’ social circle on the basis of multiple information sources related to explicit and implicit relationships that users form.
The main insights resulting from our investigation can support a set of use cases, targeting individual and collective applications. Our findings, in terms of behaviors affecting the personal propensity towards data disclosure, can support a new generation of privacy-tools providing personalized feedback to users when tuning their sharing settings. The insights from our following study can provide individuals with personalized feedback about their health status and support decision-makers towards the adoption of preventive measures for public-health. Finally, our findings in terms of new social link predictions can provide users with more accurate recommendations in social networking applications
A methodology for the design and security assessment of mobile identity management: applications to real-world scenarios
No full textThe widespread use of digital identities in our everyday life, along with the release of sensitive data on many online transactions, calls for Identity Management (IdM) solutions that are secure, privacy-aware, and compatible with new technologies, such as mobile and cloud computing. While there exist many secure IdM solutions for web applications, their adaptation in the mobile context is a new and open challenge. The majority of mobile IdM solutions currently used are based on proprietary protocols and their security analysis lacks standardization in the structure, definitions of notions and entities, and specific considerations to identify the attack surface that turns out to be quite different from well understood web scenarios. This makes a comparison among different solutions very complex or, in the worst case, misleading. To overcome these difficulties, we propose a novel methodology for the design and security assessment of mobile IdM solutions. The design space is characterized by the identification of: (i) national (e.g., SPID for Italy) and European (e.g., eIDAS) laws, regulations and guideline principles that are particularly relevant to digital identity and privacy; (ii) a list of security and usability requirements that are related to IdM solutions (e.g., single sign-on and multi-factor authentication); (iii) a set of implementation mechanisms that are relevant to authentication and authorization on mobile devices and simplify the satisfaction of the requirements in (ii). All the designed solutions use as blueprint a reference model resulting from a rational reconstruction of the mobile IdM solution adopted by Facebook and a study of the OAuth specification for native applications. Regarding the security assessment, our methodology supports
analyses ranging from semi-formal to formal. For the former, an IdM designer is required to specify the security relevant parts of the protocol using message sequence charts, the threat model and the security properties; these offer the starting point to argue whether the protocol satisfies the specified properties. For the latter, an IdM designer is required to specify the protocol flow, the attacker properties and the security properties using one of the available formal specification languages for the description of cryptographic and browser-based protocols, and verify the security property violations using an automated tool for protocol analysis. To validate our approach, we applied it to four different real-world scenarios that represent different functional and usability requirements:
1. TreC: a multi-factor authentication solution with a single sign-on experience for mobile e-Health applications.
2. Smart Community: a secure delegated access solution in the context of smart-cities.
3. DigiMat-Lab (Istituto Poligrafico e Zecca dello Stato): a mobile multi-factor authentication solution that uses as second factor the Italian electronic identity card.
4. FIDES: an IdM solution that combines federation and cross-border aspects in the context of the European single digital market.
The custom designs obtained by applying our methodology in the four scenarios above show the generality and effectiveness of our methodology.
When using formal analysis, we have re-used the specification language and tools developed in the context of the AVANTSSAR EU-founded project
Ecologia dell'architettura. Verso una nuova antropologia filosofica dell'abitare
Full text linkIl presente studio rappresenta un contributo di ricerca all’elaborazione di una teoria ecologica dell’architettura. L’idea di “ecologia” che verrà sviluppata in esso è filosofica e sistemica, perché esprime una visione integrale, biologica e relazionale dell’essere umano, oltre che dell’architettura
The influence of the inclusion of biological knowledge in statistical methods to integrate multi-omics data
Full text linkUnderstanding the relationships among biomolecules and how these relationships change between healthy and disease states is an important question in modern biology and medicine. The advances in high-throughput techniques has led to the explosion of biological data available for analysis, allowing researchers to investigate multiple molecular layers (i.e. omics data) together. The classical statistical methods could not address the challenges of combining multiple data types, leading to the development of ad hoc methodologies, which however depend on several factors. Among those, it is important to consider whether “prior knowledge” on the inter-omics relationships is available for integration. To address this issue, we thus focused on different approaches to perform three-omics integration: supervised (prior knowledge is available), unsupervised and semi-supervised. With the supervised integration of DNA methylation, gene expression and protein levels from adipocytes we observed coordinated significant changes across the three omics in the last phase of adipogenesis. However, in most cases, interactions between different molecular layers are complex and unknown: we explored unsupervised integration methods, showing that their results are influenced by method choice, pre-processing, number of integrated data types and experimental design. The strength of the inter-omics signal and the presence of noise are also proven as relevant factors. Since the inclusion of prior knowledge can highlight the former while decreasing the influence of the latter, we proposed a semi-supervised approach, showing that the inclusion of knowledge about inter-omics interactions increases the accuracy of unsupervised methods when solving the problem of sample classification
Seismic risk mitigation of "special risk" process plants through enhanced concepts and subplant hybrid simulation
Full text linkThis doctoral thesis focuses on the seismic risk mitigation of âspecial riskâ industrial facilities, like chemical, petrochemical and process industries. It is known that the impact of natural hazards, such as earthquakes, on this type of structures may cause significant accidents leading to severe consequences to both the environment and human lives; see, among others, Lanzano et al., (2015) and Krausmann et. al (2010). In particular, the most critical components in a petrochemical plant are fluid-filled storage tanks; they can experience severe damages and trigger cascading effects in neighbouring tanks due to large vibrations induced by strong earthquakes, indeed. In order to reduce these tank vibrations, an innovative type of foundation based on metamaterial concepts is investigated. Metamaterials are generally regarded as manmade structures that exhibit unusual responses not readily observed in natural materials. Due to their exceptional properties and advancements in recent years, metamaterials have entered the field of seismic engineering, and therefore, offer a novel approach to design seismic shields. As a result, an encouraging and practicable strategy for the seismic protection of liquid storage tanks is presented and validated.
On the other hand, the outcomes of this research study also aim to improve seismic risk assessment of âspecial riskâ facilities mainly through experimental dynamic analysis. In view of performing a dynamic analysis of these complex components, necessary for the global seismic risk assessment procedure, online hybrid (numerical/physical) dynamic substructuring simulations have shown their potential in enabling realistic dynamic analysis of almost any type of nonlinear structural system. At the same time, owing to faster and more accurate testing equipment, a number of different offline experimental substructuring methods, operating both in time and frequency domains, have been employed in mechanical engineering to examine dynamic substructure coupling. The scope of the study is the exploitation of different Experimental Dynamic Substructuring (EDS) methods in a complementary way to expedite a hybrid experiment/numerical simulation and, consequently, the comprehensive dynamic analysis. From this perspective, after a comparative uncertainty propagation analysis of three EDS algorithms, a new Composite-EDS (C-EDS) method is proposed and numerically validated. To the best of the authorâs knowledge, this research study presents the first algorithm used to fuse both online and
offline algorithms into a unique simulator with significant advantages in terms of dynamic analysis and seismic risk assessment of industrial plants.
Finally, the research activity is supported by the results from different experimental testing campaigns with the main purpose to investigate the complex behaviour of critical industrial components, such as Tee joints and Bolted Flanged Joints (BFJs), with particular regard to the leakage phenomena resistance. In this respect, a reliable an innovative model capable of predicting the leakage force for a generic BFJ, including the interaction between axial and shear load, is proposed and validated
Letteratura italiana e «scienze occulte» tra fin de siècle e primo Novecento
Full text linkLa tesi ha titolo Letteratura italiana e «scienze occulte» tra fin de siècle e primo Novecento. Essa si divide in tre parti: la prima è un'introduzione teorica (stato dell'arte) e storico-culturale sull'Esoterismo occidentale (le sue correnti, la sua diffusione in Italia e in Europa); una seconda, è riservata allo studio dei poeti italiani affascinati dalle scienze occulte (e.g. spiritismo, occultismo, Società teosofica e antroposofia); la terza analizza gli influssi esoterici nella prosa italiana otto/novecentesca. Tra la prima e la seconda parte è inserita una panoramica su 'letteratura ed esoterismo' nell'Europa moderna e contemporanea. Nel commento e nello studio degli irrazionalismi otto/novecenteschi e del loro influsso sulla letteratura è stato dato rilievo particolare a gruppi, cenacoli e associazioni nate per effetto del -- o comunque dedicatesi attentamente al -- fermento neo-idealista continentale. A fianco di queste realtà centrali e dei maggiori autori a esse associati (Arturo Onofri per la poesia; Antonio Fogazzaro e Luigi Capuana per la prosa), è stato interrogato più esaustivamente possibile l'impatto esoterico sulla letteratura del Bel Paese tra l'Unità e il primo dopoguerra