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Cognitive determinants of infra-humanization: the role of illusory correlation and attentional processes
Get PDFPeople commonly attribute more uniquely human characteristics to their in-group than to out-groups but do not differentially attribute the characteristics that we share with other animals. This process is called out-group de/infra-humanization. Up to now it has been conceptualized mainly as a motivated phenomenon serving many intergroup functions. Research so far has not investigated the possibility that animalistic de/infra-humanization might also have cognitive determinants. My research sought to fill this gap in the literature by suggesting that out-group infra-humanization can be conceived as an illusory correlation that people create between groups which represent (at least in one’s own experience) the majority and humanness, which is a quality unique to and shared by all human beings. Recent research on illusory correlation explains this phenomenon in terms of Kruschke’s (1996, 2001, 2003) Attention Theory of category learning (AT). AT proposes that, when learning about multiple groups, the features of the majority group are learned earlier than the features of the minority group. Once the features of the majority group are learned, attention is shifted to learn about the minority group. Impressions of the second-learned group form around those features that most clearly differentiate it from the first-learned group. Since the in-group often has a majority status and being uniquely human is a generally shared attribute, this model would suggest that we tend to associate humanness with the in-group. In turn, the association of humanness with the second-learned group (out-group) would be inhibited. Moreover, the out-group is more likely to be associated with the less common comparative attribute (i.e., non-uniquely human), strengthening out-group infra-humanization. Three experiments support this explanation of the infra-humanization effect as a result of associating humanity with the in-group. In Studies 1 and 2, we investigated whether out-group infra-humanization can result from the way people perceive and process information in case of illusory correlation where no real differences exist between the majority and minority groups. In Study 3, we investigated whether group identification modulates the basic illusory correlation effect. Implications for de/infra-humanization, illusory correlation, and stereotype formation are discussed
Some Problems Concerning Polynomials over Finite Fields, or Algebraic Divertissements
No full textIn this thesis we consider some problems concerning polynomials over finite fields.
The first topic is the action of some groups on irreducible polynomials. We describe orbits and stabilizers.
Next, we consider transformations of irreducible polynomials by quadratic and cubic maps and study the irreducibility of the polynomials obtained.
Finally, starting from PN functions and monomials, we generalize this concept, introducing k-PN monomials and classifying them for small values of k and for fields of order p, p^2 and p^4
Autonomous resource management for cloud-assisted peer-to-peer based services
No full textPeer-to-Peer (P2P) and Cloud Computing are two of the latest trends in the Internet arena. They both could be labelled as large-scale distributed systems, yet their approach is completely different: based on completely decentralized protocols exploiting edge resources the former, focusing on huge data centres the latter. Several Internet startups have quickly reached stardom by exploiting cloud resources. Instead, P2P applications still lack a well-defined business model. Recently, companies like Spotify and Wuala have started to explore how the two
worlds could be merged by exploiting (free) user resources whenever possible,
aiming at reducing the cost of renting cloud resource.
However, although very promising, this model presents challenging issues, in particular about
the autonomous regulation of the usage of P2P and cloud resources.
Next-generation services need the possibility to guarantee a minimum level of service when peer resources are not sufficient, and to exploit as much P2P resources as possible when they are abundant.
In this thesis, we answer the above research questions in the form of new algorithms and systems. We designed a family of mechanisms to self-regulate the amount of cloud resources when peer resources are not enough.
We applied and adapted these mechanisms to support different Internet applications, including storage, video streaming and online gaming.
To support a replication service, we designed an algorithm that self-regulates the cloud resources used for storing replicas by orchestrating their provisioning.
We presented CLive, a video streaming P2P framework that meet the real-time constraints on video delay by autonomously regulating the amount of cloud helpers upon need.
We proposed an architecture to support large scale on-line games, where the load
coming from the interaction of players is strategically migrated between P2P and cloud resources in an autonomous way.
Finally, we proposed a solution to the NAT problem that employs cloud resources to allow a node behind it to be seen from outside.
Using extensive simulations, we showed that hybrid infrastructures can reduce the economical effort on the service providers, while offering a level of service comparable with centralized architectures. The results of this thesis proved that the combination of Cloud Computing and P2P is one of the milestones for next generation distributed P2P-based architectures
Parallel FDTD Electromagnetic Simulation of Dispersive Plasmonic Nanostructures and Opal Photonic Crystals in the Optical Frequency Range
No full textIn the last decade, nanotechnology has enormously and rapidly developed. The technological progress has allowed the practical realization of devices that in the past have been studied only from a theoretical point of view. In particular we focus here on nanotechnologies for the optical frequency range, such as plasmonic devices and photonic crystals, which are used in many areas of engineering. Plasmonic noble metal nanoparticles are used in order to improve the photovoltaic solar cell efficiency for their forward scattering and electromagnetic field enhancement properties. Photonic crystals are used for example in low threshold lasers, biosensors and compact optical waveguide. The numerical simulation of complex problems in the field of plasmonics and photonics is cumbersome. The dispersive behavior has to be modeled in an accurate way in order to have a detailed description of the fields. Besides the code parallelization is needed in order to simulate large and realistic problems. Finite Difference Time Domain (FDTD) is the numerical method used for solving the Maxwell's equations and simulating the electromagnetic interaction between the optical radiation and the nanostructures. A modified algorithm for the Drude dispersion is proposed and validated in the case of noble metal nanoparticles. The modified approach is extended to other dispersion models from a theoretical point of view. A parallel FDTD code with a mesh refinement (subgridding) for the more detailed regions has been developed in order to speed up the simulation time. The parallel approach is also needed for the large amount of required memory due to the dimension of the analysis domain. Plasmonic nanostructures of different shapes and dimensions on the front surface of a silicon layer have been simulated. The forward field scattering has been evaluated in order to optimize the concentration of the light inside the active region of the solar cell. Some design parameters have been deduced from this study. Opal photonic crystals with different filling factors have been simulated in order to tune the optical transmittance band-gap and find a theoretical explanation to the experimental evidences
Exploiting Business Process Knowledge for Process Improvement
No full textProcesses are omnipresent in humans’ everyday activities: withdrawals from an ATM, loan requests from a bank, renewals of driver’s licenses, purchases of goods from online retail systems. In particular, the business domain has strongly embraced processes as an instrument to help in the organization of business operations, leading to so-called business processes. A business process is a set of logically-related tasks performed to achieve a defined business outcome. Business processes have a big impact on the achievement of business goals and they are widely acknowledged as one of the more important assets of any organization next to the organization’s customer basis and, more recently, data. Thus, there is a high interest in keeping business processes performing at their best and improving those that do not perform well.
Nowadays, business processes are supported by a wide range of enabling technologies, including Web services and business process engines, which enable the (partial)automation of processes. Information systems supporting the execution of processes typically store a wealth of process knowledge that includes process models, process progression information and business data. The availability of such process knowledge gives unprecedented opportunities to get insight into business processes, which leads to the question of how to exploit this knowledge for facilitating the improvement of processes.
In order to answer this question, we propose to exploit process knowledge from two different but complementary perspectives. In the first one, we take the process execution perspective and leverage on process execution data generated by information systems to analyze and understand the actual behavior of executed processes. In the second one, we take the process design perspective and propose to extract process model patterns from existing models for reuse in the design of processes. The final goal of this thesis is to facilitate process improvement by exploiting existing process knowledge not only for gaining insight into and understanding of processes but also for reusing the resulting knowledge in the improvement thereof. We have successfully applied our approaches in the context of service-based business processes and assisted dataflow-based mashup development. In the former, we validated our approach through a end-user study of the usability and understandability of our approach and tools, while in the latter the evaluations were performed through experiments run on a dataset of models from the mashup tool Yahoo! Pipes
Supercritical Water Gasification of Biomass
No full textFinding new ways to produce renewable energy is among the most important and strategic challenges of technology nowadays. Biomass is one of the ideal candidates for reliable and abundant renewable energy production, since it is largely available, universally distributed and potentially CO2 neutral, if utilized in a sustainable way. There are several processes for energy exploitation of biomass, including combustion, pyrolysis and gasification. However, traditional thermochemical technologies can be only effective with dry biomass, owing to energy considerations. As a consequence, wet biomass (e.g. municipal or agro-industrial wastes), which represents the greatest part of the overall biomass, cannot be converted into energy. This strong limitation can be overcome by a novel technology: supercritical water gasification (SCWG).
SCWG is based on reacting biomass with water above its critical point (T > 374.1°C; P > 22.1 MPa). Thanks to the unique properties of supercritical water, high gaseous yields can be achieved, as well as reduced (or even null) tar and char production. Moreover, a H2-rich gas can be obtained. Therefore, high moisture content is not a drawback anymore, being water part of the process itself.
In this thesis, SCWG is analyzed under different aspects. First of all, a comprehensive state of the art is traced. The work is then divided into two main sections: mathematical modeling and experimental activities. The first section reports three different modeling approaches for SCWG. In thermodynamic equilibrium modeling, a two-phase thermodynamic equilibrium model was built, enabling to predict products composition as a function of process parameters, as well as solids formation at equilibrium. Energy balances were also performed by means of such tool. The kinetics modeling approach was applied to methanol SCWG, developing an elementary reactions model able to highlight the main reaction pathways. Process modeling was then used to calculate the energy needs of a possible industrial SCWG process scheme, enabling to prove its energetic feasibility.
The second part of the thesis deals with experimental tests, which were executed with both real biomass and model compounds. A first campaign was performed with glucose and glucose/phenol mixtures in small metallic batch autoclaves. The catalytic effect of the reactor material (stainless steel and Inconel 625) on the gasification products composition was discussed, as well as the influence of subcritical (350°C) and supercritical (400°C) reaction conditions. Moreover, the effect of phenol addiction, inhibiting glucose gasification, was observed. In a subsequent campaign, real biomass was gasified, including beech sawdust, municipal wastes, malt spent grains and hydrothermal char. The effect of the reactor material was studied, as well as the system behavior after long time runs (16 h) and the addiction of K2CO3 as a catalyst. Finally, glucose/phenol mixtures, with increasing phenol contents, were gasified in a continuous tubular reactor at 400°C and 25 MPa, between 10 and 240 s of residence time. Results showed that phenol is hardly gasified and that methanol is a key intermediate product
Strategies for cells encapsulation and deposition
No full textA computer aided manufacturing approach to encapsulate viable mammalian cells in hydrogels and use these capsules as the building blocks for scaffolds. A novel 3D capable contactless bioprinter is presented that encapsulates cells in a alginate hydrogel through an electro hydro dynamic process and deposit these capsules on a specifically engineered substrate manufacturing scaffold without the need for further postprocessing
Production of steel matrix composites by mechanical milling and spark plasma sintering
No full textHot work tool steels (HWTSs) are ferrous alloys for tooling application, particularly developed to meet high toughness and good hot hardness. Increasing hardness generally leads to a decrease in toughness, therefore metal matrix composite (MMC) coatings and functionally graded materials have been proposed as a good solution for improving wear resistance.
In this PhD thesis powder metallurgy has been applied for the production of particle reinforced HWTSs. Mechanical milling (MM) and mechanical alloying (MA) have been considered as suited techniques for the production of powders showing higher sinterability and finer microstructure. Spark plasma sintering (SPS) has been used for the consolidation. As reinforcement a harder high speed steel (HSS) and different ceramic powders (TiB2, TiC and TiN) have been selected.
The production of HWTS/HSS blends has highlighted the negative interaction on densification of the two components due to their different sintering kinetics. This interference can be minimised by selecting powders with smaller particles size. With this respect MM was proved to be a very useful method, which enhances sintering. Fully dense blends with good dispersion of the reinforcing particles can be sintered using small sized powders and setting the particle size ratio (PSR) smaller than 1.
For the production of MMCs the formation of aggregates has been overcome by MA which promotes a uniform dispersion of hard particles into the parent steel. Among the reinforcement considered in this work, TiB2 is not suitable because it reacts with steel depleting carbon and producing TiC and brittle Fe2B. HWTS composites with 20%vol of TiC can be fully densified by SPS at 1100 °C for 30 minutes and 60 MPa uniaxial pressure. On the other hand TiN-reinforced MMC shows high resistance to densification and fully dense materials could not be produced
Understanding gene expression with a pore forming toxin
No full textThis thesis aimed to explore eukaryotic cellular processes upon the virulent attack of
low doses of a well-known pore forming toxin (staphylococcal α-hemolysin (αHL)) and
to develop a new biotech application using the same protein
Computational Approaches to Linguistic Creativity for Real World Applications
No full textRecent years have witnessed a growing interest in computational linguistic creativity, a research field at the boundary between many disciplines including natural language processing, linguistics, psychology, cognitive sciences and humanities. Even though the state-of-the-art in this field has been striding forward in the last decade, real-world applications of computational linguistic creativity are still uncommon. For comparison, computer-enhanced productivity software is significantly augmenting the skills of both casual users and professionals in other areas, such as image and signal processing.
In this thesis, we advocate three main points that computational linguistic creativity should address to achieve a higher state of maturity and demonstrate its full potential: 1) the focus on real-world applications, in which state-of-the- art technology can be leveraged to offer solutions with a practical utility for end users; 2) the adoption of an interactive paradigm in which technology collaborates with users to enhance their creativity instead of attempting to replace it; 3) the investigation of the explorative dimension of creativity, as a means to achieve the two previous points by offering users richer ways of interaction and more powerful tools that can solve a larger class of problems.We present three applications that we designed and developed to address these points: 1) a system for the interactive construction of creative names designed as a support tool for copywriters; 2) a platform for the generation of memory tips for second language learning; 3) an explorative and general-purpose framework for creative sentence generation with the potential to be deployed in a wide range of settings, including advertisement, education and entertainment. All these platforms leverage state-of-the-art technology to deliver creative results with the potential to be useful for end users. We demonstrate this point through three different evaluations, in which we show that 1) the generated neologisms are appealing and successful, and that 2) the sentences that we generate have many of the qualities of successful slogans used for advertisement and 3) they are effective mnemonic devices when used as memory aids for second language learning