Generalize policy on supporting user scenario

In this thesis we present a way of combining previously learned robot be- havior policies of different users. The main idea is to combine a set of policies, in tabular representation, into a final sub-optimal solution for the problem all users have contributed to. We assume that the features/differences of users are unknown and need to be extracted from the different policies generated from same user. This information is used to weight the importance of a set of actions to sum up two policies. The proposed approach has been tested on a virtual environment finding out that the combined policy works as a general policy suitable for all users, as it always selects actions that are satisfying the users at the border of the defined sensorial possibilities. All the assumptions has been finally verified on a real environment finding out all the limitations of the proposed model

The L2 acquisition of Spanish non-nominative subjects by adult L1 English speakers

This study investigates the adult second language (L2) acquisition of non- nominative, non-agentive subjects, a particular feature of the Spanish language also shared by other Indo-European and South Asian languages. The existence of non- nominative elements in Spec, IP with subject-like properties is well-documented in the literature. One of the first attempts to account for this phenomenon in Romance languages is Belletti and Rizzi (1988) on Italian. Masullo (1992, 1993) extends the analysis to Spanish, proposing the Non-Nominative Subject (NNSub) Parameter, whereby a language allows NNSubs as part of its core grammar only if nominative case is assigned in situ. Spanish NNSubs can appear in unaccusative, dethematized, as well as impersonal constructions, and can be dative, accusative, or locative. These constituents are shown in Masullo (1992, 1993) not to occupy an A-bar position above IP, like topics and left-dislocated constituents, but rather Spec, IP, moving from the VP to satisfy the Extended Projection Principle. Languages like English and French, in which nominative case is checked in Spec, BP, disallow NNSubs.The aim of this study is to understand the processes involved in the acquisition language (LI) in the process of acquisition. A study involving three groups of adult English L2 learners of Spanish at a British university and a control group was carried out to determine if L2 learners with a [-NNSub] LÍ setting can reset the parameter to the Spanish [+NNSub] value. The learners belonged to one of three language levels: Intermediate, Advanced and Advanced+ according to the number of years spent at university and their contact with Spanish in a Spanish speaking country. The test battery involved an aural preference task, an elicited imitation task, and a picture description task. Hypothesis A predicted that Intermediate L2 learners would show clear L1 effects on their data and that the NNSub parameter would not show resetting. Hypothesis в predicted that the more advanced L2 learners would be able to reset the NNSub parameter to accommodate NNSubs and dative case in their interlanguage. Results from the aural preference and the elicited imitation tasks show correspondence between the results per category in both tasks. Knowledge of unaccusativity and NNSubs develops steadily up to the Advanced level but it suffers a decline with the Advanced+ learners. Results from the picture description task show that competence increases from the Intermediate to the Advanced level but that the percentage of non-target forms either stays at the same level or goes up with respect to the Advanced+ group. This regression seen in the Advanced^ data might be explained by the recent exposure to naturalistic input that the Advanced learners had just had. The L2 data do not show enough evidence that the NNSub parameter has been reset. Most of the grammatical utterances contain the verbs gustar 'like' and doler 'hurt', verbs which are part of the teaching curriculum. On the other hand, grammatical utterances involving other unaccusative verbs with NNSubs are rare. The fact that teaching of these verbs is insufficient does not help the L2 learners overcome the learnability problem posed by the input. This problem stems from the L2 input not showing clear-cut signals to tell learners which verbs require a NNSub. In addition to this, native speakers' use of optional structures to substitute the constructions with NNSubs makes NNSubs even less salient in the input

Spatially resolved kinematics, galactic wind, and quenching of star formation in the luminous infrared galaxy IRAS F11506-3851

We present a multi-wavelength integral field spectroscopic study of the low-z LIRG IRAS F11506-3851, on the basis of VIMOS and SINFONI (ESO-VLT) observations. The morphology and the 2D kinematics of the gaseous (neutral and ionized) and stellar components have been mapped using the NaD doublet, the H$\alpha$ line, and the near-IR CO(2-0) and CO(3-1) bands. The kinematics of the ionized gas and the stars are dominated by rotation, with large observed velocity amplitudes and centrally peaked velocity dispersion maps. The stars lag behind the warm gas and represent a dynamically hotter system, as indicated by the observed dynamical ratios. Thanks to these IFS data we have disentangled the contribution of the stars and the ISM to the NaD feature, finding that it is dominated by the absorption of neutral gas clouds in the ISM. The neutral gas 2D kinematics shows a complex structure dominated by two components. On the one hand, the thick slowly rotating disk lags significantly compared to the ionized gas and the stars, with an irregular and off-center velocity dispersion map. On the other hand, a kpc-scale neutral gas outflow is observed along the semi-minor axis of the galaxy, as revealed by large blueshifted velocities (30-154 km/s). We derive an outflowing mass rate in neutral gas of about 48 $\dot{M_{\rm w}}$/yr. Although this implies a global mass loading factor of 1.4, the 2D distribution of the ongoing SF suggests a much larger value of mass loading factor associated with the inner regions (R$<$200 pc), where the current SF represents only 3 percent of the total. All together these results strongly suggest that we are witnessing (nuclear) quenching due to SF feedback in IRAS F11506-3851. However, the relatively large mass of molecular gas detected in the nuclear region via the H2 1-0 S(1) line suggests that further episodes of SF may take place again

Street crossing behavior in younger and older pedestrians: an eye- and head-tracking study

Background Crossing a street can be a very difficult task for older pedestrians. With increased age and potential cognitive decline, older people take the decision to cross a street primarily based on vehicles’ distance, and not on their speed. Furthermore, older pedestrians tend to overestimate their own walking speed, and could not adapt it according to the traffic conditions. Pedestrians’ behavior is often tested using virtual reality. Virtual reality presents the advantage of being safe, cost-effective, and allows using standardized test conditions. Methods This paper describes an observational study with older and younger adults. Street crossing behavior was investigated in 18 healthy, younger and 18 older subjects by using a virtual reality setting. The aim of the study was to measure behavioral data (such as eye and head movements) and to assess how the two age groups differ in terms of number of safe street crossings, virtual crashes, and missed street crossing opportunities. Street crossing behavior, eye and head movements, in older and younger subjects, were compared with non-parametric tests. Results The results showed that younger pedestrians behaved in a more secure manner while crossing a street, as compared to older people. The eye and head movements analysis revealed that older people looked more at the ground and less at the other side of the street to cross. Conclusions The less secure behavior in street crossing found in older pedestrians could be explained by their reduced cognitive and visual abilities, which, in turn, resulted in difficulties in the decision-making process, especially under time pressure. Decisions to cross a street are based on the distance of the oncoming cars, rather than their speed, for both groups. Older pedestrians look more at their feet, probably because of their need of more time to plan precise stepping movement and, in turn, pay less attention to the traffic. This might help to set up guidelines for improving senior pedestrians’ safety, in terms of speed limits, road design, and mixed physical-cognitive trainings

Effects of Alzheimer’s Disease on Visual Target Detection: A “Peripheral Bias”

Visual exploration is an omnipresent activity in everyday life, and might represent an important determinant of visual attention deficits in patients with Alzheimer’s Disease (AD). The present study aimed at investigating visual search performance in AD patients, in particular target detection in the far periphery, in daily living scenes. Eighteen AD patients and 20 healthy controls participated in the study. They were asked to freely explore a hemispherical screen, covering ±90°, and to respond to targets presented at 10°, 30°, and 50° eccentricity, while their eye movements were recorded. Compared to healthy controls, AD patients recognized less targets appearing in the center. No difference was found in target detection in the periphery. This pattern was confirmed by the fixation distribution analysis. These results show a neglect for the central part of the visual field for AD patients and provide new insights by mean of a search task involving a larger field of view

Tumble Motion Generation in Small Gasoline Engines: A New Methodological Approach for the Analysis of the Influence of the Intake Duct Geometrical Parameters

For motorbike and motor scooter applications, the optimization of the tumble generation is considered an effective way to improve the combustion system efficiency and to lower the emissions, considering also that the two-wheels layout represents an obstacle in adopting the advanced post-treatment concepts designed for the automotive applications. During the last years the deep re-examination of the engine design for lowering the engine emissions involved the two-wheel vehicles too. The IC-engine overall efficiency plays a fundamental role in determining the final raw emissions. From this point of view, the optimization of the in-cylinder flow organization is mandatory. In detail, in SI-engines the generation of a coherent tumble vortex having dimensions comparable to the engine stroke could be of primary importance to extend the engines' ignition limits toward the field of the dilute/lean mixtures. The aim of the paper is to introduce a new analysis approach for a deep insight of the 3D-CFD results performed to assess the intake duct geometry influence on the tumble motion generation during both the intake and the compression strokes. All the CFD simulations presented in the paper were performed by the AVL-FIRE v. 2010 CFD code on a SI 4 valve engine characterized by an unit displacement of 250 cm3. The tumble structure was changed during the analysis by changing the angle set defining the intake port shape. The stroke-to-bore engine ratio was kept constant to 0.7. The effects of the tumble variations were evaluated in terms of the tumble ratio, the turbulent kinetic energy and the vortex characterization at IVC. © 2013 The Authors

Visual exploration pattern in hemineglect

The analysis of eye movement parameters in visual neglect such as cumulative fixation duration, saccade amplitude, or the numbers of saccades has been used to probe attention deficits in neglect patients, since the pattern of exploratory eye movements has been taken as a strong index of attention distribution. The current overview of the literature of visual neglect has its emphasis on studies dealing with eye movement and exploration analysis. We present our own results in 15 neglect patients. The free exploration behavior was analyzed in these patients presenting 32 naturalistic color photographs of everyday scenes. Cumulative fixation duration, spatial distribution of fixations in the horizontal and vertical plane, the number and amplitude of exploratory saccades was analyzed and compared with the results of an age-matched control group. A main result of our study was that in neglect patients, fixation distribution of free exploration of natural scenes is not only influenced by the left-right bias in the horizontal direction but also by the vertical directio

A search of neutral gas outflows in nearby luminous star-forming galaxies

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Teórica. Fecha de lectura: 27-05-2016This thesis was funded by the Marie Curie Initial Training Network ELIXIR (PI: Stéphane Charlot) of the European Commission under contract PITN- GA-2008-214227 and the grants AYA2010-21161-C02-01 and AYA2012-32295 by the Spanish Ministry of Science and Innovation (MICINN). S.C. gratefully acknowledges the logistic and financial support provided by the Cavendish Laboratory (Cambridge, UK

Studio sperimentale e numerico di materiali a cambiamento di fase per il raffreddamento passivo di componenti elettronici

La tesi ha l'obiettivo di valutare l'influenza di materiali a cambiamento di fase e di schiume metalliche sul raffreddamento passivo di componenti elettronici. Si propone inoltre un modello numerico per prevedere i risultati sperimentali.ope

Development of a chemical-kinetic database for the laminar flame speed under GDI and water injection engine conditions

Abstract The use of direct injection, supercharging, stoichiometric operation and reduction of the engine displacement, necessary to limit the specific consumption without reducing the power, makes the current spark ignition engines sensible to both the detonation and the increase of the inlet turbine temperature. The current research has therefore focused on the study of strategies aimed at reducing the risk of detonation using traditional and innovative solutions such as water injection. The application and optimization of these strategies can not ignore the knowledge of physical quantities characterizing the combustion such as the laminar flame speed. The laminar burning speed is an intrinsic property of the fuel and it is function of the mixture composition (mixture fraction and dilution) and of the thermodynamic conditions. The experimental measurements of the laminar flame speed available in the literature, besides not being representative of the pressure and temperature conditions characteristic of GDI engines, rarely report the effects of dilution by EGR or water vapor. To overcome the limitations of the experimental campaign it is possible to predict the value of the laminar flame speed resorting to numerical combustion models based on chemical kinetics. The increased performance of computing systems makes affordable the use of chemical schemes with a high number of species and reactions without facing an excessive temporal cost. In this work it is presented a methodology for the construction of a laminar flame speed database based on a non-reduced kinetic scheme and an open source solver (Cantera) for a commercial gasoline surrogate under the typical conditions of GDI engines with the addition of the effects of dilution with water and EGR