Haptic robot-environment interaction for self-supervised learning in ground mobility

Dissertação para obtenção do Grau de Mestre em Engenharia Eletrotécnica e de Computadores

English Language Learning Inside and Outside the Classroom in Portugal

This study investigates the way of learning the English language in Portugal. First-year students of the faculty of Social Sciences and Humanities of New University of Lisbon were selected as participants in the case study. As data collection tools a questionnaire and focus-groups were used. 115 students completed the designed questionnaire and after that 12 students were selected for the more detailed focus-group discussions. Results of the research show that most part of the students´ English knowledge is received from outside the classroom by means of movies, songs, computer games, the Internet, communication with friends and other sources. Also, the results show that motivation is very important in language learning process and motivated students acquire the language faster and easier.

About using serious games to teach (Portuguese) sign language

Sign language is the form of communication used by Deaf people, which, in most cases have been learned since childhood. The problem arises when a non-Deaf tries to contact with a Deaf. For example, when non-Deaf parents try to communicate with their Deaf child. In most cases, this situation tends to happen when the parents did not have time to properly learn sign language. This dissertation proposes the teaching of sign language through the usage of serious games. Currently, similar solutions to this proposal do exist, however, those solutions are scarce and limited. For this reason, the proposed solution is composed of a natural user interface that is intended to create a new concept on this field. The validation of this work, consisted on the implementation of a serious game prototype, which can be used as a source for learning (Portuguese) sign language. On this validation, it was first implemented a module responsible for recognizing sign language. This first stage, allowed the increase of interaction and the construction of an algorithm capable of accurately recognizing sign language. On a second stage of the validation, the proposal was studied so that the pros and cons can be determined and considered on future works.

Gamification e game-based learning: uma abordagem lúdica à aprendizagem

Relatório de estágio de mestrado em Ensino de Informática

An ordinal shapley value for economic environments (Revised version)

We propose a new solution concept to address the problem of sharing a surplus among the agents generating it. The problem is formulated in the preferences-endowments space. The solution is defined recursively, incorporating notions of consistency and fairness and relying on properties satisfied by the Shapley value for Transferable Utility (TU) games. We show a solution exists, and call it the Ordinal Shapley value (OSV). We characterize the OSV using the notion of coalitional dividends, and furthermore show it is monotone and anonymous. Finally, similarly to the weighted Shapely value for TU games, we construct a weighted OSV as well.

An ordinal shapley value for economic environments

We propose a new solution concept to address the problem of sharing a surplus among the agents generating it. The sharing problem is formulated in the preferences-endowments space. The solution is defined in a recursive manner incorporating notions of consistency and fairness and relying on properties satisfied by the Shapley value for Transferable Utility (TU) games. We show a solution exists, and refer to it as an Ordinal Shapley value (OSV). The OSV associates with each problem an allocation as well as a matrix of concessions ``measuring'' the gains each agent foregoes in favor of the other agents. We analyze the structure of the concessions, and show they are unique and symmetric. Next we characterize the OSV using the notion of coalitional dividends, and furthermore show it is monotone in an agent's initial endowments and satisfies anonymity. Finally, similarly to the weighted Shapley value for TU games, we construct a weighted OSV as well.

Learning the ropes and embracing the rules: CFSP institutions as arenas for learning and strategic socialisation

The aim of this article is to analyse those situations in which learning and socialisation take place within the context of the Common Foreign and Security Policy (CFSP), in particular, at the level of experts in the Council Working Groups. Learning can explain the institutional development of CFSP and changes in the foreign policies of the Member States. Some scope conditions for learning and channels of institutionalisation are identified. Socialisation, resulting from learning within a group, is perceived as a strategic action by reflective actors. National diplomats, once they arrive in Brussels, learn the new code of conduct of their Working Groups. They are embedded in two environments and faced with two logics: the European one in the Council and the national one in the Ministries of Foreign Affairs (MFA). The empirical evidence supports the argument that neither rational nor sociological approaches alone can account for these processes.

Dividends and weighted values in games with externalities

We consider cooperative environments with externalities (games in partition function form) and provide a recursive definition of dividends for each coalition and any partition of the players it belongs to. We show that with this definition and equal sharing of these dividends the averaged sum of dividends for each player, over all the coalitions that contain the player, coincides with the corresponding average value of the player. We then construct weighted Shapley values by departing from equal division of dividends and finally, for each such value, provide a bidding mechanism implementing it.

Non-cooperative incentives to share knowledge in competitive environments

In this paper we study a model where non-cooperative agents may exchange knowledge in a competitive environment. As a potential factor that could induce the knowledge disclosure between humans we consider the timing of the moves of players. We develop a simple model of a multistage game in which there are only three players and competition takes place only within two stages. Players can share their private knowledge with their opponents and the knowledge is modelled as in uencing their marginal cost of e¤ort. We identify two main mechanisms that work towards knowledge disclosure. One of them is that before the actual competition starts, the stronger player of the rst stage of a game may have desire to share his knowledge with the "observer", be- cause this reduces the valuation of the prize of the weaker player of that stage and as a result his e¤ort level and probability of winning in a ght. Another mechanism is that the "observer" may have sometimes desire to share knowledge with the weaker player of the rst stage, because in this way, by increasing his probability of winning in that stage, he decreases the probability of winning of the stronger player. As a result, in the second stage the "observer" may have greater chances to meet the weaker player rather than the stronger one. Keywords: knowledge sharing, strategic knowledge disclosure, multistage contest game, non-cooperative games

Sharing the surplus in games with externalities within and across issues

We consider environments in which agents can cooperate on multiple issues and externalities are present both within and across issues. We propose a way to extend (Shapley) values that have been put forward to deal with externalities within issues to games where there are externalities within and across issues. We characterize our proposal through axioms that extend the Shapley axioms to our more general environment.

Interactions between learning and immunity in Drosophila melanogaster

Learning and immunity are two adaptive traits with roles in central aspects of an organism's life: learning allows adjusting behaviours in changing environments, while immunity protects the body integrity against parasites and pathogens. While we know a lot about how these two traits interact in vertebrates, the interactions between learning and immunity remain poorly explored in insects. During my PhD, I studied three possible ways in which these two traits interact in the model system Drosophila melanogaster, a model organism in the study of learning and in the study of immunity. Learning can affect the behavioural defences against parasites and pathogens through the acquisition of new aversions for contaminated food for instance. This type of learning relies on the ability to associate a food-related cue with the visceral sickness following ingestion of contaminated food. Despite its potential implication in infection prevention, the existence of pathogen avoidance learning has been rarely explored in invertebrates. In a first part of my PhD, I tested whether D. melanogaster, which feed on food enriched in microorganisms, innately avoid the orally-acquired 'novel' virulent pathogen Pseudomonas entomophila, and whether it can learn to avoid it. Although flies did not innately avoid this pathogen, they decreased their preference for contaminated food over time, suggesting the existence of a form of learning based likely on infection-induced sickness. I further found that flies may be able to learn to avoid an odorant which was previously associated with the pathogen, but this requires confirmation with additional data. If this is confirmed, this would be the first time, to my knowledge, that pathogen avoidance learning is reported in an insect. The detrimental effect of infection on cognition and more specifically on learning ability is well documented in vertebrates and in social insects. While the underlying mechanisms are described in detail in vertebrates, experimental investigations are lacking in invertebrates. In a second part of my PhD, I tested the effect of an oral infection with natural pathogens on associative learning of D. melanogaster. By contrast with previous studies in insects, I found that flies orally infected with the virulent P. entomophila learned better the association of an odorant with mechanical shock than uninfected flies. The effect seems to be specific to a gut infection, and so far I have not been able to draw conclusions on the respective contributions of the pathogen's virulence and of the flies' immune activity in this effect. Interestingly, infected flies may display an increased sensitivity to physical pain. If the learning improvement observed in infected flies was due partially to the activity of the immune system, my results would suggest the existence of physiological connections between the immune system and the nervous system. The basis of these connections would then need to be addressed. Learning and immunity are linked at the physiological level in social insects. Physiological links between traits often result from the expression of genetic links between these traits. However, in social insects, there is no evidence that learning and immunity may be involved in an evolutionary trade-off. I previously reported a positive effect of infection on learning in D. melanogaster. This might suggest that a positive genetic link could exist between learning and immunity. We tested this hypothesis with two approaches: the diallel cross design with inbred lines, and the isofemale lines design. The two approaches provided consistent results: we found no additive genetic correlation between learning and resistance to infection with the diallel cross, and no genetic correlation in flies which are not yet adapted to laboratory conditions in isofemale lines. Consistently with the literature, the two studies suggested that the positive effect of infection on learning I observed might not be reflected by a positive evolutionary link between learning and immunity. Nevertheless, the existence of complex genetic relationships between the two traits cannot be excluded. - L'apprentissage et l'immunité sont deux caractères à valeur adaptative impliqués dans des aspects centraux de la vie d'un organisme : l'apprentissage permet d'ajuster les comportements pour faire face aux changements de l'environnement, tandis que l'immunité protège l'intégrité corporelle contre les attaques des parasites et des pathogènes. Alors que les interactions entre l'apprentissage et l'immunité sont bien documentées chez les vertébrés, ces interactions ont été très peu étudiées chez les insectes. Pendant ma thèse, je me suis intéressée à trois aspects des interactions possibles entre l'apprentissage et l'immunité chez la mouche du vinaigre Drosophila melanogaster, qui est un organisme modèle dans l'étude à la fois de l'apprentissage et de l'immunité. L'apprentissage peut affecter les défenses comportementales contre les parasites et les pathogènes par l'acquisition de nouvelles aversions pour la nourriture contaminée par exemple. Ce type d'apprentissage repose sur la capacité à associer une caractéristique de la nourriture avec la maladie qui suit l'ingestion de cette nourriture. Malgré les implications potentielles pour la prévention des infections, l'évitement appris des pathogènes a été rarement étudié chez les invertébrés. Dans une première partie de ma thèse, j'ai testé si les mouches, qui se nourrissent sur des milieux enrichis en micro-organismes, évitent de façon innée un 'nouveau' pathogène virulent Pseudomonas entomophila, et si elles ont la capacité d'apprendre à l'éviter. Bien que les mouches ne montrent pas d'évitement inné pour ce pathogène, elles diminuent leur préférence pour de la nourriture contaminée dans le temps, suggérant l'existence d'une forme d'apprentissage basée vraisemblablement sur la maladie générée par l'infection. J'ai ensuite observé que les mouches semblent être capables d'apprendre à éviter une odeur qui était au préalable associée avec ce pathogène, mais cela reste à confirmer par la collecte de données supplémentaires. Si cette observation est confirmée, cela sera la première fois, à ma connaissance, que l'évitement appris des pathogènes est décrit chez un insecte. L'effet détrimental des infections sur la cognition et plus particulièrement sur les capacités d'apprentissage est bien documenté chez les vertébrés et les insectes sociaux. Alors que les mécanismes sous-jacents sont détaillés chez les vertébrés, des études expérimentales font défaut chez les insectes. Dans une seconde partie de ma thèse, j'ai mesuré les effets d'une infection orale par des pathogènes naturels sur les capacités d'apprentissage associatif de la drosophile. Contrairement aux études précédentes chez les insectes, j'ai trouvé que les mouches infectées par le pathogène virulent P. entomophila apprennent mieux à associer une odeur avec des chocs mécaniques que des mouches non infectées. Cet effet semble spécifique à l'infection orale, et jusqu'à présent je n'ai pas pu conclure sur les contributions respectives de la virulence du pathogène et de l'activité immunitaire des mouches dans cet effet. De façon intéressante, les mouches infectées pourraient montrer une plus grande réactivité à la douleur physique. Si l'amélioration de l'apprentissage observée chez les mouches infectées était due en partie à l'activité du système immunitaire, mes résultats suggéreraient l'existence de connections physiologiques entre le système immunitaire et le système nerveux. Les mécanismes de ces connections seraient à explorer. L'apprentissage et l'immunité sont liés sur un plan physiologique chez les insectes sociaux. Les liens physiologiques entre les caractères résultent souvent de l'expression de liens entre ces caractères au niveau génétique. Cependant, chez les insectes sociaux, il n'y a pas de preuve que l'apprentissage et l'immunité soient liés par un compromis évolutif. J'ai précédemment rapporté un effet positif de l'infection sur l'apprentissage chez la drosophile. Cela pourrait suggérer qu'une relation génétique positive existerait entre l'apprentissage et l'immunité. Nous avons testé cette hypothèse par deux approches : le croisement diallèle avec des lignées consanguines, et les lignées isofemelles. Les deux approches ont fournies des résultats similaires : nous n'avons pas détecté de corrélation génétique additive entre l'apprentissage et la résistance à l'infection avec le croisement diallèle, et pas de corrélation génétique chez des mouches non adaptées aux conditions de laboratoire avec les lignées isofemelles. En ligne avec la littérature, ces deux études suggèrent que l'effet positif de l'infection sur l'apprentissage que j'ai précédemment observé ne refléterait pas un lien évolutif positif entre l'apprentissage et l'immunité. Néanmoins, l'existence de relations génétiques complexes n'est pas exclue.

Entorns col•laboratius virtuals asíncrons basats en Web i enfocats en la gestió del coneixement = Web-based Asynchronous Collaborative Environments Focused on Knowledge Management

Report for the scientific sojourn at the University of California at Berkeley, USA, from september 2007 until july 2008. Communities of Learning Practice is an innovative paradigm focused on providing appropriate technological support to both formal and especially informal learning groups who are chiefly formed by non-technical people and who lack of the necessary resources to acquire such systems. Typically, students who are often separated by geography and/or time have the need to meet each other after classes in small study groups to carry out specific learning activities assigned during the formal learning process. However, the lack of suitable and available groupware applications makes it difficult for these groups of learners to collaborate and achieve their specific learning goals. In addition, the lack of democratic decision-making mechanisms is a main handicap to substitute the central authority of knowledge presented in formal learning.

Open video tools to support the production of online collaborative audiovisual projects : how to promote collective creation in e-learning

This paper analyses the use of open video editing tools to support the creation and production of online collaborative audiovisual projects for higher education. It focuses on the possibilities offered by these tools to promote collective creation in virtual environments.

Semi-online neural-Q_leaming for real-time robot learning

Reinforcement learning (RL) is a very suitable technique for robot learning, as it can learn in unknown environments and in real-time computation. The main difficulties in adapting classic RL algorithms to robotic systems are the generalization problem and the correct observation of the Markovian state. This paper attempts to solve the generalization problem by proposing the semi-online neural-Q_learning algorithm (SONQL). The algorithm uses the classic Q_learning technique with two modifications. First, a neural network (NN) approximates the Q_function allowing the use of continuous states and actions. Second, a database of the most representative learning samples accelerates and stabilizes the convergence. The term semi-online is referred to the fact that the algorithm uses the current but also past learning samples. However, the algorithm is able to learn in real-time while the robot is interacting with the environment. The paper shows simulated results with the "mountain-car" benchmark and, also, real results with an underwater robot in a target following behavior