Avec l'avancée du Web Sémantique et des initiatives Open Linked Data, une grande quantité de documents RDF sont disponibles sur Internet. L'objectif est de rendre ces données lisibles pour les humains et les machines, en adoptant des formats spéciaux et en les connectant à l'aide des IRIs (International Resource Identifier), qui sont des abstractions de ressources réelles du monde. L’augmentation du nombre de données publiées et partagées augmente également le nombre d’informations sensibles diffusées. En conséquence, la confidentialité des entités d'intérêts (personnes, entreprises, etc.) est un véritable défi, nécessitant des techniques spéciales pour assurer la confidentialité et la sécurité adéquate des données disponibles dans un environnement où chaque utilisateur a accès à l'information sans aucune restriction (Web).Ensuite, trois aspects principaux sont considérés pour assurer la protection de l'entité: (i) Préserver la confidentialité, en identifiant les données qui peuvent compromettre la confidentialité des entités (par exemple, les identifiants, les quasi-identifiants); (ii) Identifier l'utilité des données publiques pour diverses applications (par exemple, statistiques, tests, recherche); et (iii) Les connaissances antérieures du modèle qui peuvent être utilisées par les pirates informatiques (par exemple, le nombre de relations, une relation spécifique, l'information d'un nœud).L'anonymisation est une technique de protection de la confidentialité qui a été appliquée avec succès dans les bases de données et les graphes. Cependant, les études sur l'anonymisation dans le contexte des documents RDF sont très limitées. Ces études sont les travaux initiaux de protection des individus sur des documents RDF, puisqu'ils montrent les approches pratiques d'anonymisation pour des scénarios simples comme l'utilisation d'opérations de généralisation et d'opérations de suppression basées sur des hiérarchies. Cependant, pour des scénarios complexes, où une diversité de données est présentée, les approches d'anonymisations existantes n'assurent pas une confidentialité suffisante.Ainsi, dans ce contexte, nous proposons une approche d'anonymisation, qui analyse les voisins en fonction des connaissances antérieures, centrée sur la confidentialité des entités représentées comme des nœuds dans les documents RDF. Notre approche de l'anonymisation est capable de fournir une meilleure confidentialité, car elle prend en compte la condition de la diversité de l'environnement ainsi que les voisins (nœuds et arêtes) des entités d'intérêts. En outre, un processus d'anonymisation automatique est assuré par l'utilisation d'opérations d'anonymisations associées aux types de données. / With the advance of the Semantic Web and the Open Linked Data initiatives, a huge quantity of RDF data is available on Internet. The goal is to make this data readable for humans and machines, adopting special formats and connecting them by using International Resource Identifiers (IRIs), which are abstractions of real resources of the world. As more data is published and shared, sensitive information is also provided. In consequence, the privacy of entities of interest (e.g., people, companies) is a real challenge, requiring special techniques to ensure privacy and adequate security over data available in an environment in which every user has access to the information without any restriction (Web). Then, three main aspects are considered to ensure entity protection: (i) Preserve privacy, by identifying and treating the data that can compromise the privacy of the entities (e.g., identifiers, quasi-identifiers); (ii) Identify utility of the public data for diverse applications (e.g., statistics, testing, research); and (iii) Model background knowledge that can be used for adversaries (e.g., number of relationships, a specific relationship, information of a node). Anonymization is one technique for privacy protection that has been successfully applied in practice for databases and graph structures. However, studies about anonymization in the context of RDF data, are really limited. These studies are initial works for protecting individuals on RDF data, since they show a practical anonymization approach for simple scenarios as the use of generalization and suppression operations based on hierarchies. However, for complex scenarios, where a diversity of data is presented, the existing anonymization approaches does not ensure an enough privacy. Thus, in this context, we propose an anonymization framework, which analyzes the neighbors according to the background knowledge, focused on the privacy of entities represented as nodes in the RDF data. Our anonymization approach is able to provide better privacy, since it takes into account the l-diversity condition as well as the neighbors (nodes and edges) of entities of interest. Also, an automatic anonymization process is provided by the use of anonymization operations associated to the datatypes.

Les tâches dans les environnements virtuels immersifs sont associées à des techniques et à des dispositifs d’interaction 3D (e.g. la sélection d’objets 3D à l’aide de la main virtuelle via un flystick). Alors que les environnements et les tâches deviennent de plus en plus complexes, les techniques ne peuvent plus être les mêmes pour chaque application, voire pour les différentes situations au sein d’une application. Une solution est d’adapter l’interaction en fonction des besoins de la situation pour améliorer l’utilisabilité. Ces adaptations peuvent être effectuées manuellement par le concepteur ou l’utilisateur, ou automatiquement par le système créant ainsi une interaction adaptative. La formalisation d’une telle assistance automatique nécessite la gestion d’informations pertinentes au vu de la situation. L’ensemble de ces informations fait émerger le contexte de l’interaction. L’assistance adaptative obtenue en raisonnant à partir de ces informations est ainsi consciente du contexte. De nombreuses possibilités existent pour l’obtenir. Notre objectif est une gestion du contexte qui préserve ses degrés élevés d’expressivité et d’évolutivité tout en étant facile à intégrer. Nous proposons une modélisation de ce problème par des graphes conceptuels basés sur une ontologie et gérés par un moteur externe en logique du premier ordre. Le moteur est générique et utilise une base de connaissance contenant des faits et des règles, qui peuvent être changés dynamiquement. Nous avons intégré une notion de confiance, afin d’établir l’adéquation d’une situation à la base de connaissances. La confiance des réactions est comparée à leur impact afin de ne garder que les pertinentes tout en évitant de saturer l’utilisateur. Les applications utilisent des outils qui peuvent être contrôlés par le moteur. Des capteurs permettent d’extraire des informations sémantiques pour le contexte. Des effecteurs permettent d’agir sur l’application et d’obtenir des adaptations. Un jeu d’outils et une base de connaissance pour l’interaction 3D ont été créés. De nombreuses étapes sont introduites dans la base de connaissance pour de bonnes combinaisons et une réflexion indépendante d’outils spécifiques. Nos premières applications illustrent la compréhension de la situation, dont les intérêts et difficultés de l’utilisateur, et le déclenchement d’assistances adaptées. Une étude hors ligne montre ensuite l’accès et l’évolution des étapes du moteur selon la situation. Le raisonnement sémantique générique obtenu est alors expressif, compréhensif, extensif et modifiable dynamiquement. Pour l’interaction 3D, il permet une assistance universelle automatique, ponctuelle ou manuelle à l’utilisateur et des analyses hors-lignes d’activités ou de conceptions pour le concepteur. / Tasks in immersive virtual environments are associated with 3D interaction techniques and devices (e.g. the selection of 3D objects with the virtual hand and a flystick). As environments and tasks become more and more complex, techniques can not remain the same for each application, even for every situations of a single application. A solution is to adapt the interaction depending on the situation in order to increase usability. These adaptations can be done manually by the designer or the user, or automatically by the system thus creating an adaptative interaction. Formalisation of such assistance needs the management of pertinent information regarding the situation. Those items of information make the context emerge from the interaction. The adaptative assistance obtained by reasoning on this information is then context-aware. Numerous possibilities can be used to build one. Our objective is a context management that preserves its high degrees of expressiveness and evolutivity while being easy to plug in. We have built a model for this issue using conceptual graphs based on an ontology and managed externally with a first order logic engine. The engine is generic and uses a knowledge base with facts and rules which can be dynamically changed. We have added a confidence notion, in order to establish a situation similarity to the knowledge base. Reactions’confidences are compared to their impacts so as to keep only the pertinent ones while avoiding user overload. Applications have tools that can be controlled by the engine. Sensors are used to extract semantic information for the context. Effectors are used to act upon the application and to have adaptations. A tools set and a knowledge base have been created for 3D interaction. Numerous steps have been added in the knowledge base to obtain good combinations and a reasoning independent from specific tools. Our first applications shows the situation understanding, including user interests and difficulties, and the triggering of pertinent assistances. An off-line study illustrates the access and evolution of the internal engine steps. The built generic semantic reasoning is expressive, understandable, extensive and modifiable dynamically. For 3D interaction, it allows universal assistances for the user that can be automatic, punctual or manual and off-line activities or conceptions analysis fort he designers.

The use of Long Short Term Memory (LSTM) networks continues to yield better results in natural language processing tasks. One area which recently has seen significant improvements is semantic dependency parsing, where the current state-of-the-art model uses a multilayer LSTM combined with an attention-based scoring function to predict the dependencies. In this thesis the state of the art model is first replicated and then extended to include features based on syntactical trees, which was found to be useful in a similar model. In addition, the effect of part-of-speech tags is studied. The replicated model achieves a labeled F1 score of 93.6 on the in-domain data and 89.2 on the out-of-domain data on the DM dataset, which shows that the model is indeed replicable. Using multiple features extracted from syntactic gold standard trees of the DELPH-IN Derivation Tree (DT) type increased the labeled scores to 97.1 and 94.1 respectively, while the use of predicted trees of the Stanford Basic (SB) type did not improve the results at all. The usefulness of part-of-speech tags was found to be diminished in the presence of other features.

Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2010

Thesis (M.Ed.) --University of Limpopo, 2009. / Some dictionaries are presented in such a way that their target users could not easily retrieve the required semantic information with special reference to Xitsonga/English Dikixinari/Dictionary (2005). Semantic information in the dictionary is presented unsystematically. In some cases extra-linguistic information in the form of contextual guidance is presented, which is regarded as secondary information in the place of semantic information (which is primary). The study evaluates this dictionary in terms of the primary of semantic comments in Xitsonga/English Dictionary. The study finds that translation equivalents are not arranged systematically in the microstructure. The research concludes that extra-linguistic information in a form of contextual guidance must be systematical used in the microstructure of Xitsonga/English Dikixinary/Dictionary (2005) so that dictionary users could be able to retrieve systematic information that could help them to speak the target language in a communicative functional way. This as a result will lead to communicative success. / Not listed

Thesis (M.A.) -- Unversity of Limpopo, 2010. / N/A

La tâche Stroop est une tâche très utilisée en psychologie car elle permet entre autres l'étude des processus dit automatiques. Cependant, récemment l'utilisation d'une présentation bicolore dans cette tâche, associée aux études liées à une tâche de détection de lettre dans une tâche d'amorçage, suggère que l'accès à la sémantique ne serait pas automatique. Ce qui impliquerait une interprétation différente de la tâche Stroop. Nous avons testé l'hypothèse qu'en présentation bicolore, la diminution observée de l'effet Stroop ne serait pas dû à un blocage de la sémantique mais à une augmentation des capacités d'inhibition. Nous avons pour cela utilisé une condition "associée" qui consistait à présenter des mots associés à une couleur (par exemple "ciel" associé à bleu) afin d'étudier plus spécifiquement l'accès à la sémantique. Dans nos deux premières études reproduisant le protocole des précédentes avec un nombre de participants plus important, nous n'observons pas de diminution de l'effet Stroop associé. Nous avons ensuite utilisé les potentiels évoqués pour montrer la présence de la N400 en condition bicolore pour les mots de couleurs et associés à une couleur dans la tâche Stroop. Pour finir, après avoir testé la présence du biais attentionnel chez des patients alcoolo-dépendants avec une version française du "Alcohol Stroop Test", nous avons montré que des ressources attentionnelles étaient nécessaires pour observer une diminution de l'effet Stroop en présentation bicolore. L'ensemble de nos résultats suggère que la diminution de l'effet Stroop en présentation bicolore nécessite des ressources attentionnelles et que donc l'accès à la sémantique serait un processus automatique, mieux inhibé dans la présentation bicolore. La tâche Stroop utilisée en clinique refléterait donc bien un processus d'inhibition de processus automatiques. / The Stroop task is a well-used task in psychology, in particular because it allows the study of automatic process. Recently the use of a single letter coloring presentation in this task, associated with the studies related to a task of detection of letter, suggests that the access to semantics would not be automatic. This implies a different interpretation from the Stroop task. We tested the assumption that in single letter colored presentation, the reduction observed in the Stroop Effect would not be due to a blocking of semantics but to an increase on the capacities of inhibition. For that we used an "associated" condition where we presented words associated with a color (for example sky associated with blue) to more specifically study the access to semantics. In our two first studies reproducing the preceding protocol with a more important number of participants, we do not observe reduction in the associated stroop effect. Then we used the Potentials Evoked to show the presence of N400 in the single letter colored condition for color words and associated-words. To finish, after having tested the presence of an attentional bias among patients alcohol-dependent with a French version on Alcohol Stroop Test, we showed that attentional resources were necessary to observe a reduction in the Stroop Effect in single letter colored presentation. The whole of our results suggest that the reduction in the Stroop Effect in single letter colored presentation requires attentional resources. The semantic access would be an automatic process. The sense of the word could be inhibiting after activation in single letter colored presentation. The Stroop task used in clinical would thus reflect an inhibition capacity of automatic process.

Intelligent and autonomous robotic applications often require robots to have more information about their environment than provided by traditional occupancy maps. An example are semantic maps, which provide qualitative descriptions of the environment. While research in the area of semantic mapping has been performed, most robotic frameworks still offer only occupancy maps. In this thesis, a framework is developed to handle multi-layered 2D maps in ROS. The framework offers occupancy and semantic layers, but can be extended with new layer types in the future. Furthermore, an algorithm to automatically generate semantic maps from RGB-D images is presented. Software tests were performed to check if the framework fulfills all set requirements. It was shown that the requirements are accomplished. Furthermore, the semantic mapping algorithm was evaluated with different configurations in two test environments, a laboratory and a floor. While the object shapes of the generated semantic maps were not always accurate and some false detections occurred, most objects were successfully detected and placed on the semantic map. Possible ways to improve the accuracy of the mapping in the future are discussed.

This thesis presents work aimed at exploiting the grammar of film for the purpose of automated film understanding, and addresses the semantic gap that exists between the simplicity of features that can be currently computed in automated content indexing systems and the richness of semantics in user queries posed for media search and retrieval. The problem is set within the broader context of the need for enabling technologies for multimedia content management, and arises in response to the growing presence of multimedia data made possible by advances in storage, processing, and transmission technologies. The first demonstration of this philosophy uses the attributes of motion and shot length to define and compute a novel measure of film tempo. Tempo flow plots are defined and derived for a number of full length movies, and edge analysis is performed leading to the extraction of dramatic story sections and events signaled by their unique tempo. In addition to the development of this computable tempo measure, a study is conducted as to the usefulness of biasing it toward either of its constituents, namely motion or shot length. Thirdly, a refinement is made to the shot length normalizing mechanism, driven by the peculiar characteristics of shot length distribution exhibited by movies. The next aspect of film examined is film rhythm. In the rhythm model presented, motion behaviour is classified as being either nonexistent, fluid or staccato for a given shot. Shot neighbourhoods in movies are then grouped by proportional makeup of these motion behavioural classes to yield seven high-level rhythmic arrangements that prove adept at indicating likely scene content (e.g., dialogue or chase sequence). The second part of the investigation presents a novel computational model to detect editing patterns as either metric, accelerated, decelerated, or free. / It is also found that combined motion and editing rhythms allow us to determine that the media content has changed and hypothesize as to why this is so. Three such categories are presented along with their efficacy for capturing useful film elements (e.g., scene change precipitated by plot event). Finally, the first attempt to extract narrative structure, the prevalent 3-Act storytelling paradigm in film, is detailed. The identification of act boundaries in the narrative allows for structuralizing film at a level far higher than existing segmentation frameworks which include shot detection and scene identification, and provides a reliable basis for inferences about the semantic content of dramatic events in film. Additionally, the narrative constructs identified have analogues in many other domains, including news, training video, sitcoms, etc., making these ideas widely applicable. A novel act boundary posterior function for Act 1 and 2 is derived using a Bayesian formulation under guidance from film grammar, tested under many configurations, and the results are reported for experiments involving 25 full-length movies. The framework is shown to have a role in both the automatic and semi-interactive setting for semantic analysis of film.

This thesis intends to develop application-level access control models to address several major security issues in enterprise environments. The first goal is to provide simple and efficient authorization specifications to reduce the complexity of security management. The second goal is to provide dynamic access control for Web service applications. The third goal is to provide an access control framework for Semantic Web services. In this thesis, an Authorization-Function-Based Role-based Access Control (FB-RBAC) model is proposed for controlling enterprise systems at the application level. The unique features of the proposed model are authorization-function-based access control and constraint-based finegrained access control. This model significantly simplifies the management of an access control system by adopting roles and authorization-functions in authorization specifications. An extension of FB-RBAC, Extended FB-RBAC (ERBAC), is applied to Web service applications. New features such as credential-based access control and dynamic role assignment are added to FB-RBAC in order to address user heterogeneity and dynamicity in the Web environment. The proposed ERBAC model is then extended to support Semantic Web services. Each component of the ERBAC model is described by security ontologies. These correlated security ontologies are integrated with Semantic Web services to form a complete ontology network. Ontology-based role assignment is facilitated so that security information can be queries and discovered through a network of ontologies.