• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 3
  • 1
  • 1
  • Tagged with
  • 13
  • 13
  • 5
  • 5
  • 4
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

New networking paradigms for future wireless networks

Shams Shafigh, A. (Alireza) 29 March 2018 (has links)
Abstract With the current technological advancements, stage is being set for new ultra-responsive and robust 5G-enabled applications (e.g., virtual reality, Tactile Internet,…) to deliver critical real-time traffic. The emergence of such critical applications requires new networking models that can handle more connected devices with super high reliability and low latency communications. In the view of these research challenges, this thesis aims to propose new techno-economic models and networking paradigms needed in the redesign of wireless network architectures and protocols to support the connectivity requirements by which operators and users effectively benefit from new opportunities introduced by 5G-enabled applications. In this thesis, new paradigms in wireless network access are presented and analyzed. First, dynamic network architecture (DNA) is introduced, where certain classes of wireless terminals can be turned temporarily into an access point (AP) anytime while connected to the Internet. In this concept, a framework is proposed to optimize different aspects of this architecture. Furthermore, to dynamically reconfigure an optimum topology and adjust it to the traffic variations, a new specific encoding of genetic algorithm (GA) is presented. Then, a distributed user-centric spectrum sharing is developed based on DNA networks to enable user-provided access points pervasively share the unused resources. Next, a flexible cloud-based radio access network (FRAN) is proposed to offload traffic to DNA networks in order to provide low latency communications. In the sequel of the thesis, as a new paradigm, a context-aware resource allocation scheme based on adaptive spatial beamforming and reinforcement learning is proposed. In addition, semi-cognitive radio network (SCRN) as a new spectrum sharing model is developed to improve the utility of primary and secondary owners. / Tiivistelmä Nykyaikaisilla teknologisilla edistysaskeleilla mahdollistetaan uusien 5G-pohjaisien erittäin lyhyen vasteajan ja suuren luotettavuuden sovelluksien ilmestyminen kriittisen reaaliaikaisen informaation välittämiseen (esim. taktiiliset ja virtuaalitodellisuus-sovellukset). Näiden kaltaiset sovellukset vaativat uudenlaisia verkottumismalleja, jotka kykenevät käsittelemään enemmän laitteita suurella toimintavarmuudella ja matalalla latenssilla. Tämä väitöskirja ehdottaa näiden haasteiden valossa uusia teknis-taloudellisia malleja ja verkottumisparadigmoja, joita tarvitaan verkkoarkkitehtuurien ja -protokollien uudelleensuunnittelussa tulevaisuuden sovelluksien tarpeet huomioiden, joiden kautta operaattorit ja käyttäjät voivat hyödyntää tulevien 5G-sovelluksien tuomat mahdollisuudet. Tässä väitöskirjassa esitetään ja analysoidaan uusia paradigmoja langattomaan verkkoliityntään. Ensimmäisenä esitellään dynaaminen verkkoarkkitehtuuri (dynamic network architecture, DNA), missä tietyt langattomat terminaalit voidaan väliaikaisesti muuttaa liityntäpisteiksi milloin vain internetyhteyden ollessa käytettävissä. Tämän konseptin puitteissa ehdotetaan viitekehys sen eri osa-alueiden optimoimiseksi. Tämän lisäksi esitetään uusi spesifinen geneettisen algoritmin (GA) koodaus optimaalisen topologian dynaamiseen konfigurointiin ja sen säätämiseen tietoliikenteen määrän mukaan. Tämän jälkeen esitellään kehitetty hajautettu käyttäjäkeskeinen spektrinjako, joka perustuu DNA-verkkoihin ja joka mahdollistaa käyttämättömien resurssien kokonaisvaltaisen jakamisen käyttäjien kautta. Seuraavaksi työssä ehdotetaan joustavaa pilvipalvelu-pohjaista liityntäverkkoa (flexible cloud-based radio access network, FRAN) käyttäjädatan purkamiseksi DNA-verkoille matalalatenssisen tietoliikenteen tarjoamiseksi. Edellä mainittujen menetelmien seurauksena ehdotetaan uutta paradigmaa: Kontekstiriippuvaista resurssien allokointia perustuen adaptiiviseen spatiaaliseen keilanmuodostukseen ja vahvistusoppimiseen. Näiden lisäksi kehitetään uusi spektrinjakomalli puolikognitiivisille radioverkoille (semi-cognitive radio network, SCRN) ensisijaisien ja toissijaisien käyttäjien utiliteetin parantamiseksi.
12

Etude des pratiques de classe dans l’évolution du savoir et sa continuité : cas d’une séquence sur les circuits électriques en classe de 5ème / Study of classroom practices in the perspective of the evolution of knowledge and its continuity : case of a teaching sequence on electrical circuits at 7th grade

El sowayssi, Nada 12 September 2016 (has links)
Notre travail porte sur une analyse des pratiques de classe au cours de la mise en œuvre d’une séquence d’enseignement sur les circuits électriques en 5ème. Nous étudions la vie du savoir, son évolution et sa continuité à travers ces pratiques. Nos outils théoriques s'appuient largement sur la Théorie de l’Action Conjointe en Didactique (TACD) qui permet la description de la pratique en fournissant des outils pour cette description notamment la notion de jeu. Nous étudions dans un premier temps les effets des pratiques de classe sur la vie du savoir, ensuite nous effectuons une étude sur la continuité du savoir. Notre analyse des effets des pratiques de classe sur la vie du savoir se fonde principalement sur notre analyse en jeux et elle est complétée par une analyse au niveau microscopiques en facettes qui représentent des parties du discours de l’ordre d’une phrase ou d’une intervention portant sur un élément de savoir. L’étude de l’ensemble des jeux des séances analysées nous a permis de distinguer certains jeux particuliers du point de vue du développement du savoir. L’étude de ces jeux nous a permis de montrer l’influence des actions du professeur et des élèves sur l’évolution du savoir. Une comparaison avec ce qui était prévu par le professeur selon les propositions des concepteurs de la séquence montre deux cas de développement suivant la façon dont le professeur prend l’activité effective des élèves en considération. Dans un cas il y a un élargissement et une densification du savoir autour d’une notion, les éléments de savoirs introduits sont en cohérence et continuité avec ceux déjà introduits, et dans l’autre cas il apparaît une dispersion des éléments de savoir autour d’une notion, les éléments de savoir introduits n’ont pas ou peu de lien avec l’enjeu de savoir.Dans notre étude nous considérons que la continuité du savoir est établie grâce à des liens créés entre éléments de savoir, méthode, procédure ou discussions à propos de ces éléments, qui peuvent avoir été en jeu à différents moments de leur enseignement., Pour cette étude la méthodologie est adaptée à la définition de la continuité et à nos données, elle inclut une analyse microscopique en facettes nourrie dans certains cas par l’analyse en jeux. Nous avons construit des catégories du fonctionnement du savoir qui permettent de relier des éléments de savoir introduits à différents moments de l’enseignement. Pour cela nous avons fait appel aux niveaux de modélisation ainsi qu’aux taches épistémiques comme définir, interpréter, décrire, comparer, etc.Cette analyse a montré que le développement du savoir est principalement initié par le champ expérimental et non par des relations entre concepts. Les nouveaux concepts sont introduits lors du passage d’une description entre objets et événements à une conceptualisation ou relation entre concepts. Cette introduction est assez souvent imposée et peut expliquer des discontinuités repérées dans la séquence.Pour terminer nous proposons des perspectives pour la formation des maitres et la conception de séquences. / Our work is focused on the analysis of classroom practices during a physics teaching sequence on electrical circuits in 7th grade. We study the life of knowledge, its evolution and continuity through these practices. Our theoretical tools are largely based on the Joint Action Theory in Didactics (JATD) that allows us to describe the practices by providing tools for this description especially the concept of the learning games. We first study the effects of classroom practices on the knowledge’s life, then we study the continuity of knowledge.Our analysis of classroom practices’effects on the life of knowledge is based primarily on our learning games analysis and is completed by a microscopic level analysis of facets that represent parts of a speech at the level of a sentence or an intervention on an element of knowledge. The study of the whole learning games analysed in the studied sessions allowed us to distinguish some particular learning games from the development of knowledge perspective. The study of these games allowed us to show the influence of the actions of the teacher and students on the evolution of knowledge. A comparison with what was planned by the teacher according to the proposals of the designers of the sequence shows two cases of development according to the way the teacher takes into considerationthe actual activity of the students. In one case there is an enlargement and densification of knowledge about a concept, elements of knowledge are introduced in consistency and continuity with those already introduced. In the other case there is dispersion of knowledge elements around a concept, elements of knowledge introduced has no or little connection with the knowledge at stake.In our study we consider that the continuity of knowledge is established through links between elements of knowledge, methods, procedures or discussions about these elements, at different teaching moments. Thus, in order to study the continuity of knowledge, we built a methodology adapted to this definition and our data by relying on microscopic analysis of facets completed in some cases by our learning games analysis. We built categories of processing knowledge that allows to connect different elements of knowledge introduced at different teaching moments. For this purpose, we used the modelling levels as well as the epistemic tasks such as defining, interpreting, describing, comparing, etc. This analysis ha shown that the development of knowledge is mainly initiated by the experimental field and not by relations between concepts. The new concepts are introduced during the passage of a description between objects and events to a conceptualization or relationship between concepts. This introduction is often imposed and may explain discontinuity of knowledge identified in the sequence.Finally, we offer perspectives for teacher training and sequences design.
13

Dynamic opponent modelling in two-player games

Mealing, Richard Andrew January 2015 (has links)
This thesis investigates decision-making in two-player imperfect information games against opponents whose actions can affect our rewards, and whose strategies may be based on memories of interaction, or may be changing, or both. The focus is on modelling these dynamic opponents, and using the models to learn high-reward strategies. The main contributions of this work are: 1. An approach to learn high-reward strategies in small simultaneous-move games against these opponents. This is done by using a model of the opponent learnt from sequence prediction, with (possibly discounted) rewards learnt from reinforcement learning, to lookahead using explicit tree search. Empirical results show that this gains higher average rewards per game than state-of-the-art reinforcement learning agents in three simultaneous-move games. They also show that several sequence prediction methods model these opponents effectively, supporting the idea of using them from areas such as data compression and string matching; 2. An online expectation-maximisation algorithm that infers an agent's hidden information based on its behaviour in imperfect information games; 3. An approach to learn high-reward strategies in medium-size sequential-move poker games against these opponents. This is done by using a model of the opponent learnt from sequence prediction, which needs its hidden information (inferred by the online expectation-maximisation algorithm), to train a state-of-the-art no-regret learning algorithm by simulating games between the algorithm and the model. Empirical results show that this improves the no-regret learning algorithm's rewards when playing against popular and state-of-the-art algorithms in two simplified poker games; 4. Demonstrating that several change detection methods can effectively model changing categorical distributions with experimental results comparing their accuracies to empirical distributions. These results also show that their models can be used to outperform state-of-the-art reinforcement learning agents in two simultaneous-move games. This supports the idea of modelling changing opponent strategies with change detection methods; 5. Experimental results for the self-play convergence to mixed strategy Nash equilibria of the empirical distributions of plays of sequence prediction and change detection methods. The results show that they converge faster, and in more cases for change detection, than fictitious play.

Page generated in 0.1029 seconds