Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The implementation of a multilingual language policy for Higher Education in South Africa (2002) requires the teaching and learning of different languages as a second or additional language – also the teaching of Afrikaans for specific purposes to students as adult learners. The teaching of Afrikaans for specific purposes to students as adult learners has not received much attention in the South African context, especially research on the learning and teaching of Afrikaans for specific purposes in a university context. This research on Afrikaans as a second language has as framework the theory of Task-Based Language Learning and Teaching. The research focuses on issues relating to complexity in task-based challenges which await students in a multilingual university context and the way in which a task-based teaching syllabus contributes to these needs and challenges. The main focus of this study is to explore the possibilities of a multiperspective approach to the analysis of complexity in the design of a task-based syllabus for university students. The aim of such a multiperspective approach is to research the full spectrum of approaches which is available to research task complexity. The adequacy of the different approaches lies in the architecture of the compositionality and combination of the individual researchers’ frameworks, which each on its’ own has elements of incompleteness regarding the development of students’ interlanguage. There can be argued that the multiperspective approach to complexity in task-based syllabus design is beneficial to task design for an Afrikaans task-based syllabus at university level because each approach promotes the development of an interlanguage. The central purpose of this study is to investigate the nature and properties of communication tasks employed in generic social and academic communication in Afrikaans on a university campus in South Africa within the framework of task-based language learning and teaching, as well as syllabus design. This study analyses the communication tasks in accordance with the needs of second language learners of Afrikaans in the context of campus communication. For the purpose of the research, a needs analysis was conducted through the use of a questionnaire and interviews with university students. This needs analysis shows that students whose first language is not Afrikaans, have the need to acquire communicative skills in Afrikaans to communicate effectively with fellow students and lecturers at the university. As a result of the needs analysis ten student-student-dialogues and ten student-lecturer-dialogues were constructed to simulate campus communication. The study researches the various cognitive and linguistic taskelements.The purpose of this research is to to examine the cognitive and structural properties in a task design which address the communication needs of students and lecturers for learning generic Afrikaans for communicating on campus. A framework for the analysis of complexity in the development of a task-based syllabus for a teaching and learning program for the teaching and learning of Afrikaans as a second language in the multilingual university context of a South African university campus will be proposed. The study examines the different components of tasks and the components of designing a syllabus, and how they influence the teaching and learning of the second language. This study analyses various complexity properties of the twenty Afrikaans dialogues in order to determine criteria for syllabus designers on how tasks can be graded and sequenced within a task-based language learning and teaching syllabus for second language learners of Afrikaans. / AFRIKAANSE OPSOMMING: Die implementering van ’n meertalige taalbeleid vir Hoër Onderwys in Suid-Afrika (2002) vereis die leer en onderrig van verskillende tale as ’n tweede of addisionele taal – ook wat die onderrig van Afrikaans vir spesifieke doeleindes aan studente as volwasse leerders betref. Hierdie onderrig van Afrikaans vir spesifieke doeleindes aan volwassenes het nog nie veel aandag binne die Suid-Afrikaanse konteks ontvang nie, veral wat betref navorsing oor die leer en onderrig van Afrikaans vir spesifieke doeleindes binne ’n universiteitskonteks. Die navorsing wat vir hierdie proefskrif onderneem is, val binne die teorie van taakgebaseerde leer en onderrig. Dit fokus op die aspekte wat verband hou met taakgebaseerde kompleksiteitsuitdagings wat vir studente binne ’n meertalige universiteitskonteks voorlê en die wyse waarop ’n taakgebaseerde leer- en onderrigprogram voldoen aan hierdie behoeftes en uitdagings. Die sentrale fokus van hierdie proefskrif behels ’n ondersoek na die moontlikheid van ’n multiperspektiefbenadering tot die analise van kompleksiteit by die ontwerp van ’n Afrikaanse taakgebaseerde sillabus op universiteitsvlak. Die doel van so ’n multiperspektiefbenadering is om die volle spektrum van oorwegings wat ter sprake is in taakkompleksiteit te ondersoek. Die toereikendheid van dié spesifieke benadering lê in die argitektuur van die samehang en kombinasie van die verskillende navorsers se raamwerke wat elk op sigself tekens van onvolledigheid toon ten opsigte van die optimale ontwikkeling van die studente se intertaal. Daar word betoog dat dat hierdie multiperspektiefbenadering tot kompleksiteit in taakgebaseerde sillabusontwerp voordelig is ten opsigte van sillabusontwerp vir Afrikaans op universiteitsvlak aangesien intertaalontwikkeling optimaal binne elk van die benaderings verantwoord kan word. Die sentrale fokuspunt van die proefskrif is om ondersoek in te stel na die aard en eienskappe van kommunikasietake wat gevind word in generies sosiale en akademiese kommunikasietake in Afrikaans by ’n universiteitskampus in Suid-Afrika. Dit vind plaas binne die konteks van hedendaagse tweedetaalteorieë oor taakgebaseerde taalleer en -onderrig, sowel as sillabusontwerp. Hierdie studie analiseer die kommunikasietake aan die hand van die behoeftes van tweedetaalstudente van Afrikaans binne die konteks van kampuskommunikasie. Dié behoeftes is bepaal na aanleiding van behoefte-analises wat onder universiteitstudente onderneem is. Die behoefte-analises toon dat studente wie se eerste taal nie Afrikaans is nie, die behoefte het om Afrikaans te verwerf ten einde suksesvol te kan kommunikeer met medestudente en dosente. Na aanleiding van die behoefte-analises is tien student-student-dialoë en tien student-dosent-dialoë gekonstrueer wat verteenwoordigende kampuskommunikasie simuleer. Die doelwit van hierdie studie is om die verskeie kenmerke van take wat verband hou met kognitiewe en linguistiese kompleksiteit in ’n taakgebaseerde ontwerp te ondersoek. Die doel hiervan is om onder meer ’n raamwerk vir die analisering van kompleksiteit in ’n taakgebaseerde sillabus vir leer en onderrig van generiese Afrikaans vir kampuskommunikasie voor te stel. Saam met die ondersoek na kognitiewe en linguistiese kompleksiteit, ondersoek die proefskrif die kenmerke van sillabusontwerp om te bepaal hoe dit die leer en onderrig van Afrikaans as ’n tweede taal beïnvloed. Die insigte wat sodoende oor die kompleksiteit van die take verkry word, skep verskeie moontlikhede vir die ontwikkeling van take binne die konteks van ’n universiteitskampus met betrekking tot die leer van Afrikaans as ’n tweede taal. Voorts verskaf die studie ook ontledings met betrekking tot die kompleksiteitskenmerke van die twintig dialoë in Afrikaans sodat kriteria vir sillabusontwerpers geskep kan word waarvolgens hulle take binne die taakgebaseerde leer en onderrig kan gradeer en orden om ’n sillabus vir tweedetaalstudente van Afrikaans te ontwerp.

「真實性」是外語教學在內容設計及呈現上一項不可忽視的原則。它強調：教科書的編寫，要有意識地為學習者展現出語言在實際運用中的意義和功能。而除了文本(text)之外，有越來越多的教育者也強調「真實性的教學活動(authentic tasks/activities)」在教學過程中的重要性。本篇論文主要在探討是否現行國中英語教科書中的活動設計符合「真實性」的原則。此研究以Littlewood(2004)提出的教學活動分類作為架構，觀察台灣現行使用率最高的五套國中英語教科書中的教學活動分屬何種類型，分析及探究其中有哪些活動是符合「以真實溝通為目的」的原則，同時比較真實性教學活動分布在這五版教科書中的情況。 分析結果顯示，絕大多數的活動設計，是以學習語言形式為主要目的，極少數的活動有機會讓學習者運用語言、傳達訊息。此外，有些教科書中，甚至完全缺少以真實溝通為目的的教學活動。也就是說，透過現行的教科書，學生只是從事句型文法的練習，極少實際利用學到的語言進行溝通。顯然這些開放後由民間出版社編輯的英語教科書，就教學活動真實性的問題，尚有很大的改善空間。 / Authenticity has been regarded as one of the essential principles in EFL/ESL teaching. It is emphasized that the content of the textbooks can realistically reflect the genuine meaning and function of the language used in real-life situations. Aside from the authenticity of text itself, more and more teachers and educators recognize the value of using authentic activities for teaching and learning purposes. The thesis aims to examine whether and how the language learning activities in our EFL textbooks pertain to authenticity. We explore what authentic learning activities in these textbooks are, and how they are different as found in different textbooks. By following a rating scale developed on the basis of Littlewood’s (2004) five activity types (non-communicative learning, pre-communicative language practice, communicative language practice, structured communication and authentic communication), we evaluate and compare the language learning activities provided in five sets of English textbooks frequently used in Taiwan in terms of their task authenticity. The result of our analysis reveals that most language learning activities in the five commonly used sets of English textbooks are designed mainly for the practice of the linguistic forms. Few of the activities provide learners with the chance of exposure to real communication situations and applying their language skills in authentic ways. Even some of the textbook series don’t contain any authentic learning activities at all. It is clear that textbook writing in Taiwan still focuses on linguistic forms – a situation that has lasted for decades and more changes in textbook writing are needed in order to move forward to genuine communication.

Les architectures de calcul haute performance les plus récentes intègrent de plus en plus de nœuds de calcul qui contiennent eux-mêmes plus de cœurs. Les bus mémoires et les réseaux de communication sont soumis à un niveau d'utilisation critique. La programmation parallèle sur ces nouvelles machines nécessite de porter une attention particulière à ces problématiques pour l'écriture de nouveaux algorithmes. Nous analysons dans cette thèse un code de simulation de turbulences de plasma et proposons une refonte de la parallélisation de l'opérateur de gyromoyenne plus adapté en termes de distribution de données et bénéficiant d'un schéma de recouvrement calcul -- communication efficace. Les optimisations permettent un gain vis-à-vis des coûts de communication et de l’empreinte mémoire. Nous étudions également les possibilités d'évolution de ce code à travers la conception d'un prototype utilisant un modèle programmation par tâche et un schéma de communication asynchrone adapté. Cela permet d'atteindre un meilleur équilibrage de charge afin de maximiser le temps de calcul et de minimiser les communications entre processus. Un maillage réduit adaptatif en espace est proposé, diminuant le nombre de points sans pour autant perdre en précision, mais ajoutant de fait une couche supplémentaire de complexité. Ce prototype explore également une distribution de données différente ainsi qu'un maillage en géométrie complexe adapté aux nouvelles configurations des tokamaks. Les performances de différentes optimisations sont étudiées et comparées avec le code préexistant et un cas dimensionnant sur un grand nombre de cœurs est présenté. / Recent high performance computing architectures come with more and more cores on a greater number of computational nodes. Memory buses and communication networks are facing critical levels of use. Programming parallel codes for those architectures requires to put the emphasize on those matters while writing tailored algorithms. In this thesis, a plasma turbulence simulation code is analyzed and its parallelization is overhauled. The gyroaverage operator benefits from a new algorithm that is better suited with regard to its data distribution and that uses a computation -- communication overlapping scheme. Those optimizations lead to an improvement by reducing both execution times and memory footprint. We also study new designs for the code by developing a prototype based on task programming model and an asynchronous communication scheme. It allows us to reach a better load balancing and thus to achieve better execution times by minimizing communication overheads. A new reduced mesh is introduced, shrinking the overall mesh size while keeping the same numerical accuracy but at the expense of more complex operators. This prototype also uses a new data distribution and twists the mesh to adapt to the complex geometries of modern tokamak reactors. Performance of the different optimizations is studied and compared to that of the current code. A case scaling on a large number of cores is given.

La méthode d’imagerie la plus répandue dans l’industrie pétrolière est la RTM (Reverse Time Migration) qui repose sur la simulation de la propagation des ondes dans le sous-sol. Nous nous sommes concentrés sur un propagateur d'ondes élastiques 3D en milieu anisotrope de type TTI (Tilted Transverse Isotropic). Nous avons directement travaillé dans le code de recherche de Total DIVA (Depth Imaging Velocity Analysis), basé sur une discrétisation par la méthode de Galerkin Discontinue et le schéma Leap-Frog, et développé pour le calcul parallèle intensif – HPC (High Performance Computing). Nous avons ciblé plus particulièrement deux contributions possibles qui, si elles supposent des compétences très différentes, ont la même finalité : réduire les coûts de calculs requis pour la simulation. D'une part, les conditions aux limites classiques de type PML (Perfectly Matched Layers) ne sont pas stables dans des milieux TTI. Nous avons proposé de formuler une CLA (Conditions aux Limites Absorbantes) stable dans des milieux anisotropes. La méthode de construction repose sur les propriétés des courbes de lenteur, ce qui donne à notre approche un caractère original. D'autre part, le parallélisme initial, basé sur une décomposition de domaine et des communications par passage de messages à l'aide de la bibliothèque MPI, conduit à un déséquilibrage de charge qui détériore son efficacité parallèle. Nous avons corrigé cela en remplaçant le paradigme parallélisme par l'utilisation de la programmation à base de tâches sur support d'exécution. Cette thèse a été réalisée dans le cadre de l'action de recherche DIP (Depth Imaging Partnership) qui lie la compagnie pétrolière Total et Inria. / The most common method of Seismic Imaging is the RTM (Reverse Time Migration) which depends on wave propagation simulations in the subsurface. We focused on a 3D elastic wave propagator in anisotropic media, more precisely TTI (Tilted Transverse Isotropic). We directly worked in the Total code DIVA (Depth Imaging Velocity Analysis) which is based on a discretization by the Discontinuous Galerkin method and the Leap-Frog scheme, and developed for intensive parallel computing – HPC (High Performance Computing). We choose to especially target two contributions. Although they required very different skills, they share the same goal: to reduce the computational cost of the simulation. On one hand, classical boundary conditions like PML (Perfectly Matched Layers) are unstable in TTI media. We have proposed a formulation of a stable ABC (Absorbing Boundary Condition) in anisotropic media. The technique is based on slowness curve properties, giving to our approach an original side. On the other hand, the initial parallelism, which is based on a domain decomposition and communications by message passing through the MPI library, leads to load-imbalance and so poor parallel efficiency. We have fixed this issue by replacing the paradigm for parallelism by the use of task-based programming through runtime system. This PhD thesis have been done in the framework of the research action DIP (Depth Imaging Partnership) between the Total oil company and Inria.

本論文為一教學實驗之研究，探討如何運用以電腦科技為媒介設計創新的學習環境，激勵台灣技專院校英語低成就學生之學習動機，增進其英語聽力能力。本研究以英語歌曲作為提升學習興趣的動源，電腦輔助學習任務為提供好玩有趣學習過程的憑藉；如此，學生可由愉悅聽歌、趣味活動中實作學習並達成學習任務目標。本論文並探索英語歌曲聽力電腦輔助學習任務對學生聽力字彙與知覺能力之影響，並了解學生對教學設計之歌曲聽力學習任務之評估。由學生在全民英檢聽力、英語母音知覺測驗、及歌曲單字聽力各方面的成績進步，顯示本實驗教學能有效改善低成就學生英語字彙與聽力學。根據相關與變異數分析結果，對學習任務評估越滿意的學生英語歌曲單字聽力成績進步越大。因此，本研究所設計之英語歌曲聽力學習任務能激發學生運用電腦與相關軟體學習編輯聲音影片，來了解英語 聲音與意義的連結、訓練養成辨識斷句的知覺聽力。此教學設計融入聽力教學、任務型學習、電腦輔助學習；且以設計研究方法觀點記錄理論基礎探討、教學資源運用、英語聽力課程中歌曲時間排練及歌曲切割之投影片簡報、歌曲對嘴表演影片製作學習任務之設計執行，提供其他英語教師作為電腦輔助聽力學習活動設計之參考。 / This study is an instructional experiment on how an innovative learning environment is constructed to motivate and improve English learning of the low-achievers at Taiwanese polytechnic colleges. Thus, this research employs English popular songs as a motivator and computer-assisted task design as a mediator for the students to do listening and play with the song materials. This instructional design provides these students with concrete task experiential learning and the pursuit for goal-oriented success, along with joyful song listening and playful task activities. This research also investigates the effects of these song listening tasks on the improvement of listening vocabulary and perceptual skills of the participants as well as their appraisals toward the designed tasks: time-rehearsing, segmenting, and lip-syncing. The effects of these song listening tasks are consolidated from the participants’ improved listening test scores from the elementary GEPT Listening Test, the Perception of Spoken English Test, and the Target Lexical Listening Test, their enhanced learning motivation and involved task performance, and their affirmed appraisals about their task fondness and the task usefulness. Furthermore, this study documents the design, implementation, and evaluation of such a song listening task-based syllabus in a digital language lab, which demonstrates an integration of second language (L2) listening instruction, task-based learning and teaching (TBLT), and computer assisted language learning (CALL). The design-based research (DBR) perspectives are also adopted to explain the role of the computer-mediated context to the innovative task construction; in addition, the task features which facilitate listening skills development and stimulate learning experience are identified by the appraisal components of song fondness and easiness, task playfulness and easiness, and task usefulness. Thus, the designed listening tasks can be shared and applied to other similar learning contexts.

Made available in DSpace on 2016-06-02T20:25:23Z (GMT). No. of bitstreams: 1 6301.pdf: 13529065 bytes, checksum: 3dd0f5e7e2c7165dcea9b0758e2ff350 (MD5) Previous issue date: 2014-03-28 / This study aims at investigating the relations between a Thematic Task-Based Syllabus and the Communicative Competence (CC) of students of Portuguese as a second language. This qualitative, ethnographic - interpretative research is grounded in studies on CC (CANALE; SWAIN, 1980; CANALE, 1983; CELCE-MURCIA, 2007; HYMES, 1972) of foreign language learners in immersion context. The framework for the Thematic Task-Based Syllabus is founded on theoretical studies of Barbirato (2005), Ellis (2003), Nunan (1989). The thematic material used in this work is called Brasilidades and the theme is based on cultural perspectives of the Northeast and South parts of Brazil. The material was implemented in two courses of Portuguese as a second language in a university in the Southeastern part of Brazil. Each course lasted 30 hours, and the data was collected in the second semester of 2012 and the first semester of 2013. Some of the instruments used for data collection were: research diary, audio and video recording of the classes and questionnaires. The results suggest that the Thematic Task-Based Syllabus allow students a profound mobilization of their CC in communicative scenarios. This kind of syllabus has also shown to be consonant to the model of CC proposed by Celce-Murcia (2007) which places the discursive competence as the center of the CC model since this type of planning recovers primary functions of language such as communication and production of meaning through meaningful contexts. During the task phase, it also offers moments of interaction between students based on the discursive construction of language. / Este estudo tem por objetivo pesquisar as relações que podem ser estabelecidas entre um planejamento temático baseado em tarefas (PTBT) e a competência comunicativa (CC) em um curso de português língua estrangeira (PLE). Esta é uma pesquisa interpretativista, de cunho etnográfico, com tratamento qualitativo dos dados, alicerçada em estudos sobre a CC (CANALE; SWAIN, 1980; CANALE, 1983; CELCE-MURCIA, 2007; HYMES, 1972) de alunos de língua estrangeira em contexto de imersão. Incorporado à base deste estudo está o PTBT, ao qual os participantes desta pesquisa foram expostos. Embasamo-nos nos estudos de Barbirato (2005), Ellis (2003) e Nunan (1989) para a elaboração de um material didático chamado Brasilidades, cujo foco está nas Regiões Nordeste e Sul do país, interpretadas a partir de recortes culturais. Esse material foi implementado em duas turmas de português para estrangeiros, com carga horária de 30 horas cada curso e duração de um semestre cada turma, totalizando um ano de coleta de dados (2012-2013) em uma universidade no interior paulista. Para a coleta de dados, utilizamos caderno de observações, gravação das aulas em áudio e vídeo e questionários semiabertos. Os resultados demonstraram que o PTBT possibilita ao aluno uma profunda mobilização de sua CC perante os cenários comunicativos. Este planejamento também mostrou ser consoante com o modelo da CC proposta por Celce-Murcia (2007) que coloca o componente discursivo como centro do modelo da CC, pois o PTBT resgata funções primárias da linguagem de comunicar e produzir conhecimentos por meio de tema significativo, além de oferecer, nas tarefas, momentos de interação dos alunos fundados na construção discursiva da linguagem.

L’engagement du Conseil de l’Europe en faveur d’une éducation plurilingue intégrant altérité et diversité culturelle est fortement lié au souci de promouvoir la communication entre citoyens de langue et culture différentes, indispensable à la mobilité et à la compréhension réciproque. Dans ce nouveau référentiel s’inscrit la tendance à enseigner les disciplines non linguistiques, directement dans la L2. Cette méthode d’enseignement d’une matière par intégration d’une langue étrangère, appelée EMILE a vocation d’accélérer le processus d’apprentissage. Or, il s’est avéré, lors d’une recherche-action portant sur l’anglais juridique, qu’une méthode d’immersion complète telle qu’EMILE pouvait présenter certaines failles pour apprendre cette langue de spécialité très pointue. Pour combler ces failles, nous proposons la méthode LADMI (Linguistique appliquée à une autre discipline par méthode intégrative), qui est une modification du concept d’EMILE extrapolant à partir d’une certaine structure logique, suite à des observations particulières, afin de préserver à la fois la langue et le contenu de la DNL, le droit. / The European Council’s policy of promoting linguistic and cultural diversity in the field of acquisition-teaching of foreign languages, has led to a profoundly modified situation in language learning. With the aim of encouraging mobility among students and teachers in the European education system, pluralinguistic methods, such as TIE-CLIL (Translanguage in Europe – Content and Language Integrated Learning) are used in an attempt to accelerate immersion programmes. However, in an action research undertaken in Legal English at the University of Nice, the conclusion was drawn that language immersion is not always feasible in Law. Therefore an integrated approach, Adjunct CLIL, based on logical observations, a modification of the concept CLIL : ALDIM (Applied Linguistics to another Discipline by Integrated Method), is suggested, to preserve both the quality of the language as well as content of the non-linguistic discipline, Law.

Depuis l’avènement de l’approche communicative, puis actionnelle, en enseignement des langues secondes (L2), des chercheurs comme Ellis (2003) ont relevé les différences individuelles entre apprenants, notamment concernant le désir de communiquer (DDC), défini comme « une disposition à entrer dans un discours à un moment spécifique avec une ou des personnes spécifiques, en utilisant la L2 » (MacIntyre et al., 1998, p. 547). Il a ainsi été suggéré de faire du développement du DDC de plus en plus une priorité en enseignement des L2. À cet égard, la recherche indique que la communication assistée par ordinateur peut permettre d’augmenter le DDC (Rankin et al., 2006; Gonzalez-Lloret, 2017), en influençant l’anxiété langagière et le sentiment de compétence communicative perçu (SCCP), qui sont les deux antécédents directs du DDC. L’émergence récente de la réalité virtuelle 360 (RV360), qui peut être définie comme un environnement immersif s’appuyant sur des photos ou vidéos reproduisant le monde réel et fournissant à l’utilisateur un fort sentiment de présence, ouvre un nouveau champ d’expérimentation en DdL. Nous proposons que la RV360 permettrait aux apprenants de L2 de prendre part à des simulations quasi authentiques diminuant leur anxiété et augmentant leur SCCP, améliorant ainsi leur DDC à l’extérieur de la salle de classe. Pour répondre à notre questionnement, nous avons créé puis mis en place trois courtes tâches de simulation RV360 présentant des situations communicatives similaires à celles de la vie quotidienne des apprenants, comme payer son épicerie en français. Ces tâches sont ancrées dans la réalité sociolinguistique de l’environnement d’apprentissage : dans cette étude, Montréal, une métropole bilingue français-anglais ayant une variété régionale de français distincte. Les 19 participants à cette recherche exploratoire sont des étudiants universitaires internationaux de FLS au niveau débutant. Une méthodologie mixte (prétest et posttest quantitatifs, journaux de bord et entrevues de groupe semi-dirigées) a été adoptée pour suivre l’évolution de leur SCCP, anxiété langagière et DDC, ainsi que pour cerner leurs défis quant à la pratique du français à Montréal et leur perception des tâches RV360 en tant qu’outil d’apprentissage préparant à la communication authentique en L2. L’analyse des données indique que les défis à la communication en FLS dans le monde réel proviennent principalement d’une perception négative de son vocabulaire et de sa prononciation, combinée à l’anxiété liée à l’anticipation de ruptures de communication avec des locuteurs francophones. Face à cet écueil, les participants estiment globalement que les tâches RV360 sont un bon outil pour créer un pont entre la salle de classe et le monde réel et ainsi préparer aux interactions en L2 dans le monde réel, même si leur faible degré de difficulté et leur manque de flexibilité nuisent à leur authenticité. Les tâches RV360 ont ainsi contribué positivement (mais à degré variable selon les apprenants) à l’amélioration du DDC, principalement via le renforcement du SCCP. La discussion des résultats fournit un nouvel éclairage sur les bonnes pratiques d’enseignement et sur l’élaboration de séquences didactiques intégrant la RV360 pour favoriser le DDC au niveau débutant. Ces séquences devraient en priorité intégrer l’enseignement stratégique et mettre l’accent sur la complexification progressive des tâches et la rétroaction, tout en doublant la réalisation des tâches RV360 d’une interaction humain-humain. / Since communicative approach and task-based language teaching have placed communication at the centre of second language (L2), researchers such as Ellis (2003) have underlined the importance of individual differences between L2 learners, regarding their willingness to communicate (WTC), which is defined as "readiness to enter into discourse at a particular time with a specific person using the L2" (MacIntyre et al., 1998, p. 547). These researchers have suggested that the development of L2 WTC be made a priority of L2 teaching. In this respect, the literature shows that computer-mediated communication has a positive effect on increasing L2 learners' WTC (Rankin et al., 2006; Gonzalez-Lloret, 2017), by lowering language anxiety and increasing self-perceived communicative competence (SPCC), which are the two main antecedents of L2 WTC. One avenue for research that has not received much attention is the pedagogical use of 360 virtual reality (VR360), a promising medium for teachers hoping to increase their L2 students' WTC. VR360 can be defined as an immersive digital environment relying on 360 photos/videos from the real world and providing the user with a strong feeling of presence in “real life” situations. We propose that VR360 has the potential to provide learners with semi authentic simulations designed to lower their anxiety and increase their SPCC, leading to increased WTC. To assess this potential, we designed and implemented three short communicative VR360 tasks presenting learners with communicative situations similar to the ones they could encounter in their daily life, such as paying for groceries using L2 French. The tasks are anchored in the reality of the learning environment: in this case, Montreal, a French-English bilingual metropolis with a distinct regional variety of French. The 19 participants to this exploratory study are international university students learning L2 French at a beginner level. Mixed methodology (quantitative pre/post tests, reflective journals and semi-structured focus groups) was used to measure and probe their level of SPCC, anxiety and WTC, and to shed light on the challenges they face while trying to interact in French in Montreal and their perception of the RV360 tasks as a learning tool preparing for real-life L2 use. The data analysis indicates that the challenges to communication in L2 French in the real world mainly come from a negative perception of one’s vocabulary and pronunciation, combined with anxiety due to the anticipation of breakdowns in communication with native French speakers. Faced with this pitfall, participants generally argued that RV360 tasks are a good learning tool to bridge the classroom and the real world and thus prepare them for L2 interaction in the real world, even if the low level of difficulty and the lack of flexibility limit task authenticity. The RV360 tasks thus contributed positively (albeit to varying degrees among learners) to the improvement of their WTC, mainly via the strengthening of their SCCP. The discussion provides new insights into good teaching practices and the development of learning scenarios incorporating the RV360 to promote WTC at a beginner level. These scenarios should focus on strategic instruction, task complexity and feedback, while relying on a human-human interaction in addition to the completion of the RV360 tasks.

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To leverage the extreme parallelism of emerging architectures, so that scientific applications can fulfill their high fidelity and multi-physics potential while sustaining high efficiency relative to the limiting resource, numerical algorithms must be redesigned. Algorithmic redesign is capable of shifting the limiting resource, for example from memory or communication to arithmetic capacity. The benefit of algorithmic redesign expands greatly when introducing a tunable tradeoff between accuracy and resources. Scientific applications from diverse sources rely on dense matrix operations. These operations arise in: Schur complements, integral equations, covariances in spatial statistics, ridge regression, radial basis functions from unstructured meshes, and kernel matrices from machine learning, among others. This thesis demonstrates how to extend the problem sizes that may be treated and to reduce their execution time. Two “universes” of algorithmic innovations have emerged to improve computations by orders of magnitude in capacity and runtime. Each introduces a hierarchy, of rank or precision. Tile Low-Rank approximation replaces blocks of dense operator with those of low rank. Mixed precision approximation, increasingly well supported by contemporary hardware, replaces blocks of high with low precision. Herein, we design new high-performance direct solvers based on the synergism of TLR and mixed precision. Since adapting to data sparsity leads to heterogeneous workloads, we rely on task-based runtime systems to orchestrate the scheduling of fine-grained kernels onto computational resources. We first demonstrate how TLR permits to accelerate acoustic scattering and mesh deformation simulations. Our solvers outperform the state-of-art libraries by up to an order of magnitude. Then, we demonstrate the impact of enabling mixed precision in bioinformatics context. Mixed precision enhances the performance up to three-fold speedup. To facilitate the adoption of task-based runtime systems, we introduce the AL4SAN library to provide a common API for the expression and queueing of tasks across multiple dynamic runtime systems. This library handles a variety of workloads at a low overhead, while increasing user productivity. AL4SAN enables interoperability by switching runtimes at runtime, which permits to achieve a twofold speedup on a task-based generalized symmetric eigenvalue solver.