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  • 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.
41

Vokabulärundervisning i engelska på högstadiet och gymnasiet : Fem lärares syn på undervisning av vokabulär. / English vocabulary in the Swedish lower and upper secondary school : Five teachers' views on how to teach vocabulary

Fromheden, Katarina Hannah Ingela, Gustavsson Svedelius, Jimmy January 2023 (has links)
The purpose of this qualitative study is to compare five teachers’ beliefs about their students’ learning of vocabulary and compare that with current theories and recommended practices in the field. The method for collecting data was semi-structured interviews with teachers who teach English in both lower secondary and upper secondary schools in Sweden. The data from these interviews were then analyzed by way of thematic analysis. The results were then compared with previous research in the field of vocabulary learning drawing on studies and works of researchers such as Stuart Webb and Paul Nation among others. The results reveal a lot of similarities with the latest research on vocabulary learning. The findings of this study also indicate some differences between teacher beliefs and research. Apart from research done in the field of vocabulary learning this study has also taken the proven experience of the teachers into account. Since this study is of a qualitative kind, these results cannot be generalized in regard to Swedish teachers of English as a group but rather what some of them portray when talking on the topic of vocabulary.
42

Att utveckla läsförståelse - läsförståelsestrategier och metoder i skolan : En kvalitativ intervjustudie om fyra lärares syn på läsförståelseundervisning

Levin, Catharina January 2016 (has links)
Internationella studier, PIRLS 2011 och PISA 2012, visar svenska elevers försämrade kunskapsnivåer i läsförståelse. Skolan styrdokument från 2011, Lgr 11, uttrycker explicit undervisning av läsförståelsestrategier i ämnet svenska i grundskolans alla stadier. Den nedåtgående trenden har medfört att diskussionerna kring utvecklingen av läsförståelseundervisning har ökat. Läsforskare varnar för att lärarna lämnas att ensamma tolka hur de ska undervisa i lässtrategier som påverkar läsförståelsen. Våren 2014 lanserades läromedlet En läsande klass som är en privat satsning med ett långsiktigt mål att öka elevers läsförståelse och syftet att lyfta vikten av läsförståelse. Omfattande svensk forskning saknas dock på området. Syftet med denna studie var därför att undersöka hur undervisande lärare på låg- och mellanstadiet ser på sin läsförståelseundervisning och användandet av metoder och strategier för elever med god läsförståelse men även för elever som upplever hinder i sin läsförståelse. Undersökningen genomfördes med en kvalitativ metod med intervjuer som hade halvstrukturerad form. Fyra lärare, som alla undervisar i svenska och arbetar med läsförståelse i sin undervisning, intervjuades. Resultatet visade att samtliga lärare arbetar med läsförståelsestrategier på olika nivåer och att de använder materialet En läsande klass i olika utsträckning i sin undervisning. I resultatet kan man även utläsa att det finns ett behov hos lärare att få direktiv hur explicit läsförståelseundervisning ska bedrivas i skolan för att säkerställa kvalitet i sitt arbete med läsförståelse. / <p>Svenska</p>
43

Metalinguistic Knowledge and the Acquisition of the Spanish Subjunctive by Learners at Three Proficiency Levels

Correa, Maite January 2008 (has links)
One of the most controversial topics in Applied Linguistics is the role of learners' metalinguistic knowledge (MK) in second language (L2) learning and teaching. There seems to be no agreement between those who propose that MK is essential for L2 learning and those who believe that it can even be detrimental for L2 acquisition.Additionally, the subjunctive has been reported to be one of the most difficult structures to master for L2 learners of Spanish. It has been suggested that the subjunctive is acquired fairly late in an acquisition hierarchy of Spanish grammar and that, as a consequence, learners must reach a stage where they can produce syntactically sophisticated utterances in order to be "ready" for acquisition.Taking an Information Processing (IP) approach to language learning as a framework, this dissertation investigates the relationship between MK and grammatical accuracy by learners of Spanish at beginning, intermediate, and advanced levels of proficiency. Their MK is assessed through a set of terminology and grammaticality judgment tasks. Their mastery of the Spanish subjunctive is evaluated through a set of receptive and productive tests involving different subordinate clauses.The three groups of participants are compared with respect to their MK and their mastery of the subjunctive, and it is examined whether MK correlates with mastery of the subjunctive. Findings include: 1) an improvement on both subjunctive accuracy and terminology knowledge across levels; 2) a positive correlation between English MK and Spanish MK; 3) a positive correlation between MK and accuracy in the use of the subjunctive; and 4) agreement between the learners' acquisition hierarchy within the subjunctive and teaching order of subjunctive substructures.The findings show that MK has a positive impact on the mastery of this "difficult" structure. They are also consistent with other experimental studies that suggest that explicit instruction has a positive impact on L2 learning. The late and uneven acquisition of the subjunctive demonstrated by the subjects in this study also suports the hypothesis that there are "many subjunctives" to learn and that learners will not acquire this structure until they are developmentally ready (third year of instruction).
44

Spatially Explicit Simulation of Peatland Hydrology and Carbon Dioxide Exchange

Sonnentag, Oliver 01 August 2008 (has links)
In this research, a recent version of the Boreal Ecosystem Productivity Simulator (BEPS), called BEPS-TerrainLab, was adapted to northern peatlands and evaluated using observations made at the Mer Bleue bog located near Ottawa, Ontario, and the Sandhill fen located near Prince Albert, Saskatchewan. The code was extended and modified with a major focus on the adequate representation of northern peatlands' multi-layer canopy and the associated processes related to energy, water vapour and carbon dioxide fluxes through remotely-sensed leaf area index (LAI) maps. An important prerequisite for the successful mapping of LAI based on remote sensing imagery is the accurate measurement of LAI in the field with a standard technique such as the LAI-2000 plant canopy analyzer. As part of this research, a quick and reliable method to determine shrub LAI with the LAI-2000 instrument was developed. This method was used to collect a large number of LAI data at the Mer Bleue bog for the development of a new remote sensing-based methodology using multiple endmember spectral unmixing that allows for separate tree and shrub LAI mapping in ombrotrophic peatlands. A slight modification of this methodology allows for its application to minerotrophic peatlands and their surrounding landscapes. These LAI maps were used to explicitly represent the tree and shrub layers of the Mer Bleue bog and the tree and shrub/sedge layers of the Sandill fen within BEPS-TerrainLab. The adapted version of BEPS-TerrainLab was used to investigate the in fluence of mescoscale topography (Mer Bleue bog) and macro- and mesoscale topography (Sandhill fen) on wetness, evapotranspiration, and gross primary productivity during the snow-free period of 2004. This research suggests that future peatland ecosystem modelling efforts at regional and continental scales should include a peatland type-specific differentiation of macro- and mesoscale topographic effects on hydrology, to allow for a more realistic simulation of peatlands' soil water balance. This is an important prerequisite for the reduction of currently existing uncertainties in wetlands' contribution to North America's carbon dioxide and methane annual fluxes from an ecosystem modelling perspective.
45

Modelling evolution of anisotropy in metals using crystal plasticity

Chaloupka, Ondrej 03 1900 (has links)
Many metals used in modern engineering exhibit anisotropy. A common assumption when modelling anisotropic metals is that the level of anisotropy is fixed throughout the calculation. As it is well understood that processes such as cold rolling, forging or shock loading change the level of anisotropy, it is clear that this assumption is not accurate when dealing with large deformations. The aim of this project was to develop a tool capable to predict large deformations of a single crystal or crystalline aggregate of a metal of interest and able to trace an evolution of anisotropy within the material. The outcome of this project is a verified computational tool capable of predicting large deformations in metals. This computational tool is built on the Crystal Plasticity Finite Element Method (CPFEM). The CPFEM in this project is an implementation of an existing constitutive model, based on the crystal plasticity theory (the single crystal strength model), into the framework of the FEA software DYNA3D® . Accuracy of the new tool was validated for a large deformation of a single crystal of an annealed OFHC copper at room temperature. The implementation was also tested for a large deformation of a polycrystalline aggregate comprised of 512 crystals of an annealed anisotropic OFHC copper in a uniaxial compression and tension test. Here sufficient agreement with the experimental data was not achieved and further investigation was proposed in order to find out the cause of the discrepancy. Moreover, the behaviour of anisotropic metals during a large deformation was modelled and it was demonstrated that this tool is able to trace the evolution of anisotropy. The main benefit of having this computational tool lies in virtual material testing. This testing has the advantage over experiments in time and cost expenses. This tool and its future improvements, which were proposed, will allow studying evolution of anisotropy in FCC and BCC materials during dynamic finite deformations, which can lead to current material models improvement.
46

Caffeine Enhances Memory Performance in Young Adults during Their Non-optimal Time of Day

Sherman, Stephanie M., Buckley, Timothy P., Baena, Elsa, Ryan, Lee 14 November 2016 (has links)
Many college students struggle to perform well on exams in the early morning. Although students drink caffeinated beverages to feel more awake, it is unclear whether these actually improve performance. After consuming coffee (caffeinated or decaffeinated), college-age adults completed implicit and explicit memory tasks in the early morning and late afternoon (Experiment 1). During the morning, participants ingesting caffeine demonstrated a striking improvement in explicit memory, but not implicit memory. Caffeine did not alter memory performance in the afternoon. In Experiment 2, participants engaged in cardiovascular exercise in order to examine whether increases in physiological arousal similarly improved memory. Despite clear increases in physiological arousal, exercise did not improve memory performance compared to a stretching control condition. These results suggest that caffeine has a specific benefit for memory during students' non-optimal time of day-early morning. These findings have real-world implications for students taking morning exams.
47

Aplikace explicitně korelovaných multireferenčních metod spřažených klastrů / Aplication of explicitly correlated multi-reference coupled cluster methods

Lang, Jakub January 2014 (has links)
Nowdays, coupled cluster method belongs to one of the most used quantum chemical methods. However, the single-reference coupled cluster methods are not able to describe systems where the static correlation have an important role. Multireference coupled cluster methods developed in our group can describe both static and dy- namic correlation and can be used for problematic systems. Together with explicitly correlated wavefunction, which can properly describe the electronic cusp and speed up the convergence to the complete ba- sis set limit, they are able to calculate computationally demanding diradicals. Multireference CC calculations of tetramethylenethane have been perforemd and the performance of explicitly correlated version is discussed. Calculations of the isomerization of bicyclobu- tane using the multireference approach are presented as well. 1
48

Content based Recommendation from Explicit Ratings / Content based Recommendation from Explicit Ratings

Ferenc, Matej January 2016 (has links)
In the thesis we compare several models for prediction of user preferences. The focus is mainly on Content Based models which work with metadata about objects that are recommended. These models are compared with other models which do not use metadata for recommendation. We use three datasets and three metrics to get the results of recommendation. The goal of the thesis is to find out how can the metadata about the users and the objects enhance the standard recommender models. However, the result is that the metadata can enhance recommendation in some cases, but it varies by used metrics and dataset. This enhancement is not significant.
49

Simulação e análise no auxílio do desenvolvimento de veículos / Simulation and analysis aiding vehicle development

Spinelli, Daniel Müller 24 April 2001 (has links)
O uso de simulações computacionais no campo da engenharia vem se tornando cada vez mais freqüente. Este trabalho aplica diferentes tipos de análise, Método Multicorpos e Método dos Elementos Finitos, para estudos dinâmicos e estruturais, como ferramenta de auxílio no desenvolvimento de veículos terrestres. Através de métodos de integração numérica e posteriormente a utilização do método dos multicorpos, uma suspensão independente dianteira de um veículo foi isolada, considerada como um conjunto de corpos unidos por juntas, movidos por forças e restringidos por batentes. O comportamento dinâmico do sistema foi determinado submetendo o modelo a entradas provenientes do pavimento. O Método dos Elementos Finitos já é considerado como ferramenta potente para o cálculo estrutural. Para abordar tal tema, foi construído um modelo discretizado em Elementos Finitos de um veículo comercial completo. Este modelo foi submetido a simulações de situações de situações reais quasi-estáticas e dinâmicas, utilizando algoritmos implícito e explícito, dependendo do fenômeno considerado. A partir destes, puderam ser verificadas a performance estrutural e a segurança passiva do veículo arremessado a obstáculos cotidianos. O último estudo retrata que com a fusão dos métodos é possível, através de programas dedicados, prever a dinâmica de um modelo encriptado de um boneco tipo HYBRIDIII, quando submetido a um pulso de desaceleração no interior de um veículo com e sem bolsa de segurança(airbag). Todos os resultados obtidos foram comparados à realidade ou \"benchmark\". Os obstáculos enfrentados permitiram definir qual ferramenta melhor se encaixa num contexto de desenvolvimento dentro de uma corporação. / The use of computational tools in various engineering fields has increased over the last years. Mathematical modelling is identified as being the most adequate tool for simulating real service conditions along several product development phases. This work investigates different dynamic and structural analysis used for ground vehicle development tools. By numerical integration using the Multibody system method, an independent suspension was isolated from the car and considered as bodies connected by joints, moved by forces and constrained by stoppers. The dynamic behaviour of the systems was predicted when submitted to input exclusively from the ground. The Finite Element Method is already considered a very powerful simulation tool. In order to study the method, a full vehicle model was built and submitted to quasi-static and dynamic inputs. Both implicit and explicit methods were used to simulate different situations. The vehicle had its structural performance analysed related to durability and safety aspects. The last analysis that shows the fusion of methods is possible using dedicated computational tools to simulate the passenger kinematics by using an encrypted dummy and an airbag model under a deceleration pulse as input. AlI the results were compared to experimental and benchmark results. Also the difficulties emerged from each tool were pointed out in order to define which is the most appropriate within the development context.
50

Contribution à l'étude de l'optimisation de requêtes de services Web : une approche centrée utilisateur / Contribution to the Web Services Query Optimization Study : A User Centered Approach

Chouiref, Zahira 27 November 2017 (has links)
Durant la dernière décennie, l’évolution du Web a été marquée par une forte croissance des services publiés et qui s’est accompagnée d’une explosion considérable du nombre d’usagers dont les profils et contextes sont divers et variés. Les travaux présentés dans cette thèse traitent de l’optimisation de requêtes de services Web où le profil/contexte de l’utilisateur joue un rôle central. Il s’agit de sélectionner un service ou une combinaison de services pertinents parmi une masse importante de candidats compétitifs et capables de réaliser une tâche requise. Ces services candidats devant répondre au mieux aux exigences demandées par l’utilisateur selon un ensemble de critères non-fonctionnels. Dans notre approche, les critères non-fonctionnels considérés sont tous associés aux préférences du demandeur de service. Un intérêt plus important est alors porté à l’utilisateur qui se trouve au coeur du processus de sélection. La diversité du profil et du contexte de l’utilisateur, et également ceux des services cibles,rend ce processus encore plus complexe. Notre étude se focalise, dans un premier lieu,sur l’analyse des différentes approches de sélection de services Web existant dans la littérature. Nous mettons, notamment, en évidence leur contribution à la résolution des problèmes inhérents à la sélection des meilleurs services dans le but de satisfaire les critères non-fonctionnels formulés dans la requête. Dans un second temps, notre intérêt s’est porté sur la modélisation de spécification de l’offre et la demande de services,de leurs contextes et profils ainsi que les deux classes de préférences utilisateurs :explicites et implicites. Enfin, nous proposons une nouvelle famille d’approches d’optimisation qui intègre une stratégie de reformulation de requêtes par introduction des préférences implicites. Le concept clé de ces approches est un mécanisme d’inférence flou permettant d’accomplir un raisonnement déductif sur les informations liées au profil et contexte de l’utilisateur. Le principe consiste à combiner les deux familles de préférences utilisateur, tout en considérant conjointement les profils et les contextes des services et de l’utilisateur. L’application de la théorie des ensembles flous dans l’optimisation des requêtes à préférences des utilisateurs, en intégrant un module de raisonnement sur les informations liées à l’utilisateur, s’avère d’un intérêt majeur dans l’amélioration des qualités des résultats retournés. Nous présentons à la fin de l’étude une série d’expérimentations pour montrer la validité et la pertinence des approches proposées. / The internet has completely transformed the way how we communicate (access toinformation). Its evolution was marked by strong growth of published services which has been accompanied by a large explosion in the number of users and a diversity oftheir profiles and their contexts.The work presented in this thesis deal with the adaptive optimization of Web services queries to user needs. This problem is to select a service or a combination of relevant services from a collection of candidates able to perform a required task. These candidate services must meet the requirements requested by the user, the selection makes his/herchoice from non-functional criteria. In our approach, non-functional criteria considered are all associated with preferences of service requester. A significant interest is therefore carried to the user who is at the core of the selection system. This selection is generally considered a complex task because of the diversity of profile and context of the service,which it is performed.Our study focuses mainly on the analysis of different service selection approaches.We especially highlight their contribution to solving the problems inherent in selecting the best services in order to meet the non-functional parameters of the request. Second, our interest has focused on modeling the specification of supply and demand for services, their context and profile as well as the two families preferences : explicit and implicit. Finally, we propose a novel optimization approach that integrates a query reformulation strategy by introducing implicit preferences based on the fuzzy inference process. The idea is to combine the two families of preferences required by the user with consideration of profiles and contexts of services and the user simultaneously. The application of fuzzy set theory in the optimization of preference query of customers by integrating reasoning module on information related to the user leads of great interest in improving the quality of results. We present at the end a set of experiments to demonstrate the validity and relevance of the proposed approach.

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