Après une introduction à l’hadronthérapie et à la détection gamma prompts, cette thèse de doctorat comprend deux contributions principales: le développement d'une méthode de simulation des gamma prompt (PG) et son application dans une étude de la détection des changements dans les traitements cliniques. La méthode de réduction de variance (vpgTLE) est une méthode d'estimation de longueur de piste en deux étapes développée pour estimer le rendement en PG dans les volumes voxélisés. Comme les particules primaires se propagent tout au long de la CT du patient, les rendements de PG sont calculés en fonction de l'énergie actuelle du primaire, du matériau du voxel et de la longueur de l'étape. La deuxième étape utilise cette image intermédiaire comme source pour générer et propager le nombre de PG dans le reste de la géométrie de la scène, par exemple Dans un dispositif de détection. Pour un fantôme hétérogéné et un plan de traitement CT complet par rapport à MC analogue, à un niveau de convergence de 2% d'incertitude relative sur le rendement de PG par voxel dans la région de rendement de 90%, un gain d'environ 10^3 A été atteint. La méthode s'accorde avec les simulations analogiques MC de référence à moins de 10^-4 par voxel, avec un biais négligeable. La deuxième étude majeure menée dans portait sur l'estimation PG FOP dans les simulations cliniques. Le nombre de protons (poids spot) requis pour une estimation FOP constante a été étudié pour la première fois pour deux caméras PG optimisées, une fente multi-parallèle (MPS) et une conception de bordure de couteau (KES). Trois points ont été choisis pour une étude approfondie et, au niveau des points prescrits, on a constaté qu'ils produisaient des résultats insuffisants, ce qui rend improbable la production clinique utilisable sur le terrain. Lorsque le poids spot est artificiellement augmenté à 10^9 primaires, la précision sur le FOP atteint une précision millimétrique. Sur le décalage FOP, la caméra MPS fournit entre 0,71 - 1,02 mm (1sigma) de précision pour les trois points à 10 $ 9 $ de protons; Le KES entre 2.10 - 2.66 mm. Le regroupement de couches iso-énergétiques a été utilisé dans la détection par PG de distribution passive pour l'un des prototypes d'appareils PG. Dans le groupement iso-depth, activé par la livraison active, les taches avec des chutes de dose distales similaires sont regroupées de manière à fournir des retombées bien définies comme tentative de mélange de gamme de distance. Il est démontré que le regroupement de taches n'a pas nécessairement une incidence négative sur la précision par rapport à la tache artificiellement accrue, ce qui signifie qu'une certaine forme de groupage de points peut permettre l'utilisation clinique de ces caméras PG. Avec tous les spots ou les groupes spot, le MPS a un meilleur signal par rapport au KES, grâce à une plus grande efficacité de détection et à un niveau de fond inférieur en raison de la sélection du temps de vol. / After an introduction to particle therapy and prompt gamma detection, this doctoral dissertation comprises two main contributions: the development of a fast prompt gammas (PGs) simulation method and its application in a study of change detectability in clinical treatments. The variance reduction method (named vpgTLE) is a two-stage track length estimation method developed to estimate the PG yield in voxelized volumes. As primary particles are propagated throughout the patient CT, the PG yields are computed as function of the current energy of the primary, the material in the voxel and the step length. The second stage uses this intermediate image as a source to generate and propagate the number of PGs throughout the rest of the scene geometry, e.g. into a detection device. For both a geometrical heterogeneous phantom and a complete patient CT treatment plan with respect to analog MC, at a convergence level of 2\% relative uncertainty on the PG yield per voxel in the 90\% yield region, a gain of around $10^3$ was achieved. The method agrees with reference analog MC simulations to within $10^{-4}$ per voxel, with negligible bias. The second major study conducted in this PhD program was on PG FOP estimation in clinical simulations. The number of protons (spot weight) required for a consistent FOP estimate was investigated for the first time for two optimized PG cameras, a multi-parallel slit (MPS) and a knife edge design (KES). Three spots were selected for an in depth study, and at the prescribed spot weights were found to produce results of insufficient precision, rendering usable clinical output on the spot level unlikely. When the spot weight is artificially increased to $10^9$ primaries, the precision on the FOP reaches millimetric precision. On the FOP shift the MPS camera provides between 0.71 - 1.02 mm (1$\upsigma$) precision for the three spots at $10^9$ protons; the KES between 2.10 - 2.66 mm. Grouping iso-energy layers was employed in passive delivery PG detection for one of the PG camera prototypes. In iso-depth grouping, enabled by active delivery, spots with similar distal dose fall-offs are grouped so as to provide well-defined fall-offs as an attempt to sidestep range mixing. It is shown that grouping spots does not necessarily negatively affect the precision compared to the artificially increased spot, which means some form of spot grouping can enable clinical use of these PG cameras. With all spots or spot groups the MPS has a better signal compared to the KES, thanks to a larger detection efficiency and a lower background level due to time of flight selection.

Nous proposons dans cette thèse une nouvelle approche cumulative de recalage d'images basée sur des primitives construites à partir des lignes de niveaux. Les lignes de niveaux sont invariantes par rapport aux diverses perturbations affectant l'image tels que les changements de contraste. Par ailleurs, leur abondance dans une image suggère naturellement un processus de décision cumulatif. Nous proposons alors un algorithme récursif d'extraction des lignes de niveaux simple et efficace qui extrait les lignes par groupes rectiligne appelés ``segments''. Les segments sont ensuite groupés -- sous contrainte de proximité -- en fonction du modèle de transformation recherchée et afin de faciliter le calcul des invariants. Les primitives construites ont alors la forme de Z, Y ou W et sont classées en fonction de leur fiabilité, ce qui participe au paramétrage du processus de décision cumulatif. Le vote est multi-tours et constitué d'une phase préliminaire de construction de listes de préférences inspiré de la technique des mariages stables. Les primitives votent à une itération donnée en fonction de leur fiabilité. Chaque itération fournit ainsi un estimé de la transformation recherchée que le tour suivant peut raffiner. Ce procédé multi-tours permet, de ce fait, d'éliminer les ambiguïtés d'appariement générées par les motifs répétitifs présents dans les images. Notre approche a été validée pour recaler des images sous différents modèles de transformations allant de la plus simple (similarité) à la plus complexe (projective). Nous montrons dans cette thèse comment le choix pertinent de primitives basées sur les lignes de niveaux en conjonction avec un processus de décision cumulatif permet d'obtenir une méthode de recalage d'images robuste, générique et complète, fournissant alors différents niveaux de précision et pouvant ainsi s'appliquer à différents contextes. / In this thesis, we propose a new image registration method that relies on level-line primitives. Level-lines are robust towards contrast changes and proposed primitives inherit their robustness. Moreover, their abundance in the image is well adapted to a cumulative matching process based on a multi-stage primitive election procedure. We propose a simple recursive tracking algorithm to extract level lines by straight sets called "segments". Segments are then grouped under proximity constraints to construct primitives (Z, Y and W shapes) that are classified into categories according to their reliability. Primitive shapes are defined according to the transformation model. The cumulative process is based on a preliminary step of preference lists construction that is inspired from the stable marriage matching algorithm. Primitives vote in a given voting stage according to their reliability. Each stage provides a coarse estimate of the transformation that the next stage gets to refine. This process, in turn, eliminate gradually the ambiguity happened by incorrect correspondences. Our additional contribution is to validate further geometric transformations, from simple to complex ones, completing the path "similarity, affine, projective". We show in this thesis how the choice of level lines in conjunction with a cumulative decision process allows defining a complete robust registration approach that is tested and evaluated on several real image sequences including different type of transformations.

Nos últimos anos verificou-se um crescimento acentuado da complexidade da avaliação da segurança em Sistemas Elétricos de Potência (SEPs). O aumento das interligações, aliado à operação das redes com altos níveis de carregamento, aumenta a probabilidade de ocorrência de incidentes que podem levar o SEP à instabilidade de tensão, culminando com o colapso de tensão e grandes prejuízos à qualidade do fornecimento de energia elétrica. Neste trabalho foi proposta uma ferramenta rápida para a manutenção da segurança de SEPs no contexto da Estabilidade de Tensão (ET). Para tal, foi desenvolvida uma metodologia rápida para a análise de contingências. Selecionadas as críticas, a eliminação da criticalidade das mesmas é realizada via ações preventivas. Neste contexto, foram desenvolvidas duas abordagens para a seleção de ações preventivas. Na primeira procura-se minimizar o número de controles via técnicas de agrupamento de dados, para eliminar a criticalidade de uma contingência. Na segunda abordagem foi desenvolvida uma estratégia para obtenção de um grupo de controles para eliminar a criticalidade de todas as contingências. Ambas as abordagens baseiam-se em uma metodologia de análise de sensibilidade da margem de ET em relação aos controles preventivos que também foi proposta nesta tese. A eficácia da ferramenta foi comprovada por intermédio de simulações em um SEP. Os resultados foram bastante satisfatórios, os grupos de controles obtidos pela primeira abordagem representam um conjunto mínimo de ações preventivas para eliminar a criticalidade de uma contingência específica. Já na segunda abordagem, foi possível determinar um grupo de controles para a eliminar simultaneamente a criticalidade de todas as contingências. Como produto científico deste doutorado foram obtidas novas metodologias rápidas para a análise de segurança do SEP no contexto da ET. / The complexity of the security assessment in Electric Power Systems (EPS) has received much attention from researches in recent years. The continuous growth in the number of interconnections, allied to networks operating with high loading levels, enhance the probability of incidents that can lead the EPS to voltage instability. Voltage collapse and considerably loss of the electric supply are the principal consequences of this scenery. In this study, we propose a fast tool for supporting the EPS security, in the context of Voltage Stability (VS). To this end, a fast methodology was developed for contingency analysis. Once the critical contingencies are selected, their criticalities are eliminated through the selection of preventive actions. In this context, two approaches were developed. In the first one, we aim at minimizing eh number of controls by using clustering techniques. In this case, the principal objective is to eliminate the criticality of a contingency. In the second approach, we developed a strategy for obtaining a groups of controls in order to eliminate the criticality of all contingencies. Both approaches are based on a methodology for sensitivity analysis of the VS margin with respect to preventive controls which is also proposed in this thesis. The effectiveness of the tool was corroborated by simulations in a EPS. We found the results satisfactory, since the groups of controls achieved by the first approach represent a minimum set of preventive actions that can be taken to eliminate the criticality of a specific contingency. In the second approach, it was possible to determine a minimum group of controls that eliminate the criticality of all contingencies simultaneously. New fast methodologies for security analysis of the EPS in the context of the VS is considered the main scientific product result of this doctorate.

Content analyses of research in the literature of gifted education (Coleman, 2006; Rogers, 1999, 2006) has shown a consistent absence of research investigating methodology for instructing gifted students and for the development of expertise using new technologies. In this study, utilising electronic instructional delivery, an investigation was undertaken of the differential effects and appropriateness of matching the prior knowledge of the learner to the instructional method. Underpinned with a theoretical understanding of gifted education and cognitive load theory, a series of three experiments was designed and implemented to determine whether gifted students learn more effectively under guided discovery design than with example based instruction, while not identified as gifted ability students perform significantly better under direct example based instruction than with guided discovery. Data were collected and analysed in three stages. Experiment 1 was conducted in the novel domain of Boolean switching equations. Experiments 2 and 3 used identical test instruments with novel tasks in the semi-familiar domain of geometry. A total of 155 Years 7, 8 and 9 students at three metropolitan secondary schools participated. The study explored whether the presence of schemas, that facilitated greater problem-solving ability in gifted students, would generate clear evidence of instructional efficiency and preference for either mode of instruction. As students advanced from novice state to expert in particular domains of learning, it was anticipated that gifted students would progress from benefiting from worked example instruction to more efficient learning in guided discovery mode. This hypothesis was rejected as the results from each of the experiments did not confirm the hypothesised outcomes. There was no manifested expertise-reversal effect. The absence of any clear delineation of enhanced learning proficiency mode of instruction for gifted students does, however, contribute to the advancement and understanding of cognitive load theory and the complexity of learning strategies necessary for gifted learners.

<p>The aim of this thesis is to explore from a cultural diversity perspective, students 'views on teachers' leadership styles in the classroom and what style of management students prefer. The study uses a qualitative methodology to interviewed focus groups of students consisting of a total of twelve students at a secondary school in Botkyrka municipality. The corpus was divided into three different groups. Overall, results showed that students seem to prefer an intercultural situational leadership style. This is based on the students expressed need of wanting to be understood on the basis of their cultural background. That means that the teacher according to their background,  situation and knowledge should adapt leadership. Teachers should also be leaders who maintain balance, responsiveness and flexibility in teaching style in order to increase the motivation of students.</p>

The central research question is the extent to which gifted programming affects student academic outcomes of gifted as compared to not-gifted students and how this differs by race/ethnicity and/or poverty status. Since the identification of elementary school students as gifted is not random, propensity score matching is used to remove this bias in the estimates of the effects. A matched sample of North Carolina middle school students based on individual level data of both gifted and not-gifted students of varied racial/ethnic groups and income levels is used for this analysis. This enables a comparison of sixth, seventh, and eighth grade student achievement to determine the extent to which participating in gifted programming differentiates effects by race/ethnicity and poverty status. I show the additional test score gain, if any, from being in gifted programming compared to students not participating in gifted programs. Variations in gifted program effects across race/ethnicity and income are assessed. This research adds empirical evidence to the more qualitatively focused gifted debate by analyzing differences in student outcomes between gifted and not-gifted students in North Carolina. Since black and lower income students are less likely to participate in gifted programs, they disproportionately encounter less experienced teachers, lower expectations, and fewer resources. The extent to which these additional learning supports translate to differences in student outcomes are analyzed.

Syftet med den här studien var att undersöka, belysa och exemplifiera hur en svensk grundskola arbetar med elever som har dyslexi, dels i generella termer, dels med inriktning mot engelskundervisningen, vad gäller stöttning, hjälpmedel, bedömning och betygssättning samt i vilken mån den undersökta skolans dyslexiarbete harmonierar med styrdokumentens föreskrifter.      För att kunna undersöka det valda området användes semi-strukturerade intervjuer med tre lärare och en specialpedagog på skolan. Intervjuerna sammanställdes och analyserades.      Resultaten på studien visade att skolan arbetar medvetet för att underlätta för elever med dyslexi genom hjälpmedel och nivågrupperingar, men att lärarna ändå till stor del står frågande när det gäller vilka metoder som fungerar bäst, hur de ska handla vid misstanke om dyslexi samt bedömning och betygssättning. Resultaten visade också att engelska är ett ämne som lärarna och specialpedagogen upplever som extra svårt för elever med dyslexi. Under engelskundervisningen arbetar lärarna dock inte annorlunda med elever som har dyslexi, trots att det ämnet anses som svårare. De anser sig inte ha verktygen. / The aim of this study was to examine, illustrate and exemplify both in general terms and in the teaching of English, how a Swedish compulsory school works with pupils who have dyslexia. The study focused on support, assistance, assessment and marking, and to what extension the school’s work with dyslexia corresponds to the regulations of the steering documents.      Semi-structured interviews were chosen as the method for examining the chosen subject. Three teachers and one special educational needs teacher were interviewed. The interviews were then put together and analysed.      The results of the study showed that the school works deliberately to make school easier for pupils with dyslexia by giving them assistance and ability grouping, however, the teachers still seem to have many questions regarding teaching methods, what to do if suspecting dyslexia, assessment and marking. The results also showed that English is a subject which is considered to be especially difficult for pupils with dyslexia, by the teachers and the special educational needs teacher. During the teaching of English, the teachers do not work differently with the pupils who have dyslexia, even though English is believed to be a difficult subject to learn. The teachers do not feel that they have the right tools to do so.

The aim of this thesis is to explore from a cultural diversity perspective, students 'views on teachers' leadership styles in the classroom and what style of management students prefer. The study uses a qualitative methodology to interviewed focus groups of students consisting of a total of twelve students at a secondary school in Botkyrka municipality. The corpus was divided into three different groups. Overall, results showed that students seem to prefer an intercultural situational leadership style. This is based on the students expressed need of wanting to be understood on the basis of their cultural background. That means that the teacher according to their background,  situation and knowledge should adapt leadership. Teachers should also be leaders who maintain balance, responsiveness and flexibility in teaching style in order to increase the motivation of students.

The central research question is the extent to which gifted programming effects student academic outcomes of gifted as compared to not-gifted students and how this differs by race/ethnicity and/or poverty status. Since the identification of elementary school students as gifted is not random, propensity score matching is used to remove this bias in the estimates of the effects. A matched sample of North Carolina middle school students based on individual level data of both gifted and not-gifted students of varied racial/ethnic groups and income levels is used for this analysis. This enables a comparison of sixth, seventh, and eighth grade student achievement to determine the extent to which participating in gifted programming differentiates effects by race/ethnicity and poverty status. I show the additional test score gain, if any, from being in gifted programming compared to students not participating in gifted programs. Variations in gifted program effects across race/ethnicity and income are assessed. This research adds empirical evidence to the more qualitatively focused gifted debate by analyzing differences in student outcomes between gifted and not-gifted students in North Carolina. Since black and lower income students are less likely to participate in gifted programs, they disproportionately encounter less experienced teachers, lower expectations, and fewer resources. The extent to which these additional learning supports translate to differences in student outcomes are analyzed.

The purpose of this study has been to investigate the views of five teachers on their own leadership, and on the way they make it work in the classroom. The method was a qualitative investigation consisting of separate interviews with five elementary school teachers from three different schools in the southern part of Stockholm. The results showed that a good pedagogic leadership, successful with the pupils, can be characterised as at the same time democratic and "situation adjustable". This includes the ability to formulate the rules of conduct clearly, to take decisions and to create a good working atmosphere in the classroom, so that the pupils can feel secure, and be able to learn and develop. That however, cannot be accomplished if the teacher only maintains a negative communication, reminding the pupils of what is forbidden. A majority of the interviewed teachers emphasised the importance of positive feedback, and maintaining the work motivation of the pupils was seen as an important aspect of leadership in the classroom. A good leadership is furthermore characterised by the flexibility of the teacher in adapting to different situations and to the maturity of the pupil or group. Flexibility in adjusting the level of the lesson, and of the tasks given to the individual pupils or groups, is also an aspect of leadership. The results finally showed that the teacher should try to maintain a good personal relationship not just to the pupil but also with the parents. This makes it easier for the teacher to influence the pupils and engage them in a better performance in the classroom, scholastically as well as in terms of conduct.