Made available in DSpace on 2016-04-27T16:58:55Z (GMT). No. of bitstreams: 1 Cristiane Regina de Moura Ferreira.pdf: 2091183 bytes, checksum: 593d938f91d1a71f440cd9e6928d4929 (MD5) Previous issue date: 2009-10-09 / Secretaria da Educação do Estado de São Paulo / The present study relates a qualitative research that aims to investigate as the student, which one was concluded the 2008 High School first year, observes, realizes and understands the activities observation of regularities and generalization of patterns. This research relevance justifies itself for the subject importance Observation of Regularities and Generalization of Patterns , pointed for researchers as Stenn (1990), Orton and Orton (1999), Vale and Pimentel (2005) and Valle et al (2005), where they affirm that this resource assists the student to learn a relevant mathematics, besides revealing his algebraic comprehension. For the data collection I elaborated and I applied a diagnostic technique, inspired in the Didactic Engineering ideas, as seen in Machado (2003). The data analyses indicate that students realize pertinent observations to the regularities in the sequences and realize some generalizations of patterns, using different resolution strategies and types of semiotics representation (Duval, 2003). With regard to the understanding I can affirm that the pupils if find in development phase, therefore still need other experiences, to perfect the algebraic fluency and to reveal its thought algebraic in more efficient way / O presente estudo relata uma pesquisa qualitativa cujo objetivo foi investigar como o aluno que terminou o Primeiro ano do Ensino Médio, em 2008 observa, realiza e compreende as atividades de observação de regularidades e de generalização de padrões. A relevância dessa pesquisa se justifica pela importância do tema Observação de Regularidades e Generalização de Padrões , apontado por pesquisadores como: Stenn (1990), Orton e Orton (1999), Vale e Pimentel (2005) e Vale et al (2005), que afirmam que esse recurso auxilia o aluno a aprender uma matemática significativa, além de manifestar seu pensamento algébrico. Para a coleta de dados elaborei e apliquei um instrumento diagnóstico, inspirado nas ideias da Engenharia Didática, conforme Machado (2003). As análises dos dados indicam que os alunos realizam observações pertinentes às regularidades presentes nas sequências e realizam algumas generalizações de padrões, utilizando diferentes estratégias de resolução e diferentes tipos de registros de representação semiótica (Duval, 2003). Com relação à compreensão posso afirmar que os alunos se encontram em fase de desenvolvimento, pois necessitam ainda de outras experiências, para aperfeiçoarem a fluência algébrica e manifestar seu pensamento algébrico de maneira mais eficaz

Αντικείμενο της παρούσας διπλωματικής είναι η ανάλυση και ο έλεγχος ενός φ/β συστήματος διασυνδεδεμένου στο δίκτυο, με στόχο να παρέχει μονίμως την μέγιστη ισχύ του και η άεργος ισχύς που εγχέεται στο δίκτυο να μηδενίζεται. Το φ/β σύστημα αποτελείται από μια φ/β συστοιχία, έναν πυκνωτή και έναν DC/AC αντιστροφέα (με το κύκλωμα ελέγχου του) με τον οποίο συνδέεται στο δίκτυο μέσω ενός RL φίλτρου. Στο κύκλωμα ελέγχου περιλαμβάνεται ο έλεγχος για την ανίχνευση του σημείου μέγιστης ισχύος (MPPT ελεγκτής) καθώς και όλοι οι PI ελεγκτές που είναι απαραίτητοι τόσο για τον έλεγχο της dc τάσης όσο και για τον έλεγχο της αέργου ισχύος. Το σύστημα προσομοιώνεται στο περιβάλλον Simulink του Matlab υπό μεταβαλλόμενη ηλιακή ακτινοβολία. Αρχικά, για τον MPPT έλεγχο εφαρμόζεται η κλασική Perturb & Observe τεχνική και στη συνέχεια προτείνεται και εφαρμόζεται μια βελτιωμένη εκδοχή της, η οποία αποδεικνύεται ότι έχει μεγαλύτερη αποτελεσματικότητα. / The main subject of this diploma thesis is the analysis and the control of a grid connected Photovoltaic system, in order that it can permanently provide the maximum power and the reactive power injected to the grid could be reduced to zero as well. The P/V system consists of a P/v array, a capacitor and a DC/AC inverter (and the whole control circuit) which is connected to the grid through an RL filter. The control circuit includes the control for the detection (tracking) of the maximum power point (MPPT controller) and all the PI controllers that are necessary in order to control both the dc voltage and the reactive power. The system is simulated by the Simulink in Matlab under changing solar irradiation. Initially, for the MPPT control the classical Perturb & Observe technique is implemented and then an improved version of this technique is proposed and implemented, since it is proved to be much more efficient.

The thesis aims to analyse the content of the performance management of teachers at an elementary school. The theoretical part first defines basic terms of human resources and the latest concept of human resource management. Subsequently, the individual terms of the core area of performance management are introduced. A specification of the target organization concludes the theoretical part. The research section reveals the application of the individual components of performance management in a real environment of particular elementary schools. It was chosen the quantitative research for the research survey, particularly the technology questioning. It was used the method of semi-structured interviewing technique and the content analysis of school documents for consistency. The final section is devoted to a summary of results and the achievement of project objectives.

Cette thèse propose principalement, un algorithme État-Flow MPPT basé P&O, amélioré avec deux degrés de liberté, dans lequel le système événementiel (MPPT) de comportement est modélisé par le décrivant en terme de transition entre les états, sous certaines conditions. Secondairement, un algorithme étendu MPPT, base d'exploitation en parallèle de l'état-débit est en outre proposé d'être une solution difficile pour le contrôle indépendant du système hybride, où la caractéristique de contrôle continu peut se présenter au cours d'un certain état de travail tout en discrète, est indiquée le long des transitions d'état. Deux configurations possibles pour le système hybride sont proposées : deux convertisseurs DC/DC séparés, et un convertisseur de sortie unique à double entrée (DISO) de configurations. Enfin, il est proposé, un comportement du système DC modélisation utilisant État-Flow, menant à l'ensemble de la conception de la stratégie de commande qui concernent RES MPPT, RES et la coordination BESS, la stabilité du système d'alimentation et de régulation de la tension du bus DC. La simulation et les résultats expérimentaux valident l'efficacité et l'applicabilité de l'algorithme proposé. Les deux résultats montrent la supériorité du MPPT basé proposé État-Flow pour réduire les oscillations de puissance RESs à l'état d'équilibre dans diverses conditions d'exploitation, en plus de son démarrage plus rapide, et l’opération de transition sans divergence de la MPP, selon des conditions météorologiques variables. / This thesis primarily proposes, an improved P&O based State-Flow MPPT algorithm featuring two degree of freedom, in which the event driven system (MPPT) behaviour is modelled by describing it in terms of transitions among states under certain conditions. Secondarily, an extended parallel operating State-Flowbased MPPT algorithm is further proposed to be a challenging solution for the independent control of the hybrid system, where continuous control characteristic can present during a certain working state while discrete one is indicated along state transitions. Two possible configurations for the hybrid system are proposed; two separate DC/DC converters and dual input single output converter (DISO) configurations. Finally it is proposed, DC system behaviour modelling using State-Flow leading to the whole control strategy design which concern RESs MPPT, RESs and BESS coordination, power system stability and DC bus voltage regulation.Simulation and experimental results validate the effectiveness and applicability of the proposed algorithm, both results show the superiority of the proposed State-Flow based MPPT in reducing the RESs power oscillations at steady-state in various operating conditions in addition to its faster start-up and transition operation without divergence from the MPP during sudden varying weather conditions.

A heavy duty vehicle looses approximately 30-40 % of the energy in the fuel as waste heat through the exhaust system. Recovering this waste heat would make the vehicle meet the legislative and market demands of emissions and fuel consumption easier. This recovery is possible by transforming the waste heat to electric power using a thermoelectric generator. However, the thermoelectric generator electric characteristics makes direct usage of it unprotable, thus an electric power conditioner is necessary. First a study of dierent DC-DC converters is presented, based on that the most suitable converter for thermoelectric application is determined. In order to maximize the harvested power, maximum power point tracking algorithms have been studied and analyzed. After the investigation, the single ended primary inductor converter was simulated and implemented with a perturb and observe algorithm, and the incremental conductance algorithm. The converter was tested with a 20 W thermoelectric generator, and evaluated.The results show that the incremental conductance is more robust and stable compared to the perturb and observe algorithm. Further on, the incremental conductance also has a higher average eciency during real implementation.

1 juli år 2013 trädde en ny skollag i kraft i Sverige. Den nya lagen ger papperslösa barn i Sverige rätt till utbildning. Detta gäller både om barnet har fått avslag av Migrationsverket på sin uppehållstillståndsansökan och om barnet lever gömt och inte sökt uppehållstillstånd. Idag har papperslösa barn rätt till utbildning men detta innebär inte att dessa barn har en skolplikt, utan det avgör barnet själv eller familjen till det papperslösa barnet om rätten ska nyttjas. Denna valfrihet leder till att flera papperslösa barn inte utnyttjar sin rätt till utbildning. Det finns flera orsaker till detta som exempelvis att många papperslösa familjer inte känner till den nya skollagen och att polisen de facto har rätt att omhänderta en papperslös elev från skolan. Då det inte existerar någon garanti för att den papperslösa elevens trygghet i skolan väljer många papperslösa familjer bort denna rättighet på grund av rädslan att barnet skall bli omhändertaget av polisen. I samband med detta har vi identifierat olika dilemman för lärare, dilemman som uppstår vid en sammanstötning mellan lärares yrkesetik och lärares lagstadgade plikter såsom anmälningsplikt. I Sverige har lärare en skyldighet att anmäla, om de misstänker eller får kännedom om att ett barn far illa skall de meddela socialtjänsten. Denna anmälningsplikt orsakar ett stort dilemma för lärare då konsekvensen av en anmälning kan bli förödande för den enskilde papperslösa eleven och dennes familj. För att få en klarare bild av lärarnas dilemman utförde vi intervjuer med olika lärare på Skånska skolor. Vid intervjutillfällena fick vi förklarat för oss att dilemmat med anmälningsplikten och skyddande av papperslösa elever är någonting som lärare fruktar. Utifrån Barnkonventionen, lärares yrkesetik, tystnadsplikt samt specifik skolsekretess kan lärare skydda den enskilde papperslösa eleven. Dock så finns rädslan kvar bland lärarna om vad som händer om en specifik situation leder till att socialtjänsten måste kontaktas. Resultatet av analysen ger en bild av att lärares yrkesetik inte är så stark som andra yrkesetiker, således kan lärare stå upp mot andra myndigheter och neka deras begäran om tillträdde på skolan. / July 1 2013 a new law entered into force in Sweden. The new Education Act gives undocumented children in Sweden right to education. This is regardless whether the child has been rejected by the Migration Board on their residence permit application and shall be rejected or if the child lives in hiding and has not applied for a residence permit. Today, undocumented children's right to education does not mean that undocumented children have a school attendance, this determines the child himself or the family of the undocumented child´s the right to be utilized. This choice leads too many undocumented children do not exercise their right to education. There are several reasons for this, such that many undocumented families are not aware of the new Education Act, but also that the police actually have the right to seize an undocumented student from school. Then there exists no guarantee that the undocumented student's safety at school, many undocumented families declines this right because of the fear of being found and cared for by the police. In connection with this issue, we have identified various dilemmas for teachers, dilemmas that arise when there is a clash between teachers' professional ethics' and teachers' statutory obligations such as notification requirements to authority. In Sweden, teachers have an obligation to notify if they suspect or become aware that a child is being abused to social services. This notification requirement causes a big dilemma for teachers as the consequence of a notification can be devastating for the individual undocumented student and their family. To get a view of the teacher's dilemmas, we conducted interviews with teachers from Skåne. In the interviews we got told by teachers that the dilemma with the notification requirements and protection of undocumented students is something that teachers fear. Thanks to the Convention of Children´s Rights, teachers' professional ethics, teacher´s obligation to observe silence and confidentiality that exists at the school, teachers can protect the individual undocumented student. However, there are fears remain in the teachers about what happens if it comes to the situation where a claim must be made to social services. The results of the analysis gave us that the teachers' professional ethics is not as strong as other professional ethics so that teachers can stand up to other authorities and deny their request for the entry of the school.

Ce travail de recherche s'intéresse à la commande sans capteur mécanique du moteur synchrone à aimants permanents (MSAP) à pôles saillants, particulièrement en basse vitesse, avec détection de la position initiale du rotor. Après une présentation des techniques et approches qui ont initié nos travaux, en terme d'estimation de la vitesse et/ou de la position, nous avons choisi celles qui présentent plus d'intérêt de point de vue stabilité, robustesse, précision et simplicité d'implémentation. La première approche est basée sur le Système Adaptatif avec Modèle de Référence (MRAS). Quant à la deuxième, elle est réalisée autour d'un observateur non-linéaire pour l'estimation de la position et de la vitesse du MSAP à pôles saillants. Les deux techniques d'observation de la vitesse sont associées à une commande par orientation du flux rotorique avec la technique MLI vectorielle. Pour détecter la position initiale du rotor, nous avons utilisé une nouvelle approche qui permet d'estimer cette position avec une incertitude de ±5° mécanique. Cette nouvelle approche est basée sur l'application de signaux tests aux bornes des phases statoriques du MSAP. Des résultats de simulation et expérimentaux sont présentés tout au long de ces travaux pour valider les études théoriques de la commande vectorielle sans capteur mécanique du MSAP. Enfin, nous avons étudié et analysé les performances de la commande tolérante aux défauts sans capteur mécanique du MSAP en présence de défaillances de types transistors à l'état-off. / This research focuses on the sensorless vector control of a salient pole permanent magnet synchronous motor (PMSM), particularly at low speed, with detection of the initial rotor position. In first step, an overview of the state of the art concerning the estimation of the rotor speed as well as the initial rotor position of PMSM is addressed. From such a study, we have adopted an interesting strategy based on the model reference adaptive system (MRAS). The second step in this research consists in studying the performances and the feasibility of a non-linear observer for closed-loop vector control of salient pole PMSM. The MRAS technique as well as the non-linear observer is associated to a vector control scheme based on the field oriented strategy with space vector pulse width modulation (SVPWM). To detect the initial rotor position, we have proposed a new approach which estimates the position with a resolution of ±5° mechanical degrees. This new approach is based on applying short voltage pulses to the stator winding of salient pole PMSM. Several simulation and experimental results are presented to confirm the theoretical studies of the sensorless vector control of the salient pole PMSM drive. Finally, we have analyzed the performances of the sensorless speed fault tolerant control (FTC) of salient pole PMSM under failures related to the voltage source inverter (open circuit fault). The experimental results obtained based on the proposed techniques using nonlinear and MRAS observers have been improved in term of the reliability and allow a continuous operation of the salient pole PMSM drive even when it is supplied with two inverter legs.

Indiana University-Purdue University Indianapolis (IUPUI) / This thesis presents a converter topology for photovoltaic panels. This topology minimizes the number of switching devices used, thereby reducing power losses that arise from high frequency switching operations. The control strategy is implemented using a simple micro-controller that implements the proportional plus integral control. All the control loops are closed feedback loops hence minimizing error instantaneously and adjusting efficiently to system variations. The energy management between three components, namely, the photovoltaic panel, a battery and a DC link for a microgrid, is shown distributed over three modes. These modes are dependent on the irradiance from the sunlight. All three modes are simulated. The maximum power point tracking of the system plays a crucial role in this configuration, as it is one of the main challenges tackled by the control system. Various methods of MPPT are discussed, and the Perturb and Observe method is employed and is described in detail. Experimental results are shown for the maximum power point tracking of this system with a scaled down version of the panel's actual capability.