Play plays a significant role in early childhood education. The purpose of this essay is to contribute to knowledge and understanding by exploring preschool teachers' perspectives on the importance of play in children's learning processes. The study investigates the significance of play and discusses similarities in the view of play among preschools in both Sweden and Zimbabwe. It also compares the different conditions that exist for preschools between these two countries. Six preschool teachers, three from Zimbabwe and three from Sweden, were interviewed. Despite challenges stemming from a flawed system, the teachers recognized the importance of play in preschools. The study's findings highlight the social and academic skills that play cultivates in children. Employing a qualitative interview method, the study draws upon the theoretical frameworks of William A., Friedrich Froebel, and Susan Isaacs to inform the analysis and interpretation of the data.

With the combination of Reinforcement Learning (RL) and Artificial Neural Networks (ANNs), Deep Reinforcement Learning (DRL) agents are shifted towards being non-interpretable black-box models. Developers of DRL agents, however, could benefit from enhanced interpretability of the agents’ behavior, especially during the training process. Improved interpretability could enable developers to make informed adaptations, leading to better overall performance. The explainability methods Partial Dependence Plot (PDP), Accumulated Local Effects (ALE) and SHapley Additive exPlanations (SHAP) were considered to provide insights into how an agent’s behavior evolves during training. Additionally, a decision tree as a surrogate model was considered to enhance the interpretability of a trained agent. In a case study, the methods were tested on a Deep Deterministic Policy Gradient (DDPG) agent that was trained in an Obstacle Avoidance (OA) scenario. PDP, ALE and SHAP were evaluated towards their ability to provide explanations as well as the feasibility of their application in terms of computational overhead. The decision tree was evaluated towards its ability to approximate the agent’s policy as a post-hoc method. Results demonstrated that PDP, ALE and SHAP were able to provide valuable explanations during the training. Each method contributed additional information with their individual advantages. However, the decision tree failed to approximate the agent’s actions effectively to be used as a surrogate model.:List of Figures List of Tables List of Abbreviations 1 Introduction 2 Foundations 2.1 Machine Learning 2.1.1 Deep Learning 2.2 Reinforcement Learning 2.2.1 Markov Decision Process 2.2.2 Limitations of Optimal Solutions 2.2.3 Deep Reinforcement Learning 2.3 Explainability 2.3.1 Obstacles for Explainability Methods 3 Applied Explainability Methods 3.1 Real-Time Methods 3.1.1 Partial Dependence Plot 3.1.1.1 Incremental Partial Dependence Plots for Dynamic Modeling Scenarios 3.1.1.2 PDP-based Feature Importance 3.1.2 Accumulated Local Effects 3.1.3 SHapley Additive exPlanations 3.2 Post-Hoc Method: Global Surrogate Model 4 Case Study: Obstacle Avoidance 4.1 Environment Representation 4.2 Agent 4.3 Application Settings 5 Results 5.1 Problems of the Incremental Partial Dependence Plot 5.2 Real-Time Methods 5.2.1 Feature Importance 5.2.2 Computational Overhead 5.3 Global Surrogate Model 6 Discussion 7 Conclusion Bibliography Appendix A Incremental Partial Dependence Results

This study investigated students' perceptions of autonomy support from an instructor in relation to students' motivational beliefs on an ePortfolio project. The motivational beliefs of interest included: Effort/Importance, felt Pressure/Tension, and Value/Usefulness. These relationships were further examined with particular focus on the potential moderating role of students' culturally based learning preferences as outlined in Parrish and Linder-VanBerschot's (2010) Cultural Dimensions of Learning Framework (CDLF). This study was quasi-experimental, survey-based research supported by self-reported data collected from a convenience sample of graduate and undergraduate students. Students enrolled in a variety of courses that assigned an ePortfolio assignment received an email invitation from their instructor and self-selected to participate. Based on the responses of 35 students, the findings from this research showed significant relationships between three culturally based learning preferences and the motivational belief of Value/Usefulness. A summary of findings, limitations, and implications for further research are discussed. / Ph. D. / This study investigated students’ perceptions of autonomy support from an instructor in relation to students’ motivational beliefs on an ePortfolio project. The motivational beliefs of interest included: Effort/Importance, felt Pressure/Tension, and Value/Usefulness. These relationships were further examined with particular focus on the potential moderating role of students’ culturally based learning preferences. This study was quasi-experimental, survey-based research supported by self-reported data collected from a convenience sample of graduate and undergraduate students. Students enrolled in a variety of courses that assigned an ePortfolio assignment received an email invitation from their instructor and self-selected to participate. Based on the responses of 35 students, the findings from this research showed significant relationships between three culturally based learning preferences and the motivational belief of Value/Usefulness. A summary of findings, limitations, and implications for further research are discussed.

Introdução: A Emergência de Saúde Pública de Importância Internacional foi declarada pela Organização Mundial da Saúde em fevereiro de 2016, em decorrência da notificação e resposta do governo brasileiro ao aumento da prevalência de microcefalia e outras alterações do sistema nervoso central. Esse evento é considerado uma das epidemias de maior complexidade e impacto da história da saúde pública. Objetivo: Descrever os principais marcos da epidemia de Zika vírus (ZIKAV) no Brasil, relacionando às ações de saúde pública adotadas e caracterizar as diferenças regionais com base nas taxas de incidência de ZIKAV em gestantes e de prevalência de microcefalia em casos registrados no Sistema de Informação de Agravos de Notificação e no formulário de Registro de Eventos de Saúde Pública, no período de janeiro de 2015 a novembro de 2016. Metodologia: Foi realizada a revisão da literatura nas principais bases de dados e também da literatura cinzenta (protocolos, portarias, manuais e informes) buscando elementos que fundamentaram as ações de saúde pública e fatos que marcaram o histórico desta epidemia no Brasil. Também foi realizada análise descritiva e comparativa das bases de dados do Sistema de Informação de Agravos de Notificação (SINAN) e do formulário de Registro de Eventos de Saúde Pública (RESP), no Brasil no período de janeiro de 2015 a novembro de 2016. Resultados: Em 22 de outubro de 2015, a Secretaria de Saúde de Pernambuco notificou o aumento na prevalência de microcefalia, no Estado. Em 11 de novembro foi declarada a emergência de saúde pública de importância nacional e em 1º de fevereiro de 2016, a Organização Mundial da Saúde declara emergência de saúde pública de importância internacional. Entre 2015 e 2016, foram notificadas 41.473 gestantes com quadro clínico compatível com ZIKAV e, no mesmo período, foram notificados e confirmados 1.950 casos de microcefalia. Destes, 70% foram confirmados por método de imagem. Observou-se que em 2015 a região mais afetada foi a nordeste e em 2016, apesar de não apresentar a mesma magnitude, observou-se uma possível segunda onda de casos de microcefalia a partir do mês de junho, principalmente na região centro-oeste, corroborando com a maior circulação de casos de ZIKAV no primeiro semestre. Limitações: O uso de dados secundários (oportunidade, completitude, representatividade, subnotificação etc), a indisponibilidade de testes laboratoriais para ZIKAV, principalmente no início da epidemia em 2015, o conhecimento limitado sobre a doença e suas consequências, apesar dos avanços nos últimos meses, a indisponibilidade de série histórica de microcefalia e outras anomalias congênitas para essa condição e o proxy de infecção pelo ZIKAV: casos negativos de dengue e chikungunya e microcefalia relacionada à infecção. Conclusões: Conclui-se que o desencadeamento da resposta em suas quatro fases operacionais foi oportuno, apesar das limitações do conhecimento; fundamentou-se na Legislação e instrumentos próprios para resposta às ESP e na melhor evidência disponível em cada fase operacional. Até o final de 2016, a magnitude da Síndrome Congênita Associada à Infecção pelo Vírus Zika vírus (SCZ) não apresentou o mesmo padrão observado em 2015, sendo que a região Nordeste apresentou maior magnitude somente na primeira onda (setembro/2015-abril/2016); Em 2016, a região Centro-Oeste apresentou a maior magnitude de casos de SCZ, seguida das regiões Sudeste e Norte. Esse padrão corrobora com o nexo causal entre infecção pelo ZIKAV na gestação e a manifestação da SCZ. Muitos avanços foram alcançados nos últimos dois anos. No entanto, ainda há importantes lacunas no conhecimento científico sobre o espectro clínico dessa nova doença e fatores relacionados à transmissão e endemicidade. / Introduction: On February 2016, The World Health Organization declared Public Health Emergency of International Concern (PHEIC). This action, due to the Brazilian notification and response, after the prevalence of microcephaly and other Central Nervous System disorders increase in Northeast Region. This event is one of the most complex epidemics of the Public Health history. Objective: Describe the sequence of events which occurred from January 2015 to November 2016 in Brazil, as a result of Zika virus outbreaks and the related congenital syndrome; to characterize the main elements of the Brazilian National response to the epidemics describing the course of the dual epidemics of Zika virus (ZIKV) infection during pregnancy and microcephaly, from the registered cases at Brazilian National Notifiable Diseases Information System (SINAN) and Public Health Events Registry (RESP) forms up to the first anniversary of this declaration in Brazil. Methods: To obtain a comprehensive chronologic description, of the main epidemiologic events and of the Brazilian response, we conducted a literature review and used third party (gray literature), and fundamental elements registered at the Brazilian National Notifiable Diseases Information System (SINAN) and Public Health Events Registry (RESP) from January 2015 up to November 12th 2016. In order to describe the Brazilian response, we divided in four phases the operational response to the emergency in Brazil. Results: On October 22nd 2015 the Pernambuco Health Secretary notified the prevalence of Microcephaly increase. On November 11th 2016 the Ministry of Health declared Public Health Emergency of National Concern. On February 1st 2016 the World Health Organization declared (PHEIC) Public Health Emergency of International Concern, 41,473 pregnant women with some clinical signs, compatible with Zika virus, were notified between 2015 and 2016. In the same period, 1,950 cases of Microcephaly were reported and confirmed. From the reported cases, 70% cases were confirmed by imaging method. The Northeast Region was the most affected in 2015 and in 2016, although it did not present the same magnitude, a potential second wave of Microcephaly cases were observed, mainly in the Central Western Region. Limitations: Secondary data (opportunity, completeness, representativeness, underreporting etc.), the unavailability of laboratory tests for ZIKAV were used, mainly at the beginning of the epidemic in 2015. The limited knowledge about the disease and its consequences, despite of advanced months at the time being, combined with the unavailability of a historical series of Microcephaly and other congenital anomalies for this condition and the proxy of infection by ZIKAV: negative cases of Dengue and Chikungunya and Microcephaly related to infection. Conclusion: It was concluded that the triggering of the response, in its four operational phases, was timely despite of the knowledge limitations; it was based on the Legislation and its own instruments to respond to PHEIC, and on the most update existing evidences of the disease (self-limiting), its diagnostic and therapeutic method. To date, the magnitude of congenital syndrome associated with ZIKAV infection (SCZ) in 2016 did not follow the same pattern observed in 2015, and the Northeast Region was the region with the greatest impact of the SCZ epidemic during September 2015 thru April 2016, although with a very low expression in the end of the following year. In 2016, the pattern observed in the Central Western Region, and to a lesser extent in the Southeast and North Regions, corroborates the causal link between ZIKAV infection in pregnancy and the manifestation of Congenital Syndrome, and there are still important gaps as, scientific knowledge about the clinic aspect of this new disease and the related factors to the transmission and endemicity.

Introdução: A Emergência de Saúde Pública de Importância Internacional foi declarada pela Organização Mundial da Saúde em fevereiro de 2016, em decorrência da notificação e resposta do governo brasileiro ao aumento da prevalência de microcefalia e outras alterações do sistema nervoso central. Esse evento é considerado uma das epidemias de maior complexidade e impacto da história da saúde pública. Objetivo: Descrever os principais marcos da epidemia de Zika vírus (ZIKAV) no Brasil, relacionando às ações de saúde pública adotadas e caracterizar as diferenças regionais com base nas taxas de incidência de ZIKAV em gestantes e de prevalência de microcefalia em casos registrados no Sistema de Informação de Agravos de Notificação e no formulário de Registro de Eventos de Saúde Pública, no período de janeiro de 2015 a novembro de 2016. Metodologia: Foi realizada a revisão da literatura nas principais bases de dados e também da literatura cinzenta (protocolos, portarias, manuais e informes) buscando elementos que fundamentaram as ações de saúde pública e fatos que marcaram o histórico desta epidemia no Brasil. Também foi realizada análise descritiva e comparativa das bases de dados do Sistema de Informação de Agravos de Notificação (SINAN) e do formulário de Registro de Eventos de Saúde Pública (RESP), no Brasil no período de janeiro de 2015 a novembro de 2016. Resultados: Em 22 de outubro de 2015, a Secretaria de Saúde de Pernambuco notificou o aumento na prevalência de microcefalia, no Estado. Em 11 de novembro foi declarada a emergência de saúde pública de importância nacional e em 1º de fevereiro de 2016, a Organização Mundial da Saúde declara emergência de saúde pública de importância internacional. Entre 2015 e 2016, foram notificadas 41.473 gestantes com quadro clínico compatível com ZIKAV e, no mesmo período, foram notificados e confirmados 1.950 casos de microcefalia. Destes, 70% foram confirmados por método de imagem. Observou-se que em 2015 a região mais afetada foi a nordeste e em 2016, apesar de não apresentar a mesma magnitude, observou-se uma possível segunda onda de casos de microcefalia a partir do mês de junho, principalmente na região centro-oeste, corroborando com a maior circulação de casos de ZIKAV no primeiro semestre. Limitações: O uso de dados secundários (oportunidade, completitude, representatividade, subnotificação etc), a indisponibilidade de testes laboratoriais para ZIKAV, principalmente no início da epidemia em 2015, o conhecimento limitado sobre a doença e suas consequências, apesar dos avanços nos últimos meses, a indisponibilidade de série histórica de microcefalia e outras anomalias congênitas para essa condição e o proxy de infecção pelo ZIKAV: casos negativos de dengue e chikungunya e microcefalia relacionada à infecção. Conclusões: Conclui-se que o desencadeamento da resposta em suas quatro fases operacionais foi oportuno, apesar das limitações do conhecimento; fundamentou-se na Legislação e instrumentos próprios para resposta às ESP e na melhor evidência disponível em cada fase operacional. Até o final de 2016, a magnitude da Síndrome Congênita Associada à Infecção pelo Vírus Zika vírus (SCZ) não apresentou o mesmo padrão observado em 2015, sendo que a região Nordeste apresentou maior magnitude somente na primeira onda (setembro/2015-abril/2016); Em 2016, a região Centro-Oeste apresentou a maior magnitude de casos de SCZ, seguida das regiões Sudeste e Norte. Esse padrão corrobora com o nexo causal entre infecção pelo ZIKAV na gestação e a manifestação da SCZ. Muitos avanços foram alcançados nos últimos dois anos. No entanto, ainda há importantes lacunas no conhecimento científico sobre o espectro clínico dessa nova doença e fatores relacionados à transmissão e endemicidade. / Introduction: On February 2016, The World Health Organization declared Public Health Emergency of International Concern (PHEIC). This action, due to the Brazilian notification and response, after the prevalence of microcephaly and other Central Nervous System disorders increase in Northeast Region. This event is one of the most complex epidemics of the Public Health history. Objective: Describe the sequence of events which occurred from January 2015 to November 2016 in Brazil, as a result of Zika virus outbreaks and the related congenital syndrome; to characterize the main elements of the Brazilian National response to the epidemics describing the course of the dual epidemics of Zika virus (ZIKV) infection during pregnancy and microcephaly, from the registered cases at Brazilian National Notifiable Diseases Information System (SINAN) and Public Health Events Registry (RESP) forms up to the first anniversary of this declaration in Brazil. Methods: To obtain a comprehensive chronologic description, of the main epidemiologic events and of the Brazilian response, we conducted a literature review and used third party (gray literature), and fundamental elements registered at the Brazilian National Notifiable Diseases Information System (SINAN) and Public Health Events Registry (RESP) from January 2015 up to November 12th 2016. In order to describe the Brazilian response, we divided in four phases the operational response to the emergency in Brazil. Results: On October 22nd 2015 the Pernambuco Health Secretary notified the prevalence of Microcephaly increase. On November 11th 2016 the Ministry of Health declared Public Health Emergency of National Concern. On February 1st 2016 the World Health Organization declared (PHEIC) Public Health Emergency of International Concern, 41,473 pregnant women with some clinical signs, compatible with Zika virus, were notified between 2015 and 2016. In the same period, 1,950 cases of Microcephaly were reported and confirmed. From the reported cases, 70% cases were confirmed by imaging method. The Northeast Region was the most affected in 2015 and in 2016, although it did not present the same magnitude, a potential second wave of Microcephaly cases were observed, mainly in the Central Western Region. Limitations: Secondary data (opportunity, completeness, representativeness, underreporting etc.), the unavailability of laboratory tests for ZIKAV were used, mainly at the beginning of the epidemic in 2015. The limited knowledge about the disease and its consequences, despite of advanced months at the time being, combined with the unavailability of a historical series of Microcephaly and other congenital anomalies for this condition and the proxy of infection by ZIKAV: negative cases of Dengue and Chikungunya and Microcephaly related to infection. Conclusion: It was concluded that the triggering of the response, in its four operational phases, was timely despite of the knowledge limitations; it was based on the Legislation and its own instruments to respond to PHEIC, and on the most update existing evidences of the disease (self-limiting), its diagnostic and therapeutic method. To date, the magnitude of congenital syndrome associated with ZIKAV infection (SCZ) in 2016 did not follow the same pattern observed in 2015, and the Northeast Region was the region with the greatest impact of the SCZ epidemic during September 2015 thru April 2016, although with a very low expression in the end of the following year. In 2016, the pattern observed in the Central Western Region, and to a lesser extent in the Southeast and North Regions, corroborates the causal link between ZIKAV infection in pregnancy and the manifestation of Congenital Syndrome, and there are still important gaps as, scientific knowledge about the clinic aspect of this new disease and the related factors to the transmission and endemicity.

Introdução: A Emergência de Saúde Pública de Importância Internacional foi declarada pela Organização Mundial da Saúde em fevereiro de 2016, em decorrência da notificação e resposta do governo brasileiro ao aumento da prevalência de microcefalia e outras alterações do sistema nervoso central. Esse evento é considerado uma das epidemias de maior complexidade e impacto da história da saúde pública. Objetivo: Descrever os principais marcos da epidemia de Zika vírus (ZIKAV) no Brasil, relacionando às ações de saúde pública adotadas e caracterizar as diferenças regionais com base nas taxas de incidência de ZIKAV em gestantes e de prevalência de microcefalia em casos registrados no Sistema de Informação de Agravos de Notificação e no formulário de Registro de Eventos de Saúde Pública, no período de janeiro de 2015 a novembro de 2016. Metodologia: Foi realizada a revisão da literatura nas principais bases de dados e também da literatura cinzenta (protocolos, portarias, manuais e informes) buscando elementos que fundamentaram as ações de saúde pública e fatos que marcaram o histórico desta epidemia no Brasil. Também foi realizada análise descritiva e comparativa das bases de dados do Sistema de Informação de Agravos de Notificação (SINAN) e do formulário de Registro de Eventos de Saúde Pública (RESP), no Brasil no período de janeiro de 2015 a novembro de 2016. Resultados: Em 22 de outubro de 2015, a Secretaria de Saúde de Pernambuco notificou o aumento na prevalência de microcefalia, no Estado. Em 11 de novembro foi declarada a emergência de saúde pública de importância nacional e em 1º de fevereiro de 2016, a Organização Mundial da Saúde declara emergência de saúde pública de importância internacional. Entre 2015 e 2016, foram notificadas 41.473 gestantes com quadro clínico compatível com ZIKAV e, no mesmo período, foram notificados e confirmados 1.950 casos de microcefalia. Destes, 70% foram confirmados por método de imagem. Observou-se que em 2015 a região mais afetada foi a nordeste e em 2016, apesar de não apresentar a mesma magnitude, observou-se uma possível segunda onda de casos de microcefalia a partir do mês de junho, principalmente na região centro-oeste, corroborando com a maior circulação de casos de ZIKAV no primeiro semestre. Limitações: O uso de dados secundários (oportunidade, completitude, representatividade, subnotificação etc), a indisponibilidade de testes laboratoriais para ZIKAV, principalmente no início da epidemia em 2015, o conhecimento limitado sobre a doença e suas consequências, apesar dos avanços nos últimos meses, a indisponibilidade de série histórica de microcefalia e outras anomalias congênitas para essa condição e o proxy de infecção pelo ZIKAV: casos negativos de dengue e chikungunya e microcefalia relacionada à infecção. Conclusões: Conclui-se que o desencadeamento da resposta em suas quatro fases operacionais foi oportuno, apesar das limitações do conhecimento; fundamentou-se na Legislação e instrumentos próprios para resposta às ESP e na melhor evidência disponível em cada fase operacional. Até o final de 2016, a magnitude da Síndrome Congênita Associada à Infecção pelo Vírus Zika vírus (SCZ) não apresentou o mesmo padrão observado em 2015, sendo que a região Nordeste apresentou maior magnitude somente na primeira onda (setembro/2015-abril/2016); Em 2016, a região Centro-Oeste apresentou a maior magnitude de casos de SCZ, seguida das regiões Sudeste e Norte. Esse padrão corrobora com o nexo causal entre infecção pelo ZIKAV na gestação e a manifestação da SCZ. Muitos avanços foram alcançados nos últimos dois anos. No entanto, ainda há importantes lacunas no conhecimento científico sobre o espectro clínico dessa nova doença e fatores relacionados à transmissão e endemicidade. / Introduction: On February 2016, The World Health Organization declared Public Health Emergency of International Concern (PHEIC). This action, due to the Brazilian notification and response, after the prevalence of microcephaly and other Central Nervous System disorders increase in Northeast Region. This event is one of the most complex epidemics of the Public Health history. Objective: Describe the sequence of events which occurred from January 2015 to November 2016 in Brazil, as a result of Zika virus outbreaks and the related congenital syndrome; to characterize the main elements of the Brazilian National response to the epidemics describing the course of the dual epidemics of Zika virus (ZIKV) infection during pregnancy and microcephaly, from the registered cases at Brazilian National Notifiable Diseases Information System (SINAN) and Public Health Events Registry (RESP) forms up to the first anniversary of this declaration in Brazil. Methods: To obtain a comprehensive chronologic description, of the main epidemiologic events and of the Brazilian response, we conducted a literature review and used third party (gray literature), and fundamental elements registered at the Brazilian National Notifiable Diseases Information System (SINAN) and Public Health Events Registry (RESP) from January 2015 up to November 12th 2016. In order to describe the Brazilian response, we divided in four phases the operational response to the emergency in Brazil. Results: On October 22nd 2015 the Pernambuco Health Secretary notified the prevalence of Microcephaly increase. On November 11th 2016 the Ministry of Health declared Public Health Emergency of National Concern. On February 1st 2016 the World Health Organization declared (PHEIC) Public Health Emergency of International Concern, 41,473 pregnant women with some clinical signs, compatible with Zika virus, were notified between 2015 and 2016. In the same period, 1,950 cases of Microcephaly were reported and confirmed. From the reported cases, 70% cases were confirmed by imaging method. The Northeast Region was the most affected in 2015 and in 2016, although it did not present the same magnitude, a potential second wave of Microcephaly cases were observed, mainly in the Central Western Region. Limitations: Secondary data (opportunity, completeness, representativeness, underreporting etc.), the unavailability of laboratory tests for ZIKAV were used, mainly at the beginning of the epidemic in 2015. The limited knowledge about the disease and its consequences, despite of advanced months at the time being, combined with the unavailability of a historical series of Microcephaly and other congenital anomalies for this condition and the proxy of infection by ZIKAV: negative cases of Dengue and Chikungunya and Microcephaly related to infection. Conclusion: It was concluded that the triggering of the response, in its four operational phases, was timely despite of the knowledge limitations; it was based on the Legislation and its own instruments to respond to PHEIC, and on the most update existing evidences of the disease (self-limiting), its diagnostic and therapeutic method. To date, the magnitude of congenital syndrome associated with ZIKAV infection (SCZ) in 2016 did not follow the same pattern observed in 2015, and the Northeast Region was the region with the greatest impact of the SCZ epidemic during September 2015 thru April 2016, although with a very low expression in the end of the following year. In 2016, the pattern observed in the Central Western Region, and to a lesser extent in the Southeast and North Regions, corroborates the causal link between ZIKAV infection in pregnancy and the manifestation of Congenital Syndrome, and there are still important gaps as, scientific knowledge about the clinic aspect of this new disease and the related factors to the transmission and endemicity.

No description available.

The increasing size and complexity of datasets have accelerated the development of machine learning models and exposed the need for more scalable solutions. This thesis explores challenges associated with large-scale machine learning under data privacy constraints. With the growth of machine learning models, traditional privacy methods such as data anonymization are becoming insufficient. Thus, we delve into alternative approaches, such as differential privacy. Our research addresses the following core areas in the context of scalable privacy-preserving machine learning: First, we examine the implications of data dimensionality on privacy for the application of medical image analysis. We extend the classification algorithm Private Aggregation of Teacher Ensembles (PATE) to deal with high-dimensional labels, and demonstrate that dimensionality reduction can be used to improve privacy. Second, we consider the impact of hyperparameter selection on privacy. Here, we propose a novel adaptive technique for hyperparameter selection in differentially gradient-based optimization. Third, we investigate sampling-based solutions to scale differentially private machine learning to dataset with a large number of records. We study the privacy-enhancing properties of importance sampling, highlighting that it can outperform uniform sub-sampling not only in terms of sample efficiency but also in terms of privacy. The three techniques developed in this thesis improve the scalability of machine learning while ensuring robust privacy protection, and aim to offer solutions for the effective and safe application of machine learning in large datasets. / Den ständigt ökande storleken och komplexiteten hos datamängder har accelererat utvecklingen av maskininlärningsmodeller och gjort behovet av mer skalbara lösningar alltmer uppenbart. Den här avhandlingen utforskar tre utmaningar förknippade med storskalig maskininlärning under dataskyddskrav. För stora och komplexa maskininlärningsmodeller blir traditionella metoder för integritet, såsom datananonymisering, otillräckliga. Vi undersöker därför alternativa tillvägagångssätt, såsom differentiell integritet. Vår forskning behandlar följande utmaningar inom skalbar och integitetsmedveten maskininlärning: För det första undersöker vi hur hög data-dimensionalitet påverkar integriteten för medicinsk bildanalys. Vi utvidgar klassificeringsalgoritmen Private Aggregation of Teacher Ensembles (PATE) för att hantera högdimensionella etiketter och visar att dimensionsreducering kan användas för att förbättra integriteten. För det andra studerar vi hur valet av hyperparametrar påverkar integriteten. Här föreslår vi en ny adaptiv teknik för val av hyperparametrar i gradient-baserad optimering med garantier på differentiell integritet. För det tredje granskar vi urvalsbaserade lösningar för att skala differentiellt privat maskininlärning till stora datamängder. Vi studerar de integritetsförstärkande egenskaperna hos importance sampling och visar att det kan överträffa ett likformigt urval av sampel, inte bara när det gäller effektivitet utan även för integritet. De tre teknikerna som utvecklats i denna avhandling förbättrar skalbarheten för integritetsskyddad maskininlärning och syftar till att erbjuda lösningar för effektiv och säker tillämpning av maskininlärning på stora datamängder. / <p>QC 20231101</p>

This study aims to investigate the impact of using stories in pre-school mathematics teaching in Saudi Arabia. An intervention was designed to promote interactive teaching and learning in eight classrooms across three private schools. Integral to the intervention was a series of five stories especially written by the researcher based around the same central characters; reflecting the cultural setting familiar to the children, and with a problem-solving storyline. The stories include a range of mathematical facts, skills and concepts applicable to young learners. Additional resource materials to accompany the stories were also designed and provided for the participating teachers. The researcher adopted a qualitative, constructivist, technical action research approach and three data collection tools were used: a bibliographical questionnaire for the teachers; pre- and post-interventions semi-structured interview schedules, and classroom observations. A thematic analysis of the pre- and post-intervention data was undertaken in order to monitor the impact of using the stories in the pre-school classrooms. The study considers the findings from the data in relation to both the teachers’ and the children's’ experiences pre- and post-intervention. In particular, the impact of the intervention on teachers’ subject knowledge, attitudes, confidence and classroom practice is discussed along with the impact on children’s engagement and enjoyment of mathematics; their mathematical understanding and thinking skills. The study concludes that using stories to teach mathematics had a positive impact on the quality of teaching and learning mathematics. Using the stories prompted a positive change in teacher’s and children’s attitudes and feelings towards mathematics; a greater understanding of key mathematical ideas; and an appreciation of the value and uses of mathematics in everyday life. The implications from the study highlight the importance of providing appropriate training for pre-school teachers (and elsewhere) and the pivotal role that using stories can play in ensuring high quality mathematics teaching and learning.

Färdigheten att avkoda ord är en grundläggande förutsättning för förmågan att läsa och har därmed en avgörande roll i elevers läsutveckling. Framgångsrik undervisning krävs för att eleverna ska ges möjlighet och förutsättningar att utveckla färdigheten att avkoda, det vill säga förståelse för sambandet mellan fonem och grafem. Med detta som utgångspunkt är syftet med studien att undersöka hur sju lärare i årskurs 1 beskriver att de utformar undervisningen i avkodning för att skapa förutsättningar för att eleverna ska utveckla färdigheten att avkoda ord. Studien utgår från en kvalitativ forskningsansats samt ett sociokulturellt perspektiv på lärande och utveckling. Empiriskt material har samlats in genom semi-strukturerade intervjuer där totalt sju lärare i årskurs 1 medverkade. Lärarna var slumpvis utvalda från olika skolor i två medelstora städer i Sverige. Resultatet visar att lärare använder olika medierande verktyg i form av digitala redskap, läromedel och aktiviteter i undervisningen, där samtalet och det sociala samspelet får stort utrymme. Det framkommer även att lärare använder sig själv som verktyg i avkodningsundervisningen där läraren stöttar, utmanar och fungerar som förebild för eleverna.  Vid utformandet av undervisningen framgår dessutom att forskning och beprövad erfarenhet samt elevers olika förutsättningar är någonting lärare förhåller sig till. Resultatet synliggör att undervisning kring avkodning varierar mellan olika lärare eftersom elevers individuella behov ligger till grund vid val av verktyg och vid utformningen av undervisningen. / Decoding skills are a crucial part of students reading development, since the ability to decode words is a fundamental qualification for reading. To give the pupils the opportunity to develop knowledge of phoneme-grapheme correspondences, an effective instruction is required. In light of this, the purpose of this paper is to examine how first grade teachers describe how they design instruction to create conditions for the students to develop decoding skills. The paper is based on a qualitative research approach and a socio-cultural perspective on learning and development. Through semi-structured interviews, empirical material has been collected from a total of seven participating first grade teachers. The teachers were randomly selected from different schools in two medium-sized cities in Sweden. The results show that teachers use mediating tools in form of digital gears, teaching materials and activities, where social interaction is emphasized. Teachers also function as tools, because they support, challenge and serve as role models for the pupils. Furthermore, the results reveal that research and proven experience as well as pupils’ different pre-conditions and needs affect teachers when they create decoding instruction. The results show that pupils’ individual needs are the starting point when teachers choose tools and create decoding instruction, which is why decoding instruction varies between different teachers.