Philosophiae Doctor - PhD / Research has shown that collaborative eLearning can provide educational opportunities to groups of learners; both distance learners as well as traditional campus-based learners. It provides innovative educational methods in which learning can be constructed. The way collaborative eLearning is administered, managed, used and adopted can assist in providing information for future design and improvement of collaborative software. The objective of this research is to provide an insight into adoption and use of collaborative eLearning environments and to discover new determinants of usage. To examine the usage of an eLearning environment at the University of the Western Cape, a cross-sectional survey was conducted with Computer Science students. While this study is specific to this university, the underlying principles can be generalised to other organisational types. This study is quantitative and qualitative in nature as well as deductive and inductive. Three hundred and six valid questionnaires were analysed using quantitative methods. Soft Systems Methodology was used to manage the research process and to create conceptual models to explain the research problem and identify solutions. It was a cyclical process. Findings show that although the university’s eLearning platform is utilised, students seem to prefer free and open source platforms. They use social and collaborative applications such as WhatsApp, Telegram, Dropbox, Google Drive, Google Docs as well as email messages. Four types of technology affordances: communicative-affordance, document share-affordance, course resource-affordance, and integrity-affordance were identified as being relevant in their choice of application. Furthermore, culture—masculinity/femininity, individualism/collectivism, Uncertainty Avoidance, and Power Distance—also have an effect on the adoption of collaborative eLearning applications and software the students used for learning. Chi-Square analysis found that individualism/collectivism and Power Distance were both significant and related to the adoption and usage of collaborative eLearning. Gender was found not to be a determinant of how students view the use of collaborative eLearning software applications. Finally, it was also found that understanding use and user behaviour, could provide the theoretical guidance to inform collaborative eLearning design. The analysis and findings show that culture influences the adoption of collaborative eLearning while technology affordance plays a major role in the use of collaborative eLearning.

Esta pesquisa busca delinear características do processo de criação de objetos interativos. Isso é feito a partir da verificação de possibilidades de interlocuções de saberes advindos de quatro áreas do conhecimento - arquitetura, design, arte e computação - dentro do contexto das tecnologias digitais de informação e comunicação. Através desta perspectiva, acredita-se ser possível tanto uma compreensão mais fundamentada dos fenômenos tecnológicos do início de século XXI quanto a extração de direções para a ação no mundo contemporâneo. / This research aims to delineate characteristics from the creation process of interactive objects. This is done through the verification of interlocution possibilities from four knowledge domains - Architecture, Design, Art and Computation - inside the information and communication digital technologies context. Via this perspective, it is believed that a more fundamental understanding of the technological phenomena from the beginning of the 20th century is possible, as much as the extraction of directions for action in the contemporary world.

Esta pesquisa busca delinear características do processo de criação de objetos interativos. Isso é feito a partir da verificação de possibilidades de interlocuções de saberes advindos de quatro áreas do conhecimento - arquitetura, design, arte e computação - dentro do contexto das tecnologias digitais de informação e comunicação. Através desta perspectiva, acredita-se ser possível tanto uma compreensão mais fundamentada dos fenômenos tecnológicos do início de século XXI quanto a extração de direções para a ação no mundo contemporâneo. / This research aims to delineate characteristics from the creation process of interactive objects. This is done through the verification of interlocution possibilities from four knowledge domains - Architecture, Design, Art and Computation - inside the information and communication digital technologies context. Via this perspective, it is believed that a more fundamental understanding of the technological phenomena from the beginning of the 20th century is possible, as much as the extraction of directions for action in the contemporary world.

<p>Simulation modeling has proven beneficial in gathering insights that may aid safety policy considerations for schools, offices, and outdoor events. This is especially true when conducting a drill that is not practical or possible, such as active shooter response. However, we can improve the current modeling practices with high-fidelity simulation logic reflecting a victim's well-being. Currently, victims are modeled either as “killed,” or they continue their normal movement. The binary approach is suitable for many simulations developed to understand course trends in an event space but does not allow for more fine-tuned insights that may be beneficial when developing a safety and response protocol for a specific facility or event. Additional victim characteristics, such as tracking the location of a victim's wound and the rate of physiological decline, may be added into a model that will improve the realism and lead to an improved response protocol. The increased fidelity will be helpful when simulating and assessing the effects of volunteer response, critical care transport for medical intervention, and other first-responder interventions.</p> <p>While some think it is not possible or necessary to simulate how fast gunshot victims would lose blood, we show that a high-fidelity simulation is possible. The main counterargument is that there is no sufficient data, and also it will be challenging to implement this process as it is occurring. However, we found enough data or were able to extrapolate the missing pieces and develop a consistent and realistic blood loss model. In addition, the state of current simulation packages, such as AnyLogic, has advanced to the point where we can model a liquid system dynamic within an agent-based model. Furthermore, there is an acute benefit to conducting this type of research as it can help us develop better response policies, which result in more saved lives.</p> <p>The research aims to improve emergency-response simulation fidelity by developing a model that simulates gunshot wounds and the subsequent blood loss while accounting for a victim's age, weight, gender, and the affected area. The model also accounts for the body's compensatory response and medical interventions, such as tourniquet application, wound packing, and direct pressure. The work presents an analytical model and its implementation using agent-based modeling in AnyLogic. This AnyLogic module can be inserted into active shooter simulations that easily integrate with the existing logic. This integration happens through a high-level application programming interface (API) exposed to the user. The API allows for automatic infliction of injury and mitigation. The extensive literature review and case studies provide a sound foundation for creating the model. AnyLogic was chosen due to its common usage and versatility with other systems and computer programming languages.</p>

<p>Representation learning algorithms, as the cutting edge of modern AIs, has shown their ability to automatically solve complex tasks in diverse fields including computer vision, speech recognition, autonomous driving, biology. Unsurprisingly, representation learning applications in computer networking domains, such as network management, video streaming, traffic forecasting, are enjoying increasing interests in recent years. However, the success of representation learning algorithms is based on consistency between training and test data distribution, which can not be guaranteed in some scenario due to resource limitation, privacy or other infrastructure reasons. Caused by distribution shift in training and test data, representation learning algorithms have to apply tuned models into environments whose data distribution are solidly different from the model training. This issue is addressed as Out-Of-Distribution (OOD) Generalization, and is still an open topic in machine learning. In this dissertation, I present solutions for OOD cases found in cloud services which will be beneficial to improve user experience. First, I implement Infinity SGD which can extrapolate from light-load server log to predict server performance under heavy-load. Infinity SGD builds the bridge between light-load and heavy-load server status through modeling server status under different loads by an unified Continuous Time Markov Chain (CTMC) of same parameters. I show that Infinity SGD can perform extrapolations that no precedent works can do on real-world testbed and synthetic experiments. Next, I propose Veritas, a framework to answer what will be the user experience if a different ABR, a kind of video streaming data transfer algorithm, was used with the same server, client and connection status. Veritas strictly follows Structural Causal Model (SCM) which guarantees its power to answer what-if counterfactual and interventional questions for video streaming. I showcase that Veritas can accurately answer confounders for what-if questions on real-world emulations where on existing works can. Finally, I propose time-then-graph, a provable more expressive temporal graph neural network (TGNN) than precedent works. We empirically show that time-then-graph is a more efficient and accurate framework on forecasting traffic on network data which will serve as an essential input data for Infinity SGD. Besides, paralleling with this dissertation, I formalize Knowledge Graph (KG) as doubly exchangeable attributed graph. I propose a doubly exchangeable representation blueprint based on the formalization which enables a complex logical reasoning task with no precedent works. This work may also find potential traffic classification applications in networking field.</p>

O crescimento das necessidades de recursos computacionais gerado por novas classes de aplicações comerciais e científicas apresenta um novo tipo de desafio para infraestruturas computacionais. O acelerado crescimento das demandas por recursos promove um acelerado crescimento no número absoluto de elementos computacionais nestas. Nesse cenário, o provisionamento e a operação de sistemas tornam-se tarefas progressivamente complexas, devido primariamente ao aumento em escala. Este trabalho propõe um modelo para uma infraestrutura computacional que opera como um repositório abstrato de recursos computacionais de tempo de execução com níveis variáveis de consumo. Desenhado para operar como um ensemble (i.e. um conjunto coordenado) de recursos computacionais, grandes números de elementos são agregados em conjuntos de servidores de recursos de processamento, armazenamento e comunicação. O ensemble é concebido e implementado com ampla utilização de tecnologias de virtualização e possui um mecanismo de provisionamento e operação organizado como uma estrutura distribuída de comando e controle (Command and Control, ou C²). A implementação de uma prova de conceito de tal infraestrutura computacional é apresentada, e a validação da proposta é realizada através de uma combinação de resultados experimentais e emulação. / The increase in computing resource needs posed by new classes of commercial and scientific applications presents a new kind of challenge for computing infrastructures. The accelerated growth in resource demand leads to an accelerated growth in the absolute number of computing elements on such infrastructures. In this scenario, the provisioning and systems operations of such elements becomes a progressively complex task, due mainly to the increase in scale. This work proposes a model for a computing infrastructure that operates as an abstract repository of run-time resources with variable levels of consumption. Designed to operate as a computing ensemble, large numbers of elements are aggregated in pools of processing, storage and communication resource servers. The Computing Resource Ensemble is designed with the heavy use of virtualization technologies and has a provisioning and systems operation engine organized as a distributed Command and Control (C2) framework. A Proof of Concept implementation of such computing infrastructure is presented, and the validation of the concept is carried out by a combination of experiments and emulation.

O crescimento das necessidades de recursos computacionais gerado por novas classes de aplicações comerciais e científicas apresenta um novo tipo de desafio para infraestruturas computacionais. O acelerado crescimento das demandas por recursos promove um acelerado crescimento no número absoluto de elementos computacionais nestas. Nesse cenário, o provisionamento e a operação de sistemas tornam-se tarefas progressivamente complexas, devido primariamente ao aumento em escala. Este trabalho propõe um modelo para uma infraestrutura computacional que opera como um repositório abstrato de recursos computacionais de tempo de execução com níveis variáveis de consumo. Desenhado para operar como um ensemble (i.e. um conjunto coordenado) de recursos computacionais, grandes números de elementos são agregados em conjuntos de servidores de recursos de processamento, armazenamento e comunicação. O ensemble é concebido e implementado com ampla utilização de tecnologias de virtualização e possui um mecanismo de provisionamento e operação organizado como uma estrutura distribuída de comando e controle (Command and Control, ou C²). A implementação de uma prova de conceito de tal infraestrutura computacional é apresentada, e a validação da proposta é realizada através de uma combinação de resultados experimentais e emulação. / The increase in computing resource needs posed by new classes of commercial and scientific applications presents a new kind of challenge for computing infrastructures. The accelerated growth in resource demand leads to an accelerated growth in the absolute number of computing elements on such infrastructures. In this scenario, the provisioning and systems operations of such elements becomes a progressively complex task, due mainly to the increase in scale. This work proposes a model for a computing infrastructure that operates as an abstract repository of run-time resources with variable levels of consumption. Designed to operate as a computing ensemble, large numbers of elements are aggregated in pools of processing, storage and communication resource servers. The Computing Resource Ensemble is designed with the heavy use of virtualization technologies and has a provisioning and systems operation engine organized as a distributed Command and Control (C2) framework. A Proof of Concept implementation of such computing infrastructure is presented, and the validation of the concept is carried out by a combination of experiments and emulation.

The Dresden Database Systems Group focuses on the advancement of data management techniques from a system level as well as information management perspective. With more than 15 PhD students the research group is involved in a variety of larger research projects ranging from activities to exploit modern hardware for scalable storage engines to advancing statistical methods for large-scale time series management. The group is visible at an international level as well as actively involved in cooperations with national and regional research partners

Submitted by Verena Pereira (verenagoncalves@uefs.br) on 2018-11-14T22:49:02Z No. of bitstreams: 1 Disserta??o de Jadiane(C).pdf: 1600835 bytes, checksum: 6b3162236247731029b8ced5d94cc873 (MD5) / Made available in DSpace on 2018-11-14T22:49:02Z (GMT). No. of bitstreams: 1 Disserta??o de Jadiane(C).pdf: 1600835 bytes, checksum: 6b3162236247731029b8ced5d94cc873 (MD5) Previous issue date: 2018-07-07 / Earth's operational orbiting satellites are very useful for space science because it has great features as these services enable research and space explorations for scientific, commercial, and military interests as well. However, the increasing flow of space activities has increased the amount of debris orbiting in the operating regions, thereby increasing the chances of collisions in those areas, and allowing immeasurable damages if the satellite remains in this collision orbit. In view of the large number of operational objects, the study of evasive maneuvers for space vehicles has been growing, and this one is important in face of the possibility of collisions, not only with a single debris but with clouds of space debris. The objective of the evasive maneuver is to avoid collision, but by keeping the vehicle in its orbit nominally. The history of the phenomenon, that is, how it evolves over time, is found when the differential equation that represents the phenomenon is solved. From the point of view of Physics and Mathematics, the more realistic the model, the more difficult is the solution of the differential equations representing the phenomenon. Thus, this work seeks to present the analytical and semi-analytical solutions for the equations describing the relative dynamics between two bodies subjected to gravitational force, Chohessy-Wiltshire equations, under the influence of forces: gravitational, atmospheric drag, chemical propulsion ( exponential model and linear model), atmospheric drag plus chemical propulsion and plasma propulsion, and finally present their respective computational simulations. These simulations made it possible to show what happens to the operational satellites against a collision, for each specified model. With the contribution of the development of the atmospheric drag equation, with the drag coefficient varying / Os sat?lites operacionais em ?rbita da Terra s?o muito ?teis para a Ci?ncia Espacial, pois possuem grandes aplica??es e fun??es. Seus servi?os possibilitam pesquisas e explora??es espaciais para interesses cient?ficos, comerciais e tamb?m militares. Por?m, o crescente fluxo das atividades espaciais tem elevado a quantidade de detritos orbitando nas regi?es operacionais e, desse modo, aumentando as chances de colis?es nessas ?reas, e possibilitando imensur?veis preju?zos, caso o sat?lite permane?a nessa ?rbita de colis?o. Diante da grande quantidade de objetos operacionais e n?o operacionais, o estudo de manobras evasivas para os ve?culos espaciais torna-se urgente e necess?rio, visto a possibilidade de colis?es, n?o s? com um ?nico detrito, mas com nuvens de detritos espaciais. O objetivo da manobra evasiva ? evitar a colis?o, mas, mantendo o ve?culo em sua ?rbita nominal. A hist?ria do fen?meno, ou seja, como ele evolui no tempo, ? encontrada quando a equa??o diferencial que o representa ? resolvida. Assim obtemos a posi??o relativa entre os objetos colisionais no tempo. Do ponto de vista da F?sica e da Matem?tica, quanto mais realista for o modelo, mais dif?cil ser? a solu??o das equa??es diferenciais representantes do fen?meno. Assim, este trabalho busca apresentar as solu??es anal?ticas e semi-anal?tica para as equa??es que descrevem a din?mica relativa entre dois corpos sob a atua??o das for?as: gravitacional, de arrasto atmosf?rico, propuls?o qu?mica (modelo exponencial e modelo linear) e propuls?o plasma. Por fim, busca apresentar suas respectivas simula??es computacionais. Estas simula??es possibilitaram mostrar o que acontece com os sat?lites operacionais frente ? uma colis?o, para cada um modelo especificado. Outra contribui??o deste trabalho ? solu??o semi-anal?tica da din?mica relativa com arrasto atmosf?rico para densidade atmosf?rica n?o constante

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2017-05-29T13:06:46Z No. of bitstreams: 1 Lucas Closs_.pdf: 1614709 bytes, checksum: f513dd4879d78d758e585d56586b19bc (MD5) / Made available in DSpace on 2017-05-29T13:06:46Z (GMT). No. of bitstreams: 1 Lucas Closs_.pdf: 1614709 bytes, checksum: f513dd4879d78d758e585d56586b19bc (MD5) Previous issue date: 2017-02-20 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os constantes avanços na computação móvel e ubíqua possibilitam novos desenvolvimentos e novos recursos em diversas áreas, dentre estas, destaca-se a área da saúde. A partir destas novas possibilidades, surge então o conceito de Cuidados Ubíquos, onde são aplicados estes novos recursos com o intuito de prover melhores condições para médicos e equipes médicas no tratamento de pacientes. Utilizando então como referência o conceito de cuidados ubíquos, o presente trabalho apresenta uma nova abordagem para o monitoramento de pacientes através do uso da ciência de situação, apoiada pelo uso da Lógica Difusa, das Redes Neurais Artificiais e das Séries Temporais de Dados, dispondo com também com os dados dos pacientes coletados através dos dispositivos móveis e dos vestíveis. O modelo SAC – Situation-Aware Care objetiva então a aplicação das três fases da ciência de situação – percepção, compreensão e projeção – utilizando os dados coletados como entradas para as inferências. Visando prover uma solução que auxilie médicos e equipes médicas em diagnósticos – e em prognósticos – mais assertivos, através do monitoramento e da disponibilização de registros e de informações mais apuradas quanto ao estado de saúde dos pacientes. Para a avaliação do modelo, foram então desenvolvidos protótipos referentes aos Serviços SAC e a aplicação SAC4Mobile. O modelo SAC teve a sua avaliação em relação ao seu desempenho dos serviços e também através de caso de uso estendido, aferindo sobre a usabilidade. Avaliações por desempenho apresentaram bons indicadores de tempos de respostas e de recursos computacionais, onde que tempo médio mais elevado para o retorno de todas as requisições, 100 requisições simultâneas, foi de 5,5 segundos e o consumo de recursos computacionais não ultrapassou 18%. Assim como a avaliação sobre usabilidade teve resultados positivos, enaltecendo a relevância da proposta do modelo SAC. / The constant advances in mobile and ubiquitous computing enable new developments and new features in different areas, among thesethe health area stands out. From these new possibilities comes the concept of Ubiquitous Care, where these new resources are applied in order to provide better conditions for doctors and medical staff in the treatment of patients. Using the concept of ubiquitous care as a reference, the present work presents a new approach for monitoring patients through the use of Situation Awareness, supported by the use of Fuzzy Logic, Artificial Neural Networks and Time Series, also with patient data collected through mobile devices and wearable devices. The SAC - Situation-Aware Care model aims to apply the three phases of situation awareness - perception, comprehension and projection - using the data collected as inputs to the inferences. Aiming to provide a solution that assists physicians and medical teams in diagnostics - and prognoses - more assertive, through the monitoring and availability of records and more accurate information regarding the patient's health status.For the evaluation of the model, prototypes were developed for the SAC Services and the SAC4Mobile application. The SAC model had its evaluation in relation to its service performance and also through an extended use case, assessing the usability. Performance evaluations presented good indicators of response times and computational resources, where the highest time for the return of all the requests, 100 simultaneous requests, was 5.5 seconds and the consumption of computational resources did not exceed 18%. As well as the assessment of usability had positive results highlighting the relevance of the SAC model proposal.