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Modelagem generalista ou individualizada na construção de modelos preditivos para a identificação de insucesso acadêmicoMarcon, Paulo Fernando Benetti 31 March 2017 (has links)
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Previous issue date: 2017-03-31 / Nenhuma / O uso de recursos tecnológicos para auxiliar nas tarefas de ensino e aprendizagem é uma realidade. A disseminação de ambientes virtuais de aprendizado, como meio de promover a realização de cursos on-line, demonstra franca expansão. Além de tarefas que propiciam a ampliação dos meios de ensino, tais sistemas permitem o registro completo de todas as interações dos alunos no decorrer da realização de disciplinas. Essa gama de informação produzida pode ser utilizada para predição de estudantes em situação de risco enquanto a disciplina ocorre, o que para instituições de ensino pode representar redução nos índices de reprovação e evasão. Entretanto o número elevado de variáveis envolvidas, ainda mais quando várias disciplinas são consideradas, dificulta a construção de modelos computacionais eficientes. Desta forma, este trabalho visa investigar a construção de modelos generalistas – treinados com dados de diversas disciplinas disponíveis – contrapondo a construção de modelos
individualizados – treinados individualmente com dados de cada disciplina. Para isto um amplo conjunto de dados educacionais foi extraído, obtido de uma instituição de ensino superior, composto de diferentes cursos, disciplinas e períodos letivos, não sendo utilizadas variáveis que invadissem a privacidade dos estudantes. Uma vez definidas as características e transformações dos dados que contribuíam à identificação de insucesso acadêmico no decorrer da disciplina então foram aplicados algoritmos clássicos de Mineração de Dados seguindo ambas as abordagens, generalista e individualizada, e a cada unidade de conteúdo das disciplinas. Os
resultados obtidos demonstram vantagens e desvantagens de ambas as abordagens e que dadas as circunstâncias os modelos individualizados podem ser melhores, obtendo taxas de acerto maiores, e que em outras circunstâncias modelos generalistas apresentam um custo menor para a obtenção e manutenção dos modelos preditivos, mesmo com uma queda nos índices de acerto. / The use of technological resources to assist teaching and learning tasks is a reality. The
dissemination of virtual learning environments, as a mean of promoting online courses, shows a clear expansion. In addition to tasks that allow the expansion of teaching resources, such systems allow the complete recording of all the interactions of the students inside the courses. This range of information produced can be used to predict at-risk students while the course is taking place, which for educational institutions may represent a reduction in failure and dropout rates. However, the high number of variables involved, especially when several courses are considered, makes it difficult to construct efficient computational models. In this way, this work aims to investigate the construction of generalist models – trained with data from several available courses – counterposing the construction of individualized models – individually trained with data from each course. In this way, a broad set of educational data was extracted, obtained from a higher education institution, composed of different undergraduate programs, courses and academic periods, not using variables that invaded students' privacy. Once the
characteristics and transformations of the data that contributed to the identification of academic insuccess during the course were defined, then classical data mining algorithms were applied following both generalist and individualized approaches and to each content unit of the course. The results obtained demonstrate the advantages and disadvantages of both approaches and that given the circumstances the individualized models may be better, obtaining higher hit rates, and that in other circumstances generalist models present a lower cost for the obtaining and maintenance of the predictive models, even with a drop in hit rates.
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Regional airspace design: a structured systems engineering approachFulton, Neale Leslie, Aerospace & Mechanical Engineering, Australian Defence Force Academy, UNSW January 2002 (has links)
There has been almost fifteen years of political controversy surrounding changes to the rules and procedures by which aircraft conduct their flight within regional Australia. Decisions based on a predominately heuristic (rule of thumb) approach to design have had many adverse consequences for the integrity of the proximity warning function. A sound mathematical model is required to establish this function on a mature engineering foundation. To achieve this, the proximity warning function has been investigated as a hybrid-system. This approach recognises the dual nature of the design: that aircraft dynamics give rise to continuous mathematical models while the communication protocols controlling proximity require discrete mathematical approaches. The blending of each aspect has yielded a deeper insight into the operational limitations and failure modes of this function. The presentation of the thesis follows a design thread through the function. It begins with a description of existing standards and implementations. Risk models are then developed. The pilot interface is recognised as a primary design constraint. Mathematical models are then developed to describe the topology of flow, proximity dynamics, and the scheduling constraints associated with visual, voice, and data-link communications required by the proximity warning function. These analyses show that many aspects of design can be bounded by analytical formulae that bring new robustness to the design and resolve some of the misconceptions arising from the often inaccurate perceptions of present airspace operations. Failure modes, unaccounted for in existing designs are found to actually aggravate failure in the very situations in which the airspace design should be robust and should act to prevent collisions. In particular, there are divergences of performance between the demands required by the system design and the ability of the pilot to deliver such performances. In some cases, these failures may be traced to policy decisions such as service between Instrument Flight Rule and Visual Flight Rule category aircraft. On the basis of the conclusions of this research, a formal engineering review of the proximity warning function is required to assure the containment of the likelihood of mid-air collision for all future operations.
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Contribution of the Governing Council/Global Ministerial Environment Forum of the United Nations Environment Programme to the World Summit on Sustainable Development : note /22 March 2002 (has links)
Transmits decision SS.VII/2 of UNEP Governing Council/Global Ministerial Environment. / UN Job no.: N0230044 E. Material type: Resolutions/decisions (UN). Issued under agenda item 1, agenda document A/CONF.199/PC/1.
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Essays on banking theory and history of financial arrangementsFerreira, Murilo Resende 27 June 2014 (has links)
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Previous issue date: 2014-06-27 / This thesis contains two chapters, each one dealing with banking theory and the history of financiai arrangements. In Chapter 1, we extend a Diamond and Dybvig economy with imperfect monitoring of early withdrawals and make a welfare comparison between all possible allocations, as proposed by Prescott and Weinberg(2003) [37]. This imperfect monitoring is introduced by establishing indirect communication( trough a mean of payment) between the agents and the machine that is an aggregate of the financiai and the productive sector. The extension consists in studying allocations where a fraction of the agents can exploit imperfect monitoring and defraud the contracted arrangement by consuming more in the early period trough multiple means of payment. With limited punishment in the period of late consumption, this new allocation is called a separating allocation in contrast with pooling allocations where the agent with the ability of fraud is blocked from it by a costly mean of payment or by receiving enough future consumption to make fraud unattractive. The welfare comparison in the chosen range of parameters show that separating allocations are optimal for poor economies and pooling allocations for intermediary and rich ones. We end with a possible historical context for this kind of model, which connects with the historical narrative in chapter 2. In Chapter 2 we explore the quantitative properties of an early warning system for financiai crises based on the boom and bust framework described in more detail in appendix 1. The main variables are: real growth in equity and housing prices, the yield spread between the 10-year government bond and the 3-month interbank rate and the growth in total banking system assets. These variables display a higher degree of correct signals for recent crises (1984-2008) than comparable early warning systerns. Taking into account an increasing base-line risk ( due to increasing rates of credit expansion , lower interest rates and the accumulation of distortions) also proves to be informative and to help signaling crises in countries that did not go trough a great boom in previous years. / Esta tese contém dois capítulos, cada um lidando com a teoria e a história dos bancos e arranjos financeiros. No capítulo 1, busca-se extender uma economia Diamond-Dybvig com monitoramento imperfeito dos saques antecipados e realizar uma comparação do bem estar social em cada uma das alocações possíveis, como proposto em Presscott and Weinberg(2003). Esse monitoramento imperfeito é implementado a partir da comunicação indireta ( através de um meio de pagamento) entre os agentes e a máquina de depósitos e saques que é um agregado do setor produtivo e financeiro. A extensão consiste em estudar alocações onde uma fração dos agentes pode explorar o monitoramento imperfeito e fraudar a alocação contratada ao consumirem mais cedo além do limite, usando múltiplos meios de pagamento. Com a punição limitada no período de consumo tardio, essa nova alocação pode ser chamada de uma alocação separadora em contraste com as alocações agregadoras onde o agente com habilidade de fraudar é bloqueado por um meio de pagamento imune a fraude, mas custoso, ou por receber consumo futuro suficiente para tornar a fraude desinteressante. A comparação de bem estar na gama de parâmetros escolhida mostra que as alocações separadoras são ótimas para as economias com menor dotação e as agregadoras para as de nível intermediário e as ricas. O capítulo termina com um possível contexto histórico para o modelo, o qual se conecta com a narrativa histórica encontrada no capítulo 2. No capítulo 2 são exploradas as propriedade quantitativas de um sistema de previsão antecedente para crises financeiras, com as váriaveis sendo escolhidas a partir de um arcabouço de ``boom and bust'' descrito mais detalhadamente no apêndice 1. As principais variáveis são: o crescimento real nos preços de imóveis e ações, o diferencial entre os juros dos títulos governamentais de 10 anos e a taxa de 3 meses no mercado inter-bancário e o crescimento nos ativos totais do setor bancário. Essas variáveis produzem uma taxa mais elevada de sinais corretos para as crises bancárias recentes (1984-2008) do que os sistemas de indicadores antecedentes comparáveis. Levar em conta um risco de base crescente ( devido à tendência de acumulação de distorções no sistema de preços relativos em expansões anteriores) também provê informação e eleva o número de sinais corretos em países que não passaram por uma expansão creditícia e nos preços de ativos tão vigorosa.
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Uma Aplica??o do Algoritmo QT Clustering para Marca??o Colaborativa de Pontos Perigosos em Vias P?blicasLima, Adelson Luiz de 07 December 2012 (has links)
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Previous issue date: 2012-12-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work proposes a collaborative system for marking dangerous points in the
transport routes and generation of alerts to drivers. It consisted of a proximity warning
system for a danger point that is fed by the driver via a mobile device equipped with
GPS. The system will consolidate data provided by several different drivers and generate
a set of points common to be used in the warning system. Although the application is
designed to protect drivers, the data generated by it can serve as inputs for the responsible
to improve signage and recovery of public roads / O trabalho prop?e um sistema colaborativo para marca??o de pontos perigosos em
vias de transporte e gera??o de alertas para motoristas. Ele consistire de um sistema
de alerta de proximidade de um ponto de perigo, que ser? alimentado pelos pr?prios
motoristas atrav?s de um aparelho m?vel equipado com GPS. O sistema dever? consolidar
dados fornecidos por v?rios motoristas diferentes e gerar um conjunto de pontos comuns
que ser?o usados no sistema de alerta. Embora a aplica??o seja destinada ? prote??o
de motoristas, os dados gerados por ela poder?o servir de insumos para os ?rg?os
respons?veis melhorarem a sinaliza??o e recupera??o de vias p?blicas
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Uma arquitetura baseada na teoria do perigo para predição de ataques de segurança em redes autonômicasOliveira, Dilton Dantas de 31 January 2013 (has links)
The growth in the number of connected devices, in the volume of data traffic and of applications used has shown a significant increase in the complexity of today's networks,
leaving the activity of management increasingly difficult for network and system administrators. Management aspects, such as the security of these systems has been a major
challenge faced by the researchers, especially considering that, in parallel, there has been also a significant increase in the degree of sophistication of malicious activities. This scenario requires the development of sophisticated security systems also, in order to prevent or contain attacks increasingly destructive to systems, such as worm attacks. And the biological inspiration has been a main ally in this endeavor, bringing several concepts and new ways of thinking and solving these problems. This work used the bio-inspired concepts of Autonomic Networks (self-managing networks inspired by the functioning of the human nervous system)and Artificial Immune Systems (computer security systems inspired by the functioning of the human immune system), to define a management architecture for network self-protection, through the prediction of security attacks. This architecture incorporates the Danger Theory immune-inspired model and uses its Dendritic Cells algorithm to correlate events and detect anomalies. The architecture analysis was performed on an Early Warning System, which uses notifications received from worm already infected machines as additional information to identify the imminence of an infection in still vulnerable machines. In the experiments the gain in time obtained with this early identification was used in the Conficker worm propagation model and the results showed a reduction in the number of infected machines and, consequently, in the worm propagation across a network / O crescimento do número de dispositivos conectados, do volume de dados trafegados e das aplicações utilizadas tem evidenciado um aumento importante na complexidade das redes
atuais, deixando a atividade de gerência cada vez mais difícil para os administradores de redes e sistemas. Aspectos de gerência, como a segurança desses sistemas tem sido um dos
principais desafios enfrentados pelos pesquisadores, principalmente, considerando que, em paralelo, observa-se um também importante aumento no grau de sofisticação das atividades maliciosas. Tal cenário exige o desenvolvimento de sistemas de segurança igualmente sofisticados, com o intuito de impedir ou conter ataques cada vez mais destrutivos aos
sistemas, como os ataques de worms. E a inspiração biológica tem sido uma das grandes aliadas nesta empreitada, trazendo diversos conceitos e novas formas de pensar e resolver
esses problemas. Este trabalho utilizou os conceitos bio-inspirados das Redes Autonômicas (redes autogerenciáveis inspiradas nos funcionamento do sistema nervoso humano) e dos
Sistemas Imunes Artificiais (sistemas de segurança computacional inspirados no funcionamento do sistema imunológico humano), para definir uma arquitetura de gerência
para autoproteção de redes, através da predição de ataques de segurança. Tal arquitetura incorpora o modelo imuno-inspirado da Teoria do Perigo e utiliza o seu Algoritmo das Células Dendríticas para correlacionar eventos e detectar anomalias. A análise da arquitetura foi realizada em um Sistema de Alerta Antecipado, que usa notificações recebidas de máquinas já infectadas por worm como informação adicional para identificar a iminência de uma infecção em máquinas ainda vulneráveis. Nos experimentos o ganho de tempo obtido com essa identificação precoce foi utilizado no modelo de propagação do worm Conficker e os resultados apontaram uma redução no número de máquinas infectadas e, consequentemente, na propagação deste worm em uma rede
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Fostering Anticipatory Action via Social Protection Systems : A Case Study of the Climate Vulnerability of Flood-Exposed Social Security Allowance Beneficiaries in Bardiya District, NepalDesroches, Sabrina January 2020 (has links)
Rationale – Climate disasters represent a significant and growing proportion of the humanitarian burden and are a key factor in increasing poverty and insecurity. A myriad of studies demonstrate that aid delivered in an ex-ante fashion can be effective in mitigating losses of life, assets and livelihoods associated with climate hazards. This inquiry supplements the nascent body of research and empirical evidence base pertaining to the building of anticipatory capacity into large-scale national systems, namely via linking a Forecast-based Financing mechanism to an existing social protection system. Research question – Using the case of flood disasters in Bardiya district, Nepal, the research inquired the following: How can social protection be combined with Forecast-based Financing in order to optimise anticipatory humanitarian relief for climate-related disasters? Sub-questions – Research sub-questions guided the inquiry: (1) To what extent are current social protection beneficiaries exposed to climate-related disasters? (2) What is the specific climate vulnerability of social protection beneficiaries? (3) What are the anticipatory relief needs of climate vulnerable social protection beneficiaries? Methodology – Grounded in empirical research via the conduct of a qualitative single case study, the inquiry adopted a conceptual perspective and an exploratory design. A remote data collection strategy was applied, which included (1) a thorough desk review of key scientific literature and secondary data provided by in-field humanitarian organisations; and (2) semi-structured interviews with key informants. Key findings – The data demonstrated that the exposure of social protection beneficiaries to flood hazards is comparable to the general population. Nevertheless, an elevated climate vulnerability is evident secondary to an increased sensitivity and diminished adaptive capacity. The flood anticipatory relief needs/preferences identified include cash-based assistance, food provisions, evacuation assistance and/or enhanced Early Warning Systems. Conclusion – The research supports the utilisation of the proposed conceptual model for an integrated social protection and Forecast-based Financing mechanism, inclusive of vertical and horizontal expansion, in order to effectively identify the most climate vulnerable groups and to guide the provision of targeted anticipatory actions. The mechanism is optimised when a people-centred approach is utilised, with reference to the idiosyncratic, lifecycle and corresponding intersectional vulnerabilities of the targeted population. These findings will contribute to prospective programming in Nepal; additionally, the extent to which they can be generalised will be informed by future applied efficacy studies and comparative analyses with research from differing contexts.
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An investigation of South Africa's policy response to climate change in the context of sustainable development goalsMthembu, Dumisani Emmanuel 01 1900 (has links)
Climate change is recognized as one of the environmental challenges with disastrous
consequences for the human well-being. Hence, there is no doubt that climate change
is not only a great environmental concern, but also a developmental challenge that
overlaps at many levels. Accordingly, the global community sees climate change and
sustainable development as two major challenges of the 21st century that require
urgent collective action. The aim of the study was to investigate and analyse South
Africa’s policy response in addressing climate change, also considering the added
dynamics and imperatives presented by the 2030 Agenda for Sustainable
Development (AfSD) that enshrines 17 interwoven Sustainable Development Goals
(SDGs) and 169 targets.
In order to fulfil this task, five research objectives were developed; namely: (i) to
determine the extent to which the South African government has been involved in
domesticating and localizing the SDGs agenda (in general) since its birth in January
2016, (ii) to identify policies and institutions dealing with climate change mitigation
(including sustainable consumption and production) and document the provisions of such policies, (iii) to determine policy coverage and institutional spread regarding the
addressing of climate change adaptation and adaptive capacity, (iv) to audit and
present an inventory of institutions and major financial arrangements existing as
means of implementing climate change policy in South Africa, and (v) to establish
measures in place to improve education, awareness-raising, and human and
institutional capacity development on climate mitigation and adaptation, impact
reduction and early warning.
A research methodology was adopted which took the form of evaluation research. This
research approach is mostly used in large bureaucratic organizations such as
government to determine the extent to which a programme or policy is effective. The
research design followed a Mixed-Methods Research (MMR), which combines
qualitative and quantitative approaches. Primary data was collected from purposefully
selected respondents, who participated in the online survey and face to face
interviews. The analysis of data entailed the reduction and display of data. Data reduction and
display made it possible to code, create themes and concepts; as well as enable the
study to make cogent inferences and rational conclusions. In addition, primary data
was complemented by document analysis that scrutinized relevant documents to
climate change and sustainable development.
The study concluded that South Africa has taken reasonable steps to achieve the
SDGs because the National Development Plan (NDP) which is aligned to the SDGs
was already being implemented. The study also showed that South Africa has put in
place institutional mechanisms to implement the SDGs, even though it took longer to
put them in place and have them operationalised. The study concluded that South
Africa has policies and strategies designed to respond to climate change mitigation
and adaptation. However, there are several challenges inherent in the policies and
strategies that make them ineffective, including policy implementation inertia. While
the study confirmed that there are institutions in place to implement climate change
policies and strategies; it emerged that capacity is concentrated at the national level, as opposed to the provincial and local government levels, and relies on few experts
which makes the system vulnerable and fragile.
Regarding funding for both climate change and the SDGs, it emerged that South Africa
does not budget enough money, and relies heavily on international donations. The
study further revealed that there is dissatisfaction with the public’s involvement in
climate change management in the country. It also highlighted the need to improve
early warning systems and preparedness to respond to extreme weather events.
Hence, the study suggests that there is a need for a serious introspection with regard
to the implementation model to ensure that the issues raised by the study are resolved. / Environmental Sciences / Ph. D. (Environmental Management)
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Water security and its importance in protecting public healthRamirez, Christina M. 01 January 2012 (has links) (PDF)
The need for access to clean, healthy water is a subject that surrounds the world. The United States is fortunate to have the latest technology for access to water and treatment of water; however, one subject that hits at the heart of the nation is water security. A breach in the water systems in the U.S. would cause direct public harm because the population relies on water to sustain life. Protecting potable water systems is necessary because of natural disasters, but it has gained importance since the September 11, 2001 attacks on the U.S. Threats on the water systems from intentional attacks cause high risk in affecting public health. Water Security is an area of defense that has recently been evolving and research in this subject has increased. Detection methods are of high importance in protecting from contamination. This thesis determines the most detrimental contaminants; discusses the importance of detection methods, sensor networks, and Contamination Warning Systems (CWS); provides prevention and detection devices currently available; and explains in depth the threats, prevention, detection, response, and rehabilitation associated with water contamination events.
NOTE: Both archival copies of the manuscript were missing pages 208-210.
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Untersuchung von Methoden zur Früherkennung von Bränden in Wald- und Vegetationsgebieten / Early Detection of Fires in Areas of Forests and other VegetationSchneider, Dirk 01 August 2017 (has links) (PDF)
Dissertation of Chief Fire Officer Dipl.-Ing. M. Sc. Dirk Schneider for achieving the academic degree of Dr.-Ing. of the Faculty of Forestry, Geo and Hydro Sciences of the Technical University of Dresden with the title: “Early Detection of Fires in Areas of Forests and other Vegetation”
Fires threaten and destroy extensive forest and vegetation areas every year, endangering people and its settlements, leading to significant pressures on the environment and destroying considerable high value resources. The expenditures in manpower, logistics and finance for safety in general and fire suppression in particular are considerable. To minimize these varied and extensive consequences of fires, early detection is desirable, making an effective firefighting strategy possible. This early detection is particularly of importance in remote, large-scale areas and territories not under observation by the population, especially if they are subject to an increased or high vulnerability. After investigating and considering the causes, that repeatedly lead to forest fires not only in the Federal Republic of Germany but worldwide, the author describes different traditional and modern methods for early detection of fires in areas of forests and other vegetation. Furthermore the author develops a performance item catalog, basing on practical and economic experience, by which not only novel early warning systems can be developed, but the systems and methods described in the present study also are assessed and compared. The comparison of various early warning systems is guided not only by means of technical features, but also from an economic perspective. Financial calculation methods, staff costs and the peculiarities in public administration are particularly noted. The author also shows the different parameters that influence the selection of an appropriate early warning system for the detection of forest and vegetation areas. It becomes clear that it is the scene of the incident with its specific parameters that determines the most useful early warning system.
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