Machine learning Gaussian short rate

Dissertação para obtenção do Grau de Doutor em Estatística e Gestão do RiscoThe main theme of this thesis is the calibration of a short rate model under the risk neutral measure. The problem of calibrating short rate models arises as most of the popular models have the drawback of not fitting prices observed in the market, in particular, those of the zero coupon bonds that define the current term structure of interest rates. This thesis proposes a risk neutral Gaussian short rate model based on Gaussian processes for machine learning regression using the Vasicek short rate model as prior. The proposed model fits not only the prices that define the current term structure observed in the market but also all past prices. The calibration is done using market observed zero coupon bond prices, exclusively. No other sources of information are needed. This thesis has two parts. The first part contains a set of self-contained finished papers, one already published, another accepted for publication and the others submitted for publication. The second part contains a set of self-contained unsubmitted papers. Although the fundamental work on papers in part two is finished as well, there are some extra work we want to include before submitting them for publication. Part I: - Machine learning Vasicek model calibration with Gaussian processes In this paper we calibrate the Vasicek interest rate model under the risk neutral measure by learning the model parameters using Gaussian processes for machine learning regression. The calibration is done by maximizing the likelihood of zero coupon bond log prices, using mean and covariance functions computed analytically, as well as likelihood derivatives with respect to the parameters. The maximization method used is the conjugate gradients. We stress that the only prices needed for calibration are market observed zero coupon bond prices and that the parameters are directly obtained in the arbitrage free risk neutral measure. - One Factor Machine Learning Gaussian Short Rate In this paper we model the short rate, under the risk neutral measure, as a Gaussian process, conditioned on market observed zero coupon bonds log prices. The model is based on Gaussian processes for machine learning, using a single Vasicek factor as prior. All model parameters are learned directly under the risk neutral measure,using zero coupon bonds log prices only. The model supports observations of zero coupon bounds with distinct maturities limited to one observation per time instant. All the supported observations are automatically fitted.M2A/ISEL financing conference trips; ISEL - financing conference fees; ISEL/IPL the PROTEC scholarship; CMA/FCT/UNL - financing conference trip

Electroanalysis of Heavy Metals in the Cork of Quercus Suber

This will enable Pb(II) determination optimisation, regarding environmental aspects of the perpetuation of Quercus suber Montado (similar to Forest). It will also allow a more profound toxicological quality control of corks (barks). These two last referred aspects are very related ones, once accepted that the more advanced could the certification of the quality patterns of corks (barks) be, more will be the sustainability of Quercus suber ecosystem. Which we believe can be done, amongst other vectors, by studying such an important environmental issue as heavy metals. It is shown that Pb(II) quantification in the cork (bark) of Quercus suber tree (Cork Oak) is possible, using Differential Pulse Anodic Stripping Voltammetry (DPASV). The samples digestion was made in a mixture of H2O2 and HNO3 1:8, in a closed recipient at approximately 90 ºC. The measures were made in NaCl 0.1 M, using a Hanging Mercury Drop Electrode, a Glassy-Carbon Rod Counter Electrode, and an Ag/AgCl/KCl 3M reference electrode, after a 180 s deposition step. The results have shown the determination of a coherent stripping potential of -0.405 V (SD=0.0005 V), and a fine linear adjustment after the standard addition method (R2 = 0.997). They have also revealed the interest of further studies. The need to test other electroanalysis requisites was understood, and imposed by the proof of the complex nature of the matrix

THE IMPORTANCE OF THE CORK (BARK) OF QUERCUS SUBER IN THE

The recent absence of Lead element as catalyst in internal explosion motors, being an extremely important action for the stop of this environmental aggression, has no effect in the minimization of the harm this element does in the positions where its deposition now lays. The impact of the ubiquity of pollution, in this case Lead pollution, needs to have monitoring tools. The greatest of the tools one can have is the analysis of the content of a strong indicator. One that stands for a long time in one place, for which it is able to receive the marks of the analyte passage. Quercus suber (Cork Oak) tree is such a case. Having a life expectation ranging from 200 to 500 years (depending on the cork extraction intensity) and with a capability of regeneration of its cork coverture, it concentrates the amounts of Lead, with which it had contacted through its life, in successive layers, corresponding, the larger ones, to the high temperatures season, and the thinner ones to the low temperatures season. So, the analysis of the content of the element in a layer of cork with a given amount of years in the tree, will be a good estimator of how the content of Lead as evolved in the area. And a correct distribution of sampling trees will show much more about a greater area. The possibility of choosing years by choosing layers of cork, and the fact that the sampling will not harm the tree, if properly done, make this procedure a novel and powerful tool in the monitorization of the dispersion of heavy metals in areas populated by Quercus suber, as it is the case of big areas in Portugal, the great of the greatest in everything related with this tree, namely economically, and, in general, in the area of the Mediterranean basin. This paper announces how the electroanalytical determination of Pb(II) by Differential Pulse Anodic Stripping Voltammetry (DPASV), recently done in the Department of Chemistry of the University of Évora, already accepted for publication in Portugaliae Electrochimica Acta, has proven to allow a deeper insight into the previously discussed problematic

Avaliação do vasoactive-inotropic score para pacientes com choque séptico na UTI pediátrica

Objetivo : Vasoactive-inotropic score (VIS) j á foi validado como ferramenta para predição de mortalidade em crianças submetidas à cirurgia cardíaca, mas com resultados conflitantes em outros grupos de pacientes. O objetivo deste estudo é avaliar o papel do VIS na avaliação de paciente com choque séptico na UTI pediátrica (UTIP) e sua correlação com mortalidade. Desenho de estudo: Coorte histórica. Local: UTI pediátrica de hospital universitário quaternário no Sul do Brasil. Pacientes: Pacientes entre 1 mês e 18 anos admitidos entre j aneiro/2016 e julho/2018 com diagnóstico de choque séptico. Intervenção: Nenhuma. Principais resultados: Foram analisadas 181 admissões, com uma mortalidade de 28,7%. O VIS apresentou uma baixa capacidade discriminatória para predição de mortalidade nos pacientes com choque séptico, com a maior área sob a curva ROC de 0,69. Quando dicotomizado utilizando valores próximos a 20 ou 25, o VIS apresentou, entretanto, uma forte associação com mortalidade, com odds ratio entre 3,4 (IC 95%, 1,7-6,8) e 4,4 (IC 95%, 2,2-8,8), podendo representar a gravidade clínica desses pacientes. Referenciais mais altos, como 150 ou 200, como proposto em outros estudos, não conferiram ao escore maior valor preditivo ou i ncremento na força de associação. Conclusão: O VIS avalia principalmente o suporte hemodinâmico farmacológico, entretanto, não é capaz de predizer adequadamente a mortalidade de crianças com choque séptico. Como o choque séptico é uma entidade clínica complexa, multissistêmica, essa avaliação parcial é i mprecisa e assim, i ncapaz de predizer mortalidade. Entretanto, VIS pode ser utilizado como marcador de gravidade clínica nesses pacientes, permitindo a comparação de grupos de crianças com choque séptico e alertando para a necessidade de se decidir por alternativas terapêuticas.Objective : The Vasoactive-inotropic score (VIS) has been successfully used to predict mortality i n children submitted to cardiac surgery with controversial results i n other groups of patients. The present study aims to evaluate the role of VIS for patients with septic shock i n the PICU and i ts correlation with mortality. Design: Historical cohort. Setting : 13-bed pediatric ICU of a tertiary university hospital i n South of Brazil. Patients: Patients between 1 month and 18 years old admitted between January 2016 and July 2018 with septic shock (SS). Intervention: None. Main results: 181 admissions due to SS were i dentified, with a mortality rate of 28.7%. VIS showed a poor discrimination capacity to mortality prediction, with an area under the ROC curve of 0.69. Adopting VIS values close to 20 or 25 were strongly associated with mortality, with an odds ratio ranging from 3.4 (95% CI, 1.7-6.8) to 4.4 (95% CI, 2.2-8.8), depending on the reporting cutoff. Increasing these thresholds to values such as 150 or 200, as proposed i n other studies, were not associated with greater capacity to predict mortality or stronger association with i t. Conclusion: VIS evaluates predominantly the cardiovascular pharmacological support, however, i t was not able to accurately predict the mortality of children with SS. As SS i s a complex clinical entity affecting multiple organs, this partial assessment i s i naccurate to predict death. Otherwise, VIS can be used as a surrogate of severity of i llness, enabling comparison between groups of children with SS and alerting for alternatives therapeutic options

Protótipo do Sistema de Informações Agroflorestais - banco de dados.

Histórico da discussão do Banco de Dados de SAF. Processo metodológico. Esquema computacional do protótipo do SISAF. Situação do sustento de informações e banco de dados. Alcances do sistema. Futuras ações para o SISAF

Adaptação do programa PAC-Pórticos ao EC2 e sua integração com o conceito BIM

Atualmente existe uma grande variedade de programas de cálculo automático de estruturas de betão armado disponíveis no mercado, pois estes, cada vez mais, são inerentes ao desenvolvimento de cada projeto de estruturas. O PAC-Pórticos foi um dos primeiros a chegar ao mercado nacional surgindo no início da década de noventa. Foi totalmente desenvolvido em Portugal, tendo tido bastante sucesso nas suas vendas a nível nacional. O PAC-Pórticos não está preparado para operar diretamente nos mais recentes sistemas operativos nem foi programado para dimensionar os diversos elementos de betão armado seguindo os termos das normas mais recentes (Eurocódigos). O tema do presente trabalho vai de encontro aos atuais problemas do programa, assim sendo, definiu-se como primeiro objetivo a adaptação do PAC-Pórticos à regulamentação europeia para o betão armado. Numa 1ª fase, para a adaptação do PAC-Pórticos aos novos códigos, foi necessário estudar o programa em si, perceber o seu funcionamento e posteriormente realizar uma comparação entre a legislação para qual o software está programado, o Regulamento de Estruturas de Betão Armado e Pré-Esforçado (ainda em vigor) e a Norma Europeia correspondente a EN 1992-1-1 (Eurocódigo 2). Seguidamente, procedeu-se ao estudo e adaptação de todas as sub-rotinas de cálculo do PAC-Pórticos para o dimensionamento de vigas e pilares, tendo finalmente sido testado o novo código e comprovados os resultados obtidos com o mesmo. Na realização do presente trabalho, não foi ignorada a importância crescente da metodologia BIM que, nos dias de hoje, tende a ser implementada nos programas de cálculo de engenharia civil. Neste âmbito, o segundo objetivo é o de conseguir visualizar uma solução obtida do PAC-Pórticos numa qualquer ferramenta tridimensional BIM. Para tal, foram ponderadas várias hipóteses, mas optou-se por criar dois plug-in para o programa AutoCAD da Autodesk. O primeiro destes plug-in contempla o desenho das vigas e o segundo para os pilares, ambos em 3D e elaborados de forma automática.Currently there is a wide variety of programs available in the market for automatic calculation of reinforced concrete structures, because they are increasingly associated with the development of any structural project. The PAC-Pórticos was one of the first to reach the national market, emerging at the early nineties. It was fully developed in Portugal, having been very successful in sales at national level. Nowadays the PAC-Pórticos is not prepared to operate directly on the last operating systems and was not programmed to scale the various elements of reinforced concrete following the latest codes (Eurocodes). The theme of this work meets the current program problems, therefore, was defined as first objective to adapt the PAC-Pórticos with European regulations for reinforced concrete. To start to adapt the PAC-Pórticos to the new codes, it was necessary to study the program itself, understand how it works and after that make a comparison between the regulation that the software are programmed that is Regulamento de Estruturas de Betão Armado e Pré-esforçado - REBAP (still used) and the European one (Eurocode 2). Then proceeded to the study and adaptation of all the routines and subroutines PAC-Pórticos calculation for the design of beams and columns then it was tested all the new code and verified the results obtained with it. In this work, it is not ignored the growing importance of BIM methodology that, these days, tend to be implemented in civil engineering calculation programs. In this context, the second objective involves in seeing a solution obtained from the PAC-Pórticos in any three-dimensional BIM tool. To do this, several hypotheses have been considered, but it was decided to create two plug-in for the program AutoCAD of Autodesk. The first one of these plug-in includes the design of beams and the second the columns, both to create 3D drawings automatically

Rendimento incondicional: uma contribuição para a liberdade e autonomia do trabalho na arte

Uma parte significativa dos trabalhadores do sector cultural e criativo não tem relações laborais estáveis e as suas remunerações dependem das oportunidades que os mercados culturais proporcionam, sendo que os sub-sectores da criação e produção artística são os que mais sofrem com a precariedade e instabilidade de rendimentos. O reconhecimento das necessidades específicas destes trabalhadores e da sua importância para a sociedade tem contribuído para evoluções legislativas que, no entanto, não alteraram substancialmente as suas condições de trabalho. No mercado cultural marcado pelos objectivos financeiros de exploração do valor de consumo e de exibição das obras, a remuneração do tempo de trabalho e as relações laborais são desvalorizadas. O exercício da liberdade profissional - a liberdade de criação - está sujeito à dominação do mercado e das instituições culturais que têm poder para definir contextos de trabalho e de remuneração. A proposta de um rendimento incondicional para estes trabalhadores separa a remuneração da necessidade de trabalho a qualquer custo, oferece segurança económica, permite a liberdade de escolha, a autonomia e inovação do trabalho artístico. A sua implementação é viável em Portugal, apesar de ser necessário consenso político e social para minimizar possíveis riscos. Um projecto piloto de rendimento incondicional para o universo de trabalhadores independentes da cultura, ou para os profissionais da criação artística, seria um passo importante no estudo da sua viabilidade a toda a população.A big part of cultural and creative workers do not have stable employments and their income depends on options based in the opportunity allowed by cultural markets. Inside this diverse sector, the professionals from creation and artistic production are those more affected by precariousness and income instability. The recognition of their specific needs and the importance of their work for the society gave a huge contributions to legislative recent actions, however their work conditions remain basically the same. Being cultural markets focused on the financial results of consumption and exhibition value of artistic works, both remuneration and labour relations are devalued. The practice of professional freedom - creative freedom - is under domination of markets and cultural institutions, once they have the power to define work contexts and remuneration conditions. Proposing an unconditional income for those professionals splits the remuneration from the need of working at any cost, offers economic security to people and allows freedom of choice, autonomy and innovation to the artistic work. The implementation is possible in Portugal, although political and social consensus is necessary to minimize risks and biased approaches. An unconditional income pilot for the universe of independent cultural workers or for those professionals of artistic creation, would be an important step towards studying its viability and impact in the general population

V Encontro Luso-Brasileiro de Conservação e Restauro – uma nota introdutória

At the end of 2019, the 5th edition of the Portuguese-Brazilian Conference on Conservation and Restoration took place, and was organized by CITAR (Catholic University of Portugal) in collaboration with the Federal University of Rio de Janeiro. During the 9th and 10th of December topics were discussed related to recent events, such as the tragic fire in the National Museum of Rio de Janeiro, which occurred just over a year earlier; to the challenges posed by the conservation of new media art, contemporary art and scientific collections, as well as to the preservation of so-called more "traditional" cultural assets; without neglecting the necessary joint reflections about training on conservation and restoration on both sides of the Atlantic.Em finais de 2019 decorreu a 5ª edição dos Encontros Luso-Brasileiros de Conservação e Restauro, organizado pelo CITAR (Universidade Católica Portuguesa), com a colaboração da Universidade Federal do Rio de Janeiro (UFRJ). Durante os dias 9 e 10 de dezembro foram debatidas temáticas relacionadas com realidades próximas como o trágico incêndio no Museu Nacional do Rio de Janeiro, ocorrido pouco mais de um ano antes; os desafios colocados pela conservação dos novos media, arte contemporânea e coleções científicas, bem como com a preservação de bens culturais ditos mais “tradicionais”; sem descurar a necessária reflexão conjunta sobre a formação dos profissionais de conservação e restauro, nos dois lados do Atlântico.info:eu-repo/semantics/publishedVersio