Uncertainty in mesoscale numerical weather prediction : probabilistic forecasting of precipitation

Over the last decade, advances in numerical weather prediction (NWP) led to forecasts on even finer horizontal scales and a better representation of mesoscale processes. High-resolution mod- els provide the user with realistic weather patterns on the km-scale. However, the evaluation of such small-scale model output remains still a challenge in forecast verification and the quan- tification of forecast uncertainty. Ensembles are the main tool to assess uncertainty from NWP models. The first operational mesoscale NWP ensemble was developed by the German Meteo- rological Service (DWD) in 2010. The German-focused COSMO-DE-EPS is especially designed to improve quantitative precipitation forecasts, which is still one of the most difficult weather variables to predict. This study investigates the potential of mesoscale NWP ensembles to predict quantitative pre- cipitation. To comprise the uncertainty inherent in NWP, precipitation forecasts should take the form of probabilistic predictions. Typical point forecasts for precipitation are the probability that a certain threshold will be exceeded as well as quantiles. Quantiles are very suitable to predict quantitative precipitation and do not depend an a priori defined thresholds, as is necessary for the probability forecasts. Various statistical methods are explored to transform the ensemble forecast into probabilistic predictions, either in terms of probabilities or quantiles. An enhanced framework for statistical postprocessing of quantitative precipitation quantile predictions is de- veloped based on a Bayesian inference of quantile regression. For a further investigation of the predictive performance of quantile forecasts, the pool of verification methods is expanded by the decomposition and graphical exploration of the quantile score. The decomposition allows to attribute changes in the predictive performance of quantile forecasts either to the reliability or the information content of a forecasting scheme. Together with the Bayesian quantile regression model, this study contributes to an enhanced framework of statistical postprocessing and probabilistic forecast verification of quantitative precipitation quantile predictions derived from mesoscale NWP ensembles

Spatial Dependence and Heterogeneity in Empirical Analyses of Regional Labour Market Dynamics

Are regions within a country really independent islands? Do economic relations and effects really have a homogenous, unique size across an entire country? These two assumptions are often imposed implicitly in empirical economic and social research. In his doctoral thesis, the author discusses how statistical methods can deviate from this unrealistic model structure through employing spatial patterns in both observable variables and presumed relations. Opportunities to improve our understanding of the economy as well as chances and perils in the application of such methods are demonstrated in a number of studies on aspects of regional labour market dynamics.Warum sollen Regionen innerhalb eines Landes unabhängige Inseln sein? Und warum sollen, über das gesamte Land hinweg, einheitlich starke ökonomische oder soziale Wirkungszusammenhänge bestehen? Diese zwei Annahmen werden in der angewandten empirischen Wirtschafts- und Sozialforschung üblicherweise implizit unterstellt. Wie in statistischen Verfahren von dieser unrealistischen Modellstruktur unter Ausnutzung der räumlichen Strukturen in beobachteten Variablen und unterstellten Zusammenhängen abgewichen werden kann, diskutiert der Autor im vorliegenden Band. Möglichkeiten, unser Verständnis der Ökonomie zu vertiefen, werden ebenso verdeutlicht, wie Chancen und Tücken beim Einsatz der Methoden in Studien zu verschiedenen Aspekten der Arbeitsmarktdynamik

A multi-configuration approach to reliability based structural integrity assessment for ultimate strength

Structural Reliability treats uncertainties in structural design systematically, evaluating the levels of safety and serviceability of structures. During the past decades, it has been established as a valuable design tool for the description of the performance of structures, and lately stands as a basis in the background of the most of the modern design standards, aiming to achieve a uniform behaviour within a class of structures. Several methods have been proposed for the estimation of structural reliability, both deterministic (FORM and SORM) and stochastic (Monte Carlo Simulation etc) in nature. Offshore structures should resist complicated and, in most cases, combined environmental phenomena of greatly uncertain magnitude (eg. wind, wave, current, operational loads etc). Failure mechanisms of structural systems and components are expressed through limit state functions, which distinguish a failure and a safe region of operation. For a jacket offshore structure, which comprises of multiple tubular members interconnected in a three dimensional truss configuration, the limit state function should link the actual load or load combination acting on it locally, to the response of each structural member. Cont/d.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A multi-configuration approach to reliability based structural integrity assessment for ultimate strength

Structural Reliability treats uncertainties in structural design systematically, evaluating the levels of safety and serviceability of structures. During the past decades, it has been established as a valuable design tool for the description of the performance of structures, and lately stands as a basis in the background of the most of the modern design standards, aiming to achieve a uniform behaviour within a class of structures. Several methods have been proposed for the estimation of structural reliability, both deterministic (FORM and SORM) and stochastic (Monte Carlo Simulation etc) in nature. Offshore structures should resist complicated and, in most cases, combined environmental phenomena of greatly uncertain magnitude (eg. wind, wave, current, operational loads etc). Failure mechanisms of structural systems and components are expressed through limit state functions, which distinguish a failure and a safe region of operation. For a jacket offshore structure, which comprises of multiple tubular members interconnected in a three dimensional truss configuration, the limit state function should link the actual load or load combination acting on it locally, to the response of each structural member. Cont/d.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Behavioral microfoundations of retail credit markets :a theoretical and experimental approximation

[Resumen] La reciente crisis financiera ha renovado el interés en el papel que juega el crédito, particularmente bancario, para amplificar el ciclo económico. Esta tesis se centra en el lado de la oferta para estudiar la eficiencia informativa de los sistemas bancarios a la hora de conceder crédito a la economía. Tras una revisión de la literatura centrada en dicho objeto, establecemos la economía y finanzas conductuales como marco conceptual de nuestra investigación. Asi, comentamos en primer lugar los límites para aplicar la hipótesis del mercado eficiente, paradigma clásico en los mercados financieros, a los sistemas bancarios, y ofrecemos un enfoque alternativo en tres pasos que se basa en la literatura conductual. Después, llevamos a cabo una investigación experimental para testar el primer paso: un juego de simulación diseñado para replicar el esquema básico en el que un banco establece sus políticas de crédito. Los resultados se contrastan con los perfiles de los participantes en términos de exceso de confianza y la teoría prospectiva, para determinar si estos sesgos podrían explicar las diferentes políticas de crédito. Por último, ofrecemos un modelo teórico para analizar los pasos segundo y tercero. Asumiendo que algunos bancos tienen gerentes demasiado optimistas, el modelo muestra cómo los bancos racionales seguirían a sus competidores sesgados, y describe los límites del arbitraje en la industria que impedirían restaurar la eficiencia informativa.[Resumo]A recente crise financeira renovou o interese no papel xogado polo crédito, en particular bancario, na amplificación do ciclo económico. Esta tese céntrase no lado da oferta ao obxecto de estudar a eficiencia informativa dos sistemas bancarios cando conceden crédito á economía. Tras unha revisión das principais áreas da literatura centradas en dita cuestión, fixamos a economía e finanzas conductuais como marco conceptual da nosa investigación. Deste xeito, debatemos primeiro sobre as limitacións para aplicar a hipótese do mercado eficiente, paradigma clásico nos mercados financeiros, aos sistemas bancarios, e suxerimos un enfoque alternativo en tres pasos, baseado na literatura conductual. Logo, poñemos en práctica unha investigación experimental ao obxecto de testar o primeiro paso: un xogo de simulación deseñado para replicar o esquema básico no que un banco establece as súas políticas de crédito. Os resultados son contrastados cós perfís dos participantes en termos de exceso de confianza e a teoría prospectiva, para determinar se ditos sesgos poderían explicar diferentes políticas de crédito entre bancos. Para rematar, ofertamos un modelo teórico para analizar o segundo e terceiro paso. Asumindo que algúns bancos son dirixidos por xestores optimistas de máis, o modelo mostra como os bancos racionais seguirían aos seus sesgados competidores, e describe os límites da arbitraxe na industria que impedirían restablecer a eficiencia informativa.[Abstract] The recent financial crisis has renewed interest in the role credit plays, particularly when granted by the banking sector, to amplify the economic cycle. This thesis focuses on the credit supply side to study the informational efficiency of bank-based financial systems when granting credit to the economy. After a revision of the main areas of the literature that are devoted to such purpose, we set the behavioral economics and finance as a conceptual framework for our research. Thus, we firstly discuss the limits to apply the classic paradigm in financial markets, the efficient market hypothesis, to bank-based systems, and offer an alternative approach in three steps, based on the behavioral literature. Then, we implement an experimental research to test the first step. The experiment consists of a business simulation game designed to replicate the basics of a bank to set its credit policies. The results are tested against the participants’ profiles in terms of overconfidence and prospect theory, to determine whether these behavioral biases might explain different credit policies across banks. Finally, we offer a theoretical model to analyze the second and third steps in the behavioral approach. Assuming some banks are run by too optimistic managers, the model shows how rational banks would herd to follow their biased competitors, and describes the limits of arbitrage in the industry that would prevent informational efficiency to be restored