Flood risk management in the U.S. has contributed to overdevelopment in at-risk areas, increases in flood losses over time, significant deficits in federal emergency programs, and inequitable outcomes to households and communities. Addressing these issues in a cost-effective and socially equitable manner relies on the ability of policy analysts to identify and understand complex interactions that characterize coupled natural-human systems, and tools for accurate estimates of the risks that arise from these interactions. This dissertation addresses this need by developing and investigating a flood risk analysis system that integrates data on property locations, assessments and transactions, high resolution flood hazard models, and flood risk policy and impacts across the coterminous United States. We focus on the degree to which markets accurately value their exposure to flooding and its impacts, and the accuracy of procedures and tools to estimate flood losses. In the first chapter, we identify heterogeneous valuation of storm risk in the Florida Keys that depends on the presence of structural defense and proximity to damaged homes after Hurricane Irma. This result suggests that stranded assets, properties with increasing vulnerability to storms but unable to rebuild structures and recover wealth, and overvalued assets at risk, which raise disaster costs, can occur simultaneously. This runs counter to the common framing of competing drivers of observed market valuation. In the second, we show that conventional methods employed in flood loss assessments to achieve large spatial scales introduce large aggregation bias by sacrificing spatial resolution in inputs. This investigation adds important context to published risk assessments and highlights opportunities to improve flood loss estimation uncertainty quantification which can support more cost effective and equitable management. In the final chapter, we conduct a nationwide study to contrast the predictive accuracy of predominantly used U.S. agency flood damage prediction models and empirical alternatives using data on 846 K observed flood losses to single-family homes from 446 flood events. We find that U.S. agency models mischaracterize the relationships of losses at the lowest low and high inundation depths, for high-valued structures, and structures with basements. Evaluated alternatives improve mean accuracy on these dimensions. In extrapolation to 72.4 M single-family homes in the U.S., these differences translate into markedly different predictions of U.S.-wide flood damages to single-family homes. The results from this dissertation provide an improved empirical foundation for flood risk management that relies on the valuation and estimation of flood risk from county to continental scales.

Les systèmes avioniques sont soumis à de fortes contraintes de criticité et de temps réel. Pour certifier de telssystèmes, il est nécessaire de calculer une borne supérieure du délai de bout en bout de chaque message transmisdans le réseau. Cette thèse se focalise principalement sur l'étude des systèmes avioniques civils utilisant le réseauAFDX (Avionics Full Duplex Switched Ethernet), qui a été par exemple introduit dans l'architecture de l'AirbusA380.Dans ce contexte, nous nous sommes focalisés sur le calcul des délais de bout en bout des messages circulant dansle réseau. Parmi les méthodes existantes, nous nous sommes intéressés à la méthode des trajectoires proposéedans la littérature. Cette méthode permet de calculer des bornes supérieures du temps de traversée des messagesdans les noeuds d'un réseau AFDX. Notre première contribution a été de démontrer que cette méthode peutcalculer des délais bout en bout optimistes. Cette méthode ne peut donc pas sans modification être utilisée pourvalider les délais de bout en bout des messages transmis dans l'AFDX. Malgré l'identification des problèmes ausein de la méthode des trajectoires, il ne nous apparaît pas simple d'apporter une correction aux problèmes misen évidence. Dans un deuxième temps, nous avons proposé une nouvelle approche pour calculer ces délais quirepose sur la caractérisation pire cas du trafic que peut rencontrer un paquet, sur chaque noeud. / Avionics systems are subject to hard real-time constrainst and criticality. To certify these systems, it is neccessaryto compute the upper bound of the end-to-end delay of each message transmitted in the network. In this thesis,we mainly focus on civils avionics systems that use AFDX (Avionics Full Duplex Switched Ethernet) networkand that has been introduced in the Airbus A380 architecture.In this context, we focus in the computation of the end-to-end delays of messages crossing the network. Amongthe existing methods, we interested in the trajectory approach precedently proposed by researchers. The goal ofthis method is to compute end-to-end delay upper bounds of messages in the nodes of AFDX network. As a firstcontribution, we prove that the end-to-end delays computed by this method can be optimistic. This means thatwithout any modification, it cannot be used to validate transmission end-to-end delays for the AFDX. Despitethe identification of these optimistic problems in the trajectory approach, a solution to remove them seems notto be simple from our point of view. Hence, as a second contribution, we propose a new approach to computethese delays based on the characterization of the worst-case traffic encountered by a packet on each crossednode.