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This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact

monitoring --- damage identification --- data-driven models --- diagnostic tools --- uncertainty quantification --- structural health monitoring

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Entering or exiting the atmosphere of a celestial body is a challenging task. The
interactions between a space-vehicle and the flow surrounding it create a strong
detached wave. Complex Gas-Surface Interaction phenomena occur between the
resulting chemically reacting boundary layer and the vehicle’s surface, causing
strong heat fluxes and chemical reactions. Thermal Protection System (TPS)
are designed to protect the spacecraft.
A proper knowledge of the interactions between the flowfield and the surface of
the TPS is fundamental for the design of this part of the vehicle.
In this essay, uncertainty quantification techniques are used to study the interac-
tions between nitrogen plasma and TPS’s of carbonaceous materials. Two test-
ing campaigns, one at lower pressure (15 hPa) and one at higher ones (100, 200
hPa), performed in the Plasmatron, a high enthalpy facility in the von Karman
Institute, are analysed with the aim of comparing the Nitrogen-Carbon ablation
models proposed by Prata and the modified version suggested by Capriati.
During the experiments a plasma of Nitrogen interacts with a hemispherical
graphite sample.
Indirect uncertainties on the blowing mass flow rates for the different test cases
are analytically quantified.
A computational tool developed at the von Karman Institute is used to simulate
the flowfield along the stagnation line.
Faster propagation of the uncertainties is achieved using surrogate models. Neu-
ral Networks and Kriging models are analysed. The comparison between the
uncertainties on the experimental results and the numerical propagation of the
uncertainties on the experimental conditions of the tests using the two abla-
tion models coupled with the Stagline solver shows that the model proposed by
Capriati improves the predictions at low pressures (15hPa), whereas Prata’s ab-
lation model is bis more accurate at higher pressure campaign (100hPa, 200hPa).
None of the two ablation models seems to well capture the pressure-dependence
of the reactions; a further calibration of the model is then suggested to improve
model predictions over the entire pressure range.

uncertainty quantification, thermal protection system, nitrogen-carbon, gas-surface interaction --- Ingénierie, informatique & technologie > Ingénierie aérospatiale

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This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact

Civil engineering, surveying & building --- Environmental science, engineering & technology --- monitoring --- damage identification --- data-driven models --- diagnostic tools --- uncertainty quantification --- structural health monitoring

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This open access book features a selection of high-quality papers from the presentations at the International Conference on Spectral and High-Order Methods 2018, offering an overview of the depth and breadth of the activities within this important research area. The carefully reviewed papers provide a snapshot of the state of the art, while the extensive bibliography helps initiate new research directions.

Partial differential equations. --- Numerical analysis. --- Partial Differential Equations. --- Numerical Analysis. --- Mathematical analysis --- Partial differential equations --- Partial Differential Equations --- Numerical Analysis --- Analysis --- High-order methods --- Spectral methods --- Isogeometric methods --- Discontinuous Galerkin methods --- Wave simulation --- Uncertainty quantification --- Open access --- Differential calculus & equations --- Numerical analysis

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This open access book presents a ground-breaking approach to developing micro-foundations for demography and migration studies. It offers a unique and novel methodology for creating empirically grounded agent-based models of international migration – one of the most uncertain population processes and a top-priority policy area. The book discusses in detail the process of building a simulation model of migration, based on a population of intelligent, cognitive agents, their networks and institutions, all interacting with one another. The proposed model-based approach integrates behavioural and social theory with formal modelling, by embedding the interdisciplinary modelling process within a wider inductive framework based on the Bayesian statistical reasoning. Principles of uncertainty quantification are used to devise innovative computer-based simulations, and to learn about modelling the simulated individuals and the way they make decisions. The identified knowledge gaps are subsequently filled with information from dedicated laboratory experiments on cognitive aspects of human decision-making under uncertainty. In this way, the models are built iteratively, from the bottom up, filling an important epistemological gap in migration studies, and social sciences more broadly.

Demography. --- Population. --- Social sciences—Statistical methods. --- Emigration and immigration. --- Population and Demography. --- Statistics in Social Sciences, Humanities, Law, Education, Behavorial Sciences, Public Policy. --- Human Migration. --- Immigration --- International migration --- Migration, International --- Population geography --- Assimilation (Sociology) --- Colonization --- Human population --- Human populations --- Population growth --- Populations, Human --- Economics --- Human ecology --- Sociology --- Demography --- Malthusianism --- Historical demography --- Social sciences --- Population --- Vital statistics --- Open access --- Agent-based modelling --- Bayesian demography --- Migration modelling --- Model-based approaches --- Uncertainty quantification --- Forced migration --- Computational experiments --- Model calibration and sensitivity --- Free access --- Statistical methods.