Les enjeux environnementaux et sociétaux de la combustion de combustibles fossiles pour la production d'énergie (électrique, chauffage ou transport), nécessitent le développement de nouveaux modes de combustion, de nouvelles technologies de brûleurs et de combustibles alternatifs (gazéification de la biomasse, biofuels, ...). La vitesse de combustion laminaire est un des paramètres fondamentaux utilisé pour caractériser la combustion pré-mélangée de ces nouveaux mélanges combustibles. Cette vitesse est une donnée de référence pour le processus de validation et d'amélioration des schémas cinétiques ainsi qu'un paramètre d'entrée pour estimer la vitesse de combustion turbulente de la plupart des codes de combustion turbulente. Mais bien qu'étudiée depuis plus de 100 ans, la détermination expérimentale précise de cette vitesse reste encore un défi de par les limitations inhérentes aux configurations expérimentales utilisées, en particulier pour les conditions de pression et de température élevées. Dans ce contexte, les objectifs de ces travaux de thèse concernent l'étude, l'analyse et la caractérisation des techniques de détermination de la vitesse de combustion laminaire à partir des flammes en expansion sphérique, en proposant une réflexion sur la minimisation de l'ensemble des sources d'incertitudes possibles sur la détermination de cette vitesse. Cette approche est réalisée pour la configuration de flamme en expansion sphérique, permettant des températures et pressions élevées et maitrisées.Dans une première partie, le formalisme des définitions des vitesses de flamme laminaire existantes dans cette configuration est rappelé afin de définir les facteurs d'incertitudes liés à la mesure expérimentale de ces vitesses (grandeurs cinématiques locales et cinétique globale). En particulier, les effets liés à l'estimation de l'état thermodynamique des gaz brûlés, du rayonnement et de la diffusion différentielle sont discutés. Dans une seconde partie, plusieurs dispositifs numériques et expérimentaux utilisés au cours de cette thèse et permettant l'étude de flammes sphériques en expansion sont présentés. Une étude utilisant quatre dispositifs expérimentaux différents est proposée afin d'analyser et caractériser les incertitudes inhérentes aux mesures et à leur traitement. Enfin dans une troisième partie, une définition rigoureuse de la vitesse de consommation est proposée et une nouvelle méthodologie pour la mesurer est développée. Une validation numérique complète est présentée. Puis les incertitudes liées aux rayonnement, à la diffusion différentielle et à l’extrapolation des données mesurées sont étudiées en détails. Cette dernière étape introduit un biais qui peut être conséquent, et une nouvelle méthodologie pour exploiter des mesures brutes est proposée par une comparaison directe avecdes simulations DNS reproduisant les expériences. / Environmental and social challenges concerning the combustion of fossil fuels for energy production (electricity, building and transport) require the development of new combustion processes, new burner technologies and alternative fuels (gasification of biomass, biofuels, ...). Laminar burning velocity is one of the fundamental parameters used to characterize premixed combustion for these new fuels. This speed is a reference for the validation and improvement of kinetic schemes and an input parameter to estimate the turbulent burning velocity of most turbulent combustion codes. But even if it has been studied over 100 years, the precise experimental measurement of this velocity is still complicated due to inherent limitations in experimental configurations used, especially for high pressure and temperature conditions. In this context, this thesis work focuses on the study, analysis and characterization of the different techniques used to determine the laminar burning velocity from spherically expanding flames and proposes a reflection on the minimization of all possible uncertainty sources. This approach is achieved with confined spherical flames which allow to obtain high temperature and pressure initial conditions. In the first part, the formalism of existing laminar flame speeds in spherical expanding configuration is reminded to define the factors of uncertainty related to the experimental measurement (local kinematic and global kinetic variables). In particular, the effects associated with the estimation of the burned gases thermodynamic state, radiation and differential diffusion are discussed. In the second part, several numerical and experimental devices used in this thesis are presented. A study on four different experimental setups is proposed to analyze and characterize the uncertainties in the measurements and processing. Finally, in the third part, a rigorous definition of the consumption speed is proposed and a new methodology to measure it is developed. A complete validation based on numerical results is presented. Then uncertainties related to radiation, differential diffusion and extrapolation to zero stretch rate of measured data are detailed. This last step introduces a non-negligible bias and a new methodology to exploit raw data by a direct comparison with DNS reproducing the experiments is proposed.

Geotechnical engineering is strongly associated with large uncertainties. Exploring a medium (soil) that is almost entirely and completely hidden from us is no easy task. Investigations can be made only at discrete points, and the majority of a specific soil volume is never tested. All soils experience inherent spatial variability, which contributes to some uncertainty in the design process of a geotechnical structure. Furthermore, uncertainties also arise during testing and when design properties are inferred from these tests. To master the art of making decisions in the presence of uncertainties, probabilistic description of soil properties and reliability-based design play vital roles. Historically, the observational method (sometimes referred to as the “learn-as-you-go-approach”), sprung from ideas by Karl Terzaghi and later formulated by Ralph Peck, has been used in projects where the uncertainties are large and difficult to assess. The design approach is still highly suitable for numerous situations and is defined in Eurocode 7 for geotechnical design. In paper I, the Eurocode definition of the observational method is discussed. This paper concluded that further work in the probabilistic description of soil properties is highly needed, and, by extension, reliability-based design should be used in conjunction with the observational method. Although great progress has been made in the field of reliability-based design during the past decade, few geotechnical engineers are familiar with probabilistic approaches to design. In papers II and III, aspects of probabilistic descriptions of soil properties and reliability-based design are discussed. The connection between performing qualitative investigations and potential design savings is discussed in paper III. In the paper, uncertainties are assessed for two sets of investigations, one consisting of more qualitative investigations and hence with less uncertainty. A simplified Bayesian updating technique, referred to as “the multivariate approach”, is used to cross-validate data to reduce the evaluated total uncertainty. Furthermore, reliability-based design was used to compare the two sets of investigations with the calculated penetration depth for a sheet-pile wall. The study is a great example of how a small amount of both time and money (in the pre-investigation phase) can potentially lead to greater savings in the final design. / <p>QC 20160201</p> / TRUST, Transparent Underground Structures

The aim of this thesis is to discuss and analyse the influenceof data uncertainties with regard to the reliability of materialflow analysis (MFA) studies. MFA, as a part of environmentalsystems analysis, is a method belonging to the research field ofindustrial ecology and more specifically industrial metabolism.As such, the method strives at giving a holistic view of thecomplex world we live in, in order to reduce negativeenvironmental impact. Among other things, MFA studies have beenproposed to be useful for priority setting and following up inmunicipalities. Serving as a starting point is a local case study of flows ofnitrogen in a Swedish municipality, Västerås. The casestudy has been performed using the ComBoxmodel. The years studiedare 1995 and 1998. The main sectors in society emitting nitrogento water were identified as the agricultural and householdsectors. The dominating sectors emitting nitrogen to air wereidentified as the agricultural, transport and infrastructuresectors. As a basis for discussing data uncertainties qualitatively andquantitatively a literature survey was performed. 50 articles andbooks were identified as in some way or another dealing with datauncertainties in MFA. The literature survey showed that theuncertainties for results from a MFA study might vary between±30 % and a factor 10 depending on what kind of parameter isinvestigated. Only one method was found that dealt with datauncertainties in MFA in a complete way; a model developed byHedbrant and Sörme (HS model). When applying the HS model to the case study of nitrogen flowsin Västerås, it was found that when uncertaintyintervals were calculated the possible conclusions changed. Ofthe two pair of flows compared in relation to priority setting,none of the earlier conclusions remained. Of the three flowsanalysed in relation to following up, only the flow from onepoint source supported the same conclusion when uncertainty wasconsidered. In all, it is concluded that data uncertainties in MFAanalysis are an important aspect and that further research isneeded in order to improve input data quality estimations andframeworks for determining, calculating and presenting data, datauncertainties and results from MFA studies. However, theunderlying reality remains, e.g. that management of materialflows are important for understanding and reducing the negativeenvironmental impact. Thus, MFA is one useful tool in thiswork. <b>Keywords:</b>data uncertainties, sensitivity analysis,Material flow analysis, MFA, method to determine datauncertainties, case study, ComBox model, nitrogenflows. / NR 20140805

Les services écosystémiques (SE) désignent les bénéfices fournis par les écosystèmes à la société. En France, la législation cherche à les intégrer dans les études d’impact environnemental avec la promulgation de la Loi pour la reconquête de la biodiversité, de la nature et des paysages (2016). Pour ce faire, il est nécessaire de développer des méthodes de terrain d’estimation des SE. C’est dans ce cadre qu’une collaboration entre le Laboratoire d’Ecologie Alpine et le bureau d’études EGIS Environnement a vu le jour, afin de répondre à la question : comment quantifier les SE à l’échelle locale ?Pour cela, nous avons étudié deux SE de régulation régulièrement évoqués dans le contexte du changement global. Le service de pollinisation est essentiel pour l’alimentation humaine et est au cœur de l’actualité de par les déclins des populations d’insectes pollinisateurs. Le SE de régulation du climat global par la séquestration de carbone par les écosystèmes est d’intérêt majeur en regard des changements climatiques récents et annoncés.Nous avons suivi les quatre étapes du développement d’un protocole. Premièrement, pour le SE de pollinisation entomophile qui possède de nombreuses définitions dans la littérature, nous avons établi par une revue bibliographique un cadre conceptuel afin de définir le SE de pollinisation et d’identifier les indicateurs et leurs méthodes de mesures. Nous avons choisi pour la suite d’adopter la définition du SE de pollinisation comme la capacité de l’écosystème à soutenir la pollinisation entomophile, i.e. la présence d’insectes pollinisateurs. Deuxièmement, nous avons abordé la question du choix des indicateurs pour l’estimation de ce SE. En effet, la capacité du SE de pollinisation peut être estimée par des indicateurs directs, liés à la présence des insectes pollinisateurs sur la parcelle, et des indicateurs indirects, liés aux ressources d’alimentation et de nidification sur la parcelle d’étude et dans le paysage. Nous avons comparé les mesures de ces deux types d’indicateurs estimés en vergers et en prairies. Les objectifs étaient de tester la cohérence entre ces deux types d’indicateurs pour le SE de pollinisation et la possibilité d’une simplification du protocole d’estimation en la basant uniquement sur des indicateurs indirects. Les indicateurs indirects n’expliquaient pas une part suffisante de la variabilité observée dans les mesures d’abondance et de richesse des pollinisateurs pour permettre simplification du protocole.Troisièmement, nous avons cherché à simplifier le protocole d’estimation du SE de la régulation du climat global par la mesure des stocks de carbone en prairies et en forêts. Pour cela, nous avons comparé les estimations obtenues par des protocoles simplifiés à celles obtenues par un protocole plus complet et mesuré les incertitudes causées par ces simplifications. Le protocole d’estimation a pu ainsi être simplifié pour les deux compartiments de l’écosystème stockant le plus de carbone : la biomasse aérienne en forêt et le carbone organique du sol. Enfin, afin de tester l’applicabilité du protocole simplifié d’estimation du SE de régulation du climat global, nous l’avons testé sur des parcelles de zones humides, des écosystèmes stockant une grande quantité de carbone. Ces parcelles ont été placées dans un modèle d’états-et-transitions afin de tester si les mesures de gestion peuvent affecter les stocks de carbone des zones humides. Les actions de gestion sur la biomasse aérienne changeaient les stocks de carbone entre les zones humides herbacées et forestières. Le stock de carbone organique du sol, stock majeur dans les zones humides, ne différait pas entre les différents états étudiés, reflétant la difficulté d’agir sur ce compartiment.Cette étude montre que le développement méthodologique pour la quantification de SE sur le terrain peut mener à des protocoles simples et fiables mais que le processus de développement est différent selon les SE abordés. / Ecosystem services are benefits supplied by ecosystem to human societies. In France, recent legislation aims to include ecosystem service in environmental impact studies with the enactment of the Law for the recovery of biodiversity, nature and landscapes (2016). To do so, it is necessary to develop field methods for ecosystem service estimation. In this setting, a collaboration was established between the Laboratoire d’Ecologie Alpine and the environmental consultancy EGIS Environnement to answer the following question: how can ecosystem services be quantified at local scale?We studied two ecosystem services often cited in the global change context. The pollination service is essential for human food production. Given worldwide pollinator declines it is at the centre of scientific, citizen and political concerns. The service of global climate regulation by carbon sequestration by ecosystems is of major interest given the recent and coming climate changes.We investigated four key steps for developing a field protocol. First, the ecosystem service of entomophilous pollination has numerous definitions in the scientific literature. Thus, based on a literature review we built a conceptual framework for defining the pollination service and identifying quantifiable indicators and their measurement methods. We chose to define the pollination service as the ecosystem capacity to support entomophilous pollination, i.e. pollinating insect presence. Second, we worked on indicator selection for the pollination service estimation. Pollination capacity can be estimated through direct indicators linked to pollinator presence on the plot and through indirect indicators linked to feeding and nesting resources in the plot and in the landscape. We compared measures of these two types of indicators within orchards and grasslands. Our aims were to test consistency between both indicator types for the pollination service and the possibility of protocol simplification based on indirect indicators. Indirect indicators did not explain enough of the observed variability in pollinator abundance and richness to allow a protocol simplification.Third, we tried to simplify the estimation protocol of the ecosystem service of global climate regulation from measures of carbon stocks in grasslands and forests. We compared estimations obtained by simplified protocols to estimations obtained by a more complete protocol. We also quantified the uncertainties caused by these simplifications. The estimation protocol could be simplified for the two most important carbon pools: aboveground biomass in forests and soil organic carbon. Finally, to test the applicability of the simplified protocol of carbon stock estimations, we applied it on wetland plots. These plots were organized following in a state-and-transition model to test whether management decisions are likely to affect wetland carbon stocks. Management actions on aboveground biomass changed carbon stocks between herbaceous and forested wetland. Soil organic carbon, the major carbon stock in wetlands, was unchanged between the different studied stats, illustrating the difficulty to manage soil carbon stocks in the short term.This study shows that method development for field quantification of ecosystem service can lead to simple and reliable protocols. However, the development process is different for each ecosystem service.

In today's dynamic business landscape, companies are constantly exposed to a multitude of challenges and uncertainties that can significantly impact their operations and performance. Inflation, a worldwide pandemic, supply chain disruptions, and rising costs are just a few of the disruptive events that have occurred during the last few years. This thesis investigates the effects of inflation and uncertainties on companies operating in the furniture industry. This thesis adopts a qualitative research approach as its methodological foundation. A comprehensive review of relevant literature and studies pertaining to the subject matter is conducted. To supplement the theoretical insights, empirical data is collected through semi-structured interviews conducted with five company cases. The data collected from these interviews serves as the basis for the development of three key themes: Macroeconomics, export, and crisis management. These themes are consistently woven throughout the thesis, providing a coherent narrative for the reader. This thesis concludes that in times of uncertainties, global furniture export companies have diversified suppliers and markets, managed resources effectively, implemented proactive risk management, and cultivated strong relationships. Prioritizing crisis management, monitoring macroeconomic factors, and optimizing strategic resources have all been key for enhancing resilience and competitiveness in this industry and allows the industry to grow and advance, as in the face of adversity it becomes evident that in the middle of difficulty lies opportunity.

Covariant density functional theory (CDFT) is one of the modern theoretical tools for the description of finite nuclei and neutron stars. Its performance is defined by underlying covariant energy density functionals (CEDFs) which depend on a number of parameters. Several investigations within the CDFT framework using the relativistic Hartree-Bogoliubov (RHB) approach are discussed in this dissertation. Statistical errors in ground state observables and single-particle properties of spherical even-even nuclei and their propagation to the limits of nuclear landscape have been investigated in the covariant energy density functionals with nonlinear density dependency. The parametric correlations are studied in different classes of CEDFs; the elimination of these correlations reduces the number of independent parameters to five or six without affecting the performance of CEDFs on a global scale. Moreover, this study reveals the need to include information on deformed nuclei for the improvement of fitting protocols. A new technique for incorporating deformed nuclei data into the fitting protocol is described. Different CEDFs are optimized using this approach, resulting in a significant improvement in the nuclear mass description. A systematic investigation of the ground state and fission properties of even-even actinides and superheavy nuclei with proton numbers Z = 90 - 120 located between the two-proton and two-neutron drip lines has been performed. These results provide a necessary theoretical input for the modeling of the nuclear astrophysical rapid neutron capture process (r-process) taking place in the mergers of neutron stars. The state-of-the-art CEDFs, namely, DD-PC1, DD-ME2, NL3*, and PC-PK1, are employed in this study. Theoretical systematic uncertainties in the physical observables and their evolution as a function of proton and neutron numbers have been quantified and their major sources have been identified. The extension of the nuclear landscape to hyperheavy nuclei is investigated. The transition from ellipsoidal-like nuclear shapes to toroidal shapes is crucial for the potential expansion of the nuclear landscape to hyperheavy nuclei. The physical reasons for the stability of toroidal nuclei in the Z ~ 134 region are discussed.

Covariant density functional theory (CDFT) is a modern theoretical tool for the description of nuclear structure phenomena. Different physical observables of the ground and excited states in even-even nuclei have been studied within the CDFT framework employing three major classes of the state-of-the-art covariant energy density functionals. The global assessment of the accuracy of the description of the ground state properties and systematic theoretical uncertainties of atomic nuclei have been investigated. Large-scale axial relativistic Hartree-Bogoliubov (RHB) calculations are performed for all Z < 106 even-even nuclei between the two-proton and two-neutron drip lines. The sources of theoretical uncertainties in the prediction of the two-neutron drip line are analyzed in the framework of CDFT. We concentrate on single-particle and pairing properties as potential sources of these uncertainties. The major source of these uncertainties can be traced back to the differences in the underlying single-particle structure of the various CEDFs. A systematic search for axial octupole deformation in the actinides and superheavy nuclei with proton numbers Z = 88 - 126 and neutron numbers from two-proton drip line up to N = 210 has been performed in CDFT. The nuclei in the Z ~ 96, N ~ 196 region of octupole deformation have been investigated in detail and their systematic uncertainties have been quantified. The structure of superheavy nuclei has been reanalyzed with inclusion of quadrupole deformation. Theoretical uncertainties in the predictions of inner fission barrier heights in superheavy elements have been investigated in a systematic way. The correlations between global description of the ground state properties and nuclear matter properties have been studied. It was concluded that the strict enforcement of the constraints on the nuclear matter properties (NMP) defined in Ref. [1] will not necessary lead to the functionals with good description of ground state properties. The different aspects of the existence and stability of hyperheavy nuclei have been investigated. For the first time, we demonstrate the existence of three regions of spherical hyperheavy nuclei centered around (Z ~ 138, N ~ 230), (Z ~ 156, N ~ 310) and (Z ~ 174, N ~ 410) which are expected to be reasonably stable against spontaneous fission.

The restructuring of the electric energy market and the proliferation of intermittent renewable-energy based power generation have introduced serious challenges to power system operation emanating from the uncertainties introduced to the system variables (electricity prices, congestion levels etc.). In order to economically operate the system and efficiently run the energy market, a statistical analysis of the system variables under uncertainty is needed. Such statistical analysis can be performed through an estimation of the statistical moments of these variables. In this thesis, the Point Estimate Methods (PEMs) are applied to the optimal power flow (OPF) problem to estimate the statistical moments of the locational marginal prices (LMPs) and total generation cost under system uncertainty. An extensive mathematical examination and risk analysis of existing PEMs are performed and a new PEM scheme is introduced. The applied PEMs consist of two schemes introduced by H.P. Hong, namely, the 2n and 2n+1 schemes, and a proposed combination between Hong's and M. E Harr's schemes. The accuracy of the applied PEMs in estimating the statistical moments of system LMPs is illustrated and the performance of the suggested combination of Harr's and Hong's PEMs is shown. Moreover, the risks of the application of Hong's 2n scheme to the OPF problem are discussed by showing that it can potentially yield inaccurate LMP estimates or run into unfeasibility of the OPF problem. In addition, a new PEM configuration is also introduced. This configuration is derived from a PEM introduced by E. Rosenblueth. It can accommodate asymmetry and correlation of input random variables in a more computationally efficient manner than its Rosenblueth's counterpart. / Master of Science

En stor del av bankernas utlåning riktar sig till fastighetsbolag. I samband med bankernas utlåning så används fastigheter som säkerhet. Banken använder fastighetsvärderingar som underlag för att bedöma lånevolym och lånevillkor. Det är därför av stor vikt för den finansiella stabiliteten att värderingarna är tillförlitliga. Tillförlitliga värderingar bygger på tillgång till bra data. I dagsläget finns det en brist på denna data, vilket minskar tillförlitligheten i värderingarna. Bristen på data beror på att fastigheter generellt säljs paketerat i bolag vilket gör att köpeskillingen inte offentliggörs. Intressenter är därför beroende av aktörer i transaktioner väljer att annonsera villkoren för transaktionen. Underlaget blir dessutom tunnare på grund av att många transaktioner genomförs med komplexa strukturer som minskar insynen. Samtidigt så finns det incitament för fastighetsbolag och värderare att rapportera högre värden än fastighetens marknadsvärde. Detta då fastighetsägare kan använda sig av högre värderingar för att agera opportunistiskt, och då fastighetsägare är beställare och betalare av värderingen så skapar detta även incitament för värderare. Detta, i kombination med att fastighetsägare idag kan beställa flera värderingar och presentera den högsta för banken, skapar risker för det finansiella systemet. Denna uppsats syftar till att undersöka vilka osäkerheter det finns i värderingsprocessen, vilka incitament det finns för övervärderingar, hur regelverk möjliggör dessa, vilka risker det innebär för det finansiella systemet och förslag för hur man kan öka säkerheten i värderingsprocessen. Studien har genomförts med en kvalitativ metod genom att intervjua representanter från fem värderingsbolag och fyra fastighetsbolag. / A large part of bank lending is directed to real estate companies. In connection with bank lending, real estate is used as collateral. Banks use real estate valuations as a basis for assessing loan volumes and the terms of the loan. It is therefore of great importance for financial stability that valuations are reliable. Reliable valuations rely on the availability of good data. At present, there is a lack of such data, which reduces the reliability of valuations. The lack of data is due to the fact that real estate is generally sold packaged in companies, which means that the purchase price is not disclosed. Stakeholders are therefore dependent on actors in transactions choosing to advertise the terms of the transaction. The data is further reduced by the fact that many transactions are carried out with complex structures that reduce the transparency of the transaction. At the same time, there are incentives for real estate companies and appraisers to report higher values than the market value of the property. This is because property owners can use higher valuations to act opportunistically, and because property owners are the clients and payers of the valuation, this also creates incentives for valuers. This, combined with the fact that property owners today can order multiple valuations and present the highest to the bank, creates risks for the financial system. This paper aims to investigate the uncertainties in the valuation process, the incentives for overvaluations, how regulations enable them, and suggestions on how to increase certainty in the valuation process. The study has been conducted using a qualitative method by interviewing representatives from five leading valuation companies and four real estate companies.

Der Einsatz von hydrologischen Modellen zur Unterstützung von Planung und Betrieb von Entwässerungssystemen ist als Stand der Technik anzusehen. Realitätsnahe und sichere Modellergebnisse stellen dabei die Grundlage für eine zielgerichtete Entscheidungsfindung dar. Nur durch eine Kalibrierung können Parameter von konzeptionellen Modellen zur Berechnung des Niederschlag-Abfluss-Prozesses an die Randbedingungen des zu simulierenden technischen oder natürlichen Systems angepasst werden. Auch wenn die Kalibrierung eines Modells entscheidend zur Erhöhung der Realitätsnähe beiträgt, kann diese durch unterschiedliche Faktoren beeinflusst werden. Dies ist darauf zurückzuführen, dass bei hydrologischen Modellen nicht ausschließlich deterministische Gleichungen mit physikalisch basierten Parametern eingesetzt werden. Wesentliche Einflussfaktoren auf die Kalibrierung von urbanhydrologischen Modellen sind die gewählte Modellstruktur, die Eingangsdaten, die Kalibrierdaten, die Auswahl von Kalibrierereignissen sowie die eigentliche Kalibriermethodik. Im Rahmen dieser Arbeit wurden die Einflüsse der Kalibrierdaten, der Auswahl von Ereignissen und der Kalibriermethodik auf die Ergebnisse der automatischen Kalibrierung mittels multikriterieller Optimierungsverfahren untersucht.