Dissertations / Theses on the topic 'Propagation uncertainties'
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Stanton, Richard. "Robust acoustic beamforming in the presence of channel propagation uncertainties." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/43535.
Bertin, Michaël. "Propagation des incertitudes dans un modèle réduit de propagation des infrasons." Thesis, Cachan, Ecole normale supérieure, 2014. http://www.theses.fr/2014DENS0020/document.
The perturbation of a system can give rise to wave propagation. A classical approach to understand this phenomenon is to look for natural modes of vibration of the medium. Mathematically, finding these modes requires to seek the eigenvalues and eigenfunctions of the propagation operator. However, from a numerical point of view, the operation can be costly because the matrices can be of very large size. Furthermore, in most applications, uncertainties are inevitably associated with our model. The question then arises as to whether we should allocate significant computational resources for simulation while the accuracy of the result is not guaranteed. We propose in this thesis an approach that allows both a better understanding of the influence of uncertainties on the propagation and a significant decrease of computational costs for infrasound propagation in the atmosphere. The main idea is that all modes do not have the same importance and only a few of them is often sufficient to account for the phenomenon without a significant loss of accuracy. These modes appear to be those which are most sensitive to atmospheric disturbances. Specifically, a sensitivity analysis is used to identify the most influential structures of the atmosphere, the associated groups of modes and their associated parts of the infrasound signal. These groups of modes can be specifically targeted in a spectrum calculation with the projection of the operator onto Krylov subspaces, that allows a significant decrease of the computational cost. This method of model reduction can be applied in a statistical framework as well and estimations of the expectation and the variance of the results are carried out without a significant loss of accuracy and still with a low cost
Moreno, de Castro María [Verfasser]. "Propagation of uncertainties in mesocosm experiments on ocean acidification / María Moreno de Castro." Kiel : Universitätsbibliothek Kiel, 2016. http://d-nb.info/1102933058/34.
Davis, Daniel E. "A Technique for Evaluating the Uncertainties in Path Loss Predictions Caused by Sparsely Sampled Terrain Data." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23314.
That is accomplished by accurately solving the electromagnetic fields over many randomly rough surfaces which pass through the sparse topographic data points, many possible communication links, all of which fit the underlying data, are represented. The power variation
caused by the different surface realizations is that due to the sparse sampling. Additionally, to verify that this solution technique is a good model, experimental propagation measurements were taken, and compared to the computations.
Master of Science
Lu, Yen-Sen [Verfasser]. "Propagation of land surface model uncertainties in simulated terrestrial system states / Yen-Sen Lu." Bonn : Universitäts- und Landesbibliothek Bonn, 2018. http://d-nb.info/1161462252/34.
Geraci, Gianluca. "Schemes and Strategies to Propagate and Analyze Uncertainties in Computational Fluid Dynamics Applications." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00954413.
Saussus, Denis. "Probabilistic distributions of ultimate axial pile resistance derived from propagation of epistemic and aleatory material and model uncertainties." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/32819.
Chiang, Keng-Yen. "Thermal hydraulic limits analysis for the MIT Research Reactor low enrichment uranium core conversion using statistical propagation of parametric uncertainties." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/77069.
Cataloged from PDF version of thesis.
Includes bibliographical references.
The MIT Research Reactor (MITR) is evaluating the conversion from highly enriched uranium (HEU) to low enrichment uranium (LEU) fuel. In addition to the fuel element re-design from 15 to 18 plates per element, a reactor power upgraded from 6 MW to 7 MW is proposed in order to maintain the same reactor performance of the HEU core. Previous approaches in analyzing the impact of engineering uncertainties on thermal hydraulic limits via the use of engineering hot channel factors (EHCFs) were unable to explicitly quantify the uncertainty and confidence level in reactor parameters. The objective of this study is to develop a methodology for MITR thermal hydraulic limits analysis by statistically combining engineering uncertainties in order to eliminate unnecessary conservatism inherent in traditional analyses. This methodology was employed to analyze the Limiting Safety System Settings (LSSS) for the MITR LEU core, based on the criterion of onset of nucleate boiling (ONB). Key parameters, such as coolant channel tolerances and heat transfer coefficients, were considered as normal distributions using Oracle Crystal Ball for the LSSS evaluation. The LSSS power is determined with 99.7% confidence level. The LSSS power calculated using this new methodology is 9.1 MW, based on core outlet coolant temperature of 60 'C, and primary coolant flow rate of 1800 gpm, compared to 8.3 MW obtained from the analytical method using the EHCFs with same operating conditions. The same methodology was also used to calculate the safety limit (SL) to ensure that adequate safety margin exists between LSSS and SL. The criterion used to calculate SL is the onset of flow instability. The calculated SL is 10.6 MW, which is 1.5 MW higher than LSSS, permitting sufficient margin between LSSS and SL.
by Keng-Yen Chiang.
S.M.
Leissing, Thomas. "Nonlinear acoustic wave propagation in complex media : application to propagation over urban environments." Phd thesis, Université Paris-Est, 2009. http://tel.archives-ouvertes.fr/tel-00584398.
Dumont, Nicolas. "Méthodes numériques et modèle réduit de chimie tabulée pour la propagation d'incertitudes de cinétique chimique." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC037.
Numerical simulation plays a key role in the field of combustion today, either in the research area by permitting a better understanding of phenomenons taking place inside reactive flows or in the development of industrial application by reducing designing cost of systems. Large Eddy Simulation is at the time the most suited tool for the simulation of reactive flows. Large Eddy Simulation of reactive flows is in practice only possible thanks to a modeling of different phenomenons:- turbulence is modeled for small structures allowing to resolve only big structures which results in lower computational cost- chemistry is modeled using reduction methods which allows to drastically reduce computational costThe maturity of Large Eddy Simulation of reactive flows makes it today a reliable, predictive and promising tool. It now makes sense to focus on the impact of the parameters involved in the different models on the simulation results. This study of the impact of the modeling parameters can be seen from the perspective of uncertainties propagation, and can give interesting informations both from a practical side for the robust design of systems but also on the theoretical side in order to improve the models used and guide the experimental measurements to be made for the reliability improvement of these models.The context of this thesis is the development of efficient methods allowing the propagation of uncertainties present in the chemical kinetic parameters of the reaction mechanisms within Large Eddy Simulation, these methods having to be non-intrusive in order to take advantage of the existence of the different computation codes which are tools requiring heavy means for their development. Such a propagation of uncertainties using a brute-force method suffers from the "curse of dimensionality" because of the large number of chemical kinetic parameters, implying a practical impossibility with the current means of computation which justifies the development of efficient methods.The objective of the thesis is the development of a reduced model that can be used for uncertainties propagation in Large Eddy simulations. The handling and implementation of various tools resulting from the uncertainties propagation framework has been an essential preliminary work in this thesis in order to bring this knowledge and skills into the EM2C laboratory.The method developed in this thesis for the propagation of chemical kinetic parameters uncertainties is limited to chemistry models in which the advancement of the combustion process is summarized by the evolution of a progress variable given by a transport equation, the access to other informations being made through the use of a table. Through the study of the evolution of a constant pressure adiabatic reactor containing a homogeneous mixture of air and dihydrogen, it is shown that a large part of the uncertainties of such a system can be explained by the uncertainties of the progress variable. This makes it possible to define a chemical table that can be used to propagate uncertainties of chemical kinetic parameters in Large Eddy Simulations. The introduction of the uncertainties is then done only by the modeling of the source term present in the transport equation of the progress variable, which can be parameterized with the help of few uncertain parameters thus avoiding the "curse of dimensionality"
Clamens, Olivier. "Analyse et propagation des incertitudes associées à la dépressurisation de l’Hélium 3 sur les transitoires de puissance du réacteur CABRI." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI061/document.
CABRI is a pool type pulsed reactor designed for studying pre-irradiated nuclear fuel behavior under RIA (Reactivity Initiated Accident) conditions.The helium-3 depressurization from the transient rods system allows the insertion of up to 4 $ reactivity mainly countered by the Doppler effect when the power reaches in few milliseconds up to 200,000 times the initial 100~kW power.This thesis presents the improvements added to the power transients prediction and the associated uncertainties studies.The point kinetics calculation coupled with 1D thermal-hydraulics and heat transfer has been improved by the addition of surrogate models based on experimental analysis and Best-Estimate calculations of the helium-3 depressurization and of the reactivity effects and of the kinetics parameters.The power transients modeling improvements have a positiv impact on the CABRI tests prediction.The propagation of the experimental and of the modeling uncertainties was realized with the SPARTE code and the URANIE uncertainty platform.Finally, the power transients characteristics optimization is approached in order to improve the CABRI experiments designing
Gustafsson, Annica. "Analysis of uncertainties in fatigue load assessment : a study on one Kaplan hydro turbine during start operation." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264237.
Det finns ett förväntat behov av att kraftproduktionen i vattenkraftverk skall vara mer flexibel i framtiden. Detta leder till mer varierande driftlägen för turbinen och generatorn, såsom fler start och stop med syfte att stabilisera frekvensen i elnätet. Studier påvisar att transienta driftlägen är mer kostsamma i form av utmattningsdegradering, d.v.s. konsumtion av utmattningsliv. Vattenfall har utvecklat en metodik för att analysera inverkan av utmattningslaster verkande på löphjulet och rotorn i vattenkraftsaggregat under drift. Med en numerisk modell kan utmattningslasterna bedömas. Den ingående datan till modellen är bland annat är uppmätta storheter och given data på parameterar. Några av de ingående storheterna är lagerstyvhet, angreppspunkter för lagerkrafter och lageroljans egenskaper, etc. Flera av dessa ingående parametrar innehar osäkerheter, vilket påverkar bedömningen av utmattningslasterna. Denna studie kommer att fokusera på en kraftkomponent verkande på löphjulet. Malet med detta arbete är att svara på följande forskningsfrågor: (i) Vilka ingående parametrar, som innehar en osäkerhet, bidrar med en styrande osäkerhet i den bedömda kraften? (ii) Hur mycket uppgår den kombinerade standardosäkerheten i den bedömda kraften till? (iii) Hur påverkar kraftens osäkerhet utmattningsskadan? Den kombinerade standardosäkerheten i kraften är beräknad med metoder i fortplantning av osäkerheter. För att kunna bedöma påverkan på delskadan givet osäkerheten i kraften, så sker en statistisk analys av förhållandet mellan delskadan sammanhängande med en sannolikhet för överskridande och den förväntade delskadan. Resultatet påvisar att den styrande ingående parametern är offset i signalen för axelförskjutning, vilken uppgår till 40 % av den kombinerade standardosäkerheten i utmattningskraften. Av de nio analyserade parametrarna härrör tre av dessa lageregenskaper, d.v.s. lagerspel, oljetemperatur och angreppspunkter för lagerkrafterna, vilka tillsammans uppgår till 47.5 % av den kombinerade standardosäkerheten i utmattningskraften. Därför, för att reducera den totala osäkerheten bör fokus ligga på lageregenskaperna. Givet alla standardosäkerheter i de analyserade parametrarna så uppgår förhållandet mellan standardosäkerheten i utmattningskraften och den förväntade utmattningskraften på löphjulet till 7 %. Detta motsvarar att förhållandet mellan standardosäkerheten i delskadan och väntevärdet för delskadan uppkommer till 35 %, givet ett index av S-N-kurvan på fem. Givet standardosäkerheten i kraften och index av S-N-kurvan, kan förhållandet mellan utmattningskraften förenad med en sannolikhet för överskridande, och den förväntade utmattningskraften, d.v.s. kvoten av utmattningskraften, utvärderas. Detta resulterar att kvoten av utmattningskraften uppgår till 1.32 för en sannolikhet för överskridande på 0.0032 %, 1.09 för en sannolikhet på 10 % och 1.04 för en sannolikhet på 30 %. Dessa sannolikheter motsvarar att kvoten av delskadan, d.v.s. kvoten mellan delskadan förenad med en sannolikhet för överskridande, och den förväntade delskadan uppgår till 4, 1.56 och 1.20. Därför kan osäkerheten i utmattningskraften påverka osäkerheten i delskadan med en betydande faktor, beroende på värdet på index av S-N-kurvan. Således, resultaten från denna studie påvisar betydelsen att beakta osäkerheterna i de ingående parameterna vid bedömning av utmattningslast. Dessa resultat tillhandahåller stöd vid bedömning av lastnivåer för dimensionering av löphjul, för att slutligen kunna erhålla en korrekt säkerhetsmarginal. Detta för att inte underskatta utmattningsskadan och därmed minska risken oför oväntat utmattningshaveri.
Jannet, Basile. "Influence de la non-stationnarité du milieu de propagation sur le processus de Retournement Temporel (RT)." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22436/document.
The aim of this thesis is to measure and quantify the impacts of uncertainties in the Time Reversal (TR) process. These random variations, coming from diverse sources, can have a huge influence if they happen between the TR steps. On this perspective, the Stochastique Collocation (SC) method is used. Very good results in terms of effectiveness and accuracy had been noticed in previous studies in ElectroMagnetic Compatibility (EMC). The conclusions are still excellent here on TR problems. Although, when the problem dimension rises (high number of Random Variables (RV)), the SC method reaches its limits and the efficiency decreases. Therefore a study on Sensitivity Analysis (SA) techniques has been carried out. Indeed, these methods emphasize the respective influences of the random variables of a model. Among the various quantitative or qualitative SA techniques the Morris method and the Sobol total sensivity indices have been adopted. Since only a split of the inputs (point out of the predominant RV) is expected, they bring results at a lesser cost. That is why a novel method is built, combining SA techniques and the SC method. In a first step, the model is reduced with SA techniques. Then, the shortened model in which only the prevailing inputs remain, allows the SC method to show once again its efficiency with a high accuracy. This global process has been validated facing Monte Carlo results on several analytical and numerical TR cases subjet to random variations
Rousseau, Marie. "Propagation d'incertitudes et analyse de sensibilité pour la modélisation de l'infiltration et de l'érosion." Phd thesis, Université Paris-Est, 2012. http://pastel.archives-ouvertes.fr/pastel-00788360.
Picheral, Laura. "Contribution à la conception préliminaire robuste en ingéniérie de produit." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00992390.
Aïssani, Amina. "Optimisation fiabiliste des performances énergétiques des bâtiments." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22677/document.
In the context of growing world energy demand and environmental degradation, many actions are undertaken each year to improve the energy performance of buildings. During the design stage, the use of building energy simulations remains a valuable tool as it evaluates the possible options in terms of energy performance and comfort. However, as precision requirements increase, it becomes essential to assess the uncertainties associated with input data in simulation. This thesis focuses on the insulation design process under uncertainty, in order to limit gaps between real and predicted performance for better control of energy consumptions. This work firstly presents the current alarming energy context. We consider the main uncertainties that affect the insulation, mainly the variability of the thermophysical properties, the uncertainty on climate and the uncertainties due to workmanship defects. Experimental studies were carried out to evaluate the uncertainty associated to the intrinsic performance of healthy insulation materials on one hand, and those associated to defects in insulations on the other hand. A coupling between thermography techniques and finite element models was used to provide analytical models that assess the effective thermal performance of a defective insulation, according to the type and size of the defect. As the performance of insulation also depends on climate, it is necessary to integrate future weather data to evaluate the energy consumption. These weather data are generally estimated based on the historical climatic data of the region. However, it is still difficult to predict climate change as it depends on many uncontrollable factors. In this work, we consider the different climate scenarios proposed by climate expert groups, and the uncertainty associated to each scenario to evaluate the reliability of the insulation and to improve the decision making process. Finally, we propose a probabilistic approach to integrate uncertainties in simulation and an optimization methodology based on reliability. A new cost formulation is also proposed to improve the decision-making, through indirect losses related to comfort, pollution and living space losses
Hu, XiaoSu. "Approche probabiliste de la propagation des incertitudes dans le modèle mécano-numérique du système couplé "fémur-prothèse non cimentée"." Thesis, Clermont-Ferrand 2, 2010. http://www.theses.fr/2010CLF22065/document.
The hip arthroplasty with cementless hip prosthesis is a solution usually used for the patients suffering the problems of the musculoskeletal system. However, such a solution has a major disadvantage, pointed by all users : the lack of primary stability of the prosthesis. This weakness can cause serious complications or failure of the surgery. Therefore, to achieve a good primary fixation is a crucial point of this type of surgery to ensure a short and a long term clinical satisfaction. In order to better understand this central issue, a preoperative track is adopted. A finite element model to describe the mechanical behavior of the coupled system " femur-cementless prosthesis : DePuy Corail® "has been created and validated by the experiments in vitro. Then, in order to take into account the high variability of model parameters, inherent to the nature of the problem, the stochastic modeling of random input parameters has been introduced and a mechanical-probabilistic strategy has been proposed, on the one hand to quantify, in probabilistic terms, the effect, on the response, of the uncertainties affecting the input parameters of the model, and on the other hand to evaluate the primary stability of the bone-prosthesis system in reliability context. The practical implementation of this approach is realized by using the numerical tools based on the standard Monte Carlo method and the stochastic collocation procedure. The originality of the work presented is primarily in the proposition of a probabilistic methodology capable of taking into account the uncertainties in the problem of primary stability of cementless hip prostheses. It also lies in the potentiality of this methodology to be transplantable easily in industrial context
Larbi, Mourad. "Méthodes statistiques pour le calcul d’interférences électromagnétiques extrêmes au sein de systèmes complexes." Thesis, Rennes, INSA, 2016. http://www.theses.fr/2016ISAR0001/document.
The proliferation of electronic and radio frequency transmitters makes more complicated the system design process on the EMC point of view. This process should lead to limit the risk of interferences or defects to lowest level particularly in the context of intentional electromagnetic interferences (IEMI). Therefore, these EMC defects have to be anticipated during the design stage. However, due to the dispersion of the values taken by some parameters of the system, the deterministic modeling presents some difficulties to identify the involved risk. The poor knowledge of the uncertainties effect associated with the system, leads then to take important design margins at the price of additional costs of manufacturing. For this reason, it has become important to take into account the impact of uncertainties of the various constituent parameters of a system (at the design stage). These parameters are essentially geometric (e.g. position of wirings) or electromagnetic (e.g. intrinsic characteristics of materials) ones. They influence by nature the EMC performance of this system. This thesis work deals with the analysis of the propagation of uncertainties of these parameters on EMC model outputs. It aims at quantifying in a probabilistic form, the default risk of a system containing numerous uncertain parameters. This type of statistical analysis should also allow through sensitivity analyses, design strategies of “reliable” systems or at lower cost. In the context of targeted applications, the so-called “reliability approaches” and the “controlled stratification” method have been identified as interesting from the point of view of the analysis of extreme events. Firstly, we are dedicated to the transposition of reliability methods in an EMC context. These techniques are used to quantify the probability of failure of a system, defined as the probability of exceeding a threshold of risk. They inform through a local sensitivity analysis, on the key parameters to adjust. Secondly, we have focused our work on the controlled stratification method, not yet applied in EMC as far as we know. The objective of this approach is to estimate an extreme quantile of the interest response of a rigorous model, using of a much cheaper simple model in terms of computation time. This process allows to speed up the identification of extreme observations required for the estimation of the researched quantile. Both techniques have been applied on a complex problem in an IEMI context, to estimate the probability of occurrence of extreme interference events. They have revealed similar trends as regards to the importance of some uncertain input parameters on rare events. Both methods, properly applied, could provide a significant contribution in terms of EMC design strategy
Navas, Nunez Rafael. "Modélisation hydrologique distribuée des crues en région Cévennes-Vivarais : impact des incertitudes liées à l'estimation des précipitations et à la paramétrisation du modèle." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAU025/document.
It is known that having a precipitation observation system at high space - time resolution is crucial to obtain good results in rainfall - runoff modeling. Radar is a tool that offers quantitative precipitation estimates with very good resolution. When it is merged with a rain gauge network the advantages of both systems are achieved. However, radars estimates have different uncertainties than those obtained with the rain gauge. In the modeling process, uncertainty of precipitation interacts with uncertainty of the hydrological model. The objective of this work is: To study methods used to quantify the uncertainty in radar – raingauge merge precipitation estimation and uncertainty in hydrological modeling, in order to develop a methodology for the analysis of their individual contributions in the uncertainty of rainfall - runoff estimation.The work is divided in two parts, the first one evaluates: How the uncertainty of radar precipitation estimation can be quantified? To address the question, the geostatistical approach by Kriging with External Drift (KED) and Stochastic Generation of Precipitation was used, which allows to model the spatio - temporal structure of errors. The method was applied in the Cévennes - Vivarais region (France), where there is a very rich observation system. The second part explains: How can it be quantified the uncertainty of the hydrological simulation coming from the radar precipitation estimates and hydrological modeling process? In this point, the hydrological mesoscale computation tool was developed; it is distributed hydrological software in time continuous, within the basis of the Curve Number and the Unit Hydrograph. It was applied in 20 spatio-temporal resolutions ranging from 10 to 300 km2 and 1 to 6 hours in the Ardèche (~ 1971 km2) and the Gardon (1810 km2) basins. After a sensitivity analysis, the model was simplified with 4 parameters and the uncertainty of the chain of process was analyzed: 1) Precipitation estimation; 2) Hydrological modeling; and 3) Rainfall - runoff estimation, by using the coefficient of variation of the simulated flow.It has been shown that KED is a method that provides the standard deviation of the precipitation estimation, which can be transformed into a stochastic estimation of the local error. In the chain of processes: 1) Uncertainty in precipitation estimation increases with decreasing spatio-temporal scale, and its effect is attenuated by hydrological modeling, probably due by storage and transport properties of the basin; 2) The uncertainty of hydrological modeling depends on the simplification of hydrological processes and not on the surface of the basin; 3) Uncertainty in rainfall - runoff treatment is the result of the amplified combination of precipitation and hydrologic modeling uncertainties
Lambert, Sylvain. "Contribution à l'analyse de l'endommagement par fatigue et au dimensionnement de structures soumises à des vibrations aléatoires." Phd thesis, INSA de Rouen, 2007. http://tel.archives-ouvertes.fr/tel-00560885.
Villanueva, Juan Moises Mauricio. "Determinação de aproximação linear por partes de funções não lineares para sistemas embarcados utilizando algoritmos genéticos." Universidade Federal do Maranhão, 2005. http://tedebc.ufma.br:8080/jspui/handle/tede/377.
In several applications in electronics, the generation of nonlinear function values using low-cost embedded systems is a problem. The nonlinear functions cannot be directly implemented due to restrictions of fixed-point calculations and limited resolution that are characteristics of the architecture of the processor employed. In this work, a procedure for determining piecewise linear approximation of nonlinear functions for a low-cost embedded system is presented. In order to solve this problem, a hierarchical evolutionary algorithm has been developed for determining the position and the minimal number of breakpoints and the minimal size of the look-up table for storing these breakpoints, for generating the approximated function values. The nonlinear function can be approximated using piecewise linear functions from the obtained breakpoints. The developed algorithm is tested using the case of approximating the first quadrant of a sine function, and the obtained results are presented for different resolutions for the input and output values generation.
Em diversas aplicações em eletrônica existe o problema de gerar valores de funções não lineares utilizando-se sistemas embarcados de baixo custo. Essas funções não lineares não podem ser implementadas diretamente devido às restrições de cálculo em ponto fixo e resolução limitada, características de arquitetura do processador empregado. Nesta dissertação, apresenta-se um procedimento para a determinação de aproximação linear por partes de funções não lineares para sistemas embarcados de baixo custo. Para resolver este problema, desenvolveu-se um algoritmo hierárquico evolutivo que determinará a posição e número mínimo de pontos de quebra e tamanho mínimo da tabela de equivalência para armazenar esses pontos de quebra, para gerar os valores da função aproximada. A função não linear pode então ser aproximada por funções lineares a partir dos valores dos pontos de quebra encontrados. O algoritmo desenvolvido é testado para o caso de aproximação da função seno no primeiro quadrante, e os resultados obtidos são apresentados para diversas resoluções de entrada e de geração dos valores de saída.
Bontemps, Stéphanie. "Validation expérimentale de modèles : application aux bâtiments basse consommation." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0337/document.
Construction of low, passive and positive energy buildings is generalizing and existing buildings are being renovated. For this reason, it is essential to use simulation in order to estimate, among other things, energy and environmental performances reached by these new buildings. Expectations regarding guarantee of energy performance being more and more important, it is crucial to ensure the reliability of simulation tools being used. Indeed, simulation codes should reflect the behavior of these new kinds of buildings in the most consistent and accurate manner. Moreover, the uncertainty related to design parameters, as well as solicitations and building uses have to be taken into account in order to guarantee building energy performance during its lifetime.This thesis investigates the empirical validation of models applied to a test cell building. This validation process is divided into several steps, during which the quality of the model is evaluated as far as consistency and accuracy are concerned. Several study cases were carried out, from which we were able to identify the most influential parameters on model output, inspect the influence of time step on the empirical validation process, analyze the influence of initialization and confirm methodology’s ability to test the model
Ung, Philippe. "Simulation numérique du transport sédimentaire : aspects déterministes et stochastiques." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2019/document.
In this thesis, we are interested on the study of a sediment transport model through two different approaches. One of them concerns the numerical modelling of the problem and proposes a numerical problem-solving method based on an approximate Riemann solver for the Saint-Venant-Exner system which is one of the most common model to deal with sedimentary bed-load transport. This last one is based on a coupling between the hydraulic model of Saint-Venant and the morphodynamic model of Exner. The key point of the proposed method is the treatment of the coupling issue. Indeed, there exists two strategies; the first one consists on decoupling the resolution of the fluid part from the solid part and making them interact at fixed times whereas the second one considers a coupled approach to solve the system by jointly updating the hydraulic and solid quantities at same times. We then raise the issue of the choice of the strategy for which we suggest answers by comparing both approaches. The other one focuses on the development of a methodology to study the uncertainties related to the model previously mentioned. To this end, we propose a stochastic formulation of the Saint-Venant-Exner system and we look for characterizing the variabilities of the outputs in relation to the naturally random input parameters. This first study reveals the need for a return to the Saint-Venant system with a perturbed bed to understand the sensitivity of the hydraulic quantities on the topographical perturbations
Merheb, Rania. "Fiabilité des outils de prévision du comportement des systèmes thermiques complexes." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00969036.
Chakchouk, Mohamed. "Conceptiοn d'un détecteur de système mécatronique mobile intelligent pour observer des molécules en phase gazeuse en ΙR." Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMIR06.
This work anticipates that, in an ever-expanding digital technology world, technological breakthroughs in the analysis of data collected by spectroscopic devices will allow the almost instantaneous identification of known species observed in-situ in a specific environment, leaving the necessary in-depth analysis of unobserved species. The method derived from RBDO (Reliability Based Design Optimization) technology will be used to implement an artificial intelligence procedure to identify observed species from a mobile IR sensor. To successfully analyze the obtained data, it is necessary to appropriately assign molecular species from the observed IR data using appropriate theoretical models. This work focuses on the observation from mobile devices equipped with appropriate sensors, antennas, and electronics to capture and send raw or analyzed data from an interesting IR spectroscopic environment. It is therefore interesting if not essential to focus on symmetry-based theoretical tools for the spectroscopic analysis of molecules, which allows to identify the IR windows to be chosen for observation in the design of the device. Then, by fitting the theoretical spectroscopic parameters to the observed frequencies, the spectrum of a molecular species can be reconstructed. A deconvolution of the observed spectra is necessary before the analysis in terms of intensity, width and line center characterizing a line shape. Therefore, an adequate strategy is needed in the design to include data analysis during the observation phase, which can benefit from an artificial intelligence algorithm to account for differences in the IR spectral signature. In this regard, the analytical power of the instrument data can be improved by using the reliability-based design optimization (RBDO) methodology. Based on the multi-physics behavior of uncertainty propagation in the hierarchical system tree, RBDO uses probabilistic modeling to analyze the deviation from the desired output as feedback parameters to optimize the design in the first place. The goal of this thesis is to address IR observation window parameters to address reliability issues beyond mechatronic design to include species identification through analysis of collected data
Ben, Daoued Amine. "Modélisation de la conjonction pluie-niveau marin et prise en compte des incertitudes et de l’impact du changement climatique : application au site du Havre." Thesis, Compiègne, 2019. http://www.theses.fr/2019COMP2528.
The modeling of the combinations of flood hazard phenomena is a current issue for the scientific community which is primarily interested in urban and nuclear sites. Indeed, it is very likely that the deterministic approach exploring several scenarios has certain limits because these deterministic scenarios ensure an often excessive conservatism. Probabilistic approaches provide additional precision by relying on statistics and probabilities to complement deterministic approaches. These probabilistic approaches aim to identify and combine many possible hazard scenarios to cover many possible sources of risk. The Probabilistic Flood Hazard Assessment (PFHA) proposed in this thesis allows to characterize a quantity(ies) of interest (water level, volume, duration of immersion, ect.) at different points of interest of a site based on the distributions of the different phenomena of the flood hazard as well as the characteristics of the site. The main steps of the PFHA are: i) screening of the possible phenomena (rainfall, sea level, waves, ect.), ii) identification and probabilization of the parameters representative of the selected flood phenomena, iii) propagation of these phenomena from their sources to the point of interest on the site, iv) construction of hazard curves by aggregating the contributions of the flood phenomena. Uncertainties are an important topic of the thesis insofar as they will be taken into account in all the steps of the probabilistic approach. The work of this thesis is based on the study of the conjunction of rain and sea level and provide a new method for taking into account the temporal phase shift between the phenomena (coincidence). An aggregation model has been developed to combine the contributions of different flood phenomena. The question of uncertainties has been studied and a method based on the theory of belief functions has been used because it has various advantages (faithful modeling in cases of total ignorance and lack of information, possibility to combine information of different origins and natures, ect.). The proposed methodology is applied on the site of Le Havre in France
"Propagation of Radar Rainfall Uncertainties into Urban Flood Predictions: An Application in Phoenix, AZ." Master's thesis, 2020. http://hdl.handle.net/2286/R.I.57215.
Dissertation/Thesis
Masters Thesis Civil, Environmental and Sustainable Engineering 2020