Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 16 of 16 for “"epistemic uncertainties"”.
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A Probabilistic Decision Support System for a Performance-Based Design of Infrastructures
… of the decision problem, two main types of uncertainties may exist: 1) the aleatory uncertainty associated with the nature of the built environment (i.e., the economic, social, and environmental impacts of infrastructures must be described as probabilistic); and 2) the epistemic uncertainty …
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Redundancy in Steel Moment Frame Systems Under Seismic Excitations
… capacity are constructed; (3) both aleatory and epistemic uncertainties in demand and capacity are taken into account; (4) based on the results of (2), a uniform-risk redundancy factor, RR, for design to achieve a uniform reliability level for buildings of different redundancies is obtained. This …
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Risk-informed design changes for a passive cooling system
… The system was modeled using RELAP5-3D. The epistemic uncertainties in input parameters as well as the epistemic model uncertainties in the code were assessed and propagated through the model using Latin hypercube sampling. The changes in the design that we investigated reduced the overall …
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Failure record discounting in Bayesian analysis in Probabilistic Risk Assessment (PRA) : a space system application
… is done in such way that it displays the epistemic uncertainties that are inherent in the data and provides a better basis for the decision maker to make a decision based on his / her risk attitude. A comparison of the two methods is made based on the case study.
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On the quantification of safety margins
… and traditional safety margins to deal with the uncertainties associated with the design and operation of nuclear facilities. These concepts were formulated in the early days of development of nuclear power when these uncertainties could not be quantified. The subsequent development of …
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Decision Analysis in Fire Safety Engineering - Analysing Investments in Fire Safety
… above all at the handling of cases of large epistemic uncertainty regarding both probabilities and utilities, Bayesian decision theory serving as a basis for the development of the method. Two extensions of the decision rule used in Bayesian decision theory (the principle of maximising …
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Electromagnetic Risk Management for Dependability of Road Vehicles using Discrete Bayesian Networks
… main purposes. First, to graphically model the epistemic uncertainties considered for electromagnetic (EM) immunity risk assessment, second, to overcome the limitations of assessing EMI risks due to multiple disturbances that can be simultaneously present (multitone) in the system EM …
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Efficient Ensemble-based Bayesian Neural Networks for Depth Regression
… regression task and propose a new metric for epistemic uncertainty evaluation. MCDO has been found to demonstrate deficiencies in its capacity to predict epistemic uncertainties, while DEs and RLLEs both achieve good results. The application of the methods to depth estimation using established …
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Assessment of Model Validation, Calibration, and Prediction Approaches in the Presence of Uncertainty
… simulation and/or experimental outcomes. These uncertainties can be in the form of aleatory uncertainties due to randomness or epistemic uncertainties due to lack of knowledge. Four different approaches are used for addressing model validation and calibration: 1) the area validation metric …
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Advancing Efficiency and Safety in Autonomous Sequential Decision Making
… data efficiency through simultaneous emphasis on epistemic uncertainty and knowledge transfer, and on mitigating risks associated with agent actions through aleatory uncertainty. Initially, the thesis investigates strategies to enhance RL algorithms' adaptability and knowledge transfer across …
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Probabilistic transient analysis of fuel choices for sodium fast reactors
… running an excessive amount of simulations, the epistemic uncertainties around the random variables are sampled using importance sampling. For metallic fuel, the rate of fuel/cladding eutectic formation has typically been modeled as an Arrhenius process which depends only on the temperature of …
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Improvement of aftershock models based on Coulomb stress changes and rate-and-state dependent friction
… (1) How can we realistically model the uncertainties and heterogeneity of the mainshock stress field? (2) What is the effect of time dependent stresses in the postseismic phase on seismicity? I focus on two case studies from different tectonic settings: the Mw 9.0 Tohoku megathrust and …
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Uncertainty and sensitivity analysis of a fire-induced accident scenario involving binary variables and mechanistic codes
… the methods for the quantification of the uncertainties must also be improved. In order to gain a more meaningful insight into the methods currently in practice, it was decided that a scenario incorporating the various elements of uncertainty specific to a fire PRA would be analyzed. The …
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Approaches to earthquake scenarios validation using seismic site response
… approach in order to consider and reduce the epistemic uncertainties. The combined use and comparison of these approaches is recommended since it allows to verify the robustness of the hazard estimates and allowed us to obtain useful elements to define the seismic hazard in Catania and …
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Real-time data assimilation in nonlinear dynamical systems
… Model biases, also known as model errors or epistemic uncertainties, are difficult to infer because they are “unknown unknowns’', i.e., we may not know their functional form *a priori*. With model biases, traditional real-time data assimilation methods are ill-posed because either the …
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Probabilistische Modellierung von Versagensprozessen bei Staudämmen
… accuracy. The transformation of aleatory and epistemic uncertainties in parameters and conceptual models to probabilities of failure is performed by applying Monte-Carlo modelling techniques and related methods for variance reduction. In the course of working within the topic of internal …