document

Quantifying the impact of stiffness distributions on the dynamic behaviour of railway transition zones

Jain, A. (author), Marykovskiy, Yuriy (author), Metrikine, A. (author), van Dalen, K.N. (author)

Railway transition zones (RTZs) are regions where abrupt track stiffness changes occur that may lead to dynamic amplifications and subsequent track deterioration. The design challenges for these zones arise due to variations in material properties in both the depth (trackbed layers composed of different materials) and longitudinal directions of...

journal article 2024

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On the use of PCE based surrogate models in SXR Scatterometry

Koppert, Reint (author)

Scatterometry is a non-destructive metrology technique widely used in the semiconductor industry for the reconstruction of periodic structures from diffraction measurements. This involves solving a so-called inverse problem, which can be done by tuning the geometry parameters of a forward model such that the discrepancy between the measured...

student report 2023

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Characterizing the effects of delineation uncertainties in head and neck cancer radiotherapy

Makkinje, Andri (author)

The goal of radiotherapy is to maximize the dose to the target while minimizing the dose to normal tissue. Treatment plans are optimized for this goal and dose delivery is improved in accuracy and precision. The optimization is based on the delineations of the volumes of interest on the medical images of the patient. The problem is that these...

master thesis 2023

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Extreme-oriented sensitivity analysis using sparse polynomial chaos expansion: Application to train–track–bridge systems

Shang, Y. (author), Nogal Macho, M. (author), Teixeira, Rui (author), Wolfert, A.R.M. (author)

The use of sensitivity analysis is essential in model development for the purposes of calibration, verification, factor prioritization, and mechanism reduction. While most contributions to sensitivity methods focus on the average model response, this paper proposes a new sensitivity method focusing on the extreme response and structural limit...

journal article 2023

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PTV-based VMAT vs. robust IMPT for head-and-neck cancer: A probabilistic uncertainty analysis of clinical plan evaluation with the Dutch model-based selection

Rojo-Santiago, Jesús (author), Korevaar, Erik (author), Perko, Z. (author), Both, Stefan (author), Habraken, S.J.M. (author), Hoogeman, M.S. (author)

Background and purpose: In the Netherlands, head-and-neck cancer (HNC) patients are referred for proton therapy (PT) through model-based selection (MBS). However, treatment errors may compromise adequate CTV dose. Our aims are: (i) to derive probabilistic plan evaluation metrics on the CTV consistent with clinical metrics; (ii) to evaluate...

journal article 2023

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Robustness analysis of CTV and OAR dose in clinical PBS-PT of neuro-oncological tumors: prescription-dose calibration and inter-patient variation with the Dutch proton robustness evaluation protocol

Rojo-Santiago, Jesús (author), Habraken, S.J.M. (author), Romero, Alejandra Méndez (author), Lathouwers, D. (author), Wang, Yibing (author), Perko, Z. (author), Hoogeman, M.S. (author)

Objective. The Dutch proton robustness evaluation protocol prescribes the dose of the clinical target volume (CTV) to the voxel-wise minimum (VWmin) dose of 28 scenarios. This results in a consistent but conservative near-minimum CTV dose (D98%,CTV). In this study, we analyzed (i) the correlation between VWmin/voxel-wise maximum (VWmax)...

journal article 2023

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Polynomial Chaos Expansion-Based Enhanced Gaussian Process Regression for Wind Velocity Field Estimation from Aircraft-Derived Data

Marinescu, M. (author), Olivares, Alberto (author), Staffetti, Ernesto (author), Sun, Junzi (author)

This paper addresses the problem of spatiotemporal wind velocity field estimation for air traffic management applications. Using data obtained from aircraft, the eastward and northward components of the wind velocity field inside a specific air space are calculated as functions of time. Both short-term wind velocity field forecasting and wind...

journal article 2023

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Breaking the Curse of Dimensionality: Polynomial Chaos for Exploratory Modelling

Lyons, Jeff (author)

In light of worsening climate change and an increased interest in adapting infrastructure to cope with its effects, model-based decision support has become an essential tool for policy makers. In conditions of deep uncertainty, models may be used to explore a large space of possible system behaviours and so encourage a wider consideration of the...

master thesis 2022

document

Aircraft engine maintenance planning using model-based remaining useful life prognostics: A Master of Science Thesis

Schiettekatte, Niels (author)

Aircraft maintenance methods are shifting from conservative maintenance approaches such as a periodic maintenance approach towards predictive maintenance approaches, leading to a reduction of costs, less unexpected aircraft-on-ground events and less wasted useful life of components. In this paper, we propose a new remaining useful life...

master thesis 2022

document

Delineation uncertainties in radiotherapy: Modeling the effect of delineation uncertainties in radiotherapy with Polynomial Chaos Expansion

Springer, Sam (author)

The delineation of the regions of interest (ROIs) plays an important role in the radiotherapy workflow. The ROIs include the gross tumor volume (GTV), the clinical target volume (CTV), the planning target volume (PTV) and organs at risk (OARs). There are however uncertainties related to the delineation of the ROIs due to inter­observer...

master thesis 2021

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Adaptive approaches in metamodel-based reliability analysis: A review

Teixeira, Rui (author), Nogal Macho, M. (author), O'Connor, Alan (author)

The present work reviews the implementation of adaptive metamodeling for reliability analysis with emphasis in four main types of metamodels: response surfaces, polynomial chaos expansions, support vector machines, and Kriging models. The discussion presented is motivated by the identified spread and little interaction between metamodeling...

journal article 2021

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Reliability analysis using a multi-metamodel complement-basis approach

Teixeira, Rui (author), Martinez-Pastor, Beatriz (author), Nogal Macho, M. (author), O'Connor, Alan (author)

The present work discusses an innovative approach to metamodeling in reliability that uses a field-transversal rationale. Adaptive metamodeling in reliability is characterized by its large spectra of models and techniques with different assumptions. As a result, the reliability engineer is frequently faced with the highly challenging task of...

journal article 2021

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Accurate assessment of a Dutch practical robustness evaluation protocol in clinical PT with pencil beam scanning for neurological tumors

Rojo-Santiago, Jesús (author), Habraken, S.J.M. (author), Lathouwers, D. (author), Méndez Romero, Alejandra (author), Perko, Z. (author), Hoogeman, M.S. (author)

Background and purpose: Scenario-based robust optimization and evaluation are commonly used in proton therapy (PT) with pencil beam scanning (PBS) to ensure adequate dose to the clinical target volume (CTV). However, a statistically accurate assessment of the clinical application of this approach is lacking. In this study, we assess target...

journal article 2021

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Preliminary uncertainty and sensitivity analysis of the Molten Salt Fast Reactor steady-state using a Polynomial Chaos Expansion method

Santanoceto, M. (author), Tiberga, M. (author), Perko, Z. (author), Dulla, Sandra (author), Lathouwers, D. (author)

In this work, we present the results of a preliminary uncertainty quantification and sensitivity analysis study of the Molten Salt Fast Reactor (MSFR) behavior at steady-state performed by applying a non-intrusive Polynomial Chaos Expansion (PCE) approach. An in-house high-fidelity multi-physics simulation tool is used as reactor reference...

journal article 2021

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Wind Farm Layout Optimisation Under Uncertainty Using Surrogate Models

Chuang, Jia Shian (author)

This research aims to develop a method to create a wind farm layout that is robust against the uncertainty source, the inter-year variation of Weibull parameters and wind direction sector probabilities. A wind farm layout optimisation problem under uncertainty corresponds to optimisation under uncertainty (OUU), which is computationally...

master thesis 2020

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Improving Probabilistic Treatment Planning with Polynomial Chaos Expansion for Proton Therapy

Steinebach, Koen (author)

In proton therapy, robust treatment planning is currently used to account for uncertainties in patient alignment and proton beam range. A way to overcome the limitations of robust treatment planning is to use probabilistic treatment planning, which can be computationally expensive due to the calculations of statistical measures of stochastic...

master thesis 2020

document

Uncertainty quantification in steady state simulations of a molten salt system using polynomial chaos expansion analysis

Santanoceto, M. (author), Tiberga, M. (author), Perko, Z. (author), Dulla, Sandra (author), Lathouwers, D. (author)

Uncertainty Quantification (UQ) of numerical simulations is highly relevant in the study and design of complex systems. Among the various approaches available, Polynomial Chaos Expansion (PCE) analysis has recently attracted great interest. It belongs to non-intrusive spectral projection methods and consists of constructing system responses...

conference paper 2020

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Probabilistic Treatment Planning with Polynomial Chaos Expansion for Proton Therapy

Salverda, Jelle (author)

Radiotherapy is an important treatment type for patients with cancer. An advantage of state of the art proton therapy with respect to traditional photon therapy is the spatial energy deposition of protons, which is characterized by the Bragg peak. Due to this particular course of energy deposition, the tumor can be irradiated more precisely and...

master thesis 2019

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Using polynomial chaos expansion for wind energy

Bailleul, Wouter (author)

Surrogate models are used to approximate the expensive ‘true’ simulation codes and thus have the potential to speed up the wind farm layout optimisation problem (WFLOP). One technique to make surrogate models is Polynomial Chaos Expansion (PCE). PCE can approximate a (wind farm) model by using orthogonal polynomials which are constructed based...

master thesis 2018

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Quantifying roughness coefficient uncertainty in urban flooding simulations through a simplified methodology

Bellos, Vasilis (author), Kourtis, Ioannis M. (author), Moreno Rodenas, A. (author), Tsihrintzis, Vassilios A. (author)

A methodology is presented which can be used in the evaluation of parametric uncertainty in urban flooding simulation. Due to the fact that such simulations are time consuming, the following methodology is proposed: (a) simplification of the description of the physical process; (b) derivation of a training data set; (c) development of a data...

journal article 2017