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Diab Montero, H.A. (author)In this dissertation, I explore ensemble data assimilation methods to enhance our capability to forecast earthquakes and slow slip events, focusing on the critical challenge posed by limited information on the current stress state of faults. <br/>At the outset, the research acknowledges the inherent limitations in our current understanding of...doctoral thesis 2024
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Pang, Mijie (author), Jin, J. (author), Segers, Arjo (author), Jiang, Huiya (author), Fang, Li (author), Lin, H.X. (author), Liao, Hong (author)Super dust storms re-occurred over East Asia in 2021 spring and casted great health damages and property losses. It is essential to achieve an accurate dust forecast to reduce the damage for early warning. The forecasting system fundamentally relies on a numerical model which can forecast the full evolution of dust storms. However, large...journal article 2023
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Mohsan, M. (author), Vardon, P.J. (author), Vossepoel, F.C. (author)Data assimilation methods have been implemented on a slope stability problem, and the performance of different constitutive models and data assimilation schemes has been investigated. In the first part, a data assimilation scheme called the ensemble Kalman filter (EnKF) is implemented using a finite element model (FEM) and its performance with...conference paper 2023
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Diab Montero, H.A. (author), Li, Meng (author), van Dinther, Ylona (author), Vossepoel, F.C. (author)Our ability to forecast earthquakes and slow slip events is hampered by limited information on the current state of stress on faults. Ensemble data assimilation methods permit estimating the state by combining physics-based models and observations, while considering their uncertainties. We use an ensemble Kalman filter (EnKF) to estimate...journal article 2023
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Xiao, C. (author), Lin, H.X. (author), Leeuwenburgh, O. (author), Heemink, A.W. (author)History matching can play a key role in improving geological characterization and reducing the uncertainty of reservoir model predictions. Application of reservoir history matching is restricted by the huge computational cost by amongst others the many runs of the full model. Surrogate models with a reduced complexity are therefore used to...journal article 2022
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Menenti, M. (author), Li, Xin (author), Jia, Li (author), Yang, Kun (author), Pellicciotti, Francesca (author), Mancini, Marco (author), Shi, Jiancheng (author), Escorihuela, Maria José (author), Zheng, Chaolei (author)This project explored the integrated use of satellite, ground observations and hydrological distributed models to support water resources assessment and monitoring in High Mountain Asia (HMA). Hydrological data products were generated taking advantage of the synergies of European and Chinese data assets and space-borne observation systems....journal article 2021
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Lopez Restrepo, S. (author), Nino-Ruiz, Elias D. (author), Guzman-Reyes, Luis G. (author), Yarce, Andres (author), Quintero, O. L. (author), Pinel, Nicolas (author), Segers, Arjo (author), Heemink, A.W. (author)In this paper, we propose an efficient and practical implementation of the ensemble Kalman filter via shrinkage covariance matrix estimation. Our filter implementation combines information brought by an ensemble of model realizations, and that based on our prior knowledge about the dynamical system of interest. We perform the combination of...journal article 2021
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Lopez Restrepo, S. (author), Yarce Botero, A. (author), Pinel Pelaez, N. (author), Quintero Montoya, O.L. (author), Segers, Arjo (author), Heemink, A.W. (author)The use of low air quality networks has been increasing in recent years to study urban pollution dynamics. Here we show the evaluation of the operational Aburrá Valley’s low-cost network against the official monitoring network. The results show that the PM<sub>2.5</sub> low-cost measurements are very close to those observed by the official...journal article 2021
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Xiao, C. (author), Leeuwenburgh, O. (author), Lin, H.X. (author), Heemink, A.W. (author)Imaging-type monitoring techniques are used in monitoring dynamic processes in many domains, including medicine, engineering, and geophysics. This paper aims to propose an efficient workflow for application of such data for the conditioning of simulation models. Such applications are very common in e.g. the geosciences, where large-scale...journal article 2021
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Mider, Marcin (author), Schauer, Moritz (author), van der Meulen, F.H. (author)Suppose X is a multivariate diffusion process that is observed discretely in time. At each observation time, a transformation of the state of the process is observed with noise. The smoothing problem consists of recovering the path of the process, consistent with the observations. We derive a novel Markov Chain Monte Carlo algorithm to sample...journal article 2021
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Saredi, E. (author), Tumuluru Ramesh, Nikhilesh (author), Sciacchitano, A. (author), Scarano, F. (author)State observer techniques are investigated for the assimilation of three-dimensional velocity measurements into computational fluid dynamics simulations based on Reynolds-averaged Navier–Stokes (RANS) equations. The method relies on a forcing term, or observer, in the momentum equation, stemming from the difference between the computed velocity...journal article 2021
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de Hoon, N.H.L.C. (author)Heart and vessel diseases, or cardiovascular diseases (CVDs), are globally the main cause of mortality and morbidity. The blood flow plays an important role in their occurrence and progression. Therefore, knowledge of the blood flow is of key importance to reduce and threat these diseases. This knowledge requires both high-quality data and an...doctoral thesis 2020
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Jesus de Moraes, R. (author), Hajibeygi, H. (author), Jansen, J.D. (author)In data assimilation problems, various types of data are naturally linked to different spatial resolutions (e.g., seismic and electromagnetic data), and these scales are usually not coincident to the subsurface simulation model scale. Alternatives like upscaling/downscaling of the data and/or the simulation model can be used, but with...journal article 2020
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Lu, Y. (author), Steele-Dunne, S.C. (author), De Lannoy, Gabriëlle J.M. (author)Surface heat fluxes are vital to hydrological and environmental studies, but mapping them accurately over a large area remains a problem. In this study, brightness temperature (TB) observations or soil moisture retrievals from the NASA Soil Moisture Active Passive (SMAP) mission and land surface temperature (LST) product from the...journal article 2020
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Allaerts, D.J.N. (author), Quon, Eliot (author), Draxl, Caroline (author), Churchfield, Matthew (author)Mesoscale-to-microscale coupling (MMC) aims to address the limited scope of traditional large-eddy simulations by driving the microscale flow with information concerning large-scale weather patterns provided by mesoscale models. We present a new offline MMC technique for horizontally homogeneous microscale flow conditions, in which internal...journal article 2020
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Lu, Y. (author), Dong, Jianzhi (author), Steele-Dunne, S.C. (author)The spatial heterogeneity and temporal variation of soil moisture and surface heat fluxes are key to many geophysical and environmental studies. It has been demonstrated that they can be mapped by assimilating soil thermal and wetness information into surface energy balance models. The aim of this work is to determine whether enhancing the...journal article 2019
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Liu, K. (author), Vardon, P.J. (author), Hicks, M.A. (author)A data assimilation framework, utilising measurements of pore water pressure to sequentially improve the estimation of soil hydraulic parameters and, in turn, the prediction of slope stability, is proposed. Its effectiveness is demonstrated for an idealised numerical example involving the spatial variability of saturated hydraulic...journal article 2018
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Xie, X. (author), van Lint, J.W.C. (author), Verbraeck, A. (author)With trajectory data, a complete microscopic and macroscopic picture of traffic flow operations can be obtained. However, trajectory data are difficult to observe over large spatiotemporal regions—particularly in urban contexts—due to practical, technical and financial constraints. The next best thing is to estimate plausible trajectories from...journal article 2018
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Schwarz, Alexander (author), Dwight, R.P. (author)We investigate theoretically and numerically the use of the least-squares finite-element method (LSFEM) to approach data-assimilation problems for the steady-state, incompressible Navier-Stokes equations. Our LSFEM discretization is based on a stress-velocity-pressure (S-V-P) first-order formulation, using discrete counterparts of the Sobolev...journal article 2018
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Xiao, C. (author), Leeuwenburgh, O. (author), Lin, H.X. (author), Heemink, A.W. (author)This paper presents a non-intrusive subdomain POD-TPWL (SD POD-TPWL) for reservoir history matching through integrating domain decomposition (DD), proper orthogonal decomposition (POD), radial basis function (RBF) interpolation, and the trajectory piecewise linearization (TPWL). It is an efficient approach for model reduction and linearization...journal article 2018
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