Searched for: subject%3A%22data%255C%2Bassimilation%22
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Lopez Restrepo, S. (author), Yarce Botero, A. (author), Pinel, Nicolás (author), Quintero, O. L. (author), Segers, Arjo (author), Heemink, A.W. (author)
This work proposes a robust and non-Gaussian version of the shrinkage-based knowledge-aided EnKF implementation called Ensemble Time Local H<sub>∞</sub> Filter Knowledge-Aided (EnTLHF-KA). The EnTLHF-KA requires a target covariance matrix to integrate previously obtained information and knowledge directly into the data assimilation (DA). The...
journal article 2022
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Lopez Restrepo, S. (author)
In order to avoid the adverse effects of air pollution, efforts have been made to monitor when air pollution reaches dangerous levels. A Chemical Transport Model (CTM) can simulate trace gases and particles concentration in specific areas. These models are not entirely reliable, owing to incomplete knowledge about emissions and meteorological...
doctoral thesis 2021
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Mol, Maaike (author)
The need for accurate estimation of hydrodynamic and water quality model variables arises from the UNITED project, which aims to create high-resolutional forecasting systems for monitoring the cultivation of seaweed and flat oysters and operating of the Belgian pilot of UNITED in the coastal area of the North Sea. Accurate observations of...
master thesis 2021
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Kuipers, Lucas (author)
Being able to timely access and share accurate information to all stakeholders that can influence a supply chain is referred to as <i>supply chain visibility</i>. Supply chain visibility is crucial for increasing the resilience of a...
master thesis 2021
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Wang, Z. (author)
This dissertation's ultimate goal is to provide solutions to two problems that the promising data assimilation method, called the Particle Filter, has when applied to high dimensional non-linear models, such as those often used in hydrological research and forecasting. Two local particle filters have been proposed to overcome three major issues....
doctoral thesis 2021
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Belligoli, Z. (author)
The continuous increase in the number of flights in the last decades caused a steepgrowth of aviation-related pollution to the point that the aviation sector is responsible for3% of the global greenhouse gas emissions. Regulators have been slow at catching up withthis problem, and stringent emission targets have been put in place only very...
doctoral thesis 2021
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Xiao, C. (author)
In the community of petroleum engineering, the use of surrogate modelling techniques have recently gained more and more popularity to improve the efficiency of history matching. However, it is still not possible to fully utilize their potential in realistic applications. One of the challenges is to retain high accuracy while increasing the...
doctoral thesis 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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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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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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Yarce Botero, A. (author), Lopez Restrepo, S. (author), Pinel Pelaez, N. (author), Quintero-Montoya, Olga (author), Segers, Arjo (author), Heemink, A.W. (author)
In this work, we present the development of a 4D-Ensemble-Variational (4DEnVar) data assimilation technique to estimate NOx top-down emissions using the regional chemical transport model LOTOS-EUROS with the NO2 observations from the TROPOspheric Monitoring Instrument (TROPOMI). The assimilation was performed for a domain in the northwest of...
journal article 2021
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Evensen, Geir (author), Amezcua, Javier (author), Bocquet, Marc (author), Carrassi, Alberto (author), Farchi, Alban (author), Fowler, Alison (author), Houtekamer, Pieter L. (author), Jones, Christopher K. (author), Vossepoel, F.C. (author)
This work demonstrates the efficiency of using iterative ensemble smoothers to estimate the parameters of an SEIR model. We have extended a standard SEIR model with age-classes and compartments of sick, hospitalized, and dead. The data conditioned on are the daily numbers of accumulated deaths and the number of hospitalized. Also, it is possible...
journal article 2021
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Leeuwenburgh, O. (author), Emerick, Alexandre A. (author), Jafarpour, Behnam (author), Zhang, Dongxiao (author), Luo, Xiaodong (author)
contribution to periodical 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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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), 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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Lopez Restrepo, S. (author), Yarce Botero, A. (author), Quintero Montoya, O.L. (author), Pinel Pelaez, N. (author), Hinestroza Ramirez, J.E. (author), Nino-Ruiz, Elias David (author), Anderson Flórez, Jimmy (author), Rendón, Angela Maíra (author), Alvarez-Laínez, Monica Lucia (author), Heemink, A.W. (author)
Particulate matter (PM) is one of the most problematic pollutants in urban air. The effects of PM on human health, associated especially with PM of ≤2.5μm in diameter, include asthma, lung cancer and cardiovascular disease. Consequently, major urban centers commonly monitor PM2.5 as part of their air quality management strategies. The Chemical...
book chapter 2021
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Çakir, Bora (author)
Closure of Collar's triangle represents a complete framework of fluid-structure interactions (FSI) enabling the comprehensive understanding of different design elements compromising aeronautical applications. Experimental methods such as tomographic particle image velocimetry (Tomo-PIV) are proven to provide accurate acquisition opportunities of...
master thesis 2020
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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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Zijlker, Tammo (author)
This study aims to improve estimates of NOx emission strengths by assimilation of TROPOMI satellite retrievals in the LOTOS-EUROS chemical transport model. Nitrogen oxides (NO and NO2) play a pivotal role in atmospheric chemistry, are an important source of air pollution and contribute to nitrogen deposition over vulnerable natural areas....
master thesis 2020
Searched for: subject%3A%22data%255C%2Bassimilation%22
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