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Papers by Jarosław Wlazło

Research paper thumbnail of European Covid-19 Forecast Hub

Zenodo (CERN European Organization for Nuclear Research), Jul 7, 2022

Research paper thumbnail of European Covid-19 Forecast Hub

Zenodo (CERN European Organization for Nuclear Research), Feb 16, 2023

Research paper thumbnail of Estimating the COVID-19 prevalence from wastewater

Scientific reports, Jun 22, 2024

Wastewater based epidemiology has become a widely used tool for monitoring trends of concentratio... more Wastewater based epidemiology has become a widely used tool for monitoring trends of concentrations of different pathogens, most notably and widespread of SARS-CoV-2. Therefore, in 2022, also in Rhineland-Palatinate, the Ministry of Science and Health has included 16 wastewater treatment sites in a surveillance program providing biweekly samples. However, the mere viral load data is subject to strong fluctuations and has limited value for political deciders on its own. Therefore, the state of Rhineland-Palatinate has commissioned the University Medical Center at Johannes Gutenberg University Mainz to conduct a representative cohort study called SentiSurv, in which an increasing number of up to 12,000 participants have been using sensitive antigen selftests once or twice a week to test themselves for SARS-CoV-2 and report their status. This puts the state of Rhineland-Palatinate in the fortunate position of having time series of both, the viral load in wastewater and the prevalence of SARS-CoV-2 in the population. Our main contribution is a calibration study based on the data from 2023-01-08 until 2023-10-01 where we identified a scaling factor (0.208 ± 0.031) and a delay (5.07 ± 2.30 days) between the virus load in wastewater, normalized by the pepper mild mottle virus (PMMoV), and the prevalence recorded in the SentiSurv study. The relation is established by fitting an epidemiological model to both time series. We show how that can be used to estimate the prevalence when the cohort data is no longer available and how to use it as a forecasting instrument several weeks ahead of time. We show that the calibration and forecasting quality and the resulting factors depend strongly on how wastewater samples are normalized.

Research paper thumbnail of Starker Effekt von Schnelltests (Strong effect of rapid tests)

arXiv (Cornell University), Apr 12, 2023

Research paper thumbnail of Predictive performance of multi-model ensemble forecasts of COVID-19 across European nations

Background Short-term forecasts of infectious disease burden can contribute to situational awaren... more Background Short-term forecasts of infectious disease burden can contribute to situational awareness and aid capacity planning. Based on best practice in other fields and recent insights in infectious disease epidemiology, one can maximise the predictive performance of such forecasts if multiple models are combined into an ensemble. Here we report on the performance of ensembles in predicting COVID-19 cases and deaths across Europe between 08 March 2021 and 07 March 2022. Methods We used open-source tools to develop a public European COVID-19 Forecast Hub. We invited groups globally to contribute weekly forecasts for COVID-19 cases and deaths reported from a standardised source over the next one to four weeks. Teams submitted forecasts from March 2021 using standardised quantiles of the predictive distribution. Each week we created an ensemble forecast, where each predictive quantile was calculated as the equally-weighted average (initially the mean and then from 26th July the media...

Research paper thumbnail of Author response: Predictive performance of multi-model ensemble forecasts of COVID-19 across European nations

Research paper thumbnail of Modeling and optimizing dynamic networks: Applications in process engineering and energy supply

Simulation and Optimization in Process Engineering

Research paper thumbnail of Elastic image registration with exact mass preservation

We establish a new framework for image registration, which is based on linear elasticity and opti... more We establish a new framework for image registration, which is based on linear elasticity and optimal mass transportation theory. We combine these two arguments in order to obtain a PDE constrained optimization problem that is analytically investigated and further discretized with the finite difference method and solved by an inexact SQP algorithm. This requires to solve in each step a large sparse linear system, which has a saddle point form. Motivated by stability arguments we use a fully staggered grid for the discretization of the displacement vector field. Artificial and real world examples are presented to underline the numerical robustness of the method.

Research paper thumbnail of Notes on computational aspects of the fractional-order viscoelastic model

Journal of Engineering Mathematics

This paper deals with the computational aspect of the investigation of the relaxation properties ... more This paper deals with the computational aspect of the investigation of the relaxation properties of viscoelastic materials. The constitutive fractional Zener model is considered under continuous deformation with a jump at the origin. The analytical solution of this equation is obtained by the Laplace transform method. It is derived in a closed form in the terms of the Mittag-Leffler function. The method of numerical evaluation of the Mittag-Leffler function for arbitrary negative arguments which corresponds to physically meaningful interpretation is demonstrated. A numerical example is given to illustrate the effectiveness of this result.

Research paper thumbnail of European Covid-19 Forecast Hub

Zenodo (CERN European Organization for Nuclear Research), Jul 7, 2022

Research paper thumbnail of European Covid-19 Forecast Hub

Zenodo (CERN European Organization for Nuclear Research), Feb 16, 2023

Research paper thumbnail of Estimating the COVID-19 prevalence from wastewater

Scientific reports, Jun 22, 2024

Wastewater based epidemiology has become a widely used tool for monitoring trends of concentratio... more Wastewater based epidemiology has become a widely used tool for monitoring trends of concentrations of different pathogens, most notably and widespread of SARS-CoV-2. Therefore, in 2022, also in Rhineland-Palatinate, the Ministry of Science and Health has included 16 wastewater treatment sites in a surveillance program providing biweekly samples. However, the mere viral load data is subject to strong fluctuations and has limited value for political deciders on its own. Therefore, the state of Rhineland-Palatinate has commissioned the University Medical Center at Johannes Gutenberg University Mainz to conduct a representative cohort study called SentiSurv, in which an increasing number of up to 12,000 participants have been using sensitive antigen selftests once or twice a week to test themselves for SARS-CoV-2 and report their status. This puts the state of Rhineland-Palatinate in the fortunate position of having time series of both, the viral load in wastewater and the prevalence of SARS-CoV-2 in the population. Our main contribution is a calibration study based on the data from 2023-01-08 until 2023-10-01 where we identified a scaling factor (0.208 ± 0.031) and a delay (5.07 ± 2.30 days) between the virus load in wastewater, normalized by the pepper mild mottle virus (PMMoV), and the prevalence recorded in the SentiSurv study. The relation is established by fitting an epidemiological model to both time series. We show how that can be used to estimate the prevalence when the cohort data is no longer available and how to use it as a forecasting instrument several weeks ahead of time. We show that the calibration and forecasting quality and the resulting factors depend strongly on how wastewater samples are normalized.

Research paper thumbnail of Starker Effekt von Schnelltests (Strong effect of rapid tests)

arXiv (Cornell University), Apr 12, 2023

Research paper thumbnail of Predictive performance of multi-model ensemble forecasts of COVID-19 across European nations

Background Short-term forecasts of infectious disease burden can contribute to situational awaren... more Background Short-term forecasts of infectious disease burden can contribute to situational awareness and aid capacity planning. Based on best practice in other fields and recent insights in infectious disease epidemiology, one can maximise the predictive performance of such forecasts if multiple models are combined into an ensemble. Here we report on the performance of ensembles in predicting COVID-19 cases and deaths across Europe between 08 March 2021 and 07 March 2022. Methods We used open-source tools to develop a public European COVID-19 Forecast Hub. We invited groups globally to contribute weekly forecasts for COVID-19 cases and deaths reported from a standardised source over the next one to four weeks. Teams submitted forecasts from March 2021 using standardised quantiles of the predictive distribution. Each week we created an ensemble forecast, where each predictive quantile was calculated as the equally-weighted average (initially the mean and then from 26th July the media...

Research paper thumbnail of Author response: Predictive performance of multi-model ensemble forecasts of COVID-19 across European nations

Research paper thumbnail of Modeling and optimizing dynamic networks: Applications in process engineering and energy supply

Simulation and Optimization in Process Engineering

Research paper thumbnail of Elastic image registration with exact mass preservation

We establish a new framework for image registration, which is based on linear elasticity and opti... more We establish a new framework for image registration, which is based on linear elasticity and optimal mass transportation theory. We combine these two arguments in order to obtain a PDE constrained optimization problem that is analytically investigated and further discretized with the finite difference method and solved by an inexact SQP algorithm. This requires to solve in each step a large sparse linear system, which has a saddle point form. Motivated by stability arguments we use a fully staggered grid for the discretization of the displacement vector field. Artificial and real world examples are presented to underline the numerical robustness of the method.

Research paper thumbnail of Notes on computational aspects of the fractional-order viscoelastic model

Journal of Engineering Mathematics

This paper deals with the computational aspect of the investigation of the relaxation properties ... more This paper deals with the computational aspect of the investigation of the relaxation properties of viscoelastic materials. The constitutive fractional Zener model is considered under continuous deformation with a jump at the origin. The analytical solution of this equation is obtained by the Laplace transform method. It is derived in a closed form in the terms of the Mittag-Leffler function. The method of numerical evaluation of the Mittag-Leffler function for arbitrary negative arguments which corresponds to physically meaningful interpretation is demonstrated. A numerical example is given to illustrate the effectiveness of this result.