Variance-based sensitivity analysis for time-dependent processes

Alexanderian, Alen; Gremaud, Pierre A.; Smith, Ralph C.

doi:10.1016/j.ress.2019.106722

Cited by 46 publications

(64 citation statements)

References 46 publications

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“…Finally, from the PCE, it is possible to estimate the two sensitivity indices as the ratio between the PCE coefficients. Since the case study is evaluated in time, the implementation of time-dependent indices is implemented following [ 27 ] as: …”

Section: Methodsmentioning

confidence: 99%

Electrode positioning to investigate the changes of the thoracic bioimpedance caused by aortic dissection – a simulation study

Badeli

Melito

Reinbacher‐Köstinger

et al. 2020

Journal of Electrical Bioimpedance

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AbstractImpedance cardiography (ICG) is a non-invasive method to evaluate several cardiodynamic parameters by measuring the cardiac-synchronous changes in the dynamic transthoracic electrical impedance. ICG allows us to identify and quantify conductivity changes inside the thorax by measuring the impedance on the thorax during a cardiac cycle. Pathologic changes in the aorta, like aortic dissection, will alter the aortic shape as well as the blood flow and consequently, the impedance cardiogram. This fact distorts the evaluated cardiodynamic parameters, but it could lead to the possibility to identify aortic pathology. A 3D numerical simulation model is used to compute the impedance changes on the thorax surface in case of the type B aortic dissection. A sensitivity analysis is applied using this simulation model to investigate the suitability of different electrode configurations considering several patient-specific cases. Results show that the remarkable pathological changes in the aorta caused by aortic dissection alters the impedance cardiogram significantly.

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Section: Methodsmentioning

confidence: 99%

Electrode positioning to investigate the changes of the thoracic bioimpedance caused by aortic dissection – a simulation study

Badeli

Melito

Reinbacher‐Köstinger

et al. 2020

Journal of Electrical Bioimpedance

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“…with [a i , b i ] the physical parameter ranges for c i , adapted from [4]. The solution of the system is a random process, y = y(t; θ).…”

Section: Model Descriptionmentioning

confidence: 99%

Derivative-Based Global Sensitivity Analysis for Models with High-Dimensional Inputs and Functional Outputs

Cleaves¹,

Alexanderian²,

Guy³

et al. 2019

SIAM J. Sci. Comput.

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We present a framework for derivative-based global sensitivity analysis (GSA) for models with high-dimensional input parameters and functional outputs. We combine ideas from derivative-based GSA, random field representation via Karhunen-Loève expansions, and adjointbased gradient computation to provide a scalable computational framework for computing the proposed derivative-based GSA measures. We illustrate the strategy for a nonlinear ODE model of cholera epidemics and for elliptic PDEs with application examples from geosciences and biotransport.

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“…Therefore, an analysis that is aware of the history of the output variability is needed. The implementation of time-dependent indices, known as generalized Sobol indices [14] read as…”

Section: Polynomial Chaos Expansionmentioning

confidence: 99%

Sensitivity Analysis of a Hemodynamic-based Model for Thrombus Formation and Growth

Melito¹,

Jafarinia²,

Hochrainer³

et al. 2020

World Congress on Electrical Engineering and Computer Systems and Science

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Aortic dissection is a severe cardiovascular disease caused by the occurrence of a tear in the aortic wall. As a result, the blood penetrates the wall and makes a new blood channel called false lumen. The hemodynamic conditions in the false lumen may contribute to the formation of thrombi, which influence the patient diagnosis and outcomes. In this study, the focus is on a hemodynamic-based model of thrombus formation. Since the model construction presents sources of uncertainties in the model parameter, a variance-based sensitivity analysis is performed. Thrombus formation at a backwards-facing step is considered as a benchmark for the numerical simulations and sensitivity analysis. This geometry is capable of representing the main contributions of the model in thrombus formation. The study aims not only at getting a better insight into the model's structure but also at preparing model simplifications with the aim of future patient-specific simulations. A polynomial chaos expansion is employed as a surrogate model, from which the derivation of quantitative sensitivity indices is enhanced. In this study, nine model parameters are selected, whose actual values are not well known. The model responses taken into account are the maximum volume fraction of thrombosis, its time development, and the thrombus growth rate. The results show that the model lends itself to model reduction since some of the model parameters show little to no influence on the model's outputs. A threshold value related to the concentration of bounded platelets is identified as the key input parameter dominating the model predictions in the current geometry.

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Variance-based sensitivity analysis for time-dependent processes

Cited by 46 publications

References 46 publications

Electrode positioning to investigate the changes of the thoracic bioimpedance caused by aortic dissection – a simulation study

Electrode positioning to investigate the changes of the thoracic bioimpedance caused by aortic dissection – a simulation study

Derivative-Based Global Sensitivity Analysis for Models with High-Dimensional Inputs and Functional Outputs

Sensitivity Analysis of a Hemodynamic-based Model for Thrombus Formation and Growth

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