Uncertainty quantification and sensitivity analysis of transcranial electric stimulation for 9-subdomain human head model

Šušnjara, Anna; Verhnjak, Ožbej; Poljak, Dragan; Cvetković, Mario; Ravnik, Jure

doi:10.1016/j.enganabound.2021.10.026

Cited by 10 publications

(6 citation statements)

References 27 publications

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“…The uncertainty of the tissue electrical conductivity can be taken into account via statistical approaches such as the polynomial chaos method (PCM) or the stochastic collocation method (SCM). An interested reader could find more details on several examples of the SCM approach applied to modeling biomedical applications including transcranial electrical stimulation (TES) [38] and transcranial magnetic stimulation (TMS) [39].…”

Section: Effect Of Body Conductivitymentioning

confidence: 99%

Analysis of Magnetotherapy Device-Induced Fields Using Cylindrical Human Body Model

Cvetković,

Sučić

2024

Electronics

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This paper deals with the analysis of induced current density and the induced electric field in the body of a human exposed to the magnetic field of a magnetotherapy device. As the displacement currents at extremely low frequencies can be neglected, the biological tissues can thus be considered a weakly conducting medium, facilitating the use of a quasi-static eddy current approximation. The formulation is based on the surface integral equation for the unknown surface charges, whose numerical solution is obtained using the method of moments technique. A simplified model of the human body is utilized to examine various scenarios during the magnetotherapy procedure. The numerical results for the induced current density and the induced electric field are obtained using the proposed model. The analyses of various stimulating coil parameters, human body model parameters, and a displacement of the magnetotherapy coil were carried out to assess their effects on the induced current density. The results suggest that selection of the stimulating coil should be matched based on the size of the human body, but also that the position and orientation of the coil with respect to the body surface will result in different distributions of the induced fields. The results of this study could be useful for medical professionals by showing the importance of various magnetotherapy coil parameters for preparation of various treatment scenarios.

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Section: Effect Of Body Conductivitymentioning

confidence: 99%

Analysis of Magnetotherapy Device-Induced Fields Using Cylindrical Human Body Model

Cvetković,

Sučić

2024

Electronics

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“…The boundary integral Equation ( 5) is used as the basis of the Boundary Element Method (BEM) solver, which we developed. The numerical implementation is based on our Laplace BEM solver [38,39]. We consider the boundary Γ = ∑ l Γ l to be decomposed into boundary elements Γ l :…”

Section: Boundary Element Solution Of Stokes Flow Over a Particlementioning

confidence: 99%

“…A system of linear equations is set up for all unknowns, where in case of unknown {u x } or {q x } Equation ( 8) is used, in case of unknown {u y } or {q y } Equation ( 9) is used and in case of unknown {u z } or {q z } Equation ( 10) is used. Additional details of the BEM employed, such as implementation of integration, can be found in [38,39].…”

Section: Boundary Element Solution Of Stokes Flow Over a Particlementioning

confidence: 99%

A Model for Translation and Rotation Resistance Tensors for Superellipsoidal Particles in Stokes Flow

Štrakl

Hriberšek

Wedel

et al. 2022

JMSE

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In this paper, forces and torques on solid, non-spherical, orthotropic particles in Stokes flow are investigated by using a numerical approach on the basis of the Boundary Element Method. Different flow patterns around a particle are considered, taking into account the contributions of uniform, rotational and shear flows, to the force and the torque exerted on the particle. The expressions for the force and the toque are proposed, by introducing translation, rotation and deformation resistance tensors, which capture each of the flow patterns individually. A parametric study is conducted, considering a wide range of non-spherical particles, determined by the parametric superellipsoid surface equation. Using the results of the parametric study, an approximation scheme is derived on the basis of a multivariate polynomial expression. A coefficient matrix for the polynomial model is introduced, which is used as a tunable parameter for a minimization problem, whereby the polynomials are fitted to the data. The developed model is then put to the test by considering a few examples of particles with different shapes, while also being compared to other, currently available solutions. On top of that, the full functionality of the model is demonstrated by considering an example of a pollen grain, as a realistic non-spherical particle. First, a superellipsoid, which best fits the actual particle shape, is found from the considered range. After that, the coefficients of the translation, rotation and deformation resistance tensors are obtained from the present model and compared to the results of other available models. In the conclusion, a superior accuracy of the present model, for the considered range of particles, is established. To the best of the authors knowledge, this is also one of the first models to extend the torque prediction capabilities beyond sphere and prolate particles. At the same time, the model was demonstrated to be simple to implement and very conservative with the computational resources. As such, it is suitable for large scale studies of dispersed two-phase flows, with a large number of particles.

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“…The numerical implementation of the Stokes BEM solver described in the previous section is based on our Laplace BEM solver [11], [12]. The Stokes solver source code is freely available online.…”

Section: Numerical Implementationmentioning

confidence: 99%

Stokes Flow Induced Drag and Torque on Asbestos-Like Fibres Cannot Be Estimated by a Simplistic Ellipsoidal Approximation

Ravnik

Štrakl

Wedel

et al. 2022

WIT Transactions on Engineering Sciences

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In this paper we present an algorithm based on the Boundary Element Method for solving the Stokes flow around an arbitrarily shaped particle in multiphase flows. The objective of the algorithm is to determine the exact drag force and torque experienced by the particle during its motion in a turbulent flow field. The developed method is used to compare the predicted force and torque values on a realistic 3D model of a mineral fibre and its simplifying ellipsoidal approximation. We found that the force and torque values calculated for the real particle geometry differ greatly from the values obtained with the simplifying ellipsoidal approximation. On average, a relative error of less than 10% is achieved for only 10%-30% of the particle orientations.

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Uncertainty quantification and sensitivity analysis of transcranial electric stimulation for 9-subdomain human head model

Cited by 10 publications

References 27 publications

Analysis of Magnetotherapy Device-Induced Fields Using Cylindrical Human Body Model

Analysis of Magnetotherapy Device-Induced Fields Using Cylindrical Human Body Model

A Model for Translation and Rotation Resistance Tensors for Superellipsoidal Particles in Stokes Flow

Stokes Flow Induced Drag and Torque on Asbestos-Like Fibres Cannot Be Estimated by a Simplistic Ellipsoidal Approximation

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