###### News:

- "Asymptotics, inverse problems and applications" @ SIAM Science Imaging 2014
- "Direct and inverse problems in wave propagation" @ AIMS Conference on Dynamical Systems, Differential Equations and Applications 2014

## Dr Nicolas Chaulet

### Research Associate

Room 602

Department of Mathematics

University College London

Gower Street, London WC1E 6BT (UK)

**E-Mail:** n.chaulet (at) ucl.ac.uk

#### Research Interests

I am a Postdoctoral researcher in the Department of Mathematics at University College London. I am mainly interested in the solution and the analysis of inverse problems related to imaging from scattering of electromagnetic waves with application in medical imaging, radar imaging...

One of my main interest concerns the use of approximate models in the context of inverse problems. I have for example studied the inverse scattering problem for electromagnetic waves in the case where the scatterer to be imaged is characterised by a so-called Generalized Impedance Boundary Condition (the boundary condition involves high order surface derivatives). This kind of boundary condition is well known to produce accurate models in many situations such as the scattering of electromagnetic waves by a perfectly conducting object covered by a thin layer of dielectric. The use of such boundary conditions in this context greatly simplifies the numerical and the theoretical analysis of the underlying inverse problem and can certainly lead to efficient algorithms to solve complex imaging problems.

I am also greatly interested in practical problems arising in the solution of the Electrical Impedance Tomography inverse problem including the question of the coupling between qualitative techniques (sampling methods such as the Factorization Method) and quantitative imaging techniques (non linear optimisation with regularisation) to obtain robust images from experimental data. Another topic concerns the design of optimal protocoles to collect data in real life experiments which is of major interest for applications.

#### Keywords

- Inverse electromagnetic scattering problems with Generalized Impedance Boundary Conditions
- Electrical Impedance Tomography for brain imaging
- Non linear optimisation for inverse problems
- Asymptotic analysis of interior transmission eigenvalues
- Optimal design for invisibility cloaking