Dr Cristiana Sebu

Reader

Profile

I obtained a BSc in Theoretical Physics in 2000, followed by an MSc in Theoretical Physics in 2002 at the University of Bucharest, Romania. In 2001, I spent six months working as a Wissenschaftler Mitarbeiter at the Institut für Physik, Johannes Gutenberg Universität, Mainz, Germany. I received my PhD in Applied Mathematics in 2004 at Université Montpellier II, France, with a thesis entitled Problèmes Inverses dans la Physique Classique et Quantique under the supervision of Professors Sorin Ciulli and André Neveu. I began my academic career in 2004 as a Postdoctoral Research Fellow in Mathematical Sciences at Oxford Brookes University. I became a Lecturer in 2005 and a Senior Lecturer in Mathematical Sciences in 2006. Since 2013, I have been a Reader in the Department of Mechanical Engineering and Mathematical Sciences at Oxford Brookes University.

For the last 12 years I have produced internationally recognised research in two main fields: Inverse Problems and Mathematical Modelling. My research into Inverse Problems has been widely published and cited, and has led to numerous invitations to conferences, particularly in the area of Electrical Impedance Tomography (EIT). I have made key contributions to the theoretical development of EIT for medical applications, including the design of a ground-breaking portable EIT device for breast cancer screening, and the development of an image reconstruction algorithm for use in such screening. This was carried out in collaboration with the EIT group at Institut für Physik, Johannes Gutenberg Universität, Mainz, Germany. Research in my second area of expertise, Mathematical Modelling, has led to pioneering work in other disciplines (Physics, Biology, Engineering and Chemistry), including my collaboration with Dr Poolman and Prof Fell from Faculty of Health and Life Sciences on modular decompositions of metabolic systems published in the Journal of Theoretical Biology, which has more than 19 citations.

Much of my research is the result of international collaborations (Montpellier, Mainz, Bremen, Florianopolis, Prague) which have been financially supported by major funding bodies (EGIDE, Leverhulme Trust, German Ministry of Education).

As the Lead Mathematician of the research areas of Biomedical Imaging and Instrumentation and Applied Mathematics within the research theme Simulation, Modelling and Systems Integration at Oxford Brookes University, I have contributed to the strengthening of the profile of these two research areas by attracting postgraduate students (four PhDs and one MSc by Research student) and a Daphne Jackson post-doctoral fellow to work under my supervision.

In October 2012, in recognition of my clear and sustainable future programme of research I was awarded a position on the “Next 10” Accelerator Programme within the Faculty of Technology, Design and Environment.

Research activities

Research areas

  • Applied Mathematics
  • Non-linear Partial Differential Equations
  • Integral Equation Methods
  • Inverse problems
  • Inverse conductivity problem
  • Electrical Impedance Tomography
  • Regularization methods for ill-posed inverse problems
  • Medical imaging
  • Computational Geometry
  • Mathematical Modelling
  • Mathematical Biology
  • Theoretical Physics.

International Research Collaborations

2000-2004 EGIDE Collaborative project on “Determination of QCD parameters using methods of functional analysis” with Institut für Physik, J. Gutenberg University, Mainz, Germany.
2001-2003 Project funded by Leverhulme Trust on “Integral Equation Methods in Electrical Impedance Tomography” with the Department of Mathematical Sciences, Oxford Brookes University, United Kingdom.
2004-2006 EGIDE Collaborative project on “Analyticity and summability of perturbation series in Field Theory / Quantum Chromodynamics“ with the Department of Elementary Particles, Institute of Physics, Academy of Science, Czech Republic.
2009-2010 Developing an optimized image reconstruction algorithm for the inverse conductivity problem using level set regularization in collaboration with Prof. Michael Pidcock, Oxford Brookes University and Dr Antonio Leitao, Federal University of St. Catarina, Florianopolis, Brazil, funded by CRF.
2004-present Collaborative project on “3D conductivity reconstructions for Electrical Impedance Mammography” with Zentrum für Technomathematik, University of Bremen, Germany, partially funded by Deutsche Forschungsgemeinschaft (MA1657/14-1).
2009-present Collaborative project on “Entwicklung und Tests von dreidimensionalen Rekonstruktionalgorithmen für die EIT-Mammographie” with Institut für Physik, University of Mainz, Germany, funded by German Federal Ministry of Education (BMBF 03SCPAM3) and CRF.
2001-present Collaborative project on “Computational methods for inverse problems associated with solids subject to mechanical and thermal loads” with Institute of Mechanics, Romanian Academy, Romania, funded by Romanian National Authority for Scientific Research.

Other research collaborations

2005–present Systems Biology with Prof D Fell and Dr M Poolman, Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, OBU.
2005–present Electrode design for optimal functional electrical stimulation (FES) with Prof. C. McLeod (Imperial College) and Prof. B. Andrews (Oxford University).
2011–present Biomedical Instrumentation with Prof K Hayatleh, Department of Computing and Communication Technologies, Faculty of Technology, Design and Environment, OBU.

Referee for Peer Reviewed International Journals

  • Journal of Mathematical Physics
  • IEEE, Transactions on Medical Imaging.
  • Inverse Problems in Science and Engineering
  • Inverse Problems
  • IEEE, Transactions on Evolutionary Computation
  • Computers & Mathematics with Applications

Member of the International Organizing Committee of International Conferences

The international conference series "Inverse Problems: Modelling and Simulation" (IP:MS) is one of the primary international forums for researchers working on the theory and applications of inverse problems. The IP:MS Conferences are organized every two years and they are held under the auspices of the leading international journals Inverse Problems, Inverse and Ill-Posed Problems and Inverse Problems in Science and Engineering. Since 2008 I have been a member of the International Organising Committee of the IP:MS Conferences in recognition of my contribution to Inverse Problems at an international level.

The 5th International Conference “Inverse Problems: Modelling and Simulation” (IP:MS 2010), May 24-29, 2010, Antalya, Turkey.

The 6th International Conference “Inverse Problems: Modelling and Simulation” (IP:MS 2012), May 21-26, 2012, Antalya, Turkey.

The 7th International Conference “Inverse Problems: Modelling and Simulation” (IP:MS 2014), May 26-31, 2014, Fethiye, Turkey.

Mini-symposium organizer at International Conferences

Inverse Problems in Electrical Tomography: From Theory to Practical Applications, 5th International Conference “Inverse Problems: Modelling and Simulation” (IP:MS 2010), May 24-29, 2010, Antalya, Turkey.

The mini-symposium focused on recent theoretical and practical developments in the field of Electrical Impedance Tomography and included speakers from University of Mainz (Germany), University of Karlsruhe (Germany), Forschungszentrum Dresden Rossendorf (Germany) Dartmouth University (USA), Clemson University (USA), Oxford Brookes University.

Recent Advances in Tomography, 6th International Conference “Inverse Problems: Modelling and Simulation” (IP:MS 2012), May 21-26, 2012, Antalya, Turkey.

Research into tomographical inversion techniques has been very active in recent years. New trends in tomography have emerged and the mini-symposium aimed to appraise researchers of recent developments and innovative contributions in this area, and allow them to explore collaborations and advance the field further. It included speakers from University of Bremen (Germany), University of Würtzburg (Germany), Dartmouth University (USA), Purdue University (USA), University of Washington (USA), University of Montpellier II (France), Joseph Fourier University (France), Johann Radon Institute (Austria), Aalto University (Finland), University of Eastern Findland (Findland), Moscow State University (Russia).

Invited and plenary talks, research seminars and presentations

The international standing of my research is confirmed by the requests to give 8 invited talks and 3 plenary talks at the most important international conferences on Inverse Problems (IP:MS 2008, IP:MS 2010, IP:MS 2012, ICIPE 2008, ICIPE 2011, AIP 2011, International Conference of Inverse and Ill-Posed Problems of Mathematical Physics), and at numerous international and/or cross-disciplinary workshops (e.g. Venturefest 2011, International Workshop on Muon and Neutrino Radiography 2012, QCD International Conference 2004), and 11 research seminars at prestigious national and international universities: Leeds (UK), Warwick (UK), Birmingham (UK), Mainz (Germany), Bremen (Germany), Göttingen (Germany), Frankfurt (Germany), Academy of Sciences of Czech Republic (Czech Republic).

Post-graduate research student supervision

Husein Perez (Oct 2011 to date, FT): MPhil/PhD (Director of Studies), privately funded, Discrete mathematical models for Electrical Impedance Tomography.

Marjan Heravi (June 2012 to date, FT): MPhil/PhD (Director of Studies), privately funded, Non-iterative 2D image reconstruction algorithm for multi-frequency electrical impedance tomography.

Sam Kamperis (commenced Jan 2013, FT): MPhil/PhD (Director of Studies), funded by CRF, Optimisations of computationally complex algorithms for polyhedra.

Harry Green (Sept 2012 to date, FT): MSc(Res) (Director of Studies), privately funded, Bifurcation and chaos theory in ecological modelling using dynamical systems.

Philip Hughes (Oct 2012 to date, PT): MPhil/PhD (Second Supervisor), privately funded, Design of instrumentation amplifiers with variable filters.

Research consultancy and training through Mathslink

Since 2006, through Mathslink, I have provided research consultancy and training for research-active staff within all faculties at OBU including MATLAB training, one-to-one mathematical advice, support to joint grant applications, research design and analysis. Mathslink users include: research-active staff across the University, research students and contract research staff.

Each year I teach an intensive two-day MATLAB training course for Oxford Brookes University. Around 20 members of staff and research students attend this course. The attendees include novices and those coming back to MATLAB after a long absence. The course is extremely well received: 100% of attendees say they would definitely recommend the course to a colleague or other student and 83% of participants state that the course met all their objectives.

Thus, for seven years I have actively contributed to research developments within all faculties at OBU and my input has helped other researchers to advance their projects by providing them with new skills and tools or with new perspectives leading to pioneering work in their research fields. A concrete example is my collaboration with Prof Truesdale from the Faculty of Health and Life Sciences.

Teaching

Module Leader for

  • U08621 Linear Algebra and Analysis I
  • U08622 Linear Algebra and Analysis II
  • U08631 Numerical Analysis I
  • U08682 Numerical Analysis II (Honours Component)
  • U08680 Geometry (Honours Component)
  • U08687 Honours Topics in Mathematics (double Honours Component)
  • U08690 Mathematics Interdisciplinary Project (Honours Component)
  • U08698 Mathematical Sciences Project (double Honours Component)
  • U08699 Mathematics Project (double Honours Component)
  • P04700 Computation and Modelling

Undergraduate and postgraduate project supervision

  • Peter Craft, Special Relativity (2005).
  • Allison Robinson, Integral Equations using MATLAB (2006).
  • Ashley Twigger, Mathematical formulation of Quantum Mechanics. Analytical solutions to Schrödinger’s equation (2007).
  • Sam Kamperis, 3D Mappings of Polyhedra (2012).
  • Tobias Bauer, An Exploratory and Interactive Software Application for Reliability and Survival Analysis (2012).
  • Alex Ryzkov, Mathematical modelling and research of electric drive as a part of assembly complex (2013).
  • Luís Guilherme Serra Freire, Racing Line Prediction (2013).

Other departmental roles

Since September 2010, I have been the Exchange and Study Abroad Coordinator for Mechanical Engineering and Mathematical Sciences, identifying new markets from which to draw overseas students and establishing links with universities in order to realise this potential. As well as this developmental role, I am also directly involved in the admissions of students enrolling on exchange programmes in Mathematics and Mechanical Engineering at OBU. I am responsible for making sure that students have a coherent programme of study at an appropriate level and I act as their Academic Advisor, providing academic advice where necessary.

Another functional role that I perform at departmental level is sitting on the MEMS RKTC (Research and Knowledge Transfer Committee) which monitors and implements policy relating to research within MEMS.

Publications

Publications in Peer Reviewed International Journals

S. Ciulli, M. K. Pidcock, C. Sebu, An analytical solution for the inverse conductivity problem, Rom. J. Phys. 48(5-6): 50-61, (2003).

S. Ciulli, M. K. Pidcock, C. Sebu, On the inverse conductivity problem in the half space, Z. Angew. Math. Mech. 83(11): 731-792, (2003).

S. Ciulli, M. K. Pidcock, C. Sebu, An integral equation method for the inverse conductivity problem, Phys. Lett. A 325: 253-267, (2004).

S. Ciulli, C. Sebu, K. Schilcher, H. Spiesberger, QCD condensates from τ-decay data: A functional approach, Phys. Lett. B 595: 359-367, (2004).

P. C. Sabatier and C. Sebu, On the resolving power of electrical impedance tomography, Inverse Problems 23: 1895-1913, (2007).

M. G. Poolman, C. Sebu, M. K. Pidcock and D. A. Fell, Modular decomposition of metabolic systems via null space analysis, Journal of Theoretical Biology 249(4): 691-705, (2007).

S. Ciulli and C. Sebu, Stable Lagrange points of large planets as possible regions where WIMPs could be sought, J. Phys. A: Math. Theor. 41(33), (2008).

M. Lukaschewitsch, P. Maass, M. K. Pidcock and C. Sebu, The asymptotic behaviour of weak solutions to the forward problem of Electrical Impedance Tomography on unbounded three dimensional domains, Math. Meth. Appl. Sc. 32 (2), 206-222, (2009).

P. Maass, M. K. Pidcock and C. Sebu, A regularized solution for the inverse conductivity problem using mollifiers, Inverse Problems in Science and Engineering 18 (1), 145 -161, (2010).

C. Hähnlein, K. Schilcher, H. Spiesberger and C. Sebu, Conductivity imaging with interior potential measurements, Inverse Problems in Science and Engineering 19(5), 729-750, (2011).

V. W. Truesdale and C. Sebu, A new analytic integration of the rate equation for batch dissolution of salts in the presence of Common ion, Aquat Geochem 19, 39-56, (2013).

K-H. Georgi, C. Hähnlein, K. Schilcher, C. Sebu and H. Spiesberger, Conductivity Reconstructions Using Real Data from a New Planar Electrical Impedance Device, Inverse Problems in Science and Engineering, http://dx.doi.org/10.1080/17415977.2012.753441, (2013).

A. A. Tammam, K. Hayatleh, M. Ben-Esmael, N. Terzopoulos and C. Sebu, Critical Review of the Circuit Architecture of CFOA, accepted for publication to International Journal of Electronics.

H. Fonseca, K. Hayatleh, N Terzopoulos, F. J. Lidgey and C. Sebu, An investigation on the discrete-time nature of excess phase and jitter, accepted for publication to International Journal of Electronics.

M. Gehre, T. Kluth, C. Sebu and P. Mass, Sparse 3D reconstructions in Electrical Impedance Tomography using real data, accepted for publication in Inverse Problems in Science and Engineering.

A. A. Tamman, K. Hayatleh, C. Sebu, J. Lidgey, N. Terzopoulos and M. Ben-Esmael, Wide-Bandwidth CFOA with High CMRR Performance, submitted to Journal of Circuits, Systems, and Computers.

Peer Reviewed Conference Papers

P. Maass, M. K. Pidcock and C. Sebu, A mollifier method for the inverse conductivity problem, Proceedings of the 6th International Conference on Inverse Problems in Engineering: Theory and Practice, Journal of Physics: Conference Series 135 (2008).

T. Johansson and C. Sebu, A uniqueness result for the inverse conductivity problem, Proceedings of UKBIM7, (2009).

C. Sebu, Conductivity Reconstructions Using Real Data from a New Planar Electrical Impedance Device, Proceedings of the 7th International Conference on Inverse Problems in Engineering: Theory and Practice (ICIPE 2011).

Book Chapter

C. Sebu, Integral equation methods for inverse problems in Electrical Impedance Tomography, Inverse Problems and Computational Mechanics, Eds. Liviu Marin, Ligia Munteanu si Veturia Chiroiu, Editura Academiei, Bucharest, Romania, Vol.1 (Chapter 13) 295-313, (2011). ISBN 978-973-27-2147-6.

PhD Thesis

C. Sebu, Inverse Problems in Classical and Quantum Physics, University of Montpellier II, France, (2004).

Further details of my publications can be found at: http://scholar.google.com/scholar?start=10&q=author:C+author:Sebu&hl=en&as_sdt=1,5&as_vis=1
Dr Cristiana Sebu

CONTACT US

Department of Mechanical Engineering and Mathematical Sciences

Oxford Brookes University
Wheatley Campus
Wheatley
OXFORD OX33 1HX
United Kingdom

01865 484521
csebu@brookes.ac.uk