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User:Dhruva

Dhruva V. Raman
DPhil Candidate in Engineering Science; Systems Biology Doctoral Training Centre
Department of Engineering Science


DhruvaBioPhoto.jpg

Background

As of February 2017 I am a postdoc in the Control Group at the University of Cambridge. My new webpage can be found at http://www-control.eng.cam.ac.uk/Main/DhruvaRaman


I am a DPhil (i.e. PhD) student in the Control Group at the University of Oxford, under the supervision of Antonis Papachristodoulou and James Anderson. I completed an MMath Degree at the University of Warwick (2012) graduating with first class honours. From 2012-present, I have been on the Systems Biology Doctoral Training Centre, University of Oxford, fully funded through an EPSRC scholarship. This involved a year of taught courses in the broad field of Systems Biology, before I began my DPhil proper in October 2013.

Current Research Interests

My broad interests lie in the analysis of mathematical models of physical processes. Increasing computing power has allowed for the emergence of highly parameterised, nonlinear models of extremely complex systems. Extracting useful information from such models remains a hard task, however. I will motivate my specific interests by example. A model of a damped harmonic oscillator, derived from first principles, would incorporate three 'obvious' parameters: the mass of the oscillator, the viscous damping coefficient, and the spring constant. However behaviour is completely governed by two 'natural' parameters: the damping ratio and the angular frequency. This observation not only provides insight into the system itself, but it is important in the parameter estimation problem: the three 'obvious' parameters cannot separately be estimated from observation of the oscillator trajectory. They are 'unidentifiable'.

In a complex model with many parameters, such observations are not easy to formulate via intuition alone. Moreover, hidden unidentifiable subspaces will corrupt the parameter estimation problem. I am looking into automatic and scalable methods of uncovering such subspaces.

I am easily interested in other topics, and am happy to talk to any potential collaborators or curious non-specialists.


Publications

Valmorbida, Giorgio; DVR; James Anderson. "Bounds for Input-and State-to-Output Properties of Uncertain Linear Systems." arXiv preprint arXiv:1505.05335 (2015). Media:VRAArXivVersion.pdf

DVR ; James Anderson; Antonis Papachristodoulou. "On the performance of nonlinear dynamical systems under parameter perturbation." Automatica 63 (2016): 265-273. Media:nonlinearDSAutomatica.pdf

DVR ; James Anderson; Antonis Papachristodoulou. "A New Approach to Estimating the Robustness of Parameter Estimates to Measurement Noise ". Proceedings of the American Control Conference 2016: 1820-1825.

DVR ; James Anderson; Antonis Papachristodoulou. "Delineating Parameter Unidentifiabilities in Complex Models." arXiv preprint arXiv:1607.07705 (2016). Media:DVRJAAPunidentifiabilityPaper.pdf

Emilie Dufresne; Heather Harrington; DVR."The Geometry of Sloppiness." arXiv preprint arXiv:1608.05679 (2016).

Talks

"Bounds for Input-and State-to-Output Properties of Uncertain Linear Systems." 8th IFAC Symposium on Robust Control Design 2015; Bratislava, Slovakia.

" Sloppiness and the Length Scale of Parameter Perturbation." Workshop on Sloppy Models in Systems Neuroscience; COSYNE 2016; Snowbird, Utah.

" A New Approach for Estimating the Robustness of Parameter Estimates to Measurement Noise" American Control Conference 2016; Boston, Massachusetts.

Essays

Undergraduate Essay in 2010 about the Banach Tarski Paradox: Media:BTEssay.pdf

MMath research project in 2011/2012 about quantification of stochastic oscillators: Media:MMathessay.pdf. It contains an amusing theorem about random walks on lattices (Thm 5.5 and Example 5.7). Unfortunately the terminology is confusing.

Relevant Teaching Experience

  • 2011-2012: 1st Year Undergraduate Supervisor; University of Warwick (Had 5 tutees. Responsibilities were giving two hourly tutorials per week and marking homeworks on Real Analysis, Vector Calculus, Linear Algebra, Differential Equations and other, minor topics)
  • 2013-2014: Lab Demonstrator, Helicopter Control Lab, Department of Engineering Science, University of Oxford.
  • 2013-present: Teaching Assistant on various courses in the Systems Biology DTC, including: Mathematical Biology, Introduction to Mathematics, Introduction to MATLAB.
  • 2015: Teaching Assistant at the Autonomous Intelligent Machines and Systems CDT on the course: 'Introduction to Modern Control'

Contact Info

  • Email: dhruva.raman@eng.ox.ac.uk
  • Department Address: Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, U.K.