UK Nonlinear News,

PhD Studentships

Statistics of optical digital signal in nonlinear fibre channels

Aston University

Applications with strong mathematical background are invited for a three year PhD Mathematics Industrial CASE studentship, supported by the Engineering and Physical Sciences Research Council (EPSRC), to be undertaken within the Photonics Research Group at Aston University. The position is available to start in October 2004 (a specific date can be negotiated).

Background of the project

The development of high-bit-rate optical fibre communication links is one of the major recent global technological achievements. Optical fibres have fuelled the growth of the Internet increasing demand for new telecommunication technologies and advanced information services. The information-rate of modern fibre systems is limited by a combination of amplifier noise, fibre loss, dispersion and optical nonlinearity. Noisy communication links need special solutions, primarily Forward Error Correction (FEC) to clean up noise/errors in the information bitstream. Because of the enhanced levels of performance required in modern lightwave systems, traditional analytical or computational methods are not sufficient to accurately model the rare events that determine the overall performance of complex communication systems. For instance, in the fibre transmission lines the error can occur when a pulse (corresponding to elementary ``one'') will arrive outside the detection window. Such rare events given by the tails of the probability distribution, nevertheless, can be of importance for modern fibre transmission lines operating at very low bit-error-rates. Therefore, an accurate statistical analysis of the tails of the probability distributions in non-linear fibre channels is both of a fundamental interest and of a practical importance.

The aim of the proposed theoretical project is to develop novel mathematical/statistical methods and numerical techniques capable to describe the statistics of the rare fluctuations, which lead to errors in the digital nonlinear lightwave communication systems. The methods that will be developed as part of this project are expected to provide the basis for computational tools that can yield large reductions in the time required to determine the performance of fibre communication systems. The proposed research will also explore the relationship between coding theory, information theory and optical fibre signal transmission.

Person Specification

The successful applicant should have a good honours degree in statistical mathematics, mathematics, theoretical physics, or an appropriate allied discipline and should fulfill the eligibility criteria for EPSRC funding through UK nationality and/or residency status (See

The successful applicant will join an established theory and modelling group (more information and recent publications can be found at working on practical and theoretical problems of high-speed optical fibre communications. Relevant experience in statistics, Mote-Carlo simulations, forward-error-correction, numerical modelling and computation will be advantageous.

The financial support will be provided by the standard EPSRC stipend (£10.500 for 2004/2005 with corresponding standard EPSRC increase) plus an additional £2000 per year from the industrial partner. For informal enquiries, contact Dr Sergei Turitsyn by e-mail: .

Method of Application

A curriculum vitae, including the names and addresses of two academic referees, should be submitted to:
Dr S K Turitsyn
School of Engineering and Applied Science
Aston University
Aston Triangle
Birmingham B4 7ET
fax: (0121) 359 0156

The post is open for applications in 2004.

Source S.K. Turitsyn.

The Earth's Dynamo: Dynamics of Reversals and Excursions

University of Leeds

The Earth's magnetic field is generated by dynamo action in the liquid iron core. The dynamo is powered by convection, a process that has continued for most of geological time, leaving a magnetic record several billion years long. The geomagnetic field is chaotic and complex in both time and space, and undergoes apparently random reversals in polarity, along with more frequent events called excursions, which appear to be aborted reversals. A basic symmetry makes the dynamo equations independent of the sign of the magnetic field, and some understanding of polarity reversals comes from this basic symmetry. The overall dipolar structure of the geomagnetic field is clearly controlled by rotational forces, reflecting another basic symmetry: reflection in the equatorial plane.

The aim of this project is to combine knowledge gained from analysing simplified nonlinear models of the geodynamo process with data from large-scale numerical simulations and the paleomagnetic record. The simplified models sacrifice the detailed spatial structure of the Earth's magnetic field, simplifying the physics sufficiently that the time dependence of the model can be followed over thousands of reversal events. The predictions of the model will then be compared with highly resolved numerical models of the geodynamo, and with real data, which could lead to a powerful understanding of the evolution of the Earth's magnetic field.

The primary supervisor would be Dr A.M. Rucklidge in the Department of Applied Mathematics, University of Leeds, with co-supervisors Dr A. Jackson and Professor D. Gubbins, in the School of Earth Sciences, University of Leeds.

Support for this project comes from the Environmental Mathematics and Statistics programme of the Natural Environment Research Council (NERC).

Please contact Dr A.M. Rucklidge if you would like further information on potential PhD projects, or go to the Departmental web page for details on how to apply for admission.

Source: Dr A.M. Rucklidge

Emergent Collective Behaviour in Ensembles of Communicating Agents

University of Paisley

Research (PhD) studentship to work on Emergent Collective Behaviour in Ensembles of Communicating Agents is available in School of Computing of the University of Paisley. The approach is based on consideration of an agent ensemble as dynamical system and studying the latter with the methods of nonlinear dynamics and statistical physics. Knowledge of basic nonlinear dynamics and good computational skill are essential. Experience in and knowledge of statistical physics, chaos theory, neural and biologically-inspired computations, and swarm intelligence are desirable.

Contact: Valery Tereshko, School of Computing, University of Paisley, Paisley PA1 2BE. e-mail:

Source: Valery Tereshko.

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Page Created: 31 May 2004.
Last Updated: 18 June 2004.