TIME DOMAIN REFLECTOMETER IRREGULARITIES IN OPTICAL FIBRES

The aim of this thesis is not to present any new information but to critically review work carried out on optical fibre measurements with a particular interest in irregularities or perturbations present using the backscatter technique by Optical Time Domain Reflectometry. Optical fibre structure, principles of operation and manufacture are examined as are the principles and practicalities of the various characterising optical fibre measurements. An in-depth review of the most pertinent of the references considered is also included. Finally the practical work undertaken is described and conclusions presented

Old and New Fields on Super Riemann Surfaces

The ``new fields" or ``superconformal functions" on $N=1$ super Riemann surfaces introduced recently by Rogers and Langer are shown to coincide with the Abelian differentials (plus constants), viewed as a subset of the functions on the associated $N=2$ super Riemann surface. We confirm that, as originally defined, they do not form a super vector space.Comment: 9 pages, LaTex. Published version: minor changes for clarity, two new reference

Gauge fixing and equivariant cohomology

The supersymmetric model developed by Witten to study the equivariant cohomology of a manifold with an isometric circle action is derived from the BRST quantization of a simple classical model. The gauge-fixing process is carefully analysed, and demonstrates that different choices of gauge-fixing fermion can lead to different quantum theories.Comment: 18 pages LaTe

Constrained optimal control theory for differential linear repetitive processes

Differential repetitive processes are a distinct class of continuous-discrete two-dimensional linear systems of both systems theoretic and applications interest. These processes complete a series of sweeps termed passes through a set of dynamics defined over a finite duration known as the pass length, and once the end is reached the process is reset to its starting position before the next pass begins. Moreover the output or pass profile produced on each pass explicitly contributes to the dynamics of the next one. Applications areas include iterative learning control and iterative solution algorithms, for classes of dynamic nonlinear optimal control problems based on the maximum principle, and the modeling of numerous industrial processes such as metal rolling, long-wall cutting, etc. In this paper we develop substantial new results on optimal control of these processes in the presence of constraints where the cost function and constraints are motivated by practical application of iterative learning control to robotic manipulators and other electromechanical systems. The analysis is based on generalizing the well-known maximum and $\epsilon$-maximum principles to the

The geometry of reaction norms yields insights on classical fitness functions for Great Lakes salmon.

Life history theory examines how characteristics of organisms, such as age and size at maturity, may vary through natural selection as evolutionary responses that optimize fitness. Here we ask how predictions of age and size at maturity differ for the three classical fitness functions-intrinsic rate of natural increase r, net reproductive rate R0, and reproductive value Vx-for semelparous species. We show that different choices of fitness functions can lead to very different predictions of species behavior. In one's efforts to understand an organism's behavior and to develop effective conservation and management policies, the choice of fitness function matters. The central ingredient of our approach is the maturation reaction norm (MRN), which describes how optimal age and size at maturation vary with growth rate or mortality rate. We develop a practical geometric construction of MRNs that allows us to include different growth functions (linear growth and nonlinear von Bertalanffy growth in length) and develop two-dimensional MRNs useful for quantifying growth-mortality trade-offs. We relate our approach to Beverton-Holt life history invariants and to the Stearns-Koella categorization of MRNs. We conclude with a detailed discussion of life history parameters for Great Lakes Chinook Salmon and demonstrate that age and size at maturity are consistent with predictions using R0 (but not r or Vx) as the underlying fitness function

Building a future...An exploration of the contribution of educational provision to clients’ well-being at Southwark Day Centre for Asylum Seekers

This research project builds on previous work, ‘Beneath the Surface’ (Cogo, Inman, McCormack, Rogers 2018) which focussed on how clients at Southwark Day Centre for Asylum Seekers (SDCAS) understood and evaluated their well-being. One of the areas touched on in that research was the role of educational activities in developing the well-being of clients. This report describes in depth the ways in which the educational provision offered in the centre contributes to the well-being of clients and how this contribution might be enhanced. The report focuses on two areas of education provision; gardening and storytelling and explains how they contribute to the well-being of the clients. The interview data confirms that the activities in these two areas help to build clients’ psychological, physical and social resources and have a positive effect on how clients feel and how they function in the world. The report ends with recommendations as to how SDCAS might ensure that gardening and storytelling continue to benefit the well-being of clients and also as to what might be put in place to strengthen the activities

Stories from lockdown: the impact of the Covid19 pandemic on the well-being of clients at Southwark Day Centre for Asylum Seekers (SDCAS)

The report describes the findings of research on how the Covid 19 related lockdowns affected the well-being of clients at the Southwark Day Centre for Asylum Seekers. A small number of clients were interviewed about the practical issues of housing, food, money and about their physical and mental health during the periods of lockdowns. They were also asked about support from the Southwark Day Centre for Asylum Seekers. The report describes the experiences of these clients between March 2020 and March 202