Modelling legacy telecommunications switching systems for interaction analysis

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Properties of the Lindemann Mechanism in Phase Space

We study the planar and scalar reductions of the nonlinear Lindemann mechanism of unimolecular decay. First, we establish that the origin, a degenerate critical point, is globally asymptotically stable. Second, we prove there is a unique scalar solution (the slow manifold) between the horizontal and vertical isoclines. Third, we determine the concavity of all scalar solutions in the nonnegative quadrant. Fourth, we establish that each scalar solution is a centre manifold at the origin given by a Taylor series. Moreover, we develop the leading-order behaviour of all planar solutions as time tends to infinity. Finally, we determine the asymptotic behaviour of the slow manifold at infinity by showing that it is a unique centre manifold for a fixed point at infinity.Comment: 27 pages, 6 figure

An adequate logic for full LOTOS

We present a novel result for a logic for symbolic transition systems based on LOTOS processes. The logic is adequate with respect to bisimulation defined on symbolic transition systems

Analysis of Superoscillatory Wave Functions

Surprisingly, differentiable functions are able to oscillate arbitrarily faster than their highest Fourier component would suggest. The phenomenon is called superoscillation. Recently, a practical method for calculating superoscillatory functions was presented and it was shown that superoscillatory quantum mechanical wave functions should exhibit a number of counter-intuitive physical effects. Following up on this work, we here present more general methods which allow the calculation of superoscillatory wave functions with custom-designed physical properties. We give concrete examples and we prove results about the limits to superoscillatory behavior. We also give a simple and intuitive new explanation for the exponential computational cost of superoscillations.Comment: 20 pages, several figure

Investigation of geometric frustration in magnetic oxides

This thesis describes the experimental investigations of geometric frustration in magnetic oxides. The rare earth double perovskites Ba2HoSbO6 and Ba2ErSbO6 crystallise into the Fm3m cubic space group with the rare earth ions forming a face centred cubic arrangement of edge sharing tetrahedra. This arrangement is expected to result in geometric magnetic frustration. Previous studies have revealed no long range order or spin glass behaviour down to 1.5 K. In this work, low temperature neutron scattering measurements were carried out to investigate the magnetic behaviour below 1.5 K. The crystalline electric field was found to dominate the magnetic behaviour. Using experimental results from inelastic neutron scattering the crystal field level scheme was solved for Ba2HoSbO6 and Ba2ErSbO6. These results were used to successfully predict the observed behaviour of both systems, showing that they can be considered to behave as single ion systems down to the lowest temperature investigated of 0.06 K. As such exchange interactions and any effects of frustration are not evident at the temperatures investigated. As a further step to investigate frustration in magnetic oxides LuCuGaO4 was considered. This has triangular bilayers of magnetic Cu2+ and non-magnetic Ga3+ that are expected to lead to two dimensional geometric magnetic frustration of the Cu2+ ions. The presence of Ga3+ on the same lattice site as the Cu2+ lead to charge frustration. Polarised neutron analysis, inelastic neutron scattering and \muSR build up a coherent picture of the low temperature behaviour of the system which questions the previous belief in the literature of a spin glass transition. Instead what is found is a spin liquid state. Finally, the problem of interpreting the subtle features and signatures of frustration is considered with an alternative \muSR technique. \muSR allows local interactions to be investigated, however the problem of interpreting the results can lead to ambiguity. It is shown that it is possible to successfully implant muons outside the sample of interest and accurately measure the sample’s magnetic dipolar field. In this way \muSR can be used as a bulk magnetometer with the same frequency response as standard \muSR and it is shown that this can be useful in the investigation of frustrated materials with reference to results on Tb2Sn2O7

The specialist versus the non-specialist in achieving physical fitness

Thesis (Ed.M.)--Boston Universit

Pro-Poor Growth in Mozambique: An Exploration of its Income and Non-Income Dimensions

The purpose of this study is to assess the incidence of economic growth and social attainment in Mozambique during the 1990s. There is a growing international debate about the impact of growth on poverty and inequality. International development goals endorsed by the United Nations, the World Bank, and governments from around the world emphasize achieving quantitative targets across various dimensions of welfare including, but not limited to, income. Therefore, efforts at evaluating growth must go beyond aggregates and focus on the experience of the poor during the growth process. The methodology used here is based on growth incidence curves first developed by Ravallion and Chen (2003, 267) for income growth rates and extended to social welfare (e.g., education level, vaccination rates) indicators by Klasen (2005). Growth incidence curves show the incidence of growth across the population distribution. They have the benefit of describing how the gains from growth are distributed during the growth process. Using data from Mozambique’s 1997 and 2003 household living conditions surveys, a growth incidence curve is calculated for Mozambique using consumption as a welfare metric. Data limitations do not allow non-income growth incidence curves to be calculated; however, an approach combining quantile distributions and kernel regressions using education data is taken in the spirit of the non-income growth incidence curve approach. Consumption growth in Mozambique is demonstrated to have been pro-poor by some definitions but not others. The general conclusion about the growth of educational attainment is that it has been pro-poor as well