Critical phenomena in globally coupled excitable elements

Critical phenomena in globally coupled excitable elements are studied by focusing on a saddle-node bifurcation at the collective level. Critical exponents that characterize divergent fluctuations of interspike intervals near the bifurcation are calculated theoretically. The calculated values appear to be in good agreement with those determined by numerical experiments. The relevance of our results to jamming transitions is also mentioned.Comment: 4 pages, 3 figure

OER Evidence Report 2013-2014

The Open Educational Resources Research Hub (OER Research Hub) provides a focus for research, designed to give answers to the overall question ‘What is the impact of OER on learning and teaching practices?’ and identify the particular influence of openness. We do this by working in collaboration with projects across four education sectors (K12, college, higher education and informal) extending a network of research with shared methods and shared results. The project combines: – Targeted research collaboration with high profile OER projects – A programme of international fellowship – Global networking and expertise in OER implementation and evaluation – A hub for research data and excellence in practice This report is an interim review of evidence recorded against the key hypotheses that focus the research of the OER Research Hub project

Transparent and Flexible Thin Film Electroluminescent Devices Using HiTUS Deposition and Laser Processing Fabrication

Highly transparent thin film electroluminescent structures offering excellent switch on characteristics, high luminance and large break-down voltages have been deposited onto glass and flexible polymeric materials with no substrate heating using high target utilization sputtering. Deposition of ZnS:Mn as the active light emitting layer and Y2O3,Al2O3,Ta2O5, and HfO2 as dielectric materials arranged in single and multiple layer configurations were investigated. Devices incorporating Al2O3,HfO2 quadruple layers demonstrate the highest attainable luminance at low threshold voltage. Single pulse excimer laser irradiation of the phosphor layer prior to deposition of the top dielectric layer enhanced the luminance of the devices. The devices fabricated on glass and polymeric substrates exhibited a maximum luminance of 500 and 450 cdm−2 when driven at 270 VRMS and 220 VRMS, respectively, with a 1.0 kHz sine wave

Evaluation of elicitation methods to quantify Bayes linear models

The Bayes linear methodology allows decision makers to express their subjective beliefs and adjust these beliefs as observations are made. It is similar in spirit to probabilistic Bayesian approaches, but differs as it uses expectation as its primitive. While substantial work has been carried out in Bayes linear analysis, both in terms of theory development and application, there is little published material on the elicitation of structured expert judgement to quantify models. This paper investigates different methods that could be used by analysts when creating an elicitation process. The theoretical underpinnings of the elicitation methods developed are explored and an evaluation of their use is presented. This work was motivated by, and is a precursor to, an industrial application of Bayes linear modelling of the reliability of defence systems. An illustrative example demonstrates how the methods can be used in practice

Bayes linear kinematics in the analysis of failure rates and failure time distributions

Collections of related Poisson or binomial counts arise, for example, from a number of different failures in similar machines or neighbouring time periods. A conventional Bayesian analysis requires a rather indirect prior specification and intensive numerical methods for posterior evaluations. An alternative approach using Bayes linear kinematics in which simple conjugate specifications for individual counts are linked through a Bayes linear belief structure is presented. Intensive numerical methods are not required. The use of transformations of the binomial and Poisson parameters is proposed. The approach is illustrated in two examples, one involving a Poisson count of failures, the other involving a binomial count in an analysis of failure times

Dynamics of bootstrap percolation

Bootstrap percolation transition may be first order or second order, or it may have a mixed character where a first order drop in the order parameter is preceded by critical fluctuations. Recent studies have indicated that the mixed transition is characterized by power law avalanches, while the continuous transition is characterized by truncated avalanches in a related sequential bootstrap process. We explain this behavior on the basis of a through analytical and numerical study of the avalanche distributions on a Bethe lattice.Comment: Proceedings of the International Workshop and Conference on Statistical Physics Approaches to Multidisciplinary Problems, IIT Guwahati, India, 7-13 January 200