49,822 research outputs found
The CHIME graduate programme in health informatics
In 1999 University College London inaugurated a programme of graduate part-time Health Informatics courses to support the UK National Health Service?s Information for Health strategy. The programme has attracted students from across the UK and abroad, with a diverse range of backgrounds and skills and has proved a challenging and rewarding experience for students and tutors alike. The modular programme aims to provide a thorough grounding in the theory and practice of Health Informatics and addresses important application areas. The guiding principle is that Health Informatics graduates need to understand computers and programming but that, since the majority are not going to become programmers, programming methods should not dominate the curriculum.In the taught phase of the programme students attend college for 3 days a month and complete an assignment each month, based on home study. Students may graduate with a certificate or diploma, or go on to tackle a dissertation leading to an MSc. Research projects have included a patient record system based on speech input, a mathematical model for illustrating to patients the risks associated with smoking, an analysis of Trust staff's preparedness for Information for Health and a patient information leaflet giving advice about drug related information on the Web. As we move towards our fifth intake of students, we are in the process of evaluating our programme and carrying out a follow up study of our graduates? subsequent career pathways
Modelling of two-component turbulent mass and heat transfer in air-fed pressurised suits
This article has been accepted for publication in the Flow, Turbulence and Combustion journal.In this paper the modelling of an important industrial problem is addressed, which involves the two-component turbulent flow with heat transfer that takes place inside protective clothing. The geometry of the flow boundaries is reconstructed in a CAD system from photogrammetry scan data. The overall model is sufficiently realistic to allow, after validation, design improvements to be tested. Those presented here allow the reduction of hot spots over the worker’s body surface and increase thermal comfort.This project is funded by the Engineering and Physical Sciences Research Council and the UK Atomic Energy Authority
Heat and mass transfer in air-fed pressurised suits
Air-fed pressurised suits are used to protect workers against contamination and hazardous environments. The specic application here is the necessity for regular clean-up maintenance within the torus chamber of fusion reactors. The current design of suiting has been developed empirically. It is, therefore, very desirable to formulate a thermofluids model, which will be able to define optimum designs and operating parameters. Two factors indicate that the modelling should be as comprehensive as possible. Firstly, the overall thermofluids problem is three-dimensional and includes mass as well as heat transfer. The fluid field is complex, bounded on one side by the human body and on the other by what may be distensible, porous and multi-layer clothing.
In this paper, we report firstly the modelling necessary for the additional mass and heat transport processes. This involves the use of Fick's and Fourier's laws and conjugate heat transfer. The results of an initial validation study are presented. Temperatures at the outlet of the suits were obtained experimentally and compared with those predicted by the overall CFD model. Realistic three-dimensional geometries were used for the suit and human body. Calculations were for turbulent flow with single- and two-component (species) models
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A thermo-fluid model for protective suiting used in fusion reactor shutdown operations
In this paper we report a method of modelling the overall thermo-fluid processes which occur in protective suiting as used in the Joint European Torus (JET) fusion reactor at Culham, UK. It had three main objectives: to be as basic and
comprehensive as possible, to have an ability to model real situations and suiting, and hence to provide a tool for improvements in design. Basic thermo-fluids equations for multi-component and multi-phase flow have been developed within commercial Computational Fluid Dynamics (CFD) software to address the heat and mass (moisture) transfer processes. This is combined with a human metabolic heat load model to simulate working operations. Finally, a particular feature is the
definition of the 3-D human body/suit microclimate, via the use of an unsuited and suited mannequin. This involved a geometrical reconstruction method developed from the point cloud data given by photogrammetry. Examples of predicted temperature distributions are compared with experimental data to show the potential of the model we have used
Block CUR: Decomposing Matrices using Groups of Columns
A common problem in large-scale data analysis is to approximate a matrix
using a combination of specifically sampled rows and columns, known as CUR
decomposition. Unfortunately, in many real-world environments, the ability to
sample specific individual rows or columns of the matrix is limited by either
system constraints or cost. In this paper, we consider matrix approximation by
sampling predefined \emph{blocks} of columns (or rows) from the matrix. We
present an algorithm for sampling useful column blocks and provide novel
guarantees for the quality of the approximation. This algorithm has application
in problems as diverse as biometric data analysis to distributed computing. We
demonstrate the effectiveness of the proposed algorithms for computing the
Block CUR decomposition of large matrices in a distributed setting with
multiple nodes in a compute cluster, where such blocks correspond to columns
(or rows) of the matrix stored on the same node, which can be retrieved with
much less overhead than retrieving individual columns stored across different
nodes. In the biometric setting, the rows correspond to different users and
columns correspond to users' biometric reaction to external stimuli, {\em
e.g.,}~watching video content, at a particular time instant. There is
significant cost in acquiring each user's reaction to lengthy content so we
sample a few important scenes to approximate the biometric response. An
individual time sample in this use case cannot be queried in isolation due to
the lack of context that caused that biometric reaction. Instead, collections
of time segments ({\em i.e.,} blocks) must be presented to the user. The
practical application of these algorithms is shown via experimental results
using real-world user biometric data from a content testing environment.Comment: shorter version to appear in ECML-PKDD 201
The futures of transformations and metamaterials
AbstractThose researchers who are part of the metamaterials community stand at a fork in the road – does the maturation of metamaterial fabrication lead to a focus on applications and technology, or does it suggest an opportunity to pursue more blue-sky scientific concepts? At Metamaterials 2013 in Bordeuax, one speaker focussed explicitly on the opportunities for applications and funding on the road leading to metamaterial technology. Here, in deliberate contrast, we look instead at the interesting opportunities in curiosity-led research based around the ideas of transformation and metamaterials. The genesis of this article was the Transforming Transformation Optics meeting held at Imperial College London in December 2013
Antonio Gramsci’s impact on critical pedagogy
This paper provides an account of Antonio Gramsci’s impact on the area of critical pedagogy. It indicates the Gramscian influence on the thinking of major exponents of the field. It foregrounds Gramsci's ideas and then indicates how they have been taken up by a selection of critical pedagogy exponents who were chosen on the strength of their identification and engagement with Gramsci's ideas, some of them even having written entire essays on Gramsci. The essay concludes with a discussion concerning an aspect of Gramsci's concerns, the question of powerful knowledge, which, in the present author's view, provides a formidable challenge to critical pedagogues.peer-reviewe
Direct Observation of the Superfluid Phase Transition in Ultracold Fermi Gases
Water freezes into ice, atomic spins spontaneously align in a magnet, liquid
helium becomes superfluid: Phase transitions are dramatic phenomena. However,
despite the drastic change in the system's behaviour, observing the transition
can sometimes be subtle. The hallmark of Bose-Einstein condensation (BEC) and
superfluidity in trapped, weakly interacting Bose gases is the sudden
appearance of a dense central core inside a thermal cloud. In strongly
interacting gases, such as the recently observed fermionic superfluids, this
clear separation between the superfluid and the normal parts of the cloud is no
longer given. Condensates of fermion pairs could be detected only using
magnetic field sweeps into the weakly interacting regime. The quantitative
description of these sweeps presents a major theoretical challenge. Here we
demonstrate that the superfluid phase transition can be directly observed by
sudden changes in the shape of the clouds, in complete analogy to the case of
weakly interacting Bose gases. By preparing unequal mixtures of the two spin
components involved in the pairing, we greatly enhance the contrast between the
superfluid core and the normal component. Furthermore, the non-interacting
wings of excess atoms serve as a direct and reliable thermometer. Even in the
normal state, strong interactions significantly deform the density profile of
the majority spin component. We show that it is these interactions which drive
the normal-to-superfluid transition at the critical population imbalance of
70(5)%.Comment: 16 pages (incl. Supplemental Material), 5 figure
Extraction of Airways with Probabilistic State-space Models and Bayesian Smoothing
Segmenting tree structures is common in several image processing
applications. In medical image analysis, reliable segmentations of airways,
vessels, neurons and other tree structures can enable important clinical
applications. We present a framework for tracking tree structures comprising of
elongated branches using probabilistic state-space models and Bayesian
smoothing. Unlike most existing methods that proceed with sequential tracking
of branches, we present an exploratory method, that is less sensitive to local
anomalies in the data due to acquisition noise and/or interfering structures.
The evolution of individual branches is modelled using a process model and the
observed data is incorporated into the update step of the Bayesian smoother
using a measurement model that is based on a multi-scale blob detector.
Bayesian smoothing is performed using the RTS (Rauch-Tung-Striebel) smoother,
which provides Gaussian density estimates of branch states at each tracking
step. We select likely branch seed points automatically based on the response
of the blob detection and track from all such seed points using the RTS
smoother. We use covariance of the marginal posterior density estimated for
each branch to discriminate false positive and true positive branches. The
method is evaluated on 3D chest CT scans to track airways. We show that the
presented method results in additional branches compared to a baseline method
based on region growing on probability images.Comment: 10 pages. Pre-print of the paper accepted at Workshop on Graphs in
Biomedical Image Analysis. MICCAI 2017. Quebec Cit
Finite temperature phase diagram of a polarised Fermi condensate
The two-component Fermi gas is the simplest fermion system displaying
superfluidity, and as such finds applications ranging from the theory of
superconductivity to QCD. Ultracold atomic gases provide an exceptionally clean
realization of this system, where the interatomic interaction and the atom
species population are both independent, tuneable parameters. This allows one
to investigate the Fermi gas with imbalanced spin populations, which had
previously been experimentally elusive, and this prospect has stimulated much
theoretical activity. Here we show that the finite temperature phase diagram
contains a region of phase separation between the superfluid and normal states
that touches the boundary of second-order superfluid transitions at a
tricritical point, reminiscent of the phase diagram of He-He mixtures.
A variation of interaction strength then results in a line of tricritical
points that terminates at zero temperature on the molecular Bose-Einstein
condensate (BEC) side. On this basis, we argue that tricritical points will
play an important role in the recent experiments on polarised atomic Fermi
gases.Comment: 6 pages, 4 figures. Manuscript extended and figures modified. For
final version, see Nature Physic
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