387 research outputs found
A Scheme to Numerically Evolve Data for the Conformal Einstein Equation
This is the second paper in a series describing a numerical implementation of
the conformal Einstein equation. This paper deals with the technical details of
the numerical code used to perform numerical time evolutions from a "minimal"
set of data.
We outline the numerical construction of a complete set of data for our
equations from a minimal set of data. The second and the fourth order
discretisations, which are used for the construction of the complete data set
and for the numerical integration of the time evolution equations, are
described and their efficiencies are compared. By using the fourth order scheme
we reduce our computer resource requirements --- with respect to memory as well
as computation time --- by at least two orders of magnitude as compared to the
second order scheme.Comment: 20 pages, 12 figure
Proceedings of the Fifth Workshop on Information Theoretic Methods in Science and Engineering
These are the online proceedings of the Fifth Workshop on Information Theoretic Methods in Science and Engineering (WITMSE), which was held in the Trippenhuis, Amsterdam, in August 2012
Recent advances in directional statistics
Mainstream statistical methodology is generally applicable to data observed
in Euclidean space. There are, however, numerous contexts of considerable
scientific interest in which the natural supports for the data under
consideration are Riemannian manifolds like the unit circle, torus, sphere and
their extensions. Typically, such data can be represented using one or more
directions, and directional statistics is the branch of statistics that deals
with their analysis. In this paper we provide a review of the many recent
developments in the field since the publication of Mardia and Jupp (1999),
still the most comprehensive text on directional statistics. Many of those
developments have been stimulated by interesting applications in fields as
diverse as astronomy, medicine, genetics, neurology, aeronautics, acoustics,
image analysis, text mining, environmetrics, and machine learning. We begin by
considering developments for the exploratory analysis of directional data
before progressing to distributional models, general approaches to inference,
hypothesis testing, regression, nonparametric curve estimation, methods for
dimension reduction, classification and clustering, and the modelling of time
series, spatial and spatio-temporal data. An overview of currently available
software for analysing directional data is also provided, and potential future
developments discussed.Comment: 61 page
Numerical modelling techniques for fretting fatigue crack initiation and propagation
status: publishe
Prediction of patient-rated radiation-induced xerostomia
Een onderdeel van de behandeling van patiënten met tumoren in het hoofdhalsgebied omvat meestal radiotherapie. Bij bestraling in het hoofdhalsgebied worden delen van de speekselklieren meebestraald. Een van de meest voorkomende bijwerkingen na curatieve bestraling voor hoofdhalstumoren is daarom ook de verminderde productie van speeksel door de speekselklieren. Verminderde productie van speeksel kan leiden tot klachten van droge mond, veranderde smaak, slik- en spraakproblemen en is van invloed op de kwaliteit van leven. Het hoofddoel van dit promotieonderzoek was het ontwikkelen en valideren van multivariate predictie modellen voor verschillende aspecten van patiëntgescoorde drogemond klachten na behandeling met radiotherapie. In de analyses werden zowel de dosisverdelingen in verschillende speekselklieren als andere klinische factoren meegnomen. Uit dit proefschrift kunnen we concluderen dat verminderde speekselproductie, resulterende in matig tot ernstige patiëntgescoorde xerostomie en plakkerig speeksel, nog een frequent voorkomende bijwerking is bij patiënten die curatief behandeld zijn met (chemo)radiatie voor hoofd-halskanker. Het risico op klachten van patiëntgescoorde xerostomie en plakkerig speeksel hangt van verschillende factoren af. De bevindingen in dit proefschrift bieden mogelijke aanknopingspunten om groepen patiënten te selecteren die voordeel zouden kunnen hebben van behandelingen met nieuwe bestralingstechnieken, zoals een behandeling met protonen
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