D.I. Harvey (David)
http://repub.eur.nl/ppl/14162/
List of Publicationsenhttp://repub.eur.nl/eur_signature.png
http://repub.eur.nl/
RePub, Erasmus University RepositoryObserving Dark Worlds: A crowdsourcing experiment for dark matter mapping
http://repub.eur.nl/pub/76608/
Wed, 01 Jan 2014 00:00:01 GMT<div>D.I. Harvey</div><div>P. Kitching</div><div>J. Noah-Vanhoucke</div><div>B. Hamner</div><div>T. Salimans</div><div>N.M.M. Pires</div>
We present the results and conclusions from the citizen science competition 'Observing Dark Worlds', where we asked participants to calculate the positions of dark matter halos from 120 catalogues of simulated weak lensing galaxy data, using computational methods. In partnership with Kaggle ( http://www.kaggle.com), 357 users participated in the competition which saw 2278 downloads of the data and 3358 submissions. We found that the best algorithms improved on the benchmark code, LENSTOOL by >30% and could measure the positions of >3×1014M⊙ halos to <5″ and <1014M⊙ to within 1'. In this paper, we present a brief overview of the winning algorithms with links to available code.Sample size, lag order and critical values of seasonal unit root tests
http://repub.eur.nl/pub/11124/
Tue, 20 Jun 2006 00:00:01 GMT<div>D.I. Harvey</div><div>D.J.C. van Dijk</div>
A response surface analysis for the distributions of popular tests for seasonal unit roots in quarterly observed time series variables is presented. Five test statistics are considered, along with the most commonly used specifications of the deterministic component in the test regression; allowance is also made for the lag order in the test regression to be determined endogenously, using commonly applied selection methods. Response surface coefficients are reported, permitting simple computation of accurate critical values for 1%-, 5%- and 10%-level tests and probability values for any sample size and lag order. Accurate approximations of the asymptotic distributions are obtained in the process of constructing the response surfaces. Dependence of the critical values and the probability density functions on the sample size and lag order is investigated.