Browsing by Subject "methods: statistical"

Now showing 1 - 4 of 4
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    A new approach to the optimal target selection problem
    (2007) Elson, E C; Bassett, B A; van der Heyden, K; Vilakazi, Z Z
    Context.This paper addresses a common problem in astronomy and cosmology: to optimally select a subset of targets from a larger catalog. A specific example is the selection of targets from an imaging survey for multi-object spectrographic follow-up.Aims.We present a new heuristic optimisation algorithm, HYBRID, for this purpose and undertake detailed studies of its performance.Methods.HYBRID combines elements of the simulated annealing, MCMC and particle-swarm methods and is particularly successful in cases where the survey landscape has multiple curvature or clustering scales.Results.HYBRID consistently outperforms the other methods, especially in high-dimensionality spaces with many extrema. This means many fewer simulations must be run to reach a given performance confidence level and implies very significant advantages in solving complex or computationally expensive optimisation problems.Conclusions.HYBRID outperforms both MCMC and SA in all cases including optimisation of high dimensional continuous surfaces indicating that HYBRID is useful far beyond the specific problem of optimal target selection. Future work will apply HYBRID to target selection for the new 10 m Southern African Large Telescope in South Africa.
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    Open Access
    Generalized Fisher matrices
    (2014) Heavens, A F; Seikel, M; Nord, B D; Aich, M; Bouffanais, Y; Bassett, B A; Hobson, M P
    16.04.15 KB Ok to add accepted version to spiral
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    Open Access
    Statistical properties of dwarf novae-type cataclysmic variables: the outburst catalogue
    (2016) Coppejans, Deanne L; Körding, Elmar G; Knigge, Christian; Pretorius, Magaretha L; Woudt, Patrick A; Groot, Paul J; Van Eck, Cameron L; Drake, Andrew J
    The Outburst Catalogue contains a wide variety of observational properties for 722 dwarf nova-type (DN) cataclysmic variables (CVs) and 309 CVs of other types from the Catalina Real-time Transient Survey. In particular, it includes the apparent outburst and quiescent V-band magnitudes, duty cycles, limits on the recurrence time, upper- and lower-limits on the distance and absolute quiescent magnitudes, colour information, orbital parameters, and X-ray counterparts. These properties were determined by means of a classification script presented in this paper. The DN in the catalogue show a correlation between the outburst duty cycle and the orbital period (and outburst recurrence time), as well as between the quiescent absolute magnitude and the orbital period (and duty cycle). This is the largest sample of dwarf nova properties collected to date. Besides serving as a useful reference for individual systems and a means of selecting objects for targeted studies, it will prove valuable for statistical studies that aim to shed light on the formation and evolution of cataclysmic variables.
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    Open Access
    Towards automatic classification of all WISE sources
    (2016) Kurcz, A; Bilicki, M; Solarz, A; Krupa, M; Pollo, A; Małek, K
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