14,033 research outputs found
APPLICATION OF RECURSIVE PARTITIONING TO AGRICULTURAL CREDIT SCORING
Recursive Partitioning Algorithm (RPA) is introduced as a technique for credit scoring analysis, which allows direct incorporation of misclassification costs. This study corroborates nonagricultural credit studies, which indicate that RPA outperforms logistic regression based on within-sample observations. However, validation based on more appropriate out-of-sample observations indicates that logistic regression is superior under some conditions. Incorporation of misclassification costs can influence the creditworthiness decision.finance, credit scoring, misclassification, recursive partitioning algorithm, Agricultural Finance,
Polynomiality of monotone Hurwitz numbers in higher genera
Hurwitz numbers count branched covers of the Riemann sphere with specified
ramification, or equivalently, transitive permutation factorizations in the
symmetric group with specified cycle types. Monotone Hurwitz numbers count a
restricted subset of these branched covers, related to the expansion of
complete symmetric functions in the Jucys-Murphy elements, and have arisen in
recent work on the the asymptotic expansion of the
Harish-Chandra-Itzykson-Zuber integral. In previous work we gave an explicit
formula for monotone Hurwitz numbers in genus zero. In this paper we consider
monotone Hurwitz numbers in higher genera, and prove a number of results that
are reminiscent of those for classical Hurwitz numbers. These include an
explicit formula for monotone Hurwitz numbers in genus one, and an explicit
form for the generating function in arbitrary positive genus. From the form of
the generating function we are able to prove that monotone Hurwitz numbers
exhibit a polynomiality that is reminiscent of that for the classical Hurwitz
numbers, i.e., up to a specified combinatorial factor, the monotone Hurwitz
number in genus g with ramification specified by a given partition is a
polynomial indexed by g in the parts of the partition.Comment: 23 page
Toda Equations and Piecewise Polynomiality for Mixed Double Hurwitz Numbers
This article introduces mixed double Hurwitz numbers, which interpolate
combinatorially between the classical double Hurwitz numbers studied by
Okounkov and the monotone double Hurwitz numbers introduced recently by
Goulden, Guay-Paquet and Novak. Generalizing a result of Okounkov, we prove
that a certain generating series for the mixed double Hurwitz numbers solves
the 2-Toda hierarchy of partial differential equations. We also prove that the
mixed double Hurwitz numbers are piecewise polynomial, thereby generalizing a
result of Goulden, Jackson and Vakil
Monotone Hurwitz numbers and the HCIZ integral
In this article, we prove that the complex convergence of the HCIZ free
energy is equivalent to the non-vanishing of the HCIZ integral in a
neighbourhood of . Our approach is based on a combinatorial model for the
Maclaurin coefficients of the HCIZ integral together with classical
complex-analytic techniques.Comment: 13 page
Radiative Transfer and Radiative driving of Outflows in AGN and Starbursts
To facilitate the study of black hole fueling, star formation, and feedback
in galaxies, we outline a method for treating the radial forces on interstellar
gas due to absorption of photons by dust grains. The method gives the correct
behavior in all of the relevant limits (dominated by the central point source;
dominated by the distributed isotropic source; optically thin; optically thick
to UV/optical; optically thick to IR) and reasonably interpolates between the
limits when necessary. The method is explicitly energy conserving so that
UV/optical photons that are absorbed are not lost, but are rather redistributed
to the IR where they may scatter out of the galaxy. We implement the radiative
transfer algorithm in a two-dimensional hydrodynamical code designed to study
feedback processes in the context of early-type galaxies. We find that the
dynamics and final state of simulations are measurably but only moderately
affected by radiative forces on dust, even when assumptions about the
dust-to-gas ratio are varied from zero to a value appropriate for the Milky
Way. In simulations with high gas densities designed to mimic ULIRGs with a
star formation rate of several hundred solar masses per year, dust makes a more
substantial contribution to the dynamics and outcome of the simulation. We find
that, despite the large opacity of dust to UV radiation, the momentum input to
the flow from radiation very rarely exceeds L/c due to two factors: the low
opacity of dust to the re-radiated IR and the tendency for dust to be destroyed
by sputtering in hot gas environments. We also develop a simplification of our
radiative transfer algorithm that respects the essential physics but is much
easier to implement and requires a fraction of the computational cost.Comment: 25 pages, 17 figures, submitted to MNRA
Palestine: The communist position, the colonial question
https://stars.library.ucf.edu/prism/1845/thumbnail.jp
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