3,347 research outputs found
Inflated Beta Distributions
This paper considers the issue of modeling fractional data observed in the
interval [0,1), (0,1] or [0,1]. Mixed continuous-discrete distributions are
proposed. The beta distribution is used to describe the continuous component of
the model since its density can have quite diferent shapes depending on the
values of the two parameters that index the distribution. Properties of the
proposed distributions are examined. Also, maximum likelihood and method of
moments estimation is discussed. Finally, practical applications that employ
real data are presented.Comment: 15 pages, 4 figures. Submitted to Statistical Paper
A bajocian (Middle jurassic) marine gastropod assemblage from the badamu formation, Central Iran
Nine species of gastropods are reported from the Bajocian (Middle Jurassic) part of the Badamu Formation of Central Iran. This is the first report of a gastropod assemblage of this age from the shelves of the Kimmerian Continent. Seven species belong to the Vetigastropoda and two to the Caenogastropoda. Two new species, the pleurotomariid Bathrotomaria iranica sp. nov. and the eucyclid Eucycloidea badamuensis sp. nov., are described. The remaining species are left in open nomenclature owing to poor preservation. The composition of the gastropod association is strongly reminiscent of other Tethyan gastropod faunas, in particular those from the southern shores of the Tethys (India and Arabia) and from southern Europe. This indicates a relatively uniform distribution of gastropod faunas along the Middle Jurassic shores of the western Tethys.Fil: Ferrari, Silvia Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología.; ArgentinaFil: Binazadeh, Tayyeb. Shahid Bahonar University; IránFil: Kaim, Andrzej. Institute of Paleobiology, Polish Academy of Sciences; Poloni
Local power of the LR, Wald, score and gradient tests in dispersion models
We derive asymptotic expansions up to order for the nonnull
distribution functions of the likelihood ratio, Wald, score and gradient test
statistics in the class of dispersion models, under a sequence of Pitman
alternatives. The asymptotic distributions of these statistics are obtained for
testing a subset of regression parameters and for testing the precision
parameter. Based on these nonnull asymptotic expansions it is shown that there
is no uniform superiority of one test with respect to the others for testing a
subset of regression parameters. Furthermore, in order to compare the
finite-sample performance of these tests in this class of models, Monte Carlo
simulations are presented. An empirical application to a real data set is
considered for illustrative purposes.Comment: Submitted for publicatio
Random Finite Set Theory and Optimal Control of Large Collaborative Swarms
Controlling large swarms of robotic agents has many challenges including, but
not limited to, computational complexity due to the number of agents,
uncertainty in the functionality of each agent in the swarm, and uncertainty in
the swarm's configuration. This work generalizes the swarm state using Random
Finite Set (RFS) theory and solves the control problem using Model Predictive
Control (MPC) to overcome the aforementioned challenges. Computationally
efficient solutions are obtained via the Iterative Linear Quadratic Regulator
(ILQR). Information divergence is used to define the distance between the swarm
RFS and the desired swarm configuration. Then, a stochastic optimal control
problem is formulated using a modified L2^2 distance. Simulation results using
MPC and ILQR show that swarm intensities converge to a target destination, and
the RFS control formulation can vary in the number of target destinations. ILQR
also provides a more computationally efficient solution to the RFS swarm
problem when compared to the MPC solution. Lastly, the RFS control solution is
applied to a spacecraft relative motion problem showing the viability for this
real-world scenario.Comment: arXiv admin note: text overlap with arXiv:1801.0731
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