202,029 research outputs found
New Liu Estimators for the Poisson Regression Model: Method and Application
A new shrinkage estimator for the Poisson model is introduced in this paper. This method is a generalization of the Liu (1993) estimator originally developed for the linear regression model and will be generalised here to be used instead of the classical maximum likelihood (ML) method in the presence of multicollinearity since the mean squared error (MSE) of ML becomes inflated in that situation. Furthermore, this paper derives the optimal value of the shrinkage parameter and based on this value some methods of how the shrinkage parameter should be estimated are suggested. Using Monte Carlo simulation where the MSE and mean absolute error (MAE) are calculated it is shown that when the Liu estimator is applied with these proposed estimators of the shrinkage parameter it always outperforms the ML. Finally, an empirical application has been considered to illustrate the usefulness of the new Liu estimators.Estimation; MSE; MAE; Multicollinearity; Poisson; Liu; Simulation
Lydia H. Liu. Translingual practice : literature, national culture, and translated modernity : China, 1900-1937
This article reviews the book Translingual Practice: Literature, National Culture, and Translated Modernity—China, 1900-1937 , written by Lydia H. Liu
Laplacian spectral characterization of some graph products
This paper studies the Laplacian spectral characterization of some graph
products. We consider a class of connected graphs: , and characterize all graphs such that the
products are -DS graphs. The main result of this paper states
that, if , except for and , is -DS
graph, so is the product . In addition, the -cospectral
graphs with and have been
found.Comment: 19 pages, we showed that several types of graph product are
determined by their Laplacian spectr
Extending the range of the inductionless magnetorotational instability
The magnetorotational instability (MRI) can destabilize hydrodynamically
stable rotational flows, thereby allowing angular momentum transport in
accretion disks. A notorious problem for MRI is its questionable applicability
in regions with low magnetic Prandtl number, as they are typical for
protoplanetary disks and the outer parts of accretion disks around black holes.
Using the WKB method, we extend the range of applicability of MRI by showing
that the inductionless versions of MRI, such as the helical MRI and the
azimuthal MRI, can easily destabilize Keplerian profiles ~ 1/r^(3/2) if the
radial profile of the azimuthal magnetic field is only slightly modified from
the current-free profile ~ 1/r. This way we further show how the formerly known
lower Liu limit of the critical Rossby number, Ro=-0.828, connects naturally
with the upper Liu limit, Ro=+4.828.Comment: Growth rates added, references modified; submitted to Physical Review
Letter
75. FEIRA DO LIVRO DE LISBOA
Lisbon Book Fair, Portugal [built] Design team: marcosandmarjan. Collaboration: João Albuquerque, Shui Liu Construction: Contubos Engineering: A400 Programme: General layout of Book Fair, Cafeteria, Auditorium, Outside Esplanade, Information Pavilion Planning 3 months Construction 4 weeks Construction costs (architecture, general layout) 500000 Euros Structure: scaffolding structure behind painted and laser-cut MDF, metalsheets, glass Total construction area 1000 m2 Total layout area 60000 m
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