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Studentized U-quantile processes under dependence with applications to change-point analysis
Many popular robust estimators are -quantiles, most notably the
Hodges-Lehmann location estimator and the scale estimator. We prove a
functional central limit theorem for the sequential -quantile process
without any moment assumptions and under weak short-range dependence
conditions. We further devise an estimator for the long-run variance and show
its consistency, from which the convergence of the studentized version of the
sequential -quantile process to a standard Brownian motion follows. This
result can be used to construct CUSUM-type change-point tests based on
-quantiles, which do not rely on bootstrapping procedures. We demonstrate
this approach in detail at the example of the Hodges-Lehmann estimator for
robustly detecting changes in the central location. A simulation study confirms
the very good robustness and efficiency properties of the test. Two real-life
data sets are analyzed
Large bi-diagonal matrices and random perturbations
This is a first paper by the authors dedicated to the distribution of
eigenvalues for random perturbations of large bidiagonal Toeplitz matrices.Comment: 34 pages, 4 figure
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