84 research outputs found
Pleidooi voor sterke, compacte steden
No full textIn Strong Towns pleit Charles Marohn voor compacte, organisch groeiende steden. Recensent Frank van Oort kan een heel eind meegaan met de visie van Marohn, alleen al omdat het onderhoud van de almaar uitdijende infrastructuur in Amerikaanse steden zo goed als onbetaalbaar is. “Marohn is een overtuigd pleitbezorger van binnenstedelijke verdichting met een menselijk gezicht.
Pleidooi voor sterke, compacte steden
No full textIn Strong Towns pleit Charles Marohn voor compacte, organisch groeiende steden. Recensent Frank van Oort kan een heel eind meegaan met de visie van Marohn, alleen al omdat het onderhoud van de almaar uitdijende infrastructuur in Amerikaanse steden zo goed als onbetaalbaar is. “Marohn is een overtuigd pleitbezorger van binnenstedelijke verdichting met een menselijk gezicht.
Estimating the index of a stable law via the pot-method
No full textConsider an i.i.d. sample X1,...,Xn of random variables which are equal in distribution to Y, where Y follows a symmetric stable law with index [beta], 0Stable distribution Point process of exceedances Peaks over threshold Generalized Pareto distribution Hill estimator LAN Central sequence Asymptotic efficiency Finite sample size properties
Global sufficiency of extreme order statistics in location models of Weibull type
No full textIn Janssen and Reiss (1988) it was shown that in a location model of a Weibull type sample with shape parameter -1 < a < 1 the k(n) lower extremes are asymptotically local sufficient. In the present paper we show that even global sufficiency holds. Moreover, it turns out that convergence of the given statistical experiments in the deficiency metric does not only hold for compact parameter sets but for the whole real line
Local Asymptotic Normality in Extreme Value Index Estimation
No full textExtreme value distribution, extreme value index, domain of attraction, generalized Pareto distribution, Hill estimator, local asymptotic normality, central sequence, asymptotic efficiency,
Asymptotic sufficiency of order statistics for almost regular Weibull type densities
No full textConsider a location family which is defined via a Weibull type density having shape parameter a = 1. We treat the problem, which portion of the order statistics is asymptotically sufficient. It turns out that the intermediate order statistics are relevant
PHOTOCONDUCTIVITY DYNAMICS IN LEAD HALIDE PEROVSKITES PROBED BY SCANNING PROBE MICROSCOPY
No full text172 pagesLead halide perovskite is an emerging class of solar material that make high efficiency solar cells. Despite the impressive efficiency records, lead-halide perovskite devices suffer from reversible and irreversible changes under illumination Understanding photo-induced changes requires understanding charge dynamics and defect chemistry. We use scanning probe microscopy techniques including time resolved EFM (tr-EFM), phase-kick EFM (pk-EFM), broadband local dielectric spectroscopy (BLDS), and dissipation microscopy to probe samples response to light irradiation in number of different lead halide perovskite. Our new approach to the description of electrical scanning probe measurement has led to a powerful new interpretation of these measurements in terms of the sample impedance. We present direct evidence that the slow and fast charge dynamics ubiquitously seen in 3D lead-halide perovskites have a common origin related to a highly activated charge redistribution. Our data shows that perovskite conductivity can be highly substrate dependent due to defect chemistry presumably in the grown perovskite dictated by the growth substrate. We find absence of slow dynamics in the 2D perovskite samples. These observations and results emphasize the need to include photoionic conductivity and defect generation in perovskite solar cell device modeling
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