1,721,240 research outputs found
High‐Dimensional Dynamic Panel with Correlated Random Effects: A Semiparametric Hierarchical Empirical Bayes Approach
Full text linkA novel multivariate dynamic panel data analysis with correlated random effects
is proposed for estimating high-dimensional parameter spaces. A semiparametric
hierarchical Bayesian strategy is used to jointly address incidental parameters, endogeneity issues, and model mis-specification problems. The underlying methodology involves an ad-hoc model selection based on conjugate informative proper mixture priors to select promising subsets of predictors affecting outcomes. Monte Carlo algorithms are then conducted on the resulting submodels to construct empirical Bayes estimators and investigate ratio-optimality and posterior consistency for forecasting purposes and policy issues. An empirical approach is applied to a large
panel of economies, describing the functioning of the model. Simulations based on
Monte Carlo designs are also performed to account for relative regrets dealing with
cross-sectional heterogeneity
Three Euler's Sieves and a Fast Prime Generator (Functional Pearl)
No full textThe Euler's Sieve refines the Sieve of Eratosthenes to compute prime numbers, by crossing off each non prime number just once. Euler's Sieve is considered hard to be faithfully and efficiently coded as a purely functional stream based program. We propose three Haskell programs implementing the Euler's Sieve, all based on the idea of generating just once each composite to be crossed off. Their faithfulness with respect to the Euler's Sieve is up to costly stream unions imposed by the sequential nature of streams. Our programs outperform classical naive stream based prime generators such as trial division, but they are asymptotically worse than the O'Neill `faithful' Sieve of Eratosthenes. To circumvent the bottleneck of union of streams, we integrate our techniques inside the O'Neill program, thus obtaining a fast prime generator based on the Euler's Sieve and priority queues
Fatality rates implied by the Italian building code
No full textThe project Rischio Implicito – Norme Tecniche per le Costruzioni (RINTC) assessed the seismic structural reliability, in terms of the annual rate of earthquakes causing failure, of a large set of code-conforming buildings, designed to be located in three different sites, representative of low, mid, and high seismic hazard in Italy. It was found that seismic reliability tends to decrease significantly as the site's hazard increases, despite the design actions having the same return period at all sites. Because this is a consequence of the code's approach, the simple study presented in this paper aims to contribute to the discussion on whether the code-implied safety is yet acceptable. To this end, the annual fatality rates due to the seismic failure of the buildings from the mentioned project are computed, in a simplified manner, and compared with the annual risk from other common causes of death in Italy; the latter obtained based on data from the Italian Statistical Institute. The results, although subjected to the conventionality of the working assumptions, seem to indicate that seismic fatality risk is generally lower than that of other causes of death, by one or more orders of magnitude at the lower hazard sites. This can contribute to the discussion on seismic structural safety due to the characteristics of the Italian code that are common to state-of-the-art codes internationally
Residential code-conforming structural seismic risk maps for Italy
No full textRINTC – Rischio Implicito delle strutture progettate secondo le NTC is an Italian research project aiming at the evaluation of the seismic reliability inherent to design according to the current Italian building code. Within the project, different fixed-base residential and industrial structures typologies, as well as some base-isolated reinforced concrete buildings were addressed. The structures were located in three Italian sites characterized by different levels of seismic hazard. For each designed, modelled, and analyzed building, the seismic reliability, in term of annual failure rate, was computed. Based on these results, the aim of the study discussed in the paper is to derive national seismic risk maps for Italy in an ideal scenario where all the existing (residential) buildings would be code-conforming, either fixed-base or base-isolated. The analyses are performed at the municipality scale, combining the structural fragility functions with alternative models of probabilistic seismic hazard for Italy, and including exposure in terms of typological composition of the existing building stock. Results, presented in the form of maps of structural failure rates, generally show that: (i) despite the same return period of design seismic intensity over the country, failure rates greatly vary with the increasing hazard of the sites (generalizing one of the main outcomes of the RINTC project), (ii) the alternative hazard models produce limited variations of the failure rates, especially when global collapse is considered
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