1,721,368 research outputs found
Costruzioni idrauliche e marittime per la mitigazione del rischio e la gestione delle risorse
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Propensity Score Matching Procedure on Discharge Records: The Case of Hip Fracture Versus Elective Hip Replacement
No full textHydrodynamic Actions Induced by Seismic Motion on Hydraulic Structures. [AZIONI IDRODINAMICHE INDOTTE DA MOTI SISMICI SU STRUTTURE IDRAULICHE.]
No full textThe research study described gives a survey of the inertial actions exerted on the vessel walls as a consequence of telluric motion. Details about the seismic phenomena, the cases of induced seismicity, and the vibration periods of the structures are given. The paper reports a number of cases in which damage was caused to hydraulic structures as consequence of failure to assess the action produced by the water
Hydrodynamic Effects Induced by Seismic Events on Dams. [EFFETTI IDRODINAMICI SULLE DIGHE DI SBARRAMENTO DURANTE TERREMOTI.]
No full textThe paper presents a critical evaluation of the several theories for the assessment of the hydrodynamic strain which is exerted, during seismic motion, on the upstream facing of a gravity dam. By means of a series of numerical calculations carried out and summarized in a number of charts, the authors have applied the sensitivity analysis to all the parameters on which the inertial actions depend
Exploiting the time-dynamics of news diffusion on the Internet through a generalized Susceptible-Infected model
Full text linkWe construct a news spreading model with a time dependent contact rate which generalizes
the classical Susceptible–Infected model of epidemiology. In particular, we are interested
on the time-dynamics of the sharing and diffusion process of news on the Internet.
We focus on the counting process describing the number of connections to a given website,
characterizing the cumulative density function of its inter-arrival times. Moreover, starting
from the general form of the finite dimensional distribution of the process, we determine a
formula for the time-variable rate of the connections and establish its relationship with the
probability density function of the interarrival times. We finally show the effectiveness of
our theoretical framework analyzing a real-world dataset, the Memetracker dataset, whose
parameters characterizing the diffusion process are determined
Hydrodynamic effects induced by seismic events on dams.
No full textCritically evaluates several theories used in the assessment of the hydrodynamic strain which may be exerted on the upstream face of a gravity dams during seismic motion. Includes the analysis of Westergaard Von Karman (approximation), Zongar Housner, Kulmaci and Chopra. Describes application of sensitivity analysis to all the parameters on which the inertial actions depend. Shows that, at given stimulus frequencies the hydrodynamic action exerted by water on the facing of dam of a given height may be far higher than that considered in present standards. (from English abstract
General Nyström methods in Nordsieck form: Error analysis
No full textThe paper is concerned with the analysis of the error associated to a family of multi-value numerical methods for the solution of initial value problems based on special second order ordinary differential equations. Such methods, denoted as General Nyström methods, provide at each step point an approximation to the Nordsieck vector associated to the solution of the problem. Order issues for such methods based on the theory of rooted trees are here provided, as well as an accuracy analysis is carried out, leading to a representation of the local truncation error
Order conditions for General Linear Nystrom methods
Full text linkThe purpose of this paper is to analyze the algebraic theory of order for the family of general linear Nystrom (GLN) methods introduced in D’Ambrosio et al. (Numer. Algorithm 61(2), 331–349, 2012) with the aim to provide a general framework for the representation and analysis of numerical methods solving initial value problems based on second order ordinary differential equations (ODEs). Our investigation is carried out by suitably extending the theory of B-series for second order ODEs to the case of GLN methods, which leads to a general set of order conditions. This allows to recover the order conditions of numerical methods already known in the literature, but also to assess a general approach to study the order conditions of new methods, simply regarding them as GLN methods: the obtained results are indeed applied to both known and new methods for second order ODEs
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