16,986 research outputs found
Statistical emulation of a tsunami model for sensitivity analysis and uncertainty quantification
Due to the catastrophic consequences of tsunamis, early warnings need to be
issued quickly in order to mitigate the hazard. Additionally, there is a need
to represent the uncertainty in the predictions of tsunami characteristics
corresponding to the uncertain trigger features (e.g. either position, shape
and speed of a landslide, or sea floor deformation associated with an
earthquake). Unfortunately, computer models are expensive to run. This leads to
significant delays in predictions and makes the uncertainty quantification
impractical. Statistical emulators run almost instantaneously and may represent
well the outputs of the computer model. In this paper, we use the Outer Product
Emulator to build a fast statistical surrogate of a landslide-generated tsunami
computer model. This Bayesian framework enables us to build the emulator by
combining prior knowledge of the computer model properties with a few carefully
chosen model evaluations. The good performance of the emulator is validated
using the Leave-One-Out method
On the Evaluation of the Mechanical Behaviour of Structural Glass Elements
Glass can be considered to be a high-technology engineering material with a
multifunctional potential for structural applications. However, the conventional approach to the use
of glass is often based only on its properties of transparency and isolation. It is thus highly
appropriate and necessary to study the mechanical behaviour of this material and to develop
adequate methods and models leading to its characterisation. It is evident that the great potential of
growth for structural glass applications is an important opportunity of development for the glass
industry and the building/construction sectors. The work presented in this paper is a reflection of
this conclusion. The authors shortly present the state-of-the-art on the application of glass as a
structural element in building and construction, and refer to other potential fields of application and
available glass materials. The experimental procedures and methods adopted in three-point bending
tests performed on 500 × 100 [mm2] float, laminated and tempered glass specimens with
thicknesses between 4 and 19 mm are thoroughly described. The authors evaluated the mechanical
strength and stiffness of glass for structural applications. This work contributes to a deeper
knowledge of the properties of this material
Scaling limit for a drainage network model
We consider the two dimensional version of a drainage network model
introduced by Gangopadhyay, Roy and Sarkar, and show that the appropriately
rescaled family of its paths converges in distribution to the Brownian web. We
do so by verifying the convergence criteria proposed by Fontes, Isopi, Newman
and Ravishankar.Comment: 15 page
Relation between and from QCD
We have studied, using double ratio of QCD (spectral) sum rules, the ratio
between the masses of and X(3872) assuming that they are respectively
described by the and molecular currents. We found
(within our approximation) that the masses of these two states are almost
degenerate. Since the pion exchange interaction between these mesons is exactly
the same, we conclude that if the observed X(3872) meson is a
molecule, then the molecule should also exist with approximately the
same mass. An extension of the analysis to the -quark case leads to the same
conclusion. We also study the SU(3) breakings for the mass
ratios. Motivated by the recent Belle observation of two states, we
revise our determination of by combining results from exponential and
FESR sum rules.Comment: revised version to appear on Phys. Lett.
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