NA61/SHINE results on Bose-Einstein correlations

One of the main goals of NA61/SHINE is the investigation of the phase diagram of strongly interacting matter. NA61/SHINE observes collisions of various nuclei at different energies, allowing to study the same phenomena and observables in vastly different conditions. One of the observables related to the quark-hadron transition is the Bose-Einstein momentum correlation function of identical pions, related to the space-time structure of pion emission. In this paper we report on such measurements in Be+Be collisions at an SPS beam momentum of 150A GeV/c. Our correlation functions can be statistically well described with Levy-distributed sources, hence we also study the mT dependence of the Levy source parameters, and discuss their possible interpretations.Comment: 7 pages, 3 figures, proceedings of the Critical Point and Onset of Deconfinement Conference (CPOD 2018), Corfu, Greece, September 24 - 28, 2018, submitted to Proceedings of Scienc

A Matlab Tool For The Characterisation of Recorded Underwater Sound (Chorus)

The advent of low-cost, high-quality underwater sound recording systems has greatly increased the acquisition of large (multi-GB) acoustic datasets that can span from hours to several months in length. The task of scrutinizing such datasets to detect points of interest can be laborious, thus the ability to view large portions of the dataset in a single screen, or apply a level of automation to find or select individual sounds is required. A toolbox that can be continually revised, the user friendly“Characterisation Of Recorded Underwater Sound” (CHORUS) Matlab graphic user interface, was designed for processing such datasets, isolating signals, quantifying calibrated received levels and visually teasing out long and short term variations in the noise spectrum. A function to automatically detect, count and measure particular signals (e.g. blue whale sounds) is integrated in the toolbox, with the ability to include categorised calls of other marine fauna in the future. Sunrise and sunset times can be displayed in long-term average spectrograms of sea noise to reveal diurnal cycles in thevocal activity of marine fauna. A number of example studies are discussed where the toolbox has been used for analysing biological, natural physical and anthropogenic sounds

Deformation coupling between the Archean Pukaskwa intrusive complex and the Hemlo shear zone, Superior Province, Canada

Archean greenstone belts typically form narrow sheared basins separating bulbous tonalo-trondjhemo-granodioritic (TTG) intrusive complexes. The role played by gravity in the development of such dome-and-keel structures constitutes a key question in Archean tectonics. The Pukaskwa intrusive complex (PIC)-Hemlo greenstone belt system stands as a remarkable example of the dome-and-keel architecture that commonly occurs in Archean terrains. Abundant strain markers in the greenstone belt and in the Hemlo shear zone (HSZ) attest of late sinistral strike-slip kinematics (D2) whereas, in general, the quartzofeldspathic coarse-grained rocks of the Pukaskwa intrusive complex bear little macroscopically visible kinematic indicators, most likely due to pervasive recrystallization. The PIC consists dominantly of a heterogeneous assemblage of TTG plutonic rocks and gneisses, which overall are less dense than the greenstone rocks. The study of anisotropy of magnetic susceptibility (AMS), based on 120 stations and 1947 specimens from the PIC, reveals east-west trending prolate and plano-linear fabrics across the northern margin of the complex, i.e., along the HSZ. Since geotherms were higher in the Archean than in the present, the effective viscosity of the TTG units would have been sufficiently low to allow their diapiric ascent through denser greenstone rocks. Here we propose an alternative model where thrust tectonics is responsible for the early structuration of the PIC. Later transpressive tectonics causes strain localization along internal strike-slip shear zones and along lithological boundaries. © 2013 Elsevier B.V

Algorithms that Remember: Model Inversion Attacks and Data Protection Law

Many individuals are concerned about the governance of machine learning systems and the prevention of algorithmic harms. The EU's recent General Data Protection Regulation (GDPR) has been seen as a core tool for achieving better governance of this area. While the GDPR does apply to the use of models in some limited situations, most of its provisions relate to the governance of personal data, while models have traditionally been seen as intellectual property. We present recent work from the information security literature around `model inversion' and `membership inference' attacks, which indicate that the process of turning training data into machine learned systems is not one-way, and demonstrate how this could lead some models to be legally classified as personal data. Taking this as a probing experiment, we explore the different rights and obligations this would trigger and their utility, and posit future directions for algorithmic governance and regulation.Comment: 15 pages, 1 figur

How to account for temporal correlations with a diagonal correlation model in a nonlinear functional model : A plane fitting with simulated and real TLS measurements

To avoid computational burden, diagonal variance covariance matrices (VCM) are preferred to describe the stochasticity of terrestrial laser scanner (TLS) measurements. This simplification neglects correlations and affects least-squares (LS) estimates that are trustworthy with minimal variance, if the correct stochastic model is used. When a linearization of the LS functional model is performed, a bias of the parameters to be estimated and their dispersions occur, which can be investigated using a second-order Taylor expansion. Both the computation of the second-order solution and the account for correlations are linked to computational burden. In this contribution, we study the impact of an enhanced stochastic model on that bias to weight the corresponding benefits against the improvements. To that aim, we model the temporal correlations of TLS measurements using the Matérn covariance function, combined with an intensity model for the variance. We study further how the scanning configuration influences the solution. Because neglecting correlations may be tempting to avoid VCM inversions and multiplications, we quantify the impact of such a reduction and propose an innovative yet simple way to account for correlations with a “diagonal VCM.” Originally developed for GPS measurements and linear LS, this model is extended and validated for TLS range and called the diagonal correlation model (DCM). © 2020, The Author(s)

Numerical Model of a Reinforced Concrete Building: Earthquake Analysis and Experimental Validation

Shaking-table experiments of relatively large-scale specimens play a fundamental role in deepening our understanding of seismic response of existing structures and verification of numerical models. However, and in apparent contradiction, the preparation of such a dynamic laboratory experiment requires a-priori advanced numerical simulations, necessary to both fine-tune the test specimen properties and calibrate the input motion, as a function of the objectives of the test and capabilities and characteristics of the shaking table. This research thus concerns the development of a fibre-based finite elements model of a halfscale 3D reinforced concrete frame tested under dynamic conditions at the European Centre for Training and Research in Earthquake Engineering (EUCENTRE, Pavia, Italy). Since this reduced-scale specimen is very much based on a full-scale counterpart previously tested under pseudo-dynamic conditions at the European Laboratory for Structural Assessment (ELSA) of the Joint Research Centre (JRC, Ispra, Italy), the first part of the work consisted in verifying that the software tool employed in the numerical simulations was capable of duplicating the pseudo-dynamic real test results. Having successfully met the latter objective, the second part of the work consisted in the attempted numerical simulation of the shaking table tests, with a view to ascertain that the response of the model will be within the envisaged response targets and that the necessary input motion is compatible with the shaking-table characteristics