Roma Tre University

About: Roma Tre University is a education organization based out in Rome, Lazio, Italy. It is known for research contribution in the topics: Large Hadron Collider & Galaxy. The organization has 4434 authors who have published 15352 publications receiving 374888 citations. The organization is also known as: Universita degli Studi Roma Tre & RomaTre.

A federated architecture approach for Internet of Things security

Abstract: Internet of Things (IoT) refers to the capability to connect, communicate and remotely manage a large number of networked, automated devices via the Internet. IoT is becoming as part of daily life and aims to extend pervasive communication and networking anytime, anywhere with any device. In this context security requirements and architectures must be properly formulated, implemented in order to enforce the security policies during their life-cycle. This paper provides a survey and analysis of security in the area of IoT introducing an approach addressed to overcome the conventional security solutions and deploy a federated architecture for dynamic prevention, detection, diagnosis, isolation, and countermeasures against cyber attacks. Based on the analysis of the most common web services, the paper defines the security needs proposing a federated model to design an architecture for secure exchange of services in IoT paradigm.

Search for a heavy top-quark partner in final states with two leptons with the ATLAS detector at the LHC

Abstract: The results of a search for direct pair production of heavy top-quark partners in 4.7 fb−1 of integrated luminosity from pp collisions at s√=7 TeV collected by the ATLAS detector at the LHC are reported. Heavy top-quark partners decaying into a top quark and a neutral non-interacting particle are searched for in events with two leptons in the final state. No excess above the Standard Model expectation is observed. Limits are placed on the mass of a supersymmetric scalar top and of a spin-1/2 top-quark partner. A spin-1/2 top-quark partner with a mass between 300 GeV and 480 GeV, decaying to a top quark and a neutral non-interacting particle lighter than 100 GeV, is excluded at 95% confidence level.

Representation Theory of the Symmetric Groups: The Okounkov-Vershik Approach, Character Formulas, and Partition Algebras

Abstract: Preface 1 Representation theory of finite groups 2 The theory of Gelfand-Tsetlin bases 3 The Okounkov-Vershik approach 4 Symmetric functions 5 Content evaluation and character theory 6 The Littlewood-Richardson rule 7 Finite dimensional *-algebras 8 Schur-Weyl dualities and the partition algebra Bibliography Index

Density-tapered spiral arrays for ultrasound 3-D imaging

Abstract: The current high interest in 3-D ultrasound imaging is pushing the development of 2-D probes with a challenging number of active elements. The most popular approach to limit this number is the sparse array technique, which designs the array layout by means of complex optimization algorithms. These algorithms are typically constrained by a few steering conditions, and, as such, cannot guarantee uniform side-lobe performance at all angles. The performance may be improved by the ungridded extensions of the sparse array technique, but this result is achieved at the expense of a further complication of the optimization process. In this paper, a method to design the layout of large circular arrays with a limited number of elements according to Fermat's spiral seeds and spatial density modulation is proposed and shown to be suitable for application to 3-D ultrasound imaging. This deterministic, aperiodic, and balanced positioning procedure attempts to guarantee uniform performance over a wide range of steering angles. The capabilities of the method are demonstrated by simulating and comparing the performance of spiral and dense arrays. A good trade-off for small vessel imaging is found, e.g., in the 60Λ spiral array with 1.0Λ elements and Blackman density tapering window. Here, the grating lobe level is −16 dB, the lateral resolution is lower than 6λ the depth of field is 120Λ and, the average contrast is 10.3 dB, while the sensitivity remains in a 5 dB range for a wide selection of steering angles. The simulation results may represent a reference guide to the design of spiral sparse array probes for different application fields.

Nonperturbatively improved heavy - light mesons: Masses and decay constants

Abstract: We present a study of the heavy-light spectrum and of the D- and B-meson decay constants. The results were obtained in the quenched approximation, by using the nonperturbatively improved clover lattice action at $\ensuremath{\beta}=6.2,$ with a sample of $100$ configurations, on a ${24}^{3}\ifmmode\times\else\texttimes\fi{}64$ lattice. After a careful analysis of the systematic errors present in the extraction of the physical results, by assuming quite conservative discretization errors, we find ${f}_{{D}_{s}}=231\ifmmode\pm\else\textpm\fi{}{12}_{\ensuremath{-}1}^{+8} \mathrm{MeV},$ ${f}_{D}=211\ifmmode\pm\else\textpm\fi{}{14}_{\ensuremath{-}12}^{+2} \mathrm{MeV},$ ${f}_{{D}_{s}}{/f}_{D}=1.10(2),$ ${f}_{{B}_{s}}=204\ifmmode\pm\else\textpm\fi{}{16}_{\ensuremath{-}0}^{+36} \mathrm{MeV},$ ${f}_{B}=179\ifmmode\pm\else\textpm\fi{}{18}_{\ensuremath{-}9}^{+34} \mathrm{MeV},$ ${f}_{{B}_{s}}{/f}_{B}{=1.14(3)}_{\ensuremath{-}1}^{+1}.$ Our results, which have smaller discretization errors than many previous estimates at fixed value of the lattice spacing a, support a large value of ${f}_{B}$ in the quenched approximation.