Bluetooth Mesh Technology for the Joint Monitoring of Indoor Environments and Mobile Device Localization: A Performance Study

Bluetooth Mesh is a recent SIG standard enabling the deployment of multi-hop Wireless Sensor Networks (WSNs) over Bluetooth Low Energy (BLE) communication links. The standard introduces many novel and interesting features in the Internet of Things (IoT) domain, such as the seamless integration among sensors and mobile and wearable devices, and the support for a wide range of different IoT application profiles. At the same time, fine-grained assessments of the performance are still needed to understand the potential of the technology. In this paper, we investigate the usage of Bluetooth Mesh solutions for the joint monitoring of indoor spaces and humans. Through the deployment of a test-bed, we evaluate the performance of Bluetooth Mesh WSNs under varying traffic loads and network sizes. In addition, by exploiting the short-range, multi-hop communications, we propose a procedure for the indoor localization of mobile devices and evaluate its accuracy. The results demonstrate that the technology supports reasonable delivery ratio under high traffic loads, however the network and localization performance sharply decreases when increasing the number of hops between the source and destination nodes

A GPS-Free Flocking Model for Aerial Mesh Deployments in Disaster-Recovery Scenarios

In the aftermath of a large-scale emergency, Unmanned Aerial Vehicles (UAVs) can play a key role as mobile communication systems supporting rescue operations on the ground. At the same time, the deployment of autonomous UAV swarms still poses severe challenges in terms of distributed mobility, swarm connectivity and mesh networking. To this purpose, we propose mathsf {ELAPSE} (aErial LocAl Positioning System for Emergency), a novel, distributed framework for aerial mesh deployment that supports discovery and multi-hop connectivity among rescue personnel and emergency requesters. mathsf {ELAPSE} integrates components of swarm mobility, positioning and Quality-of-Service (QoS) support, while targeting UAV devices at different levels of hardware complexity. Three contributions are provided in this study. First, we present a novel, bio-inspired swarm mobility algorithm which natively addresses QoS-based aerial mesh connectivity, coverage of the ground nodes and UAV collision avoidance through the abstraction of virtual springs. Second, we investigates its implementation when geo-location capabilities are not available: to this aim, we propose local-based and cooperative-based techniques through which each UAV can estimate the position of its neighbours, and hence correctly adjust its direction and speed. Third, we analyze the feasibility of the mathsf {ELAPSE} framework through a twofold evaluation: i.e. a large-scale OMNeT++ simulation showing the effectiveness of the distributed mesh formation and localization techniques, and a small-case ground robotic testbed demonstrating the impact of QoS mechanisms on the system operations

Layar Ascoli Piceno. Conferenza Stampa di presentazione dell'App Mobile "Ascoli Piceno nella storia"

Conferenza Stampa di presentazione dell'App Mobile "Ascoli Piceno nella storia", promossa dalla Scuola di Architettura e Design "Eduardo Vittoria” - S.A.D. - Università di Camerino e dal Comune di Ascoli Piceno, che ha avuto l'obiettivo di presentare il lavoro svolto per la realizzazione dell'App Mobile “Ascoli Piceno nella storia” attiva ed usufruibile in città, (e quindi di mostrarne altresì l'effettivo utilizzo per la visualizzazione di contenuti 2D e 3D in Realtà Aumentata) esito del Progetto di ricerca condotto da un gruppo di ricerca della S.A.D. (Responsabile: Alessandra Meschini) grazie alla Convenzione stipulata nel febbraio 2013 con il Comune di Ascoli Piceno dal titolo: “Comunicazione e Valorizzazione dei Beni Culturali. Per la realizzazione di una applicazione “mobile” finalizzata alla fruizione dei Beni conservati presso gli Archivi e le Biblioteche del comune di Ascoli Piceno”. La Piattaforma web collegata all'App è raggiungibile all'indirizzo http:\\layar.comuneap.gov.i

Cochlear implant in prelingually hearing-impaired adults: Prognostic factors and results

Objectives. The aim of present study is to evaluate the impact of prognostic factors on the outcome in a group of prelingually hearing-impaired patients submitted to cochlear implantation (CI) at an adult age. Methods. This is a retrospective study on a cohort of prelingually severe-to-profound hearing-impaired patients cochlear implanted in adulthood and followed by a single audiology centre. We correlated post-CI results in term of speech perception with patients’ speech perception with hearing aids before implantation, history of progression of hearing loss (HL), and levels of education and cognition. The study group was composed of 49 patients. Results. Post-CI open-set recognition score in silence and noise was significantly correlated with pre-CI open-set recognition score in silence and with background noise. Patients with a history of progression of HL gained significantly better results. Furthermore, we found higher improvements in patients with a higher level of education. Conclusions. Prelingually deafened patients implanted in adulthood achieved satisfac-tory results. Significantly better results were achieved by patients with better pre-operative speech perception scores, progressive HL and higher level of education

Spin waves in ultrathin multilayers with ferromagnetic and antiferromagnetic coupling: Fe/Cu and Fe/Cr -- Presentazione orale by R. Zivieri - Conferenza internazionale

We have studied the spin modes in ultrathin multilayers in presence of ferromagnetic and antiferromagnetic coupling. We have referred to epitaxial Cu(60Å)/Fe(20Å)/Cu/Fe(60Å)/Cu(60Å) heterostructures with the Cu spacer thickness ranging between 0 Å and 33 Å. The interlayer exchange coupling between Fe films obtained by Brillouin light scattering(BLS) from thermally excited spin waves is ferromagnetic for the whole range of Cu spacer thicknesses investigated. Using the magnetic parameters determined by the fit to the BLS data, we have carried out a detailed calculation of the BLS cross-section assuming the dynamic magnetization to be uniform across each magnetic film. A very good agreement between the calculated and the measured crosssections has been obtained. To analyze the effect of the antiferromagnetic exchange coupling on the spin modes we have considered the system Fe(20 Å)/Cr(20 Å)/Fe(20 Å)/Cr(9 Å)/Fe(100 Å) with both ferromagnetic and antiferromagnetic couplings studying the acoustical and optical spin modes. A calculation of the dynamic magnetization, assumed uniform in each film, gives an explanation of the behavior of the two kinds of modes at different magnetic fields. The acoustical mode is the lowest frequency one for low applied fields, but its frequency switches with that of the optical modes at higher fields. We have also found that the system exhibits soft modes as a function of the applied field. -- Presentazione orale by R. Zivieri - Conferenza internazional

Interlayer exchange coupling in asymmetric Fe(110)/Cu/Fe(110) thin films studied by Brillouin light scattering

The magnetic properties of bcc Fe(110) bilayers separated by fcc(111) Cu films of variable thickness in the range between 0 and 33 Å have been investigated by Brillouin light scattering. The two Fe films, 20 and 60 Å thick, were grown on the 7x7 reconstructed surface of a Si(111) substrate using metal-metal epitaxy on silicon (MMES). Low-energy electron diffraction analysis revealed that the Fe films consist of bcc (110) domains in Kurdjumov-Sachs orientation. For Cu interlayer thickness larger than 6 Å, the Brillouin spectrum consists of two spin-wave modes due to the double layered structure which depends on the Cu-layer thickness. The experimental spin-wave frequency dependence on the incidence angle of light has been interpreted using a model that includes both the bulk and the interface first-order anisotropy, as well as the bilinear exchange coupling between the two Fe films. We found that, for the Cu range of thickness investigated, the bilinear coupling is always ferromagnetic, in agreement with the shape of the Kerr hysteresis loops

Brillouin light scattering in Fe(110)/Cu/Fe(110)/Cu/Si(111) heterostructures: bilinear and biquadratic exchange magnetic couplings -- Presentazione poster by R. Zivieri - Conferenza nazionale

Epitaxial Cu/Fe(20 Å)/Cu(x Å)/Fe( 60 Å) heterostructures with the Cu spacer thickness x ranging between 0 Å and 33 Å are grown on 7x7 reconstructed surface of Si (111) substrates. Fcc(111) Fe films grow epitaxially on a Cu(111) buffer layer up to a thickness of 6-8 Å, with a low-spin magnetic phase, while for larger thicknesses one observes the three-dimensional bcc Fe(110) domains in the Kurdjumov-Sachs orientation characterized by a magnetic moment close to that of bulk Fe. [1] Brillouin light scattering (BLS) from thermally excited spin waves has been exploited in order to study the interlayer exchange coupling between the two Fe films. The experimental spin wave frequency dependence on both the applied magnetic field and the incidence angle of light are simulated using a model which includes first-order intrinsic volume and interface anisotropies and takes into account both the bilinear and the biquadratic exchange interactions between the two ferromagnetic layers. The coupling is found to be ferromagnetic for the whole range of Cu spacer thicknesses investigated, in agreement with the surface magneto-optical Kerr effect (SMOKE) measurements. Using the magnetic parameters determined by the above analysis, we have carried out a detailed calculation of the BLS cross-section assuming the dynamic magnetization to be constant across each magnetic film. A very good agreement between the calculated and the measured cross sections has been obtained. References [1] G. Gubbiotti, L. Albini, S. Tacchi, G. Carlotti, R. Gunnella, and M. De Crescenzi, Phys. Rev. B 60, 17150 (1999). -- Presentazione poster by R. Zivieri - Conferenza nazional

Bilinear exchange coupling in asymmetric Fe(110)/Cu/Fe(110) thin films studied by Brillouin Light Scattering -- Presentazione poster by R. Zivieri - Conferenza internazionale

The magnetic properties of bcc Fe(110) bilayers separated by fcc(111) Cu films of variable thickness in the range between 0 and 33 Å have been investigated by Brillouin light scattering (BLS). The two Fe films, 20 and 60 Å thick, are grown on the 7x7 reconstructed surface of a Si(111) substrate using the metal-metal epitaxy on silicon technique (MMES). [1] Low energy and Kikuchi electron diffraction analysis have revealed that the Fe films grow in the Kurdjumov-Sachs (KS) orientation on the underlying Fe layers pseudomorphic with Cu(111).[2] The experimental spin-wave frequency dependence on the applied magnetic field and on the incidence angle of light is simulated using a model which includes first-order intrinsic volume and interface anisotropies. BLS study has shown that, for Cu thickness between 0 and 33 Å, the exchange coupling is ferromagnetic, in agreement with our surface magneto-optic Kerr effect measurements, and that the biquadratic coupling is not negligible. The calculated BLS cross-sections agree very well with the measured spectra. [1] G. Gubbiotti, G. Carlotti, C. Minarini, S. Loreti, R. Gunnella, and M. De Crescenzi, Surf. Sci. 449, 218 (2000). [2] G. Gubbiotti, L. Albini, S. Tacchi, G. Carlotti, R. Gunnella, and M. De Crescenzi, Phys. Rev. B 60, 17150 (1999). -- Presentazione poster by R. Zivieri -Conferenza internazional

Brillouin light scattering study of ferromagnetically coupled Cu/Fe(110)/Cu/Fe(110)/Cu/Si(111) heterostructures: bilinear exchange magnetic coupling

Epitaxial Cu(60 Å)/Fe(20 Å)/Cu(dCu)/Fe(60 Å)/Cu(60 Å) heterostructures with the Cu spacer thickness dCu ranging between 0 and 33 Å have been grown on 737 reconstructed surface of Si~111! substrates. Fcc~111! Fe films grow epitaxially on the Cu~111! buffer layer up to a thickness of 6–8 Å, while, for larger thicknesses, one observes the appearance of three-dimensional bcc Fe~110! domains in the Kurdjumov-Sachs orientation. Brillouin light scattering ~BLS! from thermally excited spin waves has been exploited in order to study the interlayer exchange coupling between the two Fe films at room temperature. The experimental spin-wave frequency dependence on the applied magnetic field is simulated using a simple model which includes first-order intrinsic volume and interface anisotropies and takes the bilinear exchange interaction between the two ferromagnetic layers into account. We have found that for thicknesses of the Cu spacer larger than 6 Å, the Brillouin spectrum consists of two spin-wave modes due to the Fe double layered structure which depends on the Cu-layer thickness. The coupling is found to be ferromagnetic for the whole range of Cu spacer thicknesses investigated. Using the magnetic parameters determined by the above analysis, we have carried out a detailed calculation of the BLS cross section assuming the dynamic magnetization to be constant across each magnetic film. A very good agreement between the calculated and the measured cross sections has been obtained