Effect of localization error on the performance of location-aided beam-management in 5G and beyond

openLe onde millimetriche sono ritenute essere la prossima frontiera per la trasmissione dei dati nelle moderne reti cellulari 5G e oltre. Tali onde però si attenuano più facilmente durante la propagazione e vengono rapidamente bloccate da ostacoli. E' necessario quindi un'operazione di beamforming, utilizzando per la trasmissione un array di antenne anziché una singola antenna. Con il beamforming è anche necessaria una procedura di ricerca tra trasmettitore e ricevitore, tale procedura è inefficiente nelle reti odierne e provoca ritardi nella trasmissione. E' possibile però sfruttare informazioni esterne per velocizzare l'allineamento, ad esempio, il ricevitore può fornire la propria posizione tramite GPS al trasmettitore cosicché quest'ultimo sappia dove indirizzare la successiva trasmissione dati. L'informazione ausiliaria in questione è però inevitabilmente soggetta ad errore che, a seconda del suo impatto, può addirittura impedire la comunicazione. Nel presente lavoro di tesi sono presentati diversi modelli di errore in scenari realistici, sono inoltre effettuate simulazioni per comprendere l'impatto che ha l'errore dell'informazione ausiliaria nell'intera procedura di beamforming.Millimeter waves are considered to be the next frontier for data transmission in modern 5G and beyond cellular networks. However, these waves attenuate more easily during propagation and are quickly blocked by obstacles. Therefore, a beamforming operation is necessary, using an array of antennas for transmission instead of a single antenna. Beamforming also requires a search procedure between the transmitter and receiver, which is inefficient in current networks and causes delays in transmission. However, external information can be leveraged to speed up the alignment process. For example, the receiver can provide its position via GPS to the transmitter, enabling the latter to know where to direct the next data transmission. Nevertheless, the auxiliary information is inevitably subject to error, which, depending on its impact, can even impede communication. This thesis presents various error models in realistic scenarios and conducts simulations to understand the impact of auxiliary information errors on the entire beamforming procedure

Settling of inertial particles in turbulent Rayleigh-Benard convection

The settling behaviour of small inertial particles in turbulent convection is a fundamental problem across several disciplines, from geophysics to metallurgy. In a geophysical context, the settling of dense crystals controls the mode of solidification of magma chambers and planetary-scale magma oceans, while rising of light bubbles of volatiles drives volcanic outgassing and the formation of primordial atmospheres. Motivated by these geophysical systems, we perform a systematic numerical study on the settling rate of particles in a rectangular two-dimensional Rayleigh-Benard system with Rayleigh number up to 10^12 and Prandtl number from 10 to 50. Under the idealized condition of spherically-shaped particles with small Reynolds number, two limiting behaviours exist for the settling velocity. On the one hand, Stokes' law applies to particles with small but finite response time, leading to a constant settling rate. On the other hand, particles with a vanishing response time are expected to settle at an exponential rate. Based on our simulations, we present a new physical model that bridges the gap between the above limiting behaviours by describing the sedimentation of inertial particles as a random process with two key components: i) the transport of particles from vigorously convecting regions into sluggish, low-velocity "piles" that naturally develop at the horizontal boundaries of the system, and ii) the probability that particles escape such low-velocity regions without settling at their base. In addition, we identify four distinct settling regimes and analyze the horizontal distribution of sedimented particles. For two of these regimes settling is particularly slow and the distribution is strongly non-uniform, with dense particles being deposited preferentially below major clusters of upwellings.Comment: 30 pages, 18 figures, submitted to Phys. Rev. Fluid

Cardiovascular Outcomes in Renal Transplant Recipients: Feasibility and Clinical Role of 2D Speckle Tracking to Assess Myocardial Function

however, few data are available about the role of 2D echocardiography (2DE) and 2D speckle tracking echocardiography (2DSTE) on renal transplant recipients (RTR). From a large cohort of RTR submitted to a supervised exercise as the prescription program, 10 subjects who were regularly trained were studied for sixth months. They underwent periodically an echo evaluation (ESAOTE MyLab 50), cardiopulmonary test (CPT) and strength test for the lower and upper limbs. The LV function study was completed with the speckle tracking longitudinal strain (Lo Strain) measure calculated by dedicated software (XStrain–Esaote) at the end of the protocol. All of the cardiovascular parameters were normal: the ejection fraction (EF) increased significantly (from 62.7 ± 4 to 67.2 ± 2.3 with p &l

Increased Carotid Thickness in Subjects with Recently-Diagnosed Diabetes from Rural Cameroon

PMCID: PMC3423396This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Fireside Corrosion of Applied and Modern Superheater-alloys Under Oxy-fuel Conditions

Abstract Operation of oxy-fuel power plants under ultra-supercritical parameters would help to overcome, to a certain extent, efficiency penalties from air separation and CO 2 -compression units. To improve the knowledge on material behavior under oxy-fuel combustion six candidate superheater alloys, varying from martensitic via iron-base austenitic to nickel-base were chosen and exposed at metal temperature of 580 °C and 650 °C to real oxy-fuel combustion conditions in 3MW combustion test rig of Enel and subsequently moved for further tests to laboratory corrosion test set-up at IFK. Exact definition of combustion conditions was based on measurements performed by IFRF

Problematiche geoambientali del territorio veneziano

Venezia, la sua laguna ed il territorio circostante sono un patrimonio artistico, storico, culturale ed ambientale tra i più noti al mondo. Il fragile equilibrio, tipico delle lagune, è per Venezia particolarmente vulnerabile; essa infatti risulta modellata da un forte contributo antropico, iniziato secoli or sono con le note deviazioni fluviali, ed è oggi esposta ad azioni antropiche di particolare rilevanza, quali quelle derivanti dalla presenza della zona industriale di Marghera che s'affaccia proprio sulla laguna. Questo delicato equilibrio è legato al particolare assetto geologico-territoriale dell'area veneziana. In questa relazione, forzatamente molto schematica in quanto sintetizza decenni di studi ed indagini a livello sia scientifico che tecnico-applicativo, si vuole indicare l'insostituibile apporto della geologia anche in un'area urbana, quale quella Veneziana. Questo "complesso urbano" è composto da una serie di centri: insulari (centro storico, Murano, Burano, Torcello, ecc.), litorali (Lido, Chioggia, Jesolo), di terraferma ed industriali (Mestre, Scorzè, Marghera, Malcontenta, Fusina, ecc.). Altra caratteristica del complesso veneziano è l'interazione dei vari centri urbani che, malgrado la dislocazione geografica, interagiscono nelle varie problematiche geoambientali con strette relazioni causa-effetto. Questa nota, frutto della collaborazione tra Enti di Ricerca, Pubbliche Amministrazioni e Liberi Professionisti, evidenzia la necessità di lavorare in modo sinergico per affrontare al meglio le complesse tematiche geologico-ambientali che si riscontrano in questo tipo di studi

Multicenter evaluation of mycobacteria growth indicator tube (MGIT) compared with the BACTEC radiometric method, BBL biphasic growth medium and Löwenstein—Jensen medium

ObjectiveTo evaluate the new BBL mycobacteria growth indicator tube (MGIT) in comparison with other media.MethodsMGIT was evaluated in 10 Italian centers on 433 clinical samples, mainly of respiratory origin and mainly smear positive, in comparison with Löwenstein—Jensen and with one or more other methods represented, according to participating centers, by the BACTEC radiometric method or by the biphasic BBL Septi-Chek AFB system. While MGIT and Löwenstein—Jensen were used for all the samples, 285 of them were also inoculated in BACTEC vials and 274 in biphasic bottles. Of these samples, 132 were investigated with all the four methods.ResultsAlthough less rapid and sensitive than the radiometric method, the results of MGIT were equal when compared with the other two media with respect to overall isolation yield; furthermore, it allowed the detection of growth in significantly shorter times.ConclusionsThe results of this study indicate the value of MGIT for the detection of mycobacteria and, thanks to its extreme simplicity of use, its suitability for small and large laboratories. Its combined use with a solid medium can substantially improve the diagnosis of mycobacterial infection

Optimizing Silanization to Functionalize Stainless Steel Wire: Towards Breast Cancer Stem Cell Isolation

Chemically modified metal surfaces have been used to recognize and capture specific cell types and biomolecules. In this work, stainless steel wires were functionalized with aptamers against breast cancer stem cell markers. Stainless steel wires were first electropolished and silanized via electrodeposition. Aptamers were then attached to the silanized surface through a cross-linker. The functionalized wires were able to capture the target cells in an in vitro test. During surface modification steps, wires were analyzed by atomic force microscopy, cyclic voltammetry, scanning electron and fluorescence microscopy to determine their surface composition and morphology. Optimized conditions of silanization (applied potential, solution pH, heat treatment temperature) for obtaining an aptamer-functionalized wire were determined in this work together with the use of several surface characterization techniques suitable for small-sized and circular wires. These modified wires have potential applications for the in vivo capture of target cells in blood flow, since their small size allows their insertion as standard guidewires in biomedical devices