WiFi emission-based vs passive radar localization of human targets

In this paper two approaches are considered for human targets localization based on the WiFi signals: the device emission-based localization and the passive radar. Localization performance and characteristics of the two localization techniques are analyzed and compared, aiming at their joint exploitation inside sensor fusion systems. The former combines the Angle of Arrival (AoA) and the Time Difference of Arrival (TDoA) measures of the device transmissions to achieve the target position, while the latter exploits the AoA and the bistatic range measures of the target echoes. The results obtained on experimental data show that the WiFi emission-based strategy is always effective for the positioning of human targets holding a WiFi device, but it has a poor localization accuracy and the number of measured positions largely depends on the device activity. In contrast, the passive radar is only effective for moving targets and has limited spatial resolution but it provides better accuracy performance, thanks to the possibility to integrate a higher number of received signals. These results also demonstrate a significant complementarity of these techniques, through a suitable experimental test, which opens the way to the development of appropriate sensor fusion techniques

Impact of beacon interval on the performance of WiFi-based passive radar against human targets

The capability of WiFi-based passive radar to detect, track and profile human targets in both indoor and outdoor environment has been widely demonstrated. This paper investigates the impact of the Beacon Interval (BI) on the passive radar performance. The results of a dedicated acquisition campaign show that both the detection capability and the localization accuracy progressively degrade as the BI increases due to both the reduction of the received beacons and to the intrinsic undersampling of the target motion. Limit values are suggested for practical applications

Synthesis And Characterization Of Polyynes End-Capped By Biphenyl Groups ({\Alpha},{\Omega}-Biphenylpolyynes)

Stable polyyne chains terminated with biphenyl end groups (a,u-biphenylpolyynes) were synthesized in a single step through a simple procedure by using the Cadiot-Chodkiewicz reaction conditions. The a,ubiphenylpolyynes were separated through HPLC analysis and identified by means of their electronic absorption spectra. The a,u-biphenylpolyynes were studied by FT-IR and Raman spectroscopy and the spectral interpretation was supported with DFT calculations. A peculiarly low reactivity of a,u-biphenylpolyynes with ozone was observed.Comment: The research leading to these results has received funding from the European Research Council Consolidator Grant EspLORE (ERC-2016-CoG Grant No.724610

Emerging Forms of Sociotechnical Organisation: The Case of the Fediverse

Recently, following events at Cambridge Analytica that put commercial social media under scrutiny, a public debate emerged around corporate digital platforms focused not only on critically analysing their social, economic, political impact but on the creation of alternative spaces of digital communication, organisation and conviviality. The key focus of this chapter is the reappropriation of technology intended as a way to conceive ‘appropriate’ social and technical organisation in opposition to the forms of exploitation and capture put in place by digital platforms. How do practices of reappropriation occur to prefigure new sociotechnical imaginaries and to shape digital spaces and infrastructures, social interactions and relations? In which ways does they engender forms of mutualism? What are the conditions required for the emergence of practices for the reappropriation of technology? What are the configurations, representations and encounters that constitute emerging digital communities? In this chapter, these questions will be examined taking into account the constitution and development of the ‘Fediverse’ – more than a social network, a network of networks – focusing on a digital community that has been at the centre of the authors’ digital ethnographical work since 2018. This case study will be analysed through different standing points and dichotomic tensions: infrastructure (de-centralisation/distribution), design (mutual conditioning/mutual aid), governance (heteronomy/autonomy)

The Comprehensive Assessment: What lessons can be learned?

Analysing the database made available by the European Central Bank and by the European Banking Authority, we evaluate the Comprehensive Assessment (CA) (Asset Quality Review and Stress Test (ST)) of banks carried out in 2014. In a nutshell, the main results are: (i) risk-adjusted capital ratios are negatively related to the Asset Quality Review shortfall, but not to the ST shortfall, whereas the leverage ratio plays a significant role in both cases; (ii) the CA predominantly concentrated on traditional credit activity rather than on banksâ\u80\u99 financial assets and (iii) the CA seems to be characterized by double standards. The Asset Quality Review was severe with banks operating in non-core countries, while medium-sized banks were either riskier or were treated severely in both exercises. The analysis leads to a puzzle: comparatively, the assessment per se led to significant adjustments for solid banks and large shortfalls for weak banks. The puzzle can be resolved by referring to the legacy of the countryâ\u80\u99s former supervisory activity and to the low level of capitalization of weak banks mostly in peripheral countries. Abbreviations: ADJ_AQR: adjustment due to the AQR; ADJ_ST: adjustment due to the ST adverse scenario; AQR: asset quality review; bps: basis points (1â\u80\u89bp is equal to 0.01%); bn: billion; CA: comprehensive assessment; CET1: common equity tier 1; CR: coverage ratio; CRD/CRR: capital requirements directive/capital requirements regulation; CVA: credit valuation adjustment; EBA: European Banking Authority; ECB: European Central Bank; LM test: Lagrange-multiplier test; NPE: Non-performing exposure; RWA: risk-weighted asset; SF_AQR: shortfall due to the AQR; SF_ST: shortfall due to the ST adverse scenario; SREP: supervisory review and evaluation process; SSM: single supervisory mechanism; ST: stress test; tr: trillion (one thousand of billions

Ancient masonry arches and vaults strengthened with TRM, SRG and FRP composites: Numerical analyses

[EN] The two arches and the three vaults experimentally described in Carozzi et al. (2017) are here analyzed with a novel robust FE lower bound limit analysis code, suitable to predict active failure mechanisms, lines of thrust and collapse loads in absence and presence of TRM, SRG and FRP reinforcement. The approach relies into a discretization into rigid-infinitely resistant quadrilateral elements for masonry, interfaces between contiguous elements exhibiting limited strength and perfectly bonded rigid-plastic trusses representing the reinforcement. For masonry, a No Tension Material NTM model can be adopted to compare with classic Heyman¿s results, but also a limited compressive and tensile strength with a cohesive frictional behavior in shear may be accounted for in a relatively simple fashion, i.e. in principle with the possibility to model shear sliding and compression crushing. Debonding and delamination of the reinforcement are considered in a conventional way, assuming trusses with a limited tensile strength derived from either experimental data available or consolidated formulas from the literature. With the knowledge of the exact position of the hinges provided by limit analysis, 2D FE static analyses with non-linearity and softening concentrated exclusively on hinges are carried out, to simply extend the knowledge beyond collapse loads estimation towards a prediction of initial stiffness and ultimate displacements. In all cases, promising agreement with experiments is observed.Part of the analyses were developed within the activities of Rete dei Laboratori Universitari di Ingegneria Sismica - ReLUIS for the research program funded by the Dipartimento di Protezione Civile.Bertolesi, E.; Milani, G.; Carozzi, FG.; Poggi, C. (2018). Ancient masonry arches and vaults strengthened with TRM, SRG and FRP composites: Numerical analyses. Composite Structures. 187:385-402. https://doi.org/10.1016/j.compstruct.2017.12.021S38540218