Perfect tag identification protocol in RFID networks

Radio Frequency IDentification (RFID) systems are becoming more and more popular in the field of ubiquitous computing, in particular for objects identification. An RFID system is composed by one or more readers and a number of tags. One of the main issues in an RFID network is the fast and reliable identification of all tags in the reader range. The reader issues some queries, and tags properly answer. Then, the reader must identify the tags from such answers. This is crucial for most applications. Since the transmission medium is shared, the typical problem to be faced is a MAC-like one, i.e. to avoid or limit the number of tags transmission collisions. We propose a protocol which, under some assumptions about transmission techniques, always achieves a 100% perfomance. It is based on a proper recursive splitting of the concurrent tags sets, until all tags have been identified. The other approaches present in literature have performances of about 42% in the average at most. The counterpart is a more sophisticated hardware to be deployed in the manufacture of low cost tags.Comment: 12 pages, 1 figur

Geometric potential of cartosat-1 stereo imagery

Cartosat-1 satellite, launched by Department of Space (DOS), Government of India, is dedicated to stereo viewing for large scale mapping and terrain modelling applications. This stereo capability fills the limited capacity of very high resolution satellites for three-dimensional point determination and enables the generation of detailed digital elevation models (DEMs) not having gaps in mountainous regions like for example the SRTM height model.The Cartosat-1 sensor offers a resolution of 2.5m GSD in panchromatic mode. One CCD-line sensor camera is looking with a nadir angle of 26' in forward direction, the other 5' aft along the track. The Institute "Area di Geodesia e Geomatica"-Sapienza Università di Roma and the Institute of Photogrammetry and Geoinformation, Leibniz University Hannover participated at the ISPRS-ISRO Cartosat-1 Scientific Assessment Programme (CSAP), in order to investigate the generation of Digital Surface Models (DSMs) from Cartosat-1 stereo scenes. The aim of this work concerns the orientation of Cartosat-1 stereo pairs, using the given RPCs improved by control points and the definition of an innovative model based on geometric reconstruction, that is used also for the RPC extraction utilizing a terrain independent approach. These models are implemented in the scientific software (SISAR-Software per Immagini Satellitari ad Alta Risoluzione) developed at Sapienza Università di Roma. In this paper the SISAR model is applied to different stereo pairs (Castelgandolfo and Rome) and to point out the effectiveness of the new model, SISAR results are compared with the corresponding ones obtained by the software OrthoEngine 10.0 (PCI Geomatica).By the University of Hannover a similar general satellite orientation program has been developed and the good results, achieved by bias corrected sensor oriented RPCs, for the test fields Mausanne (France) and Warsaw (Poland) have been described.For some images, digital height models have been generated by automatic image matching with least squares method, analysed in relation to given reference height models. For the comparison with the reference DEMs the horizontal fit of the height models to each other has been checked by adjustment

Dynamical correlations in the escape strategy of Influenza A virus

The evolutionary dynamics of human Influenza A virus presents a challenging theoretical problem. An extremely high mutation rate allows the virus to escape, at each epidemic season, the host immune protection elicited by previous infections. At the same time, at each given epidemic season a single quasi-species, that is a set of closely related strains, is observed. A non-trivial relation between the genetic (i.e., at the sequence level) and the antigenic (i.e., related to the host immune response) distances can shed light into this puzzle. In this paper we introduce a model in which, in accordance with experimental observations, a simple interaction rule based on spatial correlations among point mutations dynamically defines an immunity space in the space of sequences. We investigate the static and dynamic structure of this space and we discuss how it affects the dynamics of the virus-host interaction. Interestingly we observe a staggered time structure in the virus evolution as in the real Influenza evolutionary dynamics.Comment: 14 pages, 5 figures; main paper for the supplementary info in arXiv:1303.595

The end of ‘business as usual’? COVID-19 and the European Green Deal. Egmont European Policy Brief No. 60 May 2020

The COVID-19 pandemic has had a clear and drastic effect on our daily lives and political priorities. But what implications does it have for the EU’s climate action and the Von der Leyen Commission’s flagship policy, the European Green Deal? The crisis may be a ‘make or break’ moment for the EU to act on climate change through its recovery plan

Engaging with 'impact' agendas? Reflections on storytelling as knowledge exchange

The ‘impact agenda’, that is the whole gamut of initiatives related to knowledge exchange and public engagement that have been articulated in recent years, has had and continues to have a significant shaping influence on the way in which academics carry out their research. Within a UK context, the Research Excellence Framework (2008-2013) has made an explicit engagement with this agenda virtually compulsory for research-active academics by introducing ‘impact’ as a new criteria on which the research performance of universities, departments and individual researchers is assessed. The new emphasis on impact, defined as the ‘demonstrable contribution’ that research makes ‘to society and the economy’ beyond specialist academic audiences, has generated much discussion and controversy among academics. The ‘impact agenda’ has been critiqued on a number of grounds, ranging from diluting standards of academic excellence (Jump 2012), to limiting academic freedom by tying fundable academic enquiry to policy objectives, to concerns about the difficulties and costs involved in assessing ‘impact’ (Martin 2011). The widespread perception that academic autonomy is increasingly threatened by the twin forces of ‘audit culture’ and the commodification of higher education has been exacerbated by the broader climate of economic austerity and related cuts in university funding. Meanwhile, ‘impact’ itself remains a poorly understood and nebulous concept even as ‘impact case studies’ are embedded within REF criteria and scores. The difficulty in clearly defining the rules of the game stems from the fact that each discipline, research community and individual researcher has their own notion of ‘impact’ as it pertains to their work. Nonetheless, there is a real danger that lack of clarity, compounded with the obligatory compliance to impact assessment, may encourage a strategic ‘game-playing’ and a random incentivisation of short-term ‘impact’ activities by university management, rather than a vision of what meaningful engagement with non-academic publics may look like. In the light of this, the basic aim of this chapter is to reflect critically on the difficulties of implementing impact agendas with recourse to a Research Networking initiative (Translating Russian and East European Cultures), funded by the Arts and Humanities Research Council (AHRC). The chapter focuses on knowledge exchange, since a key and recurring point of reflection throughout the initiative concerned the nature and practice of knowledge exchange (cf. Mitton et al. 2007) across academic and non-academic ‘communities of practice’ (Wenger 1998). This topic is explored here though a case study of one particular strand of the TREEC Network Initiative dedicated to storytelling. The heart of the chapter reflects on storytelling as a way to facilitate ‘knowledge exchange’, as well as on the ability of the storytelling events organised to bring together different publics. Whilst critical of ‘impact agendas’, I proceed from the position that, as publicly funded researchers, academics have a responsibility to contribute to the wider society through their knowledge, skills and resources, and that beyond strategic compliance to impact assessment ‘knowledge exchange’, broadly defined, has always been and should remain an integral part of university activities

Measurements of B lifetimes at LHCb

Measurements of the $B_s^0$ effective lifetime in decays to CP-odd and CP-even flavour specific final states allow to probe the width difference $\Delta \Gamma_s$ and the CP-violating phase $\phi_s$ of $B^0_s-\bar{B}^0_s$ mixing box-diagram. Measurements of the effective lifetime in the decay channels $B_s^0 \rightarrow K^+ K^-$ and $\bar{B}_s^0 \rightarrow J/\psi f_0(980)$ are presented, as well as a measurement of $\Delta \Gamma_s$ and $\Gamma_s$ performed by a tagged time-dependent angular analysis of $B_s^0 \rightarrow J/\psi \phi$ decays and a measurement of the sign of $\Delta \Gamma_s$, using data collected during 2011 with the LHCb detector.Comment: Proceedings of CKM 2012, the 7th International Workshop on the CKM Unitarity Triangle, University of Cincinnati, USA, 28 September - 2 October 201

Microscopic approach to the nucleon-nucleon effective interaction and nucleon-nucleon scattering in symmetric and isospin-asymmetric nuclear matter

After reviewing our microscopic approach to nuclear and neutron-rich matter, we focus on how nucleon-nucleon scattering is impacted by the presence of a dense hadronic medium, with special emphasis on the case where neutron and proton densities are different. We discuss in detail medium and isospin asymmetry effects on the total elastic cross section and the mean free path of a neutron or a proton in isospin-asymmetric nuclear matter. We point out that in-medium cross sections play an important role in heavy-ion simulations aimed at extracting constraints on the symmetry potential. We argue that medium and isospin dependence of microscopic cross sections are the results of a complex balance among various effects, and cannot be simulated with a simple phenomenological model.Comment: Prepared for a special issue of EPJA on the nuclear symmetry energ