809 research outputs found

    On the Performance Limits of Pilot-Based Estimation of Bandlimited Frequency-Selective Communication Channels

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    In this paper the problem of assessing bounds on the accuracy of pilot-based estimation of a bandlimited frequency selective communication channel is tackled. Mean square error is taken as a figure of merit in channel estimation and a tapped-delay line model is adopted to represent a continuous time channel via a finite number of unknown parameters. This allows to derive some properties of optimal waveforms for channel sounding and closed form Cramer-Rao bounds

    Statistical Characterization and Mitigation of NLOS Errors in UWB Localization Systems

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    In this paper some new experimental results about the statistical characterization of the non-line-of-sight (NLOS) bias affecting time-of-arrival (TOA) estimation in ultrawideband (UWB) wireless localization systems are illustrated. Then, these results are exploited to assess the performance of various maximum-likelihood (ML) based algorithms for joint TOA localization and NLOS bias mitigation. Our numerical results evidence that the accuracy of all the considered algorithms is appreciably influenced by the LOS/NLOS conditions of the propagation environment

    Map-Aware Models for Indoor Wireless Localization Systems: An Experimental Study

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    The accuracy of indoor wireless localization systems can be substantially enhanced by map-awareness, i.e., by the knowledge of the map of the environment in which localization signals are acquired. In fact, this knowledge can be exploited to cancel out, at least to some extent, the signal degradation due to propagation through physical obstructions, i.e., to the so called non-line-of-sight bias. This result can be achieved by developing novel localization techniques that rely on proper map-aware statistical modelling of the measurements they process. In this manuscript a unified statistical model for the measurements acquired in map-aware localization systems based on time-of-arrival and received signal strength techniques is developed and its experimental validation is illustrated. Finally, the accuracy of the proposed map-aware model is assessed and compared with that offered by its map-unaware counterparts. Our numerical results show that, when the quality of acquired measurements is poor, map-aware modelling can enhance localization accuracy by up to 110% in certain scenarios.Comment: 13 pages, 11 figures, 1 table. IEEE Transactions on Wireless Communications, 201

    Francesco Montorsi, Lectures croisées. Étude sur les traductions de récits chevaleresques entre Italie et France autour de 1500

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    La thèse « Lectures croisées » a pour objet les traductions italiennes de récits chevaleresques français et les traductions françaises de récits chevaleresques italiens accomplies jusqu’en 1560. Elle s’insère donc à l’intersection de deux domaines, celui des textes composés au Moyen Âge et encore lus à la Renaissance (et parfois au-delà grâce, par exemple, à la Bibliothèque Bleue), et celui des échanges entre France et Italie en dehors de la culture humaniste. Par ce travail, nous espérons p..

    Pour en finir avec le Moyen Âge. Remarques sur la diffusion et l’abandon des textes médiévaux au xvie siècle

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    The article analyses the story of medieval narrative literature in the 16th century from an editorial point of view. The aim is to shed some light on the print production of ancient vernacular texts, by means of an historical reconstruction and with the help of quantitative figures and graphics. Usually researchers tend to focus on the early phase of the book-history (the shift from manuscript to print) and in the changing rhythms of publication. In a quite paradoxical way, this paper draws a great deal of attention on the last phase of the textual transmission, the decline of the texts, their deaths. Thanks to this approach, I will be able to pinpoint a watershed in the history of the medieval narrative. In the period around the 1530s, printers began to abandon many old vernacular texts, some of which had been great successes for centuries. Various reasons – both aesthetic, sociological and linguistic – explain this editorial and cultural turning point. It is worth noting that this decline precedes as much as it prepares the so-called revolution of the Pléiade generation

    Lancellotto. Versione italiana inedita del “Lancelot en prose”, éd. Luca Cadioli

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    C’est par le plus grand des hasards que, en 2011, dans le grenier d’une villa de Savone (IT), huit cahiers décousus d’un manuscrit ont été redécouverts. Ces cinquante-sept feuillets réchappés de l’oubli ont livré un fragment d’un volgarizzamento inédit du Lancelot. Cette heureuse découverte a comblé une lacune dans la réception de la légende arthurienne en Italie, où les récits les plus importants de la saga ont bénéficié de traductions (Tristan, Estoire del Saint Graal, Merlin, Queste, Mort ..
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