Intersections of the Hermitian Surface with irreducible Quadrics in even Characteristic

We determine the possible intersection sizes of a Hermitian surface $\mathcal H$ with an irreducible quadric of ${\mathrm PG}(3,q^2)$ sharing at least a tangent plane at a common non-singular point when $q$ is even.Comment: 20 pages; extensively revised and corrected version. This paper extends the results of arXiv:1307.8386 to the case q eve

Intersections of the Hermitian surface with irreducible quadrics in PG(3,q2)PG(3,q^2), qq odd

In $PG(3,q^2)$, with $q$ odd, we determine the possible intersection sizes of a Hermitian surface $\mathcal{H}$ and an irreducible quadric $\mathcal{Q}$ having the same tangent plane $\pi$ at a common point $P\in{\mathcal Q}\cap{\mathcal H}$.Comment: 14 pages; clarified the case q=

Intersection sets, three-character multisets and associated codes

In this article we construct new minimal intersection sets in ${\mathrm{AG}}(r,q^2)$ sporting three intersection numbers with hyperplanes; we then use these sets to obtain linear error correcting codes with few weights, whose weight enumerator we also determine. Furthermore, we provide a new family of three-character multisets in ${\mathrm{PG}}(r,q^2)$ with $r$ even and we also compute their weight distribution.Comment: 17 Pages; revised and corrected result

Construction of a 3-Dimensional MDS code

In this paper, we describe a procedure for constructing $q$--ary $[N,3,N-2]$--MDS codes, of length $N\leq q+1$ (for $q$ odd) or $N\leq q+2$ (for $q$ even), using a set of non--degenerate Hermitian forms in $PG(2,q^2)$.Comment: 8 Pages Minor typesetting changes; dedicatio

Progetto SI.MON.A-MAV: sviluppo e sperimentazione delle leggi di controllo del volo di un mini UAV per il monitoraggio del territorio

Lo sviluppo di velivoli senza pilota (UAV) per l’impiego civile è da tempo oggetto di ricerca presso il laboratorio di Meccanica del Volo del Dipartimento di Ingegneria Aerospaziale della Università di Pisa. La presente tesi si propone di mostrare i recenti risultati dell’attività sperimentale svolta presso il suddetto laboratorio nell’ambito del progetto SI.MON.A-MAV, avente come obiettivo la messa a punto di un sistema per il monitoraggio del territorio basato sull’utilizzo di un mini UAV. Tali attività hanno riguardato lo sviluppo e la sperimentazione di un sistema di controllo automatico del volo del velivolo, il quale è caratterizzato da una configurazione fortemente innovativa che gli consente la capacità di effettuare sia il volo a punto fisso (hovering) sia il volo traslato convenzionale. La funzionalità del sistema di controllo è stata inizialmente testata attraverso l’uso del toolbox Simulink di Matlab interfacciandolo con un simulatore di volo open source (FlightGear) con il quale è stata studiata anche la dinamica del volo del velivolo. Successivamente una campagna di prove sperimentali ha consentito di verificare il funzionamento dei vari autopiloti ed ha dimostrato l’effettiva capacità di hovering del mini UAV

A characterization of Hermitian varieties as codewords

It is known that the Hermitian varieties are codewords in the code defined by the points and hyperplanes of the projective spaces $PG(r,q^2)$. In finite geometry, also quasi-Hermitian varieties are defined. These are sets of points of $PG(r,q^2)$ of the same size as a non-singular Hermitian variety of $PG(r,q^2)$, having the same intersection sizes with the hyperplanes of $PG(r,q^2)$. In the planar case, this reduces to the definition of a unital. A famous result of Blokhuis, Brouwer, and Wilbrink states that every unital in the code of the points and lines of $PG(2,q^2)$ is a Hermitian curve. We prove a similar result for the quasi-Hermitian varieties in $PG(3,q^2)$, $q=p^{h}$, as well as in $PG(r,q^2)$, $q=p$ prime, or $q=p^2$, $p$ prime, and $r\geq 4$

Quasi--Hermitian varieties in PG(r,q^2), q even

In this paper a new example of quasi--Hermitian variety \cV in $PG(r,q^2)$, $q$ an odd power of $2$, is provided. In higher-dimensional spaces \cV can be viewed as a generalization of the Buekenhout-Tits unital in the desarguesian projective plane; see \cite{GE2}

Direct Selling: a Marketing Strategy to Shorten Distances between Production and Consumption

Direct sales became in recent years a diversification strategy increasingly used by farms to answer the CAP reform, as well as to react to the continuous price squeeze. Direct sales is in fact a form of marketing that allow farmers to retain a higher share of the final value of products. Far from being a way back to tradition, short chains and direct sales can be seen as strategies to capture new segments of demand interested in local and fresh food, and in more direct contact between consumers and suppliers. The aim of this work is to study the recent evolution of direct selling in Italy and the determinants of the adoption of this marketing strategy. The first part of the paper analyses the evolution of Italian short supply chains and the development of the related institutional framework (national laws and financial incentives). In the second part of the paper the analysis is focused on the determinants of the adoption of direct selling. Specific attention will be devoted to empirically test if the probability of using of this marketing channel is influenced by the farm location in proximity to urban areas.farm diversification, direct selling, short supply chain, periurban agriculture, discrete choice models, Marketing,

tt-Intersection sets in AG(r,q2)AG(r,q^2) and two-character multisets in PG(3,q2)PG(3,q^2)

In this article we construct new minimal intersection sets in $AG(r,q^2)$ with respect to hyperplanes, of size $q^2r-1$ and multiplicity $t$, where $t\in \ q^2r-3-q^(3r-5)/2, q^2r-3+q^(3r-5)/2-q^(3r-3)/2\$, for$r$odd or$t \in \ q^2r-3-q^(3r-4)/2, q^2r-3-q^r-2\$, for$r$even. As a byproduct, for any odd$q$we get a new family of two-character multisets in$PG(3,q^2)$. The essential idea is to investigate some point-sets in$AG(r,q^2)$ satisfying the opposite of the algebraic conditions required in [1] for quasi--Hermitian varieties