4,505 research outputs found
The local structure of the free boundary in the fractional obstacle problem
No full textBuilding upon the recent results in [M. Focardi and E. Spadaro, On the measure and the structure of the free boundary of the lower-dimensional obstacle problem, Arch. Ration. Mech. Anal. 230 2018, 1, 125-184] we provide a thorough description of the free boundary for the solutions to the fractional obstacle problem in Rn+1 with obstacle function φ (suitably smooth and decaying fast at infinity) up to sets of null Hn-1 measure. In particular, if φ is analytic, the problem reduces to the zero obstacle case dealt with in [M. Focardi and E. Spadaro, On the measure and the structure of the free boundary of the lower-dimensional obstacle problem, Arch. Ration. Mech. Anal. 230 2018, 1, 125-184] and therefore we retrieve the same results: Local finiteness of the (n-1)-dimensional Minkowski content of the free boundary (and thus of its Hausdorff measure), Hn-1-rectifiability of the free boundary, classification of the frequencies and of the blowups up to a set of Hausdorff dimension at most (n-2) in the free boundary. Instead, if φ ∈ Ck+1(Rn), k ≥ 2, similar results hold only for distinguished subsets of points in the free boundary where the order of contact of the solution with the obstacle function φ is less than k + 1
Dal Risorgimento alla Seconda guerra mondiale : Formazione, trasmissione, usi pubblici del passato nell’Italia contemporanea
No full textInterventi relativi alla presentazione dei libri di Massimo Baioni (Vedere per credere. Il racconto museale dell’Italia unita, Roma, Viella, 2020) e di Filippo Focardi (Nel cantiere della memoria. Fascismo, Resistenza, Shoah, Foibe, Roma, Viella, 2020. Attorno a questi due libri, per certi versi complementari e in dialogo tra loro, si è svolta una discussione relativa alla memoria risorgimentale e alle memorie del fascismo, della Seconda guerra mondiale, della Resistenza e della Shoah. Al di là della storiografia e del suo ruolo nella formazione di un discorso pubblico nella penisola, il dibattito ha riguardato la formazione e trasmissione del sentimento nazionale oggi in Italia, il rapporto tra gli storici e i mezzi di comunicazione attuali, la costituzione di una memoria europea. Al centro della discussione sta insomma la questione del rapporto che abbiamo oggi con la Storia, una questione fondamentale nei lavori di Baioni e di Focardi, che possono essere entrambi considerati come due «sismografi» della percezione odierna dell’idea di nazione
Name-passing calculi and crypto-primitives: A survey
No full textThe paper surveys the literature on high-level name-passing process calculi, and their extensions with cryptographic primitives. The survey is by no means exhaustive, for essentially two reasons. First, in trying to provide a coherent presentation of different ideas and techniques, one inevitably ends up leaving out the approaches that do not fit the intended roadmap. Secondly, the literature on the subject has been growing at very high rate over the years. As a consequence, we decided to concentrate on few papers that introduce the main ideas, in the hope that discussing them in some detail will provide sufficient insight for further reading
Security Abstractions and Intruder Models
No full textProcess algebraic specifications of distributed systems are increasingly being targeted at identifying security primitives well-suited as high-level programming abstractions, and at the same time adequate for security analysis and verification. Drawing on our earlier work along these lines in [Bugliesi and Focardi 2008], we investigate the expressive power of a core set of security and network abstractions that provide high-level primitives for the specifications of the honest principals in a network as well as the lower-level adversarial primitives that must be assumed available to an attacker.
We analyze various bisimulation equivalences for security, arising from endowing the intruder with (i) different adversarial capabilities and (ii) increasingly powerful control on the interaction among the distributed principals of a network. By comparing the relative strength of the bimimulation equivalences we obtain a a direct measure of the discriminating power of the intruders, hence of the expressiveness of the corresponding models
Channel Abstractions for Network Security
No full textProcess algebraic techniques for distributed systems are increasingly being targeted at identifying abstractions adequate both for high-level programming and specification, and for security analysis and verification.
Drawing on our earlier work in
[Bugliesi & Focardi 2008] F08}, we investigate the expressive power of a core set of security and network abstractions that provide high-level primitives for the specifications of the honest principals in a network, while at the same time enabling an analysis of the network-level adversarial attacks that may be mounted by an intruder.
We analyze various bisimulation equivalences for security, arising from endowing the intruder with (i) different adversarial capabilities and (ii) increasingly powerful control on the interaction among the distributed principals of a network. By comparing the relative strength of the bisimulation equivalences, we obtain a direct measure of the discriminating power of the intruder, hence of the expressiveness of the corresponding intruder model
Index-exciting CAViaR: A new empirical time-varying risk model
No full textDashan Huang, Baimin Yu, Zudi Lu, Frank J. Fabozzi, Sergio Focardi, and Masao Fukushim
ASYMPTOTIC ANALYSIS OF AMBROSIO-TORTORELLI ENERGIES IN LINEARIZED ELASTICITY
No full textWe provide an approximation result in the sense of Gamma-convergence for energies of the form integral(Omega) L-1 (e(u)) dx + a Hn-1 (J(u)) + b integral (Ju) L-0(1/2) ([u] circle dot nu(u)) dH(n-1) where Omega subset of R-n is a bounded open set with Lipschitz boundary, L-0 and L-1 are coercive quadratic forms on M-sym(nxn), a, b are positive constants, and u runs in the space of fields SBD2(Omega); i.e., it's a special field with bounded deformation such that its symmetric gradient e(u) is square integrable, and its jump set J(u) has finite (n-1)-Hausdorff measure in R-n. The approximation is performed by means of Ambrosio-Tortorellitype elliptic regularizations, the prototype example being integral(Omega) (v vertical bar e(u)vertical bar(2) + gamma epsilon vertical bar del v vertical bar(2)) dx, where (u, v) is an element of H-1(Omega, R-n) x H-1(Omega), epsilon <= v <= 1, and gamma > 0
Anthropogenic impacts on the Orbetello lagoon ecosystem
No full textThe aim of the present study was to assess the environmental quality of Orbetello lagoon (Tyrrhenian coast, Italy), using a biomonitoring method based on measuring organochlorinated pollutants in the Anguilla anguilla, chosen as sentinel organism, and remote sensing data obtained by elaboration of Landsat 7 Enhanced Thematic Mapper (ETM) data of 2002. Polychlorinated biphenyls and organochlorine pesticides were determined by gas chromatography/mass spectrometry in muscle of European eels captured in seven sites having different levels of pollution in Orbetello lagoon.
Remote sensing data and chemical analysis showed the Albegna river as a probable vehicle of
pesticides (hexachlorocyclohexanes)
Lower semi-continuity for non-coercive polyconvex integrals in the limit case
No full textLower semi-continuity results for polyconvex functionals of the calculus of variations along sequences of maps u: Omega subset of R-n -> R-m in W-1,W-m, 2 <= m <= n, weakly converging in W-1,W-m-1 are established. In addition, for m = n + 1, we also consider the autonomous case for weakly converging maps in W-1,W-n-1. © 2016 Royal Society of Edinburgh
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