88,030 research outputs found
G. Verde, Diritto processuale civile. 2. Processo di cognizione. Aggiornamento a cura di di Gian Paolo Califano
No full textRepetitive Control Meets Continuous Zero Phase Error Tracking Controller for Precise Tracking of B-Spline Trajectories
No full textIn this paper, a novel repetitive control scheme is presented and discussed, based on the so-called B-spline filters. These dynamic filters are able to generate a B-spline trajectory if they are fed with the sequence of control points defining the curve. Therefore, they are ideal tools for generating online reference signals with the prescribed level of smoothness for driving dynamic systems, possibly together with a feedforward compensator. In particular, a continuous zero phase error tracking controller (ZPETC) can be used for tracking control of nonminimum phase systems but because of its open-loop nature it cannot guarantee the robustness with respect to modeling errors and exogenous disturbances. For this reason, ZPETC and trajectory generator have been embedded in a repetitive control scheme that allows to nullify interpolation errors even in nonideal conditions, provided that the desired reference trajectory and the disturbances are periodic. This paper is based on the results presented in the conference paper [L. Biagiotti, F. Califano, and C. Melchiorri, 'Repetitive control of non-minimum phase systems along b-spline trajectories,' in Proc. IEEE 55th Conf. Decis. Control, 2016, pp. 5496-5501.], where asymptotic stability of the overall control scheme has been proved mathematically, but extends such results with an experimental validation based on a nonminimum phase system. Different models of the same physical system have been identified and used in the implementation of this model-based control scheme, allowing a real evaluation of the relationship between control system performance and model accuracy
llljus, Bruno: Ani Shinan: Schamanismus bei den Shipibo-Conibo (Ost-Peru). Verlag S&F, Tübingen, 1987, 415 páginas, dibujos, apéndices.
No full textFil: Califano, Mario.
Centro Argentino de Etnología Americana (Buenos Aires, Argentina
Editorial: Special issue: Present achievements and new frontiers in space plasmas
No full textSpace plasma physics, pushed by the impressive recent technological developments, is undergoing a period of intense progress. This progress is achieved first at the level of observations, including both remote and in situ measurements, but also on the theoretical side, mainly by means of large scale numerical simulations made possible by the dramatic increase of computational resources. In particular, three-dimensional mainly hybrid but also fully kinetic simulations are today feasible, and large intervals in spatial and time scales can at last be accessed by fluid simulations. Addressing fundamental problems such as, e.g. magnetic reconnection, nonlinear dynamics or turbulence development in the kinetic range, are no longer just a heart’s desire today
A stability analysis based on dissipativity of linear and nonlinear repetitive control
No full textThis paper deals with repetitive control (RC). More specifically, a parametrised version of the repetitive compensator, i.e. of the infinite-dimensional controller employed in RC schemes, modelled as a boundary control system (BCS) in port-Hamiltonian form is presented. Well-posedness and stability of such control scheme are rigorously addressed thanks to novel tools based on dissipativity theory and originally developed for the stabilisation of BCS. Here, the linear and the nonlinear cases are tackled, and in both the cases the classes of plants for which RC schemes are exponentially stable are determined. Moreover, and explicit motivation of perfect asymptotic tracking and disturbance rejection for exponentially stable RC systems without relying on the internal model theory is provided. To show the validity of the analysis, simulations are reported. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved
Viscoplastic simple shear at finite strains
No full textThe equations governing the simple shear deformation of an incompressible inelastic material undergoing finite strain are derived in this paper. The constitutive assumptions are kept in their most general form to allow the incorporation of widely used viscoplastic or viscoelastic models from the literature. It is shown that, while for a hyperelastic material the simple shear problem is completely determined by a single parameter, the amount of shear, in the viscoplastic case, the elastic deformation is the superposition of a triaxial stretch and a simple shear, whose determination requires the solution of three coupled nonlinear evolution equations. We evaluate such a solution for different material models and compare it with three-dimensional finite element simulations to assess its accuracy. We further assess the performance of these models using experimental data from filled rubber, focusing on their ability to capture the observed behaviour, such as the well-known Payne effect. Additionally, we extend our simple shear solution to address torsion and the extension of thin-walled cylinders. These derivations and analyses offer valuable insights for experimentalists engaged in the mechanical characterization of soft materials
T-accessibility for Nonlinear Time-Delay Systems: The general case
No full textFollowing the results recently obtained for nonlinear driftless systems affected by constant commensurate delays, a partial characterization of t - accessibility is provided for general nonlinear time-delay systems affected by constant commensurate delays. Conditions are given for this new property. The results are stated using the differential representation of time-delay systems
La Sindrome di Frey
No full textGli AA costituiscono il Gruppo di Studio della Società Italiana di Chirurgia Maxillo-Facciale coordinato dal Prof. Enrico Panzoni di Firenze. E’ uno studio frutto della esperienza di numerose Scuole italiane di Chirurgia maxillo-Facciale. Della Sindrome di Frey, dopo una ampia introduzione che comprende cenni storici e richiami di anatomia (L. Califano, A. Zupi - Napoli), vengono dettagliatamente descritti gli aspetti clinici e diagnostici (T. Cutilli – L’Aquila), gli aspetti fisiopatologici (C. Gallesio, M. Miconi – Torino), la profilassi (R. Vinci, U. Zanetti – Brescia), le metodiche di approccio terapeutico (A.B. Giannì, G. Moscato – Parma), la casistica e le considerazioni conclusive (P. Salvatori, F. Zucca – Cagliari)
Drop Size Evolution during the Phase Separation of Liquid Mixtures
No full textAfter quenching a partially miscible, initially homogeneous, critical liquid mixture to a temperature T deeply below its critical point of miscibility, we observed the formation of rapidly coalescing droplets, whose size grows linearly with time. Eventually, when their size reaches a critical length which is roughly equal to one tenth of the capillary length, the nucleating drops start sedimenting and the two phases rapidly segregate by gravity. This behavior was observed for both density-segregated and quasi-isopycnic systems, showing that gravity cannot be the driving force responsible for the enhancement of the coalescence among the nucleating drops. This result is in line with previous theoretical works based on the diffuse interface model, predicting that the phase separation of low viscosity liquid mixtures is a convection-driven process, induced by a body force which is proportional to the chemical potential gradients. Finally, at later times, following the evolution of isolated drops of the secondary emulsion, we saw that their size grows in time like t^1/3
- …
