1,721,360 research outputs found
COVID-19 e Pubblica Amministrazione: implicazioni dello smart working per il management e per la salute mentale dei lavoratori
Full text link
Nonlinear Autopilot Design for an Asymmetric Missile Using Robust Backstepping Control
No full textThis paper deals with the design of a robust nonlinear controller for a highly maneuverable missile. Stabilization and tracking are achieved, exploiting a detailed nonlinear model of the six-degree-of-freedom, nonminimum phase, uncertain, and time-varying dynamics of a non-axial-symmetric air-to-air tail-controlled missile. A robust backstepping approach is applied to the multi-input/multi-output model to achieve both bank-to-turn and skid-toturn maneuvers. Control objectives consist of following the reference signals in angle of attack, sideslip, and bank angle produced by the external guidance system, in order to pursue highly agile maneuvers. Uncertain terms, mostly due to aerodynamic coefficients and dynamic pressure, are suitably limited by bounding functions constructed using experience, a priori knowledge on system behavior, and a bit of conservatism. Robust sigmoidlike control functions are then used to dominate in size the uncertain terms. The whole control system is shown to be practically-robustly uniformly asymptotically stable and control objectives are met within a prescribed level of performance, in both bankto-turn and skid-to-turn maneuvers. Simulation results validate the quality of the proposed controller
GEOGRAPHIC VARIABILITY OF THE MILLENNIAL SEA-LEVEL CHANGES ALONG THE COASTS OF ITALY
Full text linkThe large abundance of geological and archeological evidences of past sea-level stands have made the Italian coasts a major focus for the Mediterranean Sea-level science since the beginning of 20th century. We have populated an openaccess database including the postglacial relative sea-level (RSL) data available for the coasts of Italy. The creation of this database, produced following the most recent protocols of sea-level research, also allowed to evaluate the drivers that majorly controlled the variability of the Holocene (last 12 ka BP) sea-level histories along the Italian peninsula. Major subsidence trends (driven by tectonics and sediment compaction) characterize the coastal plains of the north-eastern Adriatic and northern Tuscany. Major uplift trends (often co-seismic) were found in NE Sicily and in the southernmost tip of Calabria. The most complex RSL evolution was observed in the Phlegrean fields volcanic district where, in the same area, we observed the juxtaposition of the highest relict of a mid-Holocene shoreline (more than 34 m above the present sea-level) and evidence of Roman buildings more than 8 m below present sea level. The comparison of the Italian sea-level with the geophysical models routinely used for the prediction of the RSL position through time yielded contrasting results. In particular, our analysis showed that caution should be used in paleogeographic reconstruction for periods older than 8.0 ka BP and only based on geophysical predictions. In fact, none of the models is able to reconcile the proxy-based RSL evolution in the Early Holocene period. This proposed database is an open repository and future production of new RSL data can be easily stored following the same scheme presented in this work
Una riflessione sul ruolo politico del medico
No full textIl medico ha (anche) un ruolo politico, solo in quanto professionista, a prescindere da impegni e convinzioni individuali? L’articolo riflette su questa suggestione, con particolare riferimento alla prospettiva della psichiatria
Nanostructured sp(2)-Carbon Infiltration of Mesoporous Silicon Layers
No full textThe preparation of composite layers made of porous silicon (PS) infiltrated with nanostructured carbon is reported. These composite layers were obtained by chemical vapor infiltration (CVI) of mesoporous silicon under process conditions normally employed to grow diamond films by Hot Filament Chemical Vapour Deposition (HFCVD). Micro-Raman spectroscopy and Field Emission Gun Scanning Electron Microscopy (FEG-SEM) techniques showed that diamond nucleation density was very low whilst sp(2) carbon permeated completely, even after 1 h deposition, the thickness of the PS layers that preserved their mesoporous columnar structure
Start-up Made in Italy: un modello predittivo di exit a partire dagli indicatori di bilancio.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Incorporation of Cd2+ and Ca2+ in the ZrO2 structure: An X-ray and Raman Spectroscopy Investigation"
No full text- …
