1,721,747 research outputs found
Giovanni Federico, Il filo d'oro. L'industria mondiale della seta dalla restaurazione alla grande crisi
No full textChassagne Serge. Giovanni Federico, Il filo d'oro. L'industria mondiale della seta dalla restaurazione alla grande crisi. In: Annales. Histoire, Sciences Sociales. 53ᵉ année, N. 4-5, 1998. pp. 1028-1031
Periodic orbits of the N-body problem with the symmetry of platonic polyhedra.
No full textWe review some recently discovered periodic orbits of the N-body
problem, whose existence is proved by means of
variational methods. These orbits are minimizers of the Lagrangian
action functional in a set of -periodic loops, equivariant for the
action of a group and satisfying some topological constraints.
Both the group action and the topological constraints are defined
using the symmetry of Platonic polyhedra
Generalized averaging principle and the secular evolution of planet crossing orbits
No full textPlanet crossing orbits give rise to mathematical singularities that make it not possible
to apply the classical averaging principle to study the qualitative evolution of Near Earth Asteroids
(NEAs). Recently this principle has been generalized to deal with crossings in a mathematical model
with the planets on circular coplanar orbits. More accuracy is needed to compute the averaged
evolution of planet crossing orbits for different purposes: computing reliable crossing times for the
averaged motion, writing more precise proper elements and frequencies for NEAs, etc. In this paper
we present the generalization of the averaging principle using a model where the eccentricity and the
inclination of the planets are taken into account
Sei Sonate Per Il Clavi Cembalo : Composte E Dedicate A Sua Altezza Serenissima Anna Amalia, Duchessa Di Sassonia Weimar Ed Eisenach &c. &c, / Reichardt, Giovanni Federico. - Musikdruck. - In Berlino : Mylius, 1778 ; T. 2
Full text linkSEI SONATE PER IL CLAVI CEMBALO : COMPOSTE E DEDICATE A SUA ALTEZZA SERENISSIMA ANNA AMALIA, DUCHESSA DI SASSONIA WEIMAR ED EISENACH &C. &C, / REICHARDT, GIOVANNI FEDERICO. - MUSIKDRUCK. - IN BERLINO : MYLIUS, 1778 ; T. 2
Sei Sonate Per Il Clavi Cembalo : Composte E Dedicate A Sua Altezza Serenissima Anna Amalia, Duchessa Di Sassonia Weimar Ed Eisenach &c. &c, / Reichardt, Giovanni Federico. - Musikdruck. - In Berlino : Mylius, 1778 (-)
Sei Sonate Per Il Clavi Cembalo : Composte E Dedicate A Sua Altezza Serenissima Anna Amalia, Duchessa Di Sassonia Weimar Ed Eisenach &c. &c, / Reichardt, Giovanni Federico. - Musikdruck. - In Berlino : Mylius, 1778 ; T. 2 (T. 2) (1)
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GSRTM 1.0: un sistema cross-platform, integrato, low cost per la misurazione della risposta galvanica cutanea e la gestione di sessioni sperimentali
No full textNelle ultime due decadi abbiamo assistito alla crescente disponibilità di strumenti hardware di notevole complessità e di un costo relativamente basso. Basti pensare a come il kit robotico della Lego (Mindstorms) ha rivoluzionato il modo di pensare alla robotica. Una scienza dura e difficile che ad un tratto si è ritrovata alla portata della curiosità dei bambini (Miglino e Gigliotta, 2002; Miglino, Ponticorvo, Gigliotta e Nolfi, 2008). Ma il fenomeno hardware doveva attendere ancora qualche anno per esplodere grazie al successo indiscusso di una scheda open hardware italiana: Arduino 1. Ispirato dalla necessità di fornire ai designer uno strumento di veloce prototipizzazione, Arduino è una scheda elettronica low cost, dotata di un microprocessore e delle porte di input/output, che permette in modo rapido l'acquisizione di informazioni digitali e il controllo di attuatori di interesse. L'uso di questo tipo di schede può aver un grande ruolo nel rendere low budget le attrezzature per studiare dei fenomeni cognitivi. In particolare, in questo lavoro introduciamo GSRTM, una piattaforma hardware/software che consta di uno strumento hardware realizzato attraverso una scheda open hardware per registrare la risposta galvanica cutanea (GSR Tool 1.0), un indice fisiologico legato ad aspetti psicologici come il carico cognitivo (Nourbakhsh, Wang, Chen e Calvo, 2012) o all'esperienza emotiva (Westerink et al., 2008) ed uno strumento software (GSR Manager 1.0) in grado di gestire in maniera flessibile ed efficace sessioni sperimentali. GSR Tool 1.0: Hardware per la misurazione della risposta galvanica cutanea
Multiple Solutions in Preliminary Orbit Determination from Three Observations
Full text linkSUMMARY Charlier's theory (1910) provides a geometric interpretation of the occurrence of multiple solutions in Laplace's method of preliminary orbit determination, assuming geocentric observations. We introduce a generalization of this theory allowing to take into account topocentric observations, that is observations made from the surface of the rotating Earth. The generalized theory works for both Laplace's and Gauss' methods. We also provide a geometric definition of a curve that generalizes Charlier's limiting curve, separating regions with a different number of solutions. The results are generically different from Charlier's: they may change according to the value of a parameter that depends on the observations
On the stationary points of the squared distance between two ellipses with a common focus
No full textIn this paper we introduce an effective algebraic method for the computation of all
the stationary points of the squared distance d2 between a point on one ellipse and a point on a
second ellipse with a focus in common with the first one.
This problem comes from celestial mechanics, in which the minima between two elliptic Keplerian
orbits are relevant to study the probability of collision; some applications of our algorithm in this
field are shown.
This algorithm is based on the use of the fast Fourier transform to obtain the coefficients of the
resultant of the two bivariate components of the gradient of d2 with respect to one variable and relies
on specific tools in symbolic computation.
An upper bound to the total number of stationary points that we have to expect in this problem is also given; this is done using some tools from algebraic geometry
An algebraic method to compute the critical points of the distance function between two Keplerian orbits
No full textWe describe an efficient algorithm to compute all the critical points
of the distance function between two Keplerian orbits (either bounded
or unbounded) with a common focus. The critical values of this
function are important for different purposes, for example to evaluate
the risk of collisions of asteroids or comets with the Solar system
planets. Our algorithm is based on the algebraic elimination theory:
through the computation of the resultant of two bivariate polynomials,
we find a degree univariate polynomial whose real roots give
us one component of the critical points. We discuss also some
degenerate cases and show several examples, involving the orbits of
the known asteroids and comets
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