Nuova ricerca
 Francesco UNGUENDOLI Ricercatore Universitario presso: Dipartimento di Scienze Fisiche, Informatiche e Matematiche sede ex-Matematica

## Pubblicazioni

2018 - Stylometry and Automatic Attribution of Medieval Liturgical Monodies [Articolo su rivista]
Unguendoli, Francesco; Cristadoro, Giampaolo; Beghelli, Marco
abstract

While automatic attribution of literary text as well as stylometry evaluation are nowadays wellestablished research areas, much less has been done in the field of musicology. Here we present the results of the implementation of an automatic stylometric attribution technique to a corpus of liturgical monodies of medieval origin (the so-called Gregorian Chant, Old Roman Chant and Ambrosian Chant). The ‘unidimensional’ nature of the musical repertoires investigated (rhythmfree melody without accompaniment) allows the adoption of a known method based on a pseudodistance between frequency-vectors of n-gram of consecutive symbols. Finally, we show that some specific features of musicological interest inside the three liturgical families can be naturally extracted using a statistical analysis of n-gram distributions. The results presented show that a quantitative approach is well suited to support and accompany the investigation of refined problems in musicology

2017 - A quantitative method for the attribution of medieval liturgical monody [Relazione in Atti di Convegno]
Unguendoli, Francesco; Cristadoro, Giampaolo; Beghelli, Marco
abstract

We adapt a technique commonly used in the stylometric attribution of literary texts (based on a pseudo-distance between frequency-vectors of n-grams of letters) to the analysis of “unidimensional” musical repertoires (rhythm-free melody without accompaniment). We successfully apply the method to a corpus of liturgical monodies of medieval origin (the so-called Gregorian Chant, in comparison with the Old Roman Chant). Our results giveaﬁrstindicationthatautomaticstylometrictechniquescanbefruitfullyadopted to support the study of reﬁned problems in musicology.

2012 - Rigorous results on the bipartite mean-field model [Articolo su rivista]
M., Fedele; Unguendoli, Francesco
abstract

We consider a bipartite mean-field model in which interaction coefficients and magnetic fields depend only on the groups the particles belong to. We rigorously compute the value of the limiting pressure per particle using tail estimation techniques. We study the phase space of the model in the symmetric regime without an external field and when the interaction coefficients within the two groups are identical. Magnetic field perturbations are considered.

2008 - Correlation Inequalities for Spin Glass in one Dimension [Articolo su rivista]
P., Contucci; Unguendoli, Francesco
abstract

We prove two inequalities for the direct and truncated correlation for the nearest-neighboor one-dimensional Edwards-Anderson model with symmetric quenched dis-order. The second inequality has the opposite sign of the GKS inequality of typeII. In the non symmetric case with positive average we show that while the directcorrelation keeps its sign the truncated one changes sign when crossing a suitableline in the parameter space. That line separates the regions satisfying the GKSsecond inequality and the one proved here.

2008 - GPS navigation for precision farming [Relazione in Atti di Convegno]
Biagi, Ludovico; Capra, Alessandro; Castagnetti, Cristina; Dubbini, Marco; Unguendoli, Francesco
abstract

Precision farming, sometimes called site-specific agriculture, is a strategic task for agriculture: indeed it has the potential to reduce costs through more efficient and effective applications of crop inputs; it can also reduce environmental impacts by allowing farmers to apply inputs only where they are needed at the appropriate rate. Precision farming requires the use of new technologies, such as GPS, environmental sensors, satellites or aerial images and GIS to asses and understand variations. The present research deals with potentialities and limits of GPS for navigation in agricultural applications. GPS needs for farming applications are: − low cost in order to allow farmers to buy GPS technologies; −high precision in order to reduce the use of pesticides and fertilizers by means of an exact track. At first, static and kinematic tests have been performed, simulating the typical behaviour of an agricultural vehicle and usingdifferent kinds of GPS receivers and navigation softwares; the experimental results are presented: particularly, advantages and disadvantages of the popular Kalman filtering on trajectories are discussed. Starting from the analyses of the previous results, and taking into account the typical user requirements, a preliminary design for a new prototype has been done; particularly, both needed instrumentations and their costs and a proposal of a new navigation algorithm will be presented.

2008 - Lack of monotonicity in spin glass correlation functions [Articolo su rivista]
P., Contucci; Unguendoli, Francesco; Vernia, Cecilia
abstract

We study the response of a spin glass system with respect to the rescaling of its interaction random variables and investigate numerically the behaviour of the correlation functions with respect to the volume. While for a ferromagnet the local energy correlation functions increase monotonically with the scale and, by consequence, with respect to the volume of the system we find that in a general spin glass model those monotonicities are violated.

2005 - Interpolating greedy and reluctant algorithms [Articolo su rivista]
P., Contucci; Giardina', Cristian; Giberti, Claudio; Unguendoli, Francesco; Vernia, Cecilia
abstract

In a standard NP-complete optimization problem, we introduce an interpolating algorithm between the quick decrease along the steepest descent direction (greedy dynamics) and a slow decrease close to the level curves (reluctant dynamics). We find that, for a fixed elapsed computer time, the best performance of the optimization is reached at a special value of the interpolation parameter, considerably improving the results of the pure cases of greedy and reluctant. © 2005 Taylor & Francis Group Ltd.

2005 - Local Order at Arbitrary Distances in Finite-Dimensional Spin-Glass Models [Articolo su rivista]
Contucci, P; Unguendoli, Francesco
abstract

For a finite dimensional spin-glass model we prove local order at low temperatures for both localobservables and for products of observables at arbitrary mutual distance. When the Hamiltonianincludes the Edwards-Anderson interaction we prove bond local order, when it includes the random-field interaction we prove site local order.

2003 - Optimization Strategies in Complex Systems [Capitolo/Saggio]
L., Bussolari; P., Contucci; Giardina', Cristian; Giberti, Claudio; Unguendoli, Francesco; Vernia, Cecilia
abstract

We consider a class of combinatorial optimization problems that emerge in a variety of domains among which: condensed matter physics, theory of financial risks, error correcting codes in information transmissions, molecular and protein conformation, image restoration. We show the performances of two algorithms, the "greedy'' (quick decrease along the gradient) and the "reluctant'' (slow decrease close to the level curves) as well as those of a "stochastic convex interpolation'' of the two.Concepts like the average relaxation time and the wideness of theattraction basin are analyzed and their system size dependenceillustrated.

1998 - Absence of glassy behaviour in the deterministic spherical and XY models. [Articolo su rivista]
I., Borsari; F., Camia; S., Graffi; Unguendoli, Francesco
abstract

We consider the infinite-range spin models with Hamiltonian H = ni,j=1 Ji,j i j , where J is the quantization of a map of the torus. Although deterministic, these models are known to exhibit glassy behaviour. We show, through explicit computation of the Gibbs free energy, that unlike the random case this behaviour disappears in the corresponding spherical and continuous XY models. The only minimum of the Gibbs free energy is indeed the trivial one, even though the ground state is highly degenerate.

1998 - Deterministic spin models with glassy behaviour. [Articolo su rivista]
Unguendoli, Francesco
abstract

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1997 - Deterministic spin models with a glassy phase transition [Articolo su rivista]
I., Borsari; M., DEGLI ESPOSTI; S., Graffi; Unguendoli, Francesco
abstract

We consider the infinite-range deterministic spin models with Hamiltonian H = ni,j=1 Ji,j i j , where J is the quantization of a chaotic map of the torus. The mean-field Thouless - Anderson - Palmer (TAP) equations are derived by summing the high-temperature expansion. They predict a glassy phase transition at the critical temperature T near 0.8.

1996 - Ground states for a class of deterministic spin models with glassy behaviour [Articolo su rivista]
I., Borsari; S., Graffi; Unguendoli, Francesco
abstract

We consider the deterministic model with glassy behaviour, recently introduced by Marinari, Parisi and Ritort, with \ha\ $H=\sum_{i,j=1}^N J_{i,j}\sigma_i\sigma_j$, where $J$ is the discrete sine Fourier transform. The ground state found by these authors for $N$ odd and $2N+1$ prime is shown to become asymptotically dege\-ne\-ra\-te when $2N+1$ is a product of odd primes, and to disappear for $N$ even. This last result is based on the explicit construction of a set of eigenvectors for $J$, obtained through its formal identity with the imaginary part of the propagator of the quantized unit symplectic matrix over the $2$-torus..

1994 - Resonant harmonic oscillators and eigenvalue multiplicity [Articolo su rivista]
S., Graffi; Unguendoli, Francesco
abstract

Explicit formulas are worked out for the eigenvalue multiplicity of a systemof $n$ independent quantum harmonic oscillators in the general case of $1\leq s\leqn-1$ resonance relations among the frequencies$\om_1,\ldots,\om_n$. As a particular case we prove that, even though the quantumnumbers are always less than the degrees of freedom, the \ev s are in generalintrinsically degenerate only in the completely resonant case$s=n-1$.