1435 research outputs found
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Confronto tra metodi ottici di misura per la caratterizzazione di incisioni laser e waterjet (su materiali lapidei)
No full textVision systems have already been used in the past with OCR (Optical Character Recognition) and their application to segmentation, recognition and classification of characters has allowed the analysis of waterjet and laser engraving on marble specimens in White Carrara and Pearlato Coreno.
This work included the development of a vision system based on 3D optical grids and the use of a laser triangulation (by an optical profilometer) for the characterization and optimization of engravings, and bibliographic work on standards and OCR techniques for printed characters. Finally the two techniques are reviewed with an experimental approach
Fondazioni francescane femminili nella Provincia Tusciae del XIII secolo
No full textRIASSUNTO La storia del francescanesimo in Toscana inizia con il passaggio dello stesso san Francesco e soprattutto con la sua esperienza mistica sul Monte della Verna. Numerosissimi sono stati gli insediamenti delle varie famiglie del primo ordine e con Lucchesio da Poggibonsi si legano alla regione anche le origini dell’Ordine francescano secolare. Il presente studio ricostruisce la presenza del Secondo ordine attraverso i tempi e i luoghi di insediamento della ventina di case femminili distribuite nelle varie custodie e offre pure le linee principali della loro storia, chiusa per alcune già in epoca tardomedievale o, per la maggior parte, con le soppressioni ottocentesche e sopravvissuta oggi solo in pochi casi.
SUMMARY The history of Franciscanism in Tuscany begins with the transit of St Francis himself through the region and particularly with his mystical experience on La Verna Mount. There were in the region numerous houses of the various families of the first Order and with Lucchesio of Poggibonsi the origins of the Franciscan Secular Order are linked with Tuscany. The present study reconstructs the presence of the Second Order through the times and the places of the establishment of about twenty houses of women spread out in the various custodies and it also offers the main delineations of their history, for some already concluded in the late medieval period or, for the greater part, with the suppressions in the 19th century, and only in a few cases it has survived today
Phase diagram of the lattice SU(2) Higgs model
No full textWe perform a detailed study of the phase diagram of the lattice Higgs SU(2)
model with fixed Higgs field length. Consistently with previsions based on the
Fradkin Shenker theorem we find a first order transition line with an endpoint
whose position we determined. The diagram also shows cross-over lines: the
cross-over corresponding to the pure SU(2) bulk is also present at nonzero
coupling with the Higgs field and merges with the one that continues the line
of first order transition beyond the critical endpoint. At high temperature the
first order line becomes a crossover, whose position moves by varying the
temperature
The critical line of QCD with four degenerate quarks
No full textWe determine the pseudo-critical couplings at imaginary chemical potentials
by high-statistics Monte Carlo simulations of QCD with four degenerate quarks
at non-zero temperature and baryon density by the method of analytic
continuationan. We reveal deviations from the simple quadratic dependence on
the chemical potential visible in earlier works on the same subject. Finally,
we discuss the implications of our findings for the shape of the
pseudo-critical line at real chemical potential, comparing different possible
extrapolations
A laser gyroscope system to detect the Gravito-Magnetic effect on Earth
No full textLarge scale square ring laser gyros with a length of four meters on each side
are approaching a sensitivity of 1x10^-11 rad/s/sqrt(Hz). This is about the
regime required to measure the gravitomagnetic effect (Lense Thirring) of the
Earth. For an ensemble of linearly independent gyros each measurement signal
depends upon the orientation of each single axis gyro with respect to the
rotational axis of the Earth. Therefore at least 3 gyros are necessary to
reconstruct the complete angular orientation of the apparatus. In general, the
setup consists of several laser gyroscopes (we would prefer more than 3 for
sufficient redundancy), rigidly referenced to each other. Adding more gyros for
one plane of observation provides a cross-check against intra-system biases and
furthermore has the advantage of improving the signal to noise ratio by the
square root of the number of gyros. In this paper we analyze a system of two
pairs of identical gyros (twins) with a slightly different orientation with
respect to the Earth axis. The twin gyro configuration has several interesting
properties. The relative angle can be controlled and provides a useful null
measurement. A quadruple twin system could reach a 1% sensitivity after 3:2
years of data, provided each square ring has 6 m length on a side, the system
is shot noise limited and there is no source for 1/f- noise
On Confinement Index
No full textThe smallest integer t for which the Wilson loop W^{t} fails to exhibit area
law is known as the confinement index of a given field theory. The confinement
index provides us with subtle information on the vacuum properties of the
system. We study the behavior of the Wilson and 't Hooft loops and compute the
confinement index in a wide class of N=1 supersymmetric gauge theories. All
possible electric and magnetic screenings are taken into account. The results
found are consistent with the theta periodicity, and whenever such a check is
available, with the factorization property of Seiberg-Witten curves
Toward a well defined monopole creation operator
No full textSUMMARY The lattice implementation of monopole creation operator proves to have
problems related to bulk transitions that can possibly affect the
interpretation of its mean value as an order parameter for monopole
condensation. Preliminary evidence is presented that these unexpected
behaviours are in fact only due to lattice artefacts and do not spoil the
physical interpretation of the monopole operator
Quantum critical behavior and trap-size scaling of trapped bosons in a one-dimensional optical lattice
No full textWe study the quantum (zero-temperature) critical behaviors of confined
particle systems described by the one-dimensional (1D) Bose-Hubbard model in
the presence of a confining potential, at the Mott insulator to superfluid
transitions, and within the gapless superfluid phase. Specifically, we consider
the hard-core limit of the model, which allows us to study the effects of the
confining potential by exact and very accurate numerical results. We analyze
the quantum critical behaviors in the large trap-size limit within the
framework of the trap-size scaling (TSS) theory, which introduces a new trap
exponent theta to describe the dependence on the trap size. This study is
relevant for experiments of confined quasi 1D cold atom systems in optical
lattices. At the low-density Mott transition TSS can be shown analytically
within the spinless fermion representation of the hard-core limit. The
trap-size dependence turns out to be more subtle in the other critical regions,
when the corresponding homogeneous system has a nonzero filling f, showing an
infinite number of level crossings of the lowest states when increasing the
trap size. At the n=1 Mott transition this gives rise to a modulated TSS: the
TSS is still controlled by the trap-size exponent theta, but it gets modulated
by periodic functions of the trap size. Modulations of the asymptotic power-law
behavior is also found in the gapless superfluid region, with additional
multiscaling behaviors
Partial model checking via abstract interpretation
No full textSUMMARY Nowadays the emphasis in software engineering research is on the evolution of pre-existing sub-systems and component development. In this context, we tackle the following problem: given the formal specification of the system P, already built, how to characterize possible collaborators of P, through a given communication interface L, to the satisfaction of a given property φ. We propose an abstract interpretation framework to reason about this problem in a systematic way. Given P and L, the set of all transition systems that, composed with P and restricted by L, satisfy φ, is modeled as the abstract semantics of φ, parametric with respect to P and L. We show that the algorithm developed by Andersen (1995) [1] can be formulated in our framework
Le biblioteche, le nuove tecnologie e l'apprendimento informale
No full textIn the world of knowledge, libraries (public institutions and multimedia laboratories) become a privileged place for elaborating information and learning. Only in libraries it is possible to select, personalize and analyze information and web data. Traditional services (loan, reference, preservation) are supported by new technological instruments, that are necessary to satisfy individual needs. The social framework, that library naturally creates, is extremely important because it causes many informal educational processes that complete and fortify students curriculum. Many formative stages can take place in Italian universities libraries, before and after taking a degree. The trainer acquires many technical skills (data banks, audio and video storage mediums, electronic journals) that are always included in a social framework where the librarian gets the role of a tutor in order to simplify learning process. The teaching program is based on a tutorial workshop strategy, where students elaborate personalised projects, set themselves aims suited to their interests and studies; trainer’s motivation is the most powerful cognitive variable. The key of a library stage’s success is the problem oriented setting; that kind of trainings, in fact, are concretely integrated in educational academic programs. The concrete presence in the library is really crucial, because learning is an intrinsic form of the job itself. Library becomes a “learning environment” where students can apply different learning techniques: they practise specific tutorial projects or they can collaborate together in small teams. The strategies are always related to the constructivism pedagogical theories