635,980 research outputs found
Lattice methods and the nuclear few- and many-body problem
We begin with a brief overview of lattice calculations using chiral effective
field theory and some recent applications. We then describe several methods for
computing scattering on the lattice. After that we focus on the main goal,
explaining the theory and algorithms relevant to lattice simulations of nuclear
few- and many-body systems. We discuss the exact equivalence of four different
lattice formalisms, the Grassmann path integral, transfer matrix operator,
Grassmann path integral with auxiliary fields, and transfer matrix operator
with auxiliary fields. Along with our analysis we include several coding
examples and a number of exercises for the calculations of few- and many-body
systems at leading order in chiral effective field theory.Comment: 20 pages, 3 figures, Submitted to Lect. Notes Phys., "An advanced
course in computational nuclear physics: Bridging the scales from quarks to
neutron stars", M. Hjorth-Jensen, M. P. Lombardo, U. van Kolck, Editor
Equivalence of Deterministic One-Counter Automata is NL-complete
We prove that language equivalence of deterministic one-counter automata is
NL-complete. This improves the superpolynomial time complexity upper bound
shown by Valiant and Paterson in 1975. Our main contribution is to prove that
two deterministic one-counter automata are inequivalent if and only if they can
be distinguished by a word of length polynomial in the size of the two input
automata
On the Complex Network Structure of Musical Pieces: Analysis of Some Use Cases from Different Music Genres
This paper focuses on the modeling of musical melodies as networks. Notes of
a melody can be treated as nodes of a network. Connections are created whenever
notes are played in sequence. We analyze some main tracks coming from different
music genres, with melodies played using different musical instruments. We find
out that the considered networks are, in general, scale free networks and
exhibit the small world property. We measure the main metrics and assess
whether these networks can be considered as formed by sub-communities. Outcomes
confirm that peculiar features of the tracks can be extracted from this
analysis methodology. This approach can have an impact in several multimedia
applications such as music didactics, multimedia entertainment, and digital
music generation.Comment: accepted to Multimedia Tools and Applications, Springe
On the Modeling of Musical Solos as Complex Networks
Notes in a musical piece are building blocks employed in non-random ways to
create melodies. It is the "interaction" among a limited amount of notes that
allows constructing the variety of musical compositions that have been written
in centuries and within different cultures. Networks are a modeling tool that
is commonly employed to represent a set of entities interacting in some way.
Thus, notes composing a melody can be seen as nodes of a network that are
connected whenever these are played in sequence. The outcome of such a process
results in a directed graph. By using complex network theory, some main metrics
of musical graphs can be measured, which characterize the related musical
pieces. In this paper, we define a framework to represent melodies as networks.
Then, we provide an analysis on a set of guitar solos performed by main
musicians. Results of this study indicate that the presented model can have an
impact on audio and multimedia applications such as music classification,
identification, e-learning, automatic music generation, multimedia
entertainment.Comment: to appear in Information Science, Elsevier. Please cite the paper
including such information. arXiv admin note: text overlap with
arXiv:1603.0497
The role of angularity in route choice: an analysis of motorcycle courier GPS traces
The paths of 2425 individual motorcycle trips made in London
were analyzed in order to uncover the route choice decisions made
by drivers. The paths were derived from global positioning system (GPS)
data collected by a courier company for each of their drivers, using algorithms
developed for the purpose of this paper. Motorcycle couriers were
chosen due to the fact that they both know streets very well and that
they do not rely on the GPS to guide their navigation. Each trace was
mapped to the underlying road network, and two competing hypotheses
for route choice decisions were compared: (a) that riders attempt to
minimize the Manhattan distance between locations and (b) that they
attempt to minimize the angular distance. In each case, the distance actually
traveled was compared to the minimum possible either block or
angular distance through the road network. It is usually believed that
drivers who know streets well will navigate trips that reduce Manhattan
distance; however, here it is shown that angularity appears to play an
important role in route choice. 63% of trips made took the minimum
possible angular distance between origin and destination, while 51% of
trips followed the minimum possible block distance. This implies that
impact of turns on cognitive distance plays an important role in decision
making, even when a driver has good knowledge of the spatial network
OpenJML: Software verification for Java 7 using JML, OpenJDK, and Eclipse
OpenJML is a tool for checking code and specifications of Java programs. We
describe our experience building the tool on the foundation of JML, OpenJDK and
Eclipse, as well as on many advances in specification-based software
verification. The implementation demonstrates the value of integrating
specification tools directly in the software development IDE and in automating
as many tasks as possible. The tool, though still in progress, has now been
used for several college-level courses on software specification and
verification and for small-scale studies on existing Java programs.Comment: In Proceedings F-IDE 2014, arXiv:1404.578
Teaching Theoretical Physics: the cases of Enrico Fermi and Ettore Majorana
We report on theoretical courses by Fermi and Majorana, giving evidence of
the first appearance and further development of Quantum Mechanics teaching in
Italy. On the basis of original documents, we make a comparison between Fermi's
and Majorana's approaches. A detailed analysis is carried out of Fermi's course
on Theoretical Physics attended by Majorana in 1927-28. Three (previously
unknown) programs on advanced Physics courses submitted by Majorana to the
University of Rome between 1933 and 1936 and the course he held in Naples in
1938 complete our analysis: Fermi's phenomenological approach resounded in
Majorana, who however combined it with a deeper theoretical approach, closer to
the modern way of presenting Quantum Mechanics.Comment: latex, 21 pages; a contribution in the centenary of the birth of
Ettore Majoran
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