10,543 research outputs found
Unsupervised edge map scoring: a statistical complexity approach
We propose a new Statistical Complexity Measure (SCM) to qualify edge maps
without Ground Truth (GT) knowledge. The measure is the product of two indices,
an \emph{Equilibrium} index obtained by projecting the edge map
into a family of edge patterns, and an \emph{Entropy} index ,
defined as a function of the Kolmogorov Smirnov (KS) statistic.
This new measure can be used for performance characterization which includes:
(i)~the specific evaluation of an algorithm (intra-technique process) in order
to identify its best parameters, and (ii)~the comparison of different
algorithms (inter-technique process) in order to classify them according to
their quality.
Results made over images of the South Florida and Berkeley databases show
that our approach significantly improves over Pratt's Figure of Merit (PFoM)
which is the objective reference-based edge map evaluation standard, as it
takes into account more features in its evaluation
Probabilistic Graphical Models on Multi-Core CPUs using Java 8
In this paper, we discuss software design issues related to the development
of parallel computational intelligence algorithms on multi-core CPUs, using the
new Java 8 functional programming features. In particular, we focus on
probabilistic graphical models (PGMs) and present the parallelisation of a
collection of algorithms that deal with inference and learning of PGMs from
data. Namely, maximum likelihood estimation, importance sampling, and greedy
search for solving combinatorial optimisation problems. Through these concrete
examples, we tackle the problem of defining efficient data structures for PGMs
and parallel processing of same-size batches of data sets using Java 8
features. We also provide straightforward techniques to code parallel
algorithms that seamlessly exploit multi-core processors. The experimental
analysis, carried out using our open source AMIDST (Analysis of MassIve Data
STreams) Java toolbox, shows the merits of the proposed solutions.Comment: Pre-print version of the paper presented in the special issue on
Computational Intelligence Software at IEEE Computational Intelligence
Magazine journa
The biophysical perspective of a middle income economy: Material Flows in Mexico
We analyse natural resource use dynamics in the Mexican economy during the last three decades. Despite low and uneven economic growth, the extraction and use of materials in the Mexican economy has continuously increased during the last 30 years. In this period, population growth rather than economic growth was the main driving force for biophysical growth. In addition, fundamental changes have taken place in the primary sectors, in manufacturing, and in household consumption and these are reflected in an increasing emphasis on the use of fossil fuels and construction materials. Mexico’s economy has been strongly influenced by international trade since the country commenced competing in international markets. In the 1970s, Mexico mainly exported primary resources. This pattern has changed and manufactured goods now have a much greater importance due to a boom in assembling industries. In contrast with other Latin American countries, Mexico has achieved a diversification of production, moving towards technology-intensive products and a better mix in its export portfolio. However, crude oil exports still represent the single most important export good. Mexico’s material consumption is still well below the OECD average but is growing fast and the current resource use patterns may well present serious social and environmental problems to the medium and long term sustainability of Mexico’s economy and community. Information on natural resource use and resource productivity could provide valuable guidance for economic policy planning in Mexico.Natural resources, resource use patterns and dynamics, physical accounting, material flows, resource use efficiency, Mexico
Constraints to the magnetospheric properties of T Tauri stars - II. The Mg II ultraviolet feature
The atmospheric structure of T Tauri Stars (TTSs) and its connection with the
large scale outflow is poorly known. Neither the effect of the magnetically
mediated inter- action between the star and the disc in the stellar atmosphere
is well understood. The Mg II multiplet is a fundamental tracer of TTSs
atmospheres and outflows, and is the strongest feature in the near-ultraviolet
spectrum of TTSs. The International Ultraviolet Explorer and Hubble Space
Telescope data archives provide a unique set to study the main physical
compounds contributing to the line profile and to derive the properties of the
line formation region. The Mg II profiles of 44 TTSs with resolution 13,000 to
30,000 are available in these archives. In this work, we use this data set to
measure the main observables: flux, broadening, asymmetry, terminal velocity of
the outflow, and the velocity of the Discrete Absorption Components. For some
few sources repeated observations are available and variability has been
studied. There is a warm wind that at sub-AU scales absorbs the blue wing of
the Mg II profiles. The main result found in this work is the correlation
between the line broadening, Mg II flux, terminal velocity of the flow and
accretion rate. Both outflow and magnetospheric plasma contribute to the Mg II
flux. The flux-flux correlation between Mg II and C IV or He II is confirmed;
however, no correlation is found between the Mg II flux and the ultraviolet
continuum or the H2 emission.Comment: 21 pages, 20 figure
Constraints to the magnetospheric properties of T Tauri stars. I. The C II], Fe II] and Si II] ultraviolet features
The C II] feature at ~2325 Angstrom is very prominent in the spectra of T
Tauri stars (TTSs). This feature is a quintuplet of semiforbidden transitions
excited at electron temperatures around 10,000 K that, together with the nearby
Si II] and Fe II] features, provides a reliable optically thin tracer for
accurate measurement of the plasma properties in the magnetospheres of TTSs.
The spectra of 20 (out of 27) TTSs observed with the Space Telescope Imaging
Spectrograph (STIS) on board the Hubble Space Telescope (HST) have good enough
signal to noise ratio (S/N) at the C II] wavelength. For these stars we have
determined electron densities (ne) and temperatures (Te) in the line emission
region as well as the profile broadening (sigma). For most of the stars in the
sample (17) we obtain 10^{4.1} < Te < 10^{4.5} K and 10^{8} < ne < 10^{12}
cm^{-3}. These stars have suprathermal line broadening (35 < sigma < 165 km
s^{-1}), except TW Hya and CY Tau with thermal line broadening. Both C II] line
luminosity and broadening are found to correlate with the accretion rate. Line
emission seems to be produced in the magnetospheric accretion flow, close to
the disk. There are three exceptions: DG Tau, RY Tau and FU Ori. The line
centroids are blueshifted indicating that the line emission in these three
stars is dominated by the outflow.Comment: 13 pages, 15 figures, published in MNRAS minor change
The Biophysical Perspective of a Middle Income Economy: Material Flows in Mexico
In this paper we analyse natural resource use dynamics in the Mexican economy during the last three decades. Despite low and uneven economic growth, the extraction and use of materials in the Mexican economy has continuously increased over the last 30 years. During this time, population growth, rather than economic growth, has been the main driving force for biophysical growth. In addition, a fundamental change in the primary sectors, in manufacturing as well as in household consumption, has taken place and is reflected in an increasing importance of fossil fuel and construction materials use. Mexico’s economy is strongly influenced by international trade since the country has opened up for competition on international markets. In the 1970s, Mexico’s main export was primary resources. This has changed and manufactured goods now have much greater importance due to a boom in assembling industries. Mexico, unlike other Latin American countries, has achieved a diversification of production moving towards technology intensive products and now has a better mix in its export portfolio. However, crude oil exports still represent the single most important export commodity. Mexico’s material consumption is still well bellow the OECD average but is growing fast and the current resource use patterns may well present serious social and environmental problems for the medium and long term sustainability of Mexico’s economy and communities. Information on natural resource use and resource productivity could provide valuable information to guide economic policy planning for Mexico’s future.physical accounting, material flows, resource productivity, Mexico
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