15,485 research outputs found
Stretchable electronics for artificial skin
Postprint (published version
A Framework for Evaluating Land Use and Land Cover Classification Using Convolutional Neural Networks
Analyzing land use and land cover (LULC) using remote sensing (RS) imagery is essential
for many environmental and social applications. The increase in availability of RS data has led to the
development of new techniques for digital pattern classification. Very recently, deep learning (DL)
models have emerged as a powerful solution to approach many machine learning (ML) problems.
In particular, convolutional neural networks (CNNs) are currently the state of the art for many image
classification tasks. While there exist several promising proposals on the application of CNNs to
LULC classification, the validation framework proposed for the comparison of different methods
could be improved with the use of a standard validation procedure for ML based on cross-validation
and its subsequent statistical analysis. In this paper, we propose a general CNN, with a fixed
architecture and parametrization, to achieve high accuracy on LULC classification over RS data
from different sources such as radar and hyperspectral. We also present a methodology to perform
a rigorous experimental comparison between our proposed DL method and other ML algorithms
such as support vector machines, random forests, and k-nearest-neighbors. The analysis carried out
demonstrates that the CNN outperforms the rest of techniques, achieving a high level of performance
for all the datasets studied, regardless of their different characteristics.Ministerio de Economía y Competitividad TIN2014-55894-C2-1-RMinisterio de Economía y Competitividad TIN2017-88209-C2-2-
Comparison of theoretical heat transfer model with results from experimental monitoring installed in a refurbishment with ventilated facade
One of the main points to consider when a building is renovated is the improvement of its energy efficiency, minimizing the heat loss through the enclosures and its heating consumption. Under this scope idea a ventilated facade was designed and incorporated in an educational building located in the city of Burgos (Spain). The main objective of this document is a comparison between the theoretical model of heat transfer across the building envelope separating the environment and the interior space, and the heat intake through a linear regression model with installed experimental monitoring. For this it has been necessary to carry out an exhaustive study of the thermal transmission of each one of the materials that make up the thermal envelope of the building, as well as the linear thermal bridges that can be produced before and after the renovation. In addition, thanks to the monitoring installed in the demonstrator building, the interior and exterior temperatures and the heat consumption of each of the radiators is known. In this way expected and real energy savings have been compared
Making more flexible ATISMART+ model for traffic simulations using a CAS
Traffic simulations usually require the search of a path to join two different
points. Dijkstra’s algorithm [1] is one of the most commonly used for this task due
to its easiness and quickness. In [2, 3] we developed an accelerated time simulation
of car traffic in a smart city using Dijkstra’s algorithm to compute the paths.
Dijkstra’s algorithm provides a shortest path between two different points but
this is not a realistic situation for simulations. For example, in a car traffic situa-
tion, the driver may not know the shortest path to follow. This ignorance can be
produced, among others, because one of the following two facts: the driver may
not know the exact length of the lanes, or, even knowing the exact length, the driver
may not know how to find the shortest path. Even more, in many cases, a mixture
of both facts occurs.
A more realistic simulation should therefore consider these kind of facts. The
algorithm used to compute the path from one point to another in a traffic simulation
might consider the possibility of not using the shortest path.
In this talk, we use a new probabilistic extension of Dijkstra’s algorithm which
covers the above two situations. For this matter, two different modifications in Di-
jkstra’s algorithm have been introduced: using non-exact length in lanes, and the
choice of a non-shortest path between two different points. Both modifications are
used in a non-deterministic way by means of using probability distributions (classi-
cal distributions such as Normal or Poisson distributions or even "ad hoc" ones). A
precise, fast, natural and elegant way of working with such probability distributions
is the use of a CAS in order to deal with exact and explicit computations.
As an example of use of this extension of Dijkstra’s algorithm, we will show
the ATISMART+ model. This model provides more realistic accelerated time sim-
ulations of car traffics in a smart city and was first introduced in [4] and extended
in [5]. This model was developed combining J
AVA
for the GUI and M
AXIMA
for
the mathematical core of the algorithm.
The studies developed in the above mentioned works, dealt with Poisson, Ex-
ponential, Uniform and Normal distributions. In this talk we will introduce, as
a novelty, the possibility of using other continuous probability distributions such
as: Lognormal, Weibul, Gamma, Beta, Chi-Square, Student’s t, Z, Pareto, Lo-
gistic, Cauchy or Irwin-Hall, and other discrete distributions such as: Bernouille,
Rademacher, Binomial, Geometric, Negative Binomial or Hypergeometric. Even
1
more, this new version allows to deal with any “ad-hoc” continuous, discrete or
mixed user’s distributions. This fact improves the flexibility of ATISMART+ model.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Modular Planar Antenna at X-band for satellite communications
An antenna which has been conceived as a portable system for satellite communications based on the recommendations ITU-R S.580-6 [1] and ITU-R S.465-5 [2] for small antennas, i.e., with a diameter lower than 50 wavelengths, is introduced. It is a planar and a compact structure with a size of 40×40×2 cm. The antenna is formed by an array of 256 printed elements covering a large bandwidth (14.7%) at X-Band. The specification includes transmission (Tx) and reception (Rx) bands simultaneously. The printed antenna has a radiation pattern with a 3dB beamwidth of 5°, over a 31dBi gain, and a dual and an interchangeable circular polarizatio
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