7,397 research outputs found
Magnetic-field control of near-field radiative heat transfer and the realization of highly tunable hyperbolic thermal emitters
We present a comprehensive theoretical study of the magnetic field dependence
of the near-field radiative heat transfer (NFRHT) between two parallel plates.
We show that when the plates are made of doped semiconductors, the near-field
thermal radiation can be severely affected by the application of a static
magnetic field. We find that irrespective of its direction, the presence of a
magnetic field reduces the radiative heat conductance, and dramatic reductions
up to 700% can be found with fields of about 6 T at room temperature. We show
that this striking behavior is due to the fact that the magnetic field
radically changes the nature of the NFRHT. The field not only affects the
electromagnetic surface waves (both plasmons and phonon polaritons) that
normally dominate the near-field radiation in doped semiconductors, but it also
induces hyperbolic modes that progressively dominate the heat transfer as the
field increases. In particular, we show that when the field is perpendicular to
the plates, the semiconductors become ideal hyperbolic near-field emitters.
More importantly, by changing the magnetic field, the system can be
continuously tuned from a situation where the surface waves dominate the heat
transfer to a situation where hyperbolic modes completely govern the near-field
thermal radiation. We show that this high tunability can be achieved with
accessible magnetic fields and very common materials like n-doped InSb or Si.
Our study paves the way for an active control of NFRHT and it opens the
possibility to study unique hyperbolic thermal emitters without the need to
resort to complicated metamaterials.Comment: 21 pages, 10 figure
Seeing Majorana fermions in time-of-flight images of spinless fermions coupled by s-wave pairing
The Chern number, nu, as a topological invariant that identifies the winding
of the ground state in the particle-hole space, is a definitive theoretical
signature that determines whether a given superconducting system can support
Majorana zero modes. Here we show that such a winding can be faithfully
identified for any superconducting system (p-wave or s-wave with spin-orbit
coupling) through a set of time-of-flight measurements, making it a diagnostic
tool also in actual cold atom experiments. As an application, we specialize the
measurement scheme for a chiral topological model of spinless fermions. The
proposed model only requires the experimentally accessible s-wave pairing and
staggered tunnelling that mimics spin-orbit coupling. By adiabatically
connecting this model to Kitaev's honeycomb lattice model, we show that it
gives rise to nu = \pm 1 phases, where vortices bind Majorana fermions, and
nu=\pm 2 phases that emerge as the unique collective state of such vortices.
Hence, the preparation of these phases and the detection of their Chern numbers
provide an unambiguous signature for the presence of Majorana modes. Finally,
we demonstrate that our detection procedure is resilient against most
inaccuracies in experimental control parameters as well as finite temperature.Comment: 9+4 pages, 11 figures, expanded versio
Indoor outdoor detection
Abstract. This thesis shows a viable machine learning model that detects Indoor or Outdoor on smartphones. The model was designed as a classification problem and it was trained with data collected from several smartphone sensors by participants of a field trial conducted. The data collected was labeled manually either indoor or outdoor by the participants themselves. The model was then iterated over to lower the energy consumption by utilizing feature selection techniques and subsampling techniques. The model which uses all of the data achieved a 99 % prediction accuracy, while the energy efficient model achieved 92.91 %. This work provides the tools for researchers to quantify environmental exposure using smartphones
Human and Object Recognition with a High-resolution tactile sensor
This paper 1 describes the use of two artificial intelligence methods for object
recognition via pressure images from a high-resolution tactile sensor. Both meth-
ods follow the same procedure of feature extraction and posterior classification
based on a supervised Supported Vector Machine (SVM). The two approaches
differ on how features are extracted: while the first one uses the Speeded-Up
Robust Features (SURF) descriptor, the other one employs a pre-trained Deep
Convolutional Neural Network (DCNN). Besides, this work shows its applica-
tion to object recognition for rescue robotics, by distinguishing between differ-
ent body parts and inert objects. The performance analysis of the proposed
methods is carried out with an experiment with 5-class non-human and 3-class
human classification, providing a comparison in terms of accuracy and compu-tational load. Finally, it is discussed how feature-extraction based on SURF can be obtained up to five times faster compared to DCNN. On the other hand, the
accuracy achieved using DCNN-based feature extraction can be 11.67% superior
to SURF.Proyecto DPI2015-65186-R
European Commission under grant agreement BES-2016-078237.
Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
Inferencia del origen del bovino Criollo Cubano a través del análisis de patri- y matrilinajes
Antes de descubrimiento, no existÃan bovinos en América. Los primeros, fueron introducidos en la Antillas Mayores (La Española, Puerto Rico, Jamaica y Cuba), y desde allà trasladados al resto de Latinoamérica. Actualmente, existen en Cuba alrededor de 1300 bovinos Criollos, concentrados principalmente en la región oriental. Con el objetivo de analizar el origen materno de esta raza y detectar eventos contemporáneos de flujo génico por vÃa paterna, se analizó un fragmento de 240 pb del D-loop mitocondrial (mtADN) y 5 microsatélites del cromosoma Y (BTY), en 36 hembras y 21 machos respectivamente. La diversidad genética se estimó mediante el número de haplotipos, el número de sitios polimórficos, el número de diferencias nucleotÃdicas entre pares de secuencias y el Ãndice de diversidad nucleotÃdica, mientras que el análisis filogenético se realizó utilizando el método de median joining network. Dicho análisis permitió detectar 15 haplotipos mitocondriales (10 del haplogrupo europeo T3, 3 del africano T1, 1 del cercano oriente T2 y 1 ambiguo T1-T3) y 3 haplotipos en el BTY, ambos del haplogrupo cebuÃno Y3. En el mtADN se detectaron 23 sitios polimórficos con una diversidad nucleotÃdica de 0,014 y 3,36 diferencias medias entre pares de secuencias. En conclusión, la población de bovinos Criollos Cubanos presentó una composición haplotÃpica mitocondrial comparable a la de otras razas criollas y mediterráneas, hecho que concuerda con su origen histórico. El BTY evidenció altos niveles de introgresion paterna de genes del zebú.Cattle was absent from America before the discovery. Initially, bovine were brought to Greater Antilles (La Española, Puerto Rico, Jamaica and Cuba islands), and in the course of a few years, they were taken from Caribbean islands to the rest of Latin America. Nowadays, Cuban Creole cattle population is about 1300 heads, mainly located in the eastern region of the island. With the aim of analyzing the maternal origin of Cuban Creole cattle and detect possible contemporaneous, male mediated, gene flow, a 240 pb fragment of mitochondrial D-loop (mtDNA) and five microsatellites of Y chromosome (BTY) were studied in 36 dams and 21 sires, respectively. Genetic diversity was evaluated through number of haplotypes, mean number of pairwise differences and nucleotide diversity. The phylogenetic analysis was performed using a median joining. A total of 15 mtDNA haplotypes were detected in the studied population (10 from the European haplogroup T3, 3 from the African T1, 1 from the Nearern East T2, and 1 ambiguous T1-T3). The number of polymorphic sites, the mean nucleotide diversity, and the mean number of pairwise differences were 23, 0.014 and 3.36, respectively. Two patrilinages were detected, both belonging to the Y3 Zebu haplogroup. In conclusion, Cuban Creole cattle population had a mtDNA haplotypic composition similar to the observed in Creole and Mediterranean breeds, what is in concordance with its historical origin. Y chromosome analysis evidenced a male mediated process of zebu introgression.Fil: Liron, Juan Pedro. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Acosta, A.. Centro Nacional de Sanidad Agropecuaria. Laboratorio de Genética Molecular; CubaFil: Rogberg Muñoz, Andres. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Uffo, O.. Centro Nacional de Sanidad Agropecuaria. Laboratorio de Genética Molecular; CubaFil: Posik, Diego Manuel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Garcia, J.. Ministerio de la Agricultura. Dirección Nacional de Genética; CubaFil: Peral Garcia, Pilar. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentin
Mobile Robot Lab Project to Introduce Engineering Students to Fault Diagnosis in Mechatronic Systems
This document is a self-archiving copy of the accepted version of the paper.
Please find the final published version in IEEEXplore: http://dx.doi.org/10.1109/TE.2014.2358551This paper proposes lab work for learning fault detection and diagnosis (FDD) in mechatronic systems. These skills are important for engineering education because FDD is a key capability of competitive processes and products. The intended outcome of the lab work is that students become aware of the importance of faulty conditions and learn to design FDD strategies for a real system. To this end, the paper proposes a lab project where students are requested to develop a discrete event dynamic system (DEDS) diagnosis to cope with two faulty conditions in an autonomous mobile robot task. A sample solution is discussed for LEGO Mindstorms NXT robots with LabVIEW. This innovative practice is relevant to higher education engineering courses related to mechatronics, robotics, or DEDS. Results are also given of the application of this strategy as part of a postgraduate course on fault-tolerant mechatronic systems.This work was supported in part by the Spanish CICYT under Project DPI2011-22443
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