Antiferromagnetic O(N) models in four dimensions

We study the antiferromagnetic O(N) model in the F_4 lattice. Monte Carlo simulations are applied for investigating the behavior of the transition for N=2,3. The numerical results show a first order nature but with a large correlation length. The $N \to \infty$ limit is also considered with analytical methods.Comment: 14 pages, 3 postscript figure

Key features of a succesful invasive macroalgae: the case of asparagopsis taxiformis in Alboran Sea

Asparagopsis taxiformis (Bonnemaisoniales, Rhodophyta) is considered one of the most invasive seaweeds in the Mediterranean, and is included in the spanish checklist of invasive species. Recorded for first time in Southern Spain nearly twenty years ago, we are now ready to highlight its key features to have become a successful invader in Alboran Sea. Genetic studies showed that only one lineage of this species complex, is invasive in Alboran Sea, the lineage 2, which exhibits a wide physiological plasticity, exhibited in a wide thermal adaptation of performances of photosynthetic parameters like Pmax and α. Furthermore, the species is able to inhabit from shallow subtidal up to depths over -30m, due to its low Ic. The species exhibits a trigenetic life-cycle, with an invasive gametophyte dominating the host community, and a free-living tetrasporophyte (Falkenbergia phase) being the dispersal one. The gametophyte is present all the year round, and exhibits a high recruitment and vegetative growth capacity, which support more than 90% of the community biomass. Furthermore, sexual reproduction was perfomed during the whole year, except in winter months, accounting in summer months with more than 50% of the population with reproductive structures. Minimum size for reproduction was low (4-6 cm), considering the maximal size observed for the species in the study site (30 cm). Statistical anaylisis has shown no relationship of reproduction with environmental factors, such as nutrients or temperatura. These features, together with some other more, become A. taxiformis in an invasive species already well settled in Alboran Sea.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

ENRICHME integration of ambient intelligence and robotics for AAL

Technological advances and affordability of recent smart sensors, as well as the consolidation of common software platforms for the integration of the latter and robotic sensors, are enabling the creation of complex active and assisted living environments for improving the quality of life of the elderly and the less able people. One such example is the integrated system developed by the European project ENRICHME, the aim of which is to monitor and prolong the independent living of old people affected by mild cognitive impairments with a combination of smart-home, robotics and web technologies. This paper presents in particular the design and technological solutions adopted to integrate, process and store the information provided by a set of fixed smart sensors and mobile robot sensors in a domestic scenario, including presence and contact detectors, environmental sensors, and RFID-tagged objects, for long-term user monitoring an

Latent topic-based super-resolution for remote sensing

This letter presents a novel single-image Super-Resolution (SR) approach based on latent topics specially designed to remote sensing imagery. The proposed approach pursues to super-resolve topics uncovered from low-resolution images instead of super-resolving image patches themselves. An experimental comparison is con- ducted using nine di ff erent SR methods over four aerial image data- sets. Experiments revealed the potential of latent topics in remote sensing SR by reporting that the proposed approach is able to provide a competitive advantage especially in low noise conditions.This work was supported by the Spanish Ministry of Economy under the projects ESP2013-48458- C4-3-P and ESP2016-79503-C2-2-P, by Generalitat Valenciana through project PROMETEO-II/2014/ 062, and by Universitat Jaume I through project P11B2014-09

Single-frame super-resolution in remote sensing: a practical overview

Image acquisition technology is improving very fast from a performance point of view. However, there are physical restrictions that can only be solved using software processing strategies. This is particularly true in the case of super resolution (SR) methodologies. SR techniques have found a fertile application field in airborne and space optical acquisition platforms. Single-frame SR methods may be advantageous for some remote-sensing platforms and acquisition time conditions. The contributions of this article are basically two: (1) to present an overview of single-frame SR methods, making a comparative analysis of their performance in different and challenging remote-sensing scenarios, and (2) to propose a new single-frame SR taxonomy, and a common validation strategy. Finally, we should emphasize that, on the one hand, this is the first time, to the best of our knowledge, that such a review and analysis of single SR methods is made in the framework of remote sensing, and, on the other hand, that the new single-frame SR taxonomy is aimed at shedding some light when classifying some types of single-frame SR methods.This work was supported by the Spanish Ministry of Economy under the project ESP2013 - 48458-C4-3-P, by Generalitat Valenciana through project PROMETEO-II/2014/062, and by Universitat Jaume I through project P11B2014-09

CMOS-3D smart imager architectures for feature detection

This paper reports a multi-layered smart image sensor architecture for feature extraction based on detection of interest points. The architecture is conceived for 3-D integrated circuit technologies consisting of two layers (tiers) plus memory. The top tier includes sensing and processing circuitry aimed to perform Gaussian filtering and generate Gaussian pyramids in fully concurrent way. The circuitry in this tier operates in mixed-signal domain. It embeds in-pixel correlated double sampling, a switched-capacitor network for Gaussian pyramid generation, analog memories and a comparator for in-pixel analog-to-digital conversion. This tier can be further split into two for improved resolution; one containing the sensors and another containing a capacitor per sensor plus the mixed-signal processing circuitry. Regarding the bottom tier, it embeds digital circuitry entitled for the calculation of Harris, Hessian, and difference-of-Gaussian detectors. The overall system can hence be configured by the user to detect interest points by using the algorithm out of these three better suited to practical applications. The paper describes the different kind of algorithms featured and the circuitry employed at top and bottom tiers. The Gaussian pyramid is implemented with a switched-capacitor network in less than 50 μs, outperforming more conventional solutions.Xunta de Galicia 10PXIB206037PRMinisterio de Ciencia e Innovación TEC2009-12686, IPT-2011-1625-430000Office of Naval Research N00014111031

Disseny i implementació d'una font commutada CC/CC d'elevada tensió d'entrada per alimentar equips elèctrics industrials

L'objectiu d'aquest projecte és el disseny, control i implementació d'una font d'alimentació aïllada que parteix d'un bus de tensió contínua de 800 V per generar a la sortida una tensió contínua de 24 V i 3 A. La topologia de convertidor CC/CC utilitzada és Full-Bridge, la qual utilitzarà una estratègia de commutació Phase Shift. El transformador d'aquest convertidor utilitza la tecnologia de transformadors planars (transformadors, els debanats dels quals es troben incorporats en la pròpia placa de circuit imprès). S'ha creat un circuit d'arrencada basat en el component comercial IXCP10M90S del fabricant IXYS, capaç de suportar l'elevada tensió d'entrada. El sistema de control està format per dos microcontroladors Piccolo TMS320F28027 de Texas Instruments, els quals es comuniquen a través d'un bus SPI aïllat. Pel que fa al sistema de control, s'ha escollit un control en doble llaç, controlant tant el corrent que travessa la bobina de sortida, com la tensió en borns del condensador de la sortida. Així, aquest document està estructurat en tres blocs principals: Estudi dels convertidors i teoria de funcionament del convertidor Full-Bridge. Disseny del convertidor i de tots els sistemes associats. Creació del prototip i anàlisi dels resultats. La primera part és una introducció en el camp dels convertidors estàtics, on s'estudiaran les diferents topologies existents. A continuació s'aprofundirà en la topologia Full-Bridge utilitzada. La segona part es centra en el disseny i simulació de la font. Per fer-ho es realitzaràn simulacions del seu funcionament i es presentaràn les alternatives i eleccions adoptades durant aquesta fase de disseny. En l'última part, es dissenyaràn les PCB del prototip de la font i es construirà, a de realitzar els assajos pertinents. Finalment, s'ha comprovat que el prototip creat ha complert amb éxit les sol·licitacions demanades en el procés de disseny

Next-Best-Sense: a multi-criteria robotic exploration strategy for RFID tags discovery

Automated exploration is one of the most relevant applications of autonomous robots. In this paper, we suggest a novel online coverage algorithm called Next-Best-Sense (NBS), an extension of the Next-Best-View class of exploration algorithms that optimizes the exploration task balancing multiple criteria. This novel algorithm is applied to the problem of localizing all Radio Frequency Identification (RFID) tags with a mobile robotic platform that is equipped with a RFID reader. We cast this problem as a coverage planning problem by defining a basic sensing operation -- a scan with the RFID reader -- as the field of “view” of the sensor. NBS evaluates candidate locations with a global utility function which combines utility values for travel distance, information gain, sensing time, battery status and RFID information gain, generalizing the use of Multi-Criteria Decision Making. We developed an RFID reader and tag model in the Gazebo simulator for validation. Experiments performed both in simulation and with a real robot suggest that our NBS approach can successfully localize all the RFID tags while minimizing navigation metrics such sensing operations, total traveling distance and battery consumption. The code developed is publicly available on the authors' repository

Impact of day/night time land surface temperature in soil moisture disaggregation algorithms

Since its launch in 2009, the ESA’s SMOS mission is providing global soil moisture (SM) maps at ~40 km, using the first L-band microwave radiometer on space. Its spatial resolution meets the needs of global applications, but prevents the use of the data in regional or local applications, which require higher spatial resolutions (~1-10 km). SM disaggregation algorithms based generally on the land surface temperature (LST) and vegetation indices have been developed to bridge this gap. This study analyzes the SM-LST relationship at a variety of LST acquisition times and its influence on SM disaggregation algorithms. Two years of in situ and satellite data over the central part of the river Duero basin and the Iberian Peninsula are used. In situ results show a strong anticorrelation of SM to daily maximum LST (R˜-0.5 to -0.8). This is confirmed with SMOS SM and MODIS LST Terra/Aqua at day time-overpasses (R˜-0.4 to -0.7). Better statistics are obtained when using MODIS LST day (R˜0.55 to 0.85; ubRMSD˜0.04 to 0.06 m3 /m3 ) than LST night (R˜0.45 to 0.80; ubRMSD˜0.04 to 0.07 m3 /m3 ) in the SM disaggregation. An averaged ensemble of day and night MODIS LST Terra/Aqua disaggregated SM estimates also leads to robust statistics (R˜0.55 to 0.85; ubRMSD˜0.04 to 0.07 m3 /m3 ) with a coverage improvement of ~10-20 %.Peer ReviewedPostprint (published version