483 research outputs found
Transfer learning or design a custom CNN for tactile object recognition
International Workshop on Robotac: New Progress in Tactile Perception and Learning in RoboticsNovel tactile sensors allow treating pressure lectures as standard images due to its highresolution. Therefore, computer vision algorithms such as Convolutional Neural Networks
(CNNs) can be used to identify objects in contact. In this work, a high-resolution tactile
sensor has been attached to a robotic end-effector to identify objects in contact. Moreover,
two CNNs-based approaches have been tested in an experiment of classification of pressure
images. These methods include a transfer learning approach using a pre-trained CNN on an
RGB images dataset and a custom-made CNN trained from scratch with tactile information.
A comparative study of performance between them has been carried out.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Spanish project DPI2015-65186-R, the European Commission under grant agreement BES-2016-078237, the educational project PIE-118 of the
University of Malag
Monitorización de víctimas con manipuladores aéreos en operaciones de búsqueda y rescate
En este trabajo se presenta el primer dispositivo de monitorización de víctimas para su colocación automática con robots manipuladores aéreos. Se trata de un sistema sensorial distribuido para la evaluación de forma continua del estado de salud de víctimas de catástrofes. Se describen el sensor diseñado y el sistema de comunicaciones, así como la aplicación mediante la colocación del sensor basado en el uso de sistemas aéreos no tripulados (UAS) o robots manipuladores aéreos. El dispositivo de monitorización continua ofrece ventajas sobre el sistema de triage actual ya que permite obtener datos de la evolución de cada víctima.
Recoge medidas de las constantes vitales de las víctimas, que son publicadas mediante protocolos de Internet de las Cosas (IoT) que permiten su procesado de forma remota. Además, posee métodos basados en aprendizaje profundo para la detección automática de la posición relativa de la muñeca del brazo de una persona con respecto al manipulador aéreo. Se han realizado experimentos preliminares de obtención de medidas y de colocación de sensores mediante una versión preliminar del sensor, cuyos resultados se incluyenUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Control a Baja Velocidad de una Rueda con Motor de Accionamiento Directo mediante Ingeniería Basada en Modelos
Los motores de corriente continua sin escobillas (BLDC) con accionamiento directo suponen una solución compacta para la tracción en vehículos eléctricos, si bien requieren detectar la posición del rotor, habitualmente mediante un codificador angular de efecto Hall dentro del mismo motor. No obstante, la ausencia de reductora y a la dificultad de añadir un codificador angular de precisión suponen un reto para lograr un control preciso a baja velocidad, especialmente si se hace uso de controladoras industriales donde las posibilidades de programación son limitadas. Este trabajo propone aplicar una estrategia de ingeniería basada en modelos (MDE) para el control a baja velocidad de una rueda con motor BLDC de accionamiento directo. En particular, se presenta la solución para un caso de estudio basado en hardware de bajo coste que incluye una tarjeta Arduino Due, una controladora Roboteq HBL2360 y un interfaz de comunicación de bus CAN. La solución MDE basada en Simulink ofrece simplicidad conceptual, capacidad de adaptación a nuevas especificaciones de diseño usando herramientas de diseño avanzadas y generación de código automática. El artículo ofrece resultados experimentales obtenidos sobre el sistema real.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech, CICYT DPI2015-65186-R y el proyecto de Innovación educativa de la Universidad de Málaga PIE 15-18
Sistema de enfoque basado en dos espejos elípticos y un espejo plano rotatorio para un radar a 300 GHz
A focusing system for a 300 GHz radar with two target distances (5m and 10m) is proposed, having 1cm resolution in both cases. The focusing system is based on a gaussian telescope scheme and it has been designed using gaussian beam quasi-optical propagation theory with a homemade Matlab analysis tool. It has been translated into a real focusing system based on two elliptical mirrors and a plane mirror in order to have scanning capabilities and validated using the commercial antenna software GRAS
Changes in retinal OCT and their correlations with neurological disability in early ALS patients, a follow-up study
Background: To compare early visual changes in amyotrophic lateral sclerosis (ALS) patients with healthy controls in a baseline exploration, to follow-up the patients after 6 months, and to correlate these visual changes with neurological disability. Methods: All patients underwent a comprehensive neurological and ophthalmological examination. A linear mixed analysis and Bonferroni p-value correction were performed, testing four comparisons as follows: Control baseline vs. control follow-up, control baseline vs. ALS baseline, control follow-up vs. ALS follow-up, and ALS baseline vs. ALS follow-up. Results: The mean time from the diagnosis was 10.80 +/- 5.5 months. The analysis of the optical coherence tomography (OCT) showed: (1) In ALS baseline vs. control baseline, a macular significantly increased thickness of the inner macular ring temporal and inferior areas; (2) in ALS follow-up vs. ALS baseline, a significant macular thinning in the inner and outer macular ring inferior areas; (3) in ALS follow-up vs. ALS baseline, a significant peripapillary retinal nerve fiber layer (pRNFL) thinning in the superior and inferior quadrants; and (4) ALS patients showed a moderate correlation between some OCT pRNFL parameters and Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) score. Conclusion: The OCT showed retinal changes in patients with motoneuron disease and could serve as a complementary tool for studying ALS
Beach Leveling Using a Remotely Piloted Aircraft System (RPAS): Problems and Solutions
The size and great dynamism of coastal systems require faster and more automated mapping methods like the use of a remotely piloted aircraft system (RPAS) or unmanned aerial vehicle (UAV). This method allows for shorter intervals between surveys. The main problem for surveying using low-altitude digital photogrammetry in beach areas is their visual homogeneity. Obviously, the fewer the homologous points defined by the program, the lower the accuracy. Moreover, some factors influence the error performed in photogrammetric techniques, such as flight height, flight time, percentage of frame overlap (side and forward), and the number of ground control points (GCPs). A total of 72 different cases were conducted varying these factors, and the results were analyzed. Among the conclusions, it should be highlighted that the error for noon flights is almost double that for the early morning flights. Secondly, there is no appreciable difference regarding the side overlap. But, on the other side, RMSE increased to three times (from 0.05 to 0.15 m) when forward overlap decreased from 85% to 70%. Moreover, relative accuracy is 0.05% of the flying height which means a significant increase in error (66%) between flights performed at 60 and 100 m height). Furthermore, the median of the error for noon flights (0.12 m) is almost double that for the early morning flights (0.07 m) because of the higher percentage of grids with data for early flights. Therefore, beach levelings must never be performed at noon when carried out by RPAS. Eventually, a new parameter has been considered: the relationship between the number of GCPs and the surface to be monitored. A minimum value of 7 GCP/Ha should be taken into account when designing a beach leveling campaign using RPAS.Fundacion Campus Tecnologico de Algeciras; Coastal Engineering Research group (University of Cadiz
Identification of soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) as a possible biomarker of subclinical atherosclerosis
OBJECTIVES: Assessment of vascular risk in asymptomatic patients and the response to medical therapy is a major challenge for prevention of cardiovascular events. Our aim was to identify proteins differentially released by healthy versus atherosclerotic arterial walls, which could be found in plasma and serve as markers of atherosclerosis.
METHODS AND RESULTS: We have analyzed supernatants obtained from cultured human carotid plaques and healthy arteries by surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry ProteinChip System. Surface-enhanced laser-desorption/ionization analysis unveiled an 18.4-kDa peak released in lower amount by carotid plaques than normal endarteries. This protein was identified as soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK). To confirm that sTWEAK was the protein of interest, Western blot and enzyme-linked immunosorbent assay were performed. Both techniques confirmed that sTWEAK levels were decreased in carotid plaque supernatants. Subsequent measurement of sTWEAK in plasma showed a reduced concentration in subjects with carotid stenosis (N=30) compared with healthy subjects matched by sex and age (N=28) (P<0.001). Furthermore, in a test population of 106 asymptomatic subjects, we showed that sTWEAK concentrations negatively correlated with the carotid intima-media thickness (r=-0.4; P<0.001), an index of subclinical atherosclerosis.
CONCLUSIONS: These results suggest that sTWEAK could be a potential biomarker of atherosclerosis
Magnetic phase diagram of nanostructured zinc ferrite as a function of inversion degree delta
Magnetic properties of spinel zinc ferrites are strongly linked to the synthesis method and the processing route since they control the microstructure of the resulting material. In this work, ZnFe_2O_4 nanoparticles were synthesized by the mechanochemical reaction of stoichiometric ZnO and alpha-Fe2O3, and single-phase ZnFe_2O_4 was obtained after 150 h of milling. The as-milled samples, with a high inversion degree, were subjected to different thermal annealings up to 600 ºC to control the inversion degree and, consequently, the magnetic properties. The as-milled samples, with a crystallite size of 11 nm and inversion degree delta = 0.57, showed ferrimagnetic behavior even above room temperature, as shown by Rietveld refinements of the X-ray diffraction pattern and superconducting quantum interference device magnetometry. The successive thermal treatments at 300, 400, 500, and 600 degrees C decrease delta from 0.15 to 0.18, affecting the magnetic properties. A magnetic phase diagram as a function of delta can be inferred from the results: for delta 0.5, a new antiferromagnetic order appeared due to the overpopulation of nonmagnetic Zn on octahedral sites that leads to equally distributed magnetic cations in octahedral and tetrahedral sites
Elevated circulating metalloproteinase 7 predicts recurrent cardiovascular events in patients with carotid stenosis: a prospective cohort study
Background: Major adverse cardiovascular events are the main cause of morbidity and mortality over the long
term in patients undergoing carotid endarterectomy. There are few reports assessing the prognostic value of
markers of inflammation in relation to the risk of cardiovascular disease after carotid endarterectomy. Here, we
aimed to determine whether matrix metalloproteinases (MMP-1, MMP-2, MMP-7, MMP-9 and MMP-10), tissue
inhibitor of MMPs (TIMP-1) and in vivo inflammation studied by 18F-FDG-PET/CT predict recurrent cardiovascular
events in patients with carotid stenosis who underwent endarterectomy.
Methods: This prospective cohort study was carried out on 31 consecutive patients with symptomatic (23/31) or
asymptomatic (8/31) severe (> 70%) carotid stenosis who were scheduled for carotid endarterectomy between July
2013 and March 2016. In addition, 26 healthy controls were included in the study. Plasma and serum samples were
collected 2 days prior to surgery and tested for MMP-1, MMP-2, MMP-7, MMP-9, MMP-10, TIMP-1, high-density
lipoprotein, low-density lipoprotein, high-sensitivity C-reactive protein and erythrocyte sedimentation rate. 18F-FDGPET/CT focusing on several territories’ vascular wall metabolism was performed on 29 of the patients because of no
presurgical availability in 2 symptomatic patients. Histological and immunohistochemical studies were performed
with antibodies targeting MMP-10, MMP-9, TIMP-1 and CD68.
Results: The patients with carotid stenosis had significantly more circulating MMP-1, MMP-7 and MMP-10 than the
healthy controls. Intraplaque TIMP-1 was correlated with its plasma level (r = 0.42 P = .02) and with 18F-FDG uptake
(r = 0.38 P = .05). We did not find any correlation between circulating MMPs and in vivo carotid plaque metabolism
assessed by 18F-FDG-PET. After a median follow-up of 1077 days, 4 cerebrovascular, 7 cardiovascular and 11
peripheral vascular events requiring hospitalization were registered. Circulating MMP-7 was capable of predicting
events over and above the traditional risk factors (HR = 1.15 P = .006). When the model was associated with the
variables of interest, the risk predicted by 18F-FDG-PET was not significant.
Conclusions: Circulating MMP-7 may represent a novel marker for recurrent cardiovascular events in patients with
moderate to severe carotid stenosis. MMP-7 may reflect the atherosclerotic burden but not plaque inflammation in
this specific vascular territory
Cryptographic Security Through a Hardware Root of Trust
This work presents a novel approach to a Hardware Root-of-Trust that leverages System-on-Chip technology for the implementation of hardware cryptographic functions. Taking advantage of the processing power of a System-on-Chip, the solution established promotes hardware-based security solutions over software-only solutions. The proposed Root-of-Trust, developed around a Xilinx Zynq-7000 SoC device, integrates components based on cryptographic algorithms and physical phenomena. This innovative Root-of-Trust is tailored to support a spectrum of security tasks within cryptographic systems, including device-specific identifiers and keys, encryption and decryption, hashing, and signature generation and verification. The study adopts a unified design methodology, capitalizing on collaborative efforts to efficiently develop hardware primitives that significantly contribute to enhancing security in computing environments. Aligned with the advantages of reconfigurable hardware, this Hardware Root-of-Trust addresses the critical need for robust hardware-level security and introduces a set of countermeasures to fortify the design against potential threats.This research was supported in part by the SPIRS Project with Grant Agreement No. 952622 under the EU H2020 research and innovation programme. The authors want to thank the ARES Project PID2020-116664RB-100 funded by MCIN/AEI/10.13039/501100011033 and the EU NextGeneration EU/PRTR, and the Programa Operativo FEDER 2014-2020 and Consejería de Economía, Conocimiento, Empresas y Universidad de la Junta de Andalucía under Project US-1380823. M.C.M.R. holds a postdoc fellowship from the Andalusia Government with support from PO FSE of EU.Peer reviewe
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