179 research outputs found

    General queuing model for optimal seamless delivery of payload processing in multi-core processors

    Get PDF
    This is a pre-print of an article published in The Journal of Supercomputing. The final authenticated version is available online at: https://doi.org/10.1007/s11227-017-2109-4.Recent developments in unmanned aerial systems (UAS) provide new opportunities in remote sensing application. In contrast to satellite and conventional (manned) aerial tasks, UAS flights can be operated in a very short period of time. UAS can also be more specifically focused toward a given task such as crop reconnaissance or electric line tower inspection. For some applications, the delivery time of the remote sensing results is crucial. The current three-phase procedure of data acquisition, data downloading and data processing, performed sequentially in time, represents a drawback that reduces the benefits of using unmanned aerial systems. In this paper, we present a parallel processing strategy, based on queuing theory, in which the data processing phase is performed on board in parallel with data acquisition. The unmanned aerial system payload has been enlarged with low-cost, lightweight, multi-core boards to facilitate remote sensing data processing during flight. The storage of the raw sensing data is also done for possible further analysis; however, the ultimate decision support information can be seamless delivered to the customer upon landing. Furthermore, text alarms and limited imagery can also be provided during flight.Peer ReviewedPostprint (author's final draft

    The effect of stellar activity on the LiI 6708, NaI 5896 and KI 7699 \AA lines: A comparison with the Pleiades, field stars and the Sun

    Get PDF
    An analytical model has been developed to empirically study the effects of stellar spots and faculae on the observed equivalent widths of Li {\sc i} 6708, Na {\sc i} 5896 and K {\sc i} 7699 \AA lines (and abundances in the case of lithium) in late-type stars, taking into account the changes in the observed magnitudes and colors. Solar spectra corresponding to different active regions are used as input data and a range of filling factors are applied to simulate the surfaces of stars with different levels of activity. Detailed comparisons between predicted and observed photometric colors and equivalent widths are made for late-type stars of the Pleiades and the field. The observed dispersions in K {\sc i} and Li {\sc i} equivalent widths for Pleiades stars can be partially accounted by the simultaneous effects of activity on colors and the line formation, indicating that the lithium-rotation connection suggested for ~0.7-0.9 Msun Pleiades stars could be due in part to the stellar activity. However, under realistic values for the filling factors, only a small portion of the observed spread could be explained by these effect

    Electrodeposition of Indium on W and Cu electrodes in the Deep Eutectic Solvent choline chloride-ethylene glycol (1:2).

    Get PDF
    Producción CientíficaA procedure for drying the deep eutectic solvent (DES) choline chloride - ethylene glycol, ChCl-EG (1:2), based on the use of molecular sieves has been developed, being the final water content of the electrolyte 145±5 ppm. In this dried DES, the stability of InCl and InCl3 as well as the electrochemical behaviour of their solutions has been investigated using electrochemical techniques, X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). Experiments performed under a N2 atmosphere show that InCl3, dissolved in the rich chloride media as InClp 3-p, is reduced on a tungsten electrode to indium metal via only one electrochemical step. Conversely, InCl undergoes the following disproportionation reaction when dissolved in the eutectic ChCl-EG (1:2) 3InCl(s) + (p − 3)Cl− ⇌ 2In(0) + InClp − 3 p generating In(0) and giving place to identical electrochemical signals as those obtained after the addition of InCl3 to the DES. On a tungsten electrode, nucleation and crystal growth of In plays an important role in the electrodeposition process. Chronoamperometric results were consistent with instantaneous three dimensional nucleation on a finite number of active sites with diffusion controlled growth of the nuclei, whatever the applied overpotential and temperature. Mass transport towards the electrode is a diffusion process, and the following empirical expression for the temperature dependence of the diffusion coefficient was calculated. LnD = −(3.58 ± 0.22)–(3665 ± 76) T − 1 The electro-reduction of In(III) solutions was also investigated at a copper substrate. The resulting cyclic voltammograms evidenced the formation of In-Cu intermetallic compounds. Hence, In-Cu alloy films were obtained by continuous potentiostatic electrolysis and intensiostatic pulse electrolysis. The obtained samples, characterized by XRD and SEM, revealed the formation of the metastable CuIn phase that could be transformed into Cu11In9 by thermal annealing.Consejería de Educación of the Junta de Castilla y León Project VA171U14 for financial support. S. García, also thanks the youth employment operative programme (European Social Fund, ESF, and youth employment initiative, YEI)

    Enhancing drones for law enforcement and capacity monitoring at open large events

    Get PDF
    Police tasks related with law enforcement and citizen protection have gained a very useful asset in drones. Crowded demonstrations, large sporting events, or summer festivals are typical situations when aerial surveillance is necessary. The eyes in the sky are moving from the use of manned helicopters to drones due to costs, environmental impact, and discretion, resulting in local, regional, and national police forces possessing specific units equipped with drones. In this paper, we describe an artificial intelligence solution developed for the Castelldefels local police (Barcelona, Spain) to enhance the capabilities of drones used for the surveillance of large events. In particular, we propose a novel methodology for the efficient integration of deep learning algorithms in drone avionics. This integration improves the capabilities of the drone for tasks related with capacity control. These tasks have been very relevant during the pandemic and beyond. Controlling the number of persons in an open area is crucial when the expected crowd might exceed the capacity of the area and put humans in danger. The new methodology proposes an efficient and accurate execution of deep learning algorithms, which are usually highly demanding for computation resources. Results show that the state-of-the-art artificial intelligence models are too slow when utilised in the drone standard equipment. These models lose accuracy when images are taken at altitudes above 30 metres. With our new methodology, these two drawbacks can be overcome and results with good accuracy (96% correct segmentation and between 20% and 35% mean average proportional error) can be obtained in less than 20 s.This research was partially funded by the AGAUR research agency of Catalonia under grant number 2020PANDE00141 and by the Ministry of Science and Education of Spain under grant number PID2020-116377RB-C21.Peer ReviewedPostprint (published version

    Understanding the implications of the future unmanned air traffic growth

    Get PDF
    In the next years, the unmanned air business is expected to have an average annual growth rate of 14.5 per cent. Last-mile delivery, inspection works and security tasks are the most expected missions that those unmanned aircraft (UA) will execute. Most of these missions are well suited for multi-copters: small airframes with vertical take-off and landing capabilities. Large fleets of UA will be managed by new aerial logistic centers where flight plans will be created and monitored, the payload will be prepared, and fast battery replacement will allow continuous flights to obtain maximum benefit. Beyond visual line-of-sight capabilities is a must for those logistic center businesses. Anticipating the scalability of unmanned aircraft growth is the aim of this paper. For this, a simulation tool has been developed which generates unmanned traffic flights from completely parameterized inputs: the geographic area and the type and number of operations, aircraft and operators. For this paper, the tested scenario is a logistics industrial polygon with increasing delivery traffic, the Martorell industrial area (5.8 km2). Flights have a random altitude from 80 m to 120 m. En- route phases have some slight turns to make them more realistic. The time of departure follows a Box-Muller algorithm during the declared business hours, centered in the peak declared hour.This work was funded by the Ministry of Economy, Industry, and Competitiveness of Spain under GrantNumber TRA2016-77012-RPeer ReviewedPostprint (published version

    The brown dwarf population in the Chamaeleon I cloud

    Get PDF
    We present the results of a multiband survey for brown dwarfs in the Chamaeleon I dark cloud with the Wide Field Imager (WFI) camera at the ESO/MPG 2.2-m telescope on La Silla (Chile). The survey has revealed a substantial population of brown dwarfs in this southern star forming region. Candidates were selected from R, I and H-alpha imaging observations. We also observed in two medium-band filters, M855 and M915, for the purpose of spectral type determination. The former filter covers a wavelength range containing spectral features characteristic of M-dwarfs, while the latter lies in a relatively featureless wavelength region for these late-type objects. A correlation was found between spectral type and (M855-M915) colour index for mid- to late M-type objects and early L-type dwarfs. With this method, we identify most of our object candidates as being of spectral type M5 or later. Our results show that there is no strong drop in the number of objects for the latest spectral types, hence brown dwarfs may be as abundant as low-mass stars in this region. Also, both kind of objects have a similar spatial distribution. We derive an index α=0.6±0.1\alpha = 0.6 \pm 0.1 of the mass function in this region of dispersed star formation, in good agreement with the values obtained in other star forming regions and young clusters. Some of the brown dwarfs have strong H-alpha emission, suggesting mass accretion. For objects with published infrared photometry, we find that strong H-alpha emission is related to a mid-infrared excess, indicative of the existence of a circumstellar disk.Comment: Accepted for publication in Astronomy & Astrophysic

    Spectroscopy of Very Low Mass Stars and Brown Dwarfs in the Lambda Orionis Star Forming Region. I. Enlarging the census down to the planetary mass domain in Collinder 69

    Get PDF
    Whilst there is a generally accepted evolutionary scheme for the formation of low-mass stars, the analogous processes when moving down in mass to the brown dwarfs regime are not yet well understood. In this first paper we try to build the most complete and unbiased spectroscopically confirmed census of the population of Collinder 69, the central cluster of the Lambda Orionis star forming region, as a first step in addressing the question of how brown dwarfs and planetary mass objects form. We have studied age dependent features in optical and near-infrared spectra of candidate members to the cluster (such as alkali lines and accretion associated indicators). In addition, we have complemented that study with the analysis of other youth indicators like X-ray emission or mid-infrared excess. We have confirmed the membership to Collinder 69 of \sim90 photometric candidate members. As a byproduct we have determined a temperature scale for young M, very low-mass stars and brown dwarfs. We have assembled one of the most complete Initial Mass Functions from 0.016 to 20 M\odot. And, finally, we have studied the implications of the spatial distribution of the confirmed members on the proposed mechanisms of brown dwarfs formation.Comment: Accepted for publication in A&

    Programa de rehabilitación cardíaca mediante un entrenamiento de tenis adaptado

    Full text link
    The aims of this study were to determine the effect of a cardiac rehabilitation program, based on the adjustment of a sports modality (tennis), on differentes laboratory analysis variables (triglycerides, cholesterol,cholesterol LDL, cholesterol HDL and glucose ) And and on an exercise stress test (metabolics equivalent-METs-, time of effort, systolic pressure, dyastolic pressure, maximum cardiac frecuencia and double product). The study involved 7 patients with low risk myocardial heart attack. The ages was include between 48 and 63 years old. By the end of the program, which has lasted 3 months, triglycerides, cholesterol, exercise capacity and double product had improved significantly (p<.005 for all).Los objetivos de este estudio son evaluar los efectos de nuestro programa de rehabilitación cardiaca, basado en la adaptación de una modalidad deportiva (tenis), sobre diferentes variables del perfil lipídico (triglicéridos, colesterol, cLDL, cHDL, y glucosa) así como en la prueba de esfuerzo (MET, tiempo de esfuerzo, presión sistólica, presión diastólica, frecuencia cardíaca máxima y doble producto). Analizamos a 7 pacientes con infarto agudo de miocardio de bajo riesgo. Las edades estaban comprendidas entre los 48 y 63 años. Tras la realización del programa, que ha tenido 3 meses de duración, se han producido mejoras significativas a nivel de triglicéridos, colesterol, capacidad funcional valorada en equivalentes metabólicos y doble producto (p<.005 para todos)

    Mass loss at the lowest stellar masses

    Full text link
    We report the discovery of a jet in a [SII] image of Par-Lup3-4, a remarkable M5-type pre-main sequence object in the Lupus 3 star-forming cloud. The spectrum of this star is dominated by the emission lines commonly interpreted as tracers of accretion and outflows. Par-Lup3-4 is therefore at the very low-mass end of the exciting sources of jets. High resolution spectroscopy shows that the [SII] line profile is double-peaked, implying that the low excitation jet is seen at a small angle (probably larger than 8 degrees) with respect to the plane of the sky. The width of the H_alpha line suggests a dominating contribution from the accretion columns and from the shocks on the stellar surface. Unresolved H_alpha emission coming from an object located at 4.2" from Par-Lup3-4 is detected at a position angle ~30 degrees or ~210 degrees, with no counterpart seen either in visible or infrared images.We also confirm previous evidence of strong mass loss from the very low mass star LS-RCrA 1, with spectral type M6.5 or later. All its forbidden lines are blueshifted with respect to the local standard of rest (LSR) of the molecular cloud at a position very close to the object and the line profile of the [OI] lines is clearly asymmetric. Thus, the receding jet could be hidden by a disk which is not seen edge-on. If an edge-on disk does not surround Par-Lup3-4 or LS-RCrA 1, an alternative explanation, possibly based on the effects of mass accretion, is required to account for their unusually low luminosities.Comment: Accepted for publication in A&A, 8 pages, 5 figures, 2 table

    LSCF-CGO nanocomposite cathodes deposited in a single step by spraypyrolysis.

    Get PDF
    La0.6Sr0.4Co0.2Fe0.8O3-δ-Ce0.9Gd0.1O1.95 (LSCF-CGO) nanostructured cathodes with different LSCF-content are prepared in a single step by spray-pyrolysis deposition, simplifying notably the fabrication process compared to the traditional methods. The phase formation, structure, microstructure and electrochemical properties of the cathodes are investigated as a function of the CGO-content and the temperature by using X-ray diffraction, electron microscopy and impedance spectroscopy. The addition of CGO to LSCF limits the grain growth, giving rise to fine particles of approximately 30 nm of diameter after sintering at 800 °C. A small particle size of 50 nm is retained even after sintering at 1000 °C. However, the polarization resistance, determined by impedance spectroscopy, is not significantly improved with the CGO-addition. The performance of these nanocomposite electrodes, investigated in NiOeCGO anode-supported cells, shows an improved power density of 0.9 Wcm−2 at 650 °C, compared to 0.56 Wcm−2 for a conventional screen-printed cathode
    corecore