440 research outputs found

    Discriminant parallel perceptrons

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    Proceedings of 22nd International Conference on Artificial Neural Networks, Lausanne, Switzerland, September 11-14, 2012The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-33266-1_70In this work we will apply Diffusion Maps (DM), a recent technique for dimensionality reduction and clustering, to build local models for wind energy forecasting. We will compare ridge regression models for K–means clusters obtained over DM features, against the models obtained for clusters constructed over the original meteorological data or principal components, and also against a global model. We will see that a combination of the DM model for the low wind power region and the global model elsewhere outperforms other options.With partial support of Spain’s CICyT, projects TIC 01–572, TIN2004–07676

    Link layer Connectivity as a Service for Ad-hoc Microservice Platforms

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    Microservice platforms have brought many advantages to support the deployment of light-weight applications at both near the edge and data centers. Still, their suitability to support telecommunication and vertical services beyond the network edge is far from being a reality. On one hand, their flat networking approach does not support the establishment of link-layer connectivity among the different components of telecommunication and vertical services (e.g., access points, routers, specific-purpose servers, etc.) due to their reliance on high-level APIs. On the other hand, their networking approach has not been designed to operate over ad hoc networks built by the resource-constrained devices that may be available beyond the network edge. This can lead to suboptimal behaviors for the delivery of data traffic between microservices. This article presents the results of a research collaboration between Universidad Carlos III of Madrid and Telefónica: L2S-M. Our solution provides a programmable data plane that enables the establishment of on-demand link layer connectivity between microservices on ad hoc networks. This solution has the flexibility to execute different algorithms to build traffic paths between microservices, as well as to react against temporary link breakdowns, which could be present in these types of networks. The article presents a proof of concept for a functional validation of L2S-M, using an aerial ad hoc network deployed at 5TONIC Laboratory in collaboration with Telefonica. The validation results showcase the proper operation of L2S-M as a networking service for microservice platforms in ad hoc networks, including its ability to reconfigure the programmable data plane when link disruptions occur.This article has been supported by the TRUE5G (PID2019-108713RB681) project funded by the Spanish National Research Agency (MCIN/AEI/10.13039/5011000110) and by the H2020 FISHY Project (Grant agreement ID: 952644)

    Distribución del sistema del carbonato al sur de las Islas Canarias en la primavera del año 2000

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    The measurement of the surface molar fraction of CO2 (atmosphere and sea water) and water column pHT, total alkalinity, AT, nutrients and oxygen were carried out in spring 2000 at the European Station for Time Series in the Ocean at the Canary Islands (ESTOC) and in the area located south of the Canary Islands. The significant eddy field strongly affecting the pattern of the chemical and carbonate system variables is presented and discussed. A mixing model based on the thermohaline properties of the water masses was established. The model explained over 97% of the variability found in the distribution of the chemical variables. Intermediate waters to the south of the Canary Islands show a high contribution of Antarctic waters with about 5% of pure Antarctic Intermediate Water. Moreover, the surface structure affected the atmosphere-ocean carbon dioxide exchange, making the area act as a CO2 sink taking up 9.1 mmol m-2 week-1, corresponding to 0.03 Mt of CO2 which were taken up by the area in a week at the end of March 2000.Durante la primavera del año 2000 se realizaron medidas en las aguas superficiales de la fracción molar de CO2 (atmósfera y océano) y en la columna de agua de pHT, alcalinidad total, AT, nutrientes y oxígeno, para la Estación Europea Oceánica de Series Temporales de Canarias (ESTOC) y al sur de las islas Canarias. En este trabajo se presenta y discute el efecto del importante campo de remolinos presente en el área sobre la distribución de las variables químicas y del sistema de carbonato. Se ha establecido un modelo de mezcla, basado en las propiedades termohalinas de las diferentes masas de agua, que explica el 97% de la variabilidad encontrada en la distribución de las variables químicas. Las aguas intermedias al sur de las islas Canarias están caracterizadas por la alta contribución del agua Antártica intermedia diluida, que corresponde con una contribución próxima al 5% de agua Antártica intermedia pura. Por otro lado, las estructuras superficiales afectan al intercambio de CO2 atmósfera-océano, actuando el área como un sumidero de dióxido de carbono incorporando 9.1 mmol m-2 semana-1, que se corresponde con 0.03 MTon de CO2 captadas por el área y en una semana a finales de marzo del 2000

    Turbulence Hierarchy in a Random Fibre Laser

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    Turbulence is a challenging feature common to a wide range of complex phenomena. Random fibre lasers are a special class of lasers in which the feedback arises from multiple scattering in a one-dimensional disordered cavity-less medium. Here, we report on statistical signatures of turbulence in the distribution of intensity fluctuations in a continuous-wave-pumped erbium-based random fibre laser, with random Bragg grating scatterers. The distribution of intensity fluctuations in an extensive data set exhibits three qualitatively distinct behaviours: a Gaussian regime below threshold, a mixture of two distributions with exponentially decaying tails near the threshold, and a mixture of distributions with stretched-exponential tails above threshold. All distributions are well described by a hierarchical stochastic model that incorporates Kolmogorov's theory of turbulence, which includes energy cascade and the intermittence phenomenon. Our findings have implications for explaining the remarkably challenging turbulent behaviour in photonics, using a random fibre laser as the experimental platform.Comment: 9 pages, 5 figure

    A simulational and theoretical study of the spherical electrical double layer for a size-asymmetric electrolyte: the case of big coions

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    Monte Carlo simulations of a spherical macroion, surrounded by a size-asymmetric electrolyte in the primitive model, were performed. We considered 1:1 and 2:2 salts with a size ratio of 2 (i.e., with coions twice the size of counterions), for several surface charge densities of the macrosphere. The radial distribution functions, electrostatic potential at the Helmholtz surfaces, and integrated charge are reported. We compare these simulational data with original results obtained from the Ornstein-Zernike integral equation, supplemented by the hypernetted chain/hypernetted chain (HNC/HNC) and hypernetted chain/mean spherical approximation (HNC/MSA) closures, and with the corresponding calculations using the modified Gouy-Chapman and unequal-radius modified Gouy-Chapman theories. The HNC/HNC and HNC/MSA integral equations formalisms show good concordance with Monte Carlo "experiments", whereas the notable limitations of point-ion approaches are evidenced. Most importantly, the simulations confirm our previous theoretical predictions of the non-dominance of the counterions in the size-asymmetric spherical electrical double layer [J. Chem. Phys. 123, 034703 (2005)], the appearance of anomalous curvatures at the outer Helmholtz plane and the enhancement of charge reversal and screening at high colloidal surface charge densities due to the ionic size asymmetry.Comment: 11 pages, 7 figure

    Optical Characterization of a Single Quantum Emitter Based on Vanadium Phthalocyanine Molecules

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    Single quantum emitters play a fundamental role in the development of quantum technologies such as quantum repeaters, and quantum information processing. Isolating individual molecules with stable optical emission is an essential step for these applications, specially for those molecules that present large coherence times at room temperature. Among them, vanadium-oxide phthalocyanine (VOPc) molecules stand out as promising candidates due to their large coherence times measured in ensemble. However, the optical properties of individual molecules have not yet been reported. Here we show that single VOPc molecules with stable optical properties at room temperature can be isolated. We find that the optical response of the molecule under laser illumination of different polarization agrees well with a system having pyramidal C4v_{4v} symmetry. Furthermore, the molecule reveals a non-radiative transition rate that depends on the excitation wavelength when its lifetime is interrogated. We provide theoretical calculations that support our experimental findings and provide insight to the role of phonons and internal electronic structure of the molecule. These results demonstrate that this single paramagnetic molecule can function as a single quantum emitter while displaying optical stability under ambient conditions to have their intrinsic properties investigated

    The electrical double layer for a fully asymmetric electrolyte around a spherical colloid: an integral equation study

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    The hypernetted chain/mean spherical approximation (HNC/MSA) integral equation is obtained and solved numerically for a totally asymmetric primitive model electrolyte around a spherical macroparticle. The ensuing radial distribution functions show a very good agreement when compared to our Monte Carlo and molecular dynamics simulations for spherical geometry and with respect to previous anisotropic reference HNC calculations in the planar limit. We report an analysis of the potential vs charge relationship, radial distribution functions, mean electrostatic potential and cumulative reduced charge for representative cases of 1:1 and 2:2 salts with a size asymmetry ratio of 2. Our results are collated with those of the Modified Gouy-Chapman (MGC) and unequal radius Modified Gouy-Chapman (URMGC) theories and with those of HNC/MSA in the restricted primitive model (RPM) to assess the importance of size asymmetry effects. One of the most striking characteristics found is that,\textit{contrary to the general belief}, away from the point of zero charge the properties of an asymmetric electrical double layer (EDL) are not those corresponding to a symmetric electrolyte with the size and charge of the counterion, i.e. \textit{counterions do not always dominate}. This behavior suggests the existence of a new phenomenology in the EDL that genuinely belongs to a more realistic size-asymmetric model where steric correlations are taken into account consistently. Such novel features can not be described by traditional mean field theories like MGC, URMGC or even by enhanced formalisms, like HNC/MSA, if they are based on the RPM.Comment: 29 pages, 13 figure

    DICER1 tumor predisposition syndrome: An evolving story initiated with the pleuropulmonary blastoma

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    DICER1 syndrome (OMIM 606241, 601200) is a rare autosomal dominant familial tumor predisposition disorder with a heterozygous DICER1 germline mutation. The most common tumor seen clinically is the pleuropulmonary blastoma (PPB), a lung neoplasm of early childhood which is classified on its morphologic features into four types (IR, I, II and III) with tumor progression over time within the first 4-5 years of life from the prognostically favorable cystic type I to the unfavorable solid type III. Following the initial report of PPB, its association with other cystic neoplasms was demonstrated in family studies. The detection of the germline mutation in DICER1 provided the opportunity to identify and continue to recognize a number seemingly unrelated extrapulmonary neoplasms: Sertoli-Leydig cell tumor, gynandroblastoma, embryonal rhabdomyosarcomas of the cervix and other sites, multinodular goiter, differentiated and poorly differentiated thyroid carcinoma, cervical-thyroid teratoma, cystic nephroma-anaplastic sarcoma of kidney, nasal chondromesenchymal hamartoma, intestinal juvenile-like hamartomatous polyp, ciliary body medulloepithelioma, pituitary blastoma, pineoblastoma, primary central nervous system sarcoma, embryonal tumor with multilayered rosettes-like cerebellar tumor, PPB-like peritoneal sarcoma, DICER1-associated presacral malignant teratoid neoplasm and other non-neoplastic associations. Each of these neoplasms is characterized by a second somatic mutation in DICER1. In this review, we have summarized the salient clinicopathologic aspects of these tumors whose histopathologic features have several overlapping morphologic attributes particularly the primitive mesenchyme often with rhabdomyoblastic and chondroid differentiation and an uncommitted spindle cell pattern. Several of these tumors have an initial cystic stage from which there is progression to a high grade, complex patterned neoplasm. These pathologic findings in the appropriate clinical setting should serve to alert the pathologist to the possibility of a DICER1-associated neoplasm and initiate appropriate testing on the neoplasm and to alert the clinician about the concern for a DICER1 mutation

    NFV orchestration on intermittently available SUAV platforms: challenges and hurdles

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    Proceeding of: IEEE INFOCOM 2019 - IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS MiSARN 2019: Mission-Oriented Wireless Sensor, UAV and Robot Networking), 29 April-2 May 2019 Paris, FranceIn this paper, we analyze the main challenges and issues related with the orchestration of Virtualized Network Functions (VNFs) on Small Unmanned Aerial Vehicles (SUAVs). Our analysis considers a reference scenario where a number of SUAVs are deployed over a delimited geographic area and provide a mobile cloud environment that supports the deployment of functionalities using Network Functions Virtualization (NFV) technologies. The orchestration of services in this reference scenario presents different challenges, due to the constrained capacity and limited lifetime of battery-powered SUAVs, the intermittent availability of network communications, and the need to consider enhanced policies for the allocation of virtual functions to SUAVs. Finally, we perform a first exploratory evaluation of the identified challenges and issues, using a well-known and widely adopted virtualized infrastructure manager, i.e., OpenStack.This article has been partially supported by the European H2020 5GRANGE project (grant agreement 777137), and by the 5GCity project (TEC2016-76795- C6-3-R) funded by the Spanish Ministry of Economy and Competitiveness
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