Matrix completion and extrapolation via kernel regression

Matrix completion and extrapolation (MCEX) are dealt with here over reproducing kernel Hilbert spaces (RKHSs) in order to account for prior information present in the available data. Aiming at a faster and low-complexity solver, the task is formulated as a kernel ridge regression. The resultant MCEX algorithm can also afford online implementation, while the class of kernel functions also encompasses several existing approaches to MC with prior information. Numerical tests on synthetic and real datasets show that the novel approach performs faster than widespread methods such as alternating least squares (ALS) or stochastic gradient descent (SGD), and that the recovery error is reduced, especially when dealing with noisy data

Non-perturbative renormalization of lattice operators in coordinate space

We present the first numerical implementation of a non-perturbative renormalization method for lattice operators, based on the study of correlation functions in coordinate space at short Euclidean distance. The method is applied to compute the renormalization constants of bilinear quark operators for the non-perturbative O(a)-improved Wilson action in the quenched approximation. The matching with perturbative schemes, such as MS-bar, is computed at the next-to-leading order in continuum perturbation theory. A feasibility study of this technique with Neuberger fermions is also presented.Comment: 11 pages and 9 figures, LaTeX2

Effect of hydrogen addition on the OH* and CH* chemiluminescence emissions of premixed combustion of methane-air mixtures

[EN] Chemiluminescence emissions measurements of OH* and CH* are used to characterize the combustion of blends of methane and hydrogen in air in a constant volume combustion bomb, with two sets of initial conditions. The combined results of combustion development cover from 0.1 to 2.5 MPa. Burning velocity, heat release and unburned/burned gas temperatures are obtained from the pressure by using a two-zone thermodynamic combustion diagnostic model. Intensity of OH* and CH* increases with the initial temperature and the percentage of hydrogen, in parallel with the usual increase in burning velocity. The timings of the peaks of OH* and CH* chemiluminescence emissions are found to correlate respectively with the maximum rate of heat release and flame temperature. These results show that both chemiluminescence signals can be used to monitorize the burning process in combustion devices operating in the pressure range studied.Reyes, M.; Tinaut, F.; Giménez, B.; Pastor, JV. (2018). Effect of hydrogen addition on the OH* and CH* chemiluminescence emissions of premixed combustion of methane-air mixtures. International Journal of Hydrogen Energy. 43(42):19778-19791. https://doi.org/10.1016/j.ijhydene.2018.09.005S1977819791434

Asparagus : fibrousness during storage

Espárragos verdes cv. UC-157 F2, seleccionados y clasificados, se preenfriaron por inmersión en agua a 0 °C y 200 ppm de cloro activo, inmediatamente después de su cosecha. Luego, se los conservó con distintas modalidades: • Testigo (0 - 2 °C y 95 % HR). • Atmósfera modificada (0 - 2 °C y 95 - 100 % HR), cubriendo cada atado con película autoadherente de PVC. • Atmósfera controlada (0 °C, 90 % HR, 2 % CO2 y 5,5 % O2). Durante la conservación se extrajeron periódicamente muestras para controlar la evolución de la fibrosidad, utilizando presiómetro con cuchilla adaptada de acero inoxidable (0,43 mm de espesor). Para la determinación se realizó el cizallamiento del turión a intervalos de 2 cm desde la punta, registrando los kgf requeridos. El estudio realizado demostró que para evaluar la evolución de fibrosidad de los turiones durante la conservación basta una sola medición, a distancia prefijada entre los 6 - 16 cm desde la punta. La conservación en atmósfera modificada es la más conveniente ya que tanto las selecciones L como XL mantuvieron mejor dureza.It was worked with green asparagus cv. UC-157 F2; after harvest they were sorted and classified, inmediately they were precooled by inmersion in cold water to 0 ºC with 200 ppm of active chlorine; then they were conditioned in different storage modalities: • Test (0 - 2 °C and 95 % RH). • Modified atmosphere (0 - 2 °C and 95 - 100 % RH) using PVC film. • Controlled atmosphere (0 °C, 90 % RH, 2 % CO2 and 5,5 % O2). During the storage it was taken samples periodically and controlled the evolution of the fibrousness, using a penetrometer adapted with stainless steel knife (0,43 mm of thickness). For the determination it was done the shearing of the stalk each 2 cm from the top and registered the kgf required. With this study it concludes that, for evaluate the fibrousness evolution of the stalks during storage, is enough to do only one measuring to a predetermine distance between 6 and 16 cm from the top. It is demonstrated, too, the convenience of modified atmosphere modality storage where both selections L and XL maintain a better firmness degree.Fil: Giménez, Adriana B.. Universidad Nacional de Cuyo. Facultad de Ciencias AgrariasFil: Bauzá, Mónica. Universidad Nacional de Cuyo. Facultad de Ciencias AgrariasFil: Roby, Héctor R. . Universidad Nacional de Cuyo. Facultad de Ciencias AgrariasFil: Llera, Joaquín. Universidad Nacional de Cuyo. Facultad de Ciencias Agraria

Non perturbative renormalization in coordinate space

We present an exploratory study of a gauge-invariant non-perturbative renormalization technique. The renormalization conditions are imposed on correlation functions of composite operators in coordinate space on the lattice. Numerical results for bilinears obtained with overlap and O(a)-improved Wilson fermions are presented. The measurement of the quark condensate is also discussed.Comment: Lattice2003(improve), 3 page

Four-colour photometry of eclipsing binaries. XL, uvby light curves for the B-type systems DW Carinae, BF Centauri, AC Velorum, and NSV 5783

Aims. In order to increase the limited number of B-stars with accurately known dimensions, and also the number of well studied eclipsing binaries in open clusters, we have undertaken observations and studies of four southern double-lined eclipsing B-type binaries; DWCar, BF Cen, ACVel, and NSV 5783. Methods. Complete uvby light curves were observed between January 1982 and April 1991 at the Danish 0.5 m telescope at ESO La Silla, since 1985 known as the Strömgren Automatic Telescope (SAT). Standard indices for the systems and the comparison stars,as well as additional minima observations for ACVel, have been obtained later at SAT. For DWCar and ACVel, high-resolution spectra for definitive spectroscopic orbits have also been obtained; they are presented as part of the detailed analyses of these systems. A few spectra of NSV 5783 are included in the present paper. Results. For all four systems, the first modern accurate light curves have been established. DWCar is a detached system consisting of two nearly identical components. It is member of the young open cluster Cr228. A detailed analysis, based on the new light curves and 29 high-resolution spectra, is published separately. BFCen is semidetached and is member of NGC 3766. Modern spectra are needed for a detailed study. ACVel is a detached system with at least one more star. A full analysis, based on the new light curves and 18 high-resolution spectra, is published separately. NSV 5783 is discovered to be an eclipsing binary consisting of two well-detached components in an 11-day period eccentric (e = 0.18) orbit. Secondary eclipse is practically total. From the light curves and a few high-resolution spectra, accurate photometric elements and preliminary absolute dimensions have been determined. The quite similar components have masses of about 5 M and radii of about 3.5 R, and they seem to have evolved just slightly off the ZAMS. The measured rotational velocities (≈150 km s−1) are about 6 times those corresponding to pseudosynchronization

Generalization error bounds for kernel matrix completion and extrapolation

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Prior information can be incorporated in matrix completion to improve estimation accuracy and extrapolate the missing entries. Reproducing kernel Hilbert spaces provide tools to leverage the said prior information, and derive more reliable algorithms. This paper analyzes the generalization error of such approaches, and presents numerical tests confirming the theoretical resultsThis work is supported by ERDF funds (TEC2013-41315-R and TEC2016-75067-C4-2), the Catalan Government (2017 SGR 578), and NSF grants(1500713, 1514056, 1711471 and 1509040).Peer ReviewedPostprint (published version

Influence of Production Strategy on Gross Waste Output and Temporal Pattern of Gilthead Seabream (Sparus Aurata) Farming: Implications for Environmental Management

This study compares the farm management model used in the Mediterranean gilthead seabream (GHSB; Sparus aurata) industry (S1)—stepped entry of juveniles throughout the year with several production cycles and fish ages overlapping in a single farm—with that used in the salmon industry (S2)—the whole is farm filled with fish that are the same age at once with a fallowing period between rearing cycles—in terms of waste production by coupling digestibility coefficients with growth, feeding, and eating behavior models into a mass balance model. We considered the total C, N, and P content in the different waste fractions (particulate and dissolved wastes). The model, which simulated real farming conditions, showed relevant quantitative and qualitative differences between both strategies, with stocked biomass and water temperature as the main drivers, the amount of feed wasted by chewing as the most relevant fraction differentiating both strategies, and the fallowing period as the main distinguishing management feature. We discuss the influence of both farming strategies on some key performance and environmental aspects, such as benthic recovery, the breakdown of the life cycle of pathogens, and adaptability to climate change. Our results suggest that changing the GHSB industry’s production model is necessary for its sustainability.Versión del edito