464 research outputs found
An antimaximum principle for periodic solutions of a forced oscillator
Consider the equation of the linear oscillator u '' + u = h(theta), where the forcing term h : R -> R is 2 pi-periodic and positive. We show that the existence of a periodic solution implies the existence of a positive solution. To this aim we establish connections between this problem and some separation questions of convex analysis.Paris Observatory gran
Visibilidad internacional de las Revistas Españolas de Historia Moderna
Spanish history journals, the same as other publications, are being submitted from different methodological criteria to quality control. One of these criteria is to try to establish the levels of international visibility of each of them. In the following work a small group of Spanish Modern History journals has been analised
Hernández Corchete, Sira (ed.) (2012), "La Guerra Civil televisada. La representación de la contienda en la ficción y el documental español"
Visibilidad internacional de las revistas españolas de historia medieval
Spanish journals of history, like publications in other fields, are being submitted to quality evaluations based on very diverse methodological criteria. One of these methodological perspectives attempts to establish the level of international visibility of each journal. This study analyzes a limited group of Spanish journals of medieval history
How many Keplerian arcs are there between two points of spacetime?
We consider the Keplerian arcs around a fixed Newtonian center joining two
prescribed distinct positions in a prescribed flight time. We prove that,
putting aside the "opposition case" where infinitely many planes of motion are
possible, there are at most two such arcs of each "type". There is a bilinear
quantity that we call b which is in all the cases a good parameter for the
Keplerian arcs joining two distinct positions. The flight time satisfies a
"variational" differential equation in b, and is a convex function of b.Comment: 16 pages, 3 figure
Bifurcation of closed orbits from equilibria of Newtonian systems with Coriolis forces
We consider autonomous Newtonian systems with Coriolis forces in two
and three dimensions and study the existence of branches of periodic orbits
emanating from equilibria. We investigate both degenerate and nondegenerate
situations. While Lyapunov’s center theorem applies locally in the nondegen-
erate, nonresonant context, equivariant degree theory provides a global answer
which is significant also in some degenerate cases.
We apply our abstract results to a problem from Celestial Mechanics. More
precisely, in the three-dimensional version of the Restricted Triangular Four-
Body Problem with possibly different primaries our results show the existence
of at least seven branches of periodic orbits emanating from the stationary
points
NILM techniques for intelligent home energy management and ambient assisted living: a review
The ongoing deployment of smart meters and different commercial devices has made electricity disaggregation feasible in buildings and households, based on a single measure of the current and, sometimes, of the voltage. Energy disaggregation is intended to separate the total power consumption into specific appliance loads, which can be achieved by applying Non-Intrusive Load Monitoring (NILM) techniques with a minimum invasion of privacy. NILM techniques are becoming more and more widespread in recent years, as a consequence of the interest companies and consumers have in efficient energy consumption and management. This work presents a detailed review of NILM methods, focusing particularly on recent proposals and their applications, particularly in the areas of Home Energy Management Systems (HEMS) and Ambient Assisted Living (AAL), where the ability to determine the on/off status of certain devices can provide key information for making further decisions. As well as complementing previous reviews on the NILM field and providing a discussion of the applications of NILM in HEMS and AAL, this paper provides guidelines for future research in these topics.Agência financiadora:
Programa Operacional Portugal 2020 and Programa Operacional Regional do Algarve
01/SAICT/2018/39578
Fundação para a Ciência e Tecnologia through IDMEC, under LAETA:
SFRH/BSAB/142998/2018
SFRH/BSAB/142997/2018
UID/EMS/50022/2019
Junta de Comunidades de Castilla-La-Mancha, Spain:
SBPLY/17/180501/000392
Spanish Ministry of Economy, Industry and Competitiveness (SOC-PLC project):
TEC2015-64835-C3-2-R MINECO/FEDERinfo:eu-repo/semantics/publishedVersio
Gravitational lensing by wave dark matter halos
Wave Dark Matter (WaveDM) has recently gained attention as a viable candidate
to account for the dark matter content of the Universe. In this paper we
explore the extent to which dark matter halos in this model, and under what
conditions, are able to reproduce strong lensing systems. First, we
analytically explore the lensing properties of the model -- finding that a pure
WaveDM density profile, a soliton profile, produces a weaker lensing effect
than other similar cored profiles. Then we analyze models with a soliton
embedded in an NFW profile, as has been found in numerical simulations of
structure formation. We use a benchmark model with a boson mass of
, for which we see that there is a bi-modality in the
contribution of the external NFW part of the profile, and actually some of the
free parameters associated with it are not well constrained. We find that for
configurations with boson masses -- , a range of
masses preferred by dwarf galaxy kinematics, the soliton profile alone can fit
the data but its size is incompatible with the luminous extent of the lens
galaxies. Likewise, boson masses of the order of , which
would be consistent with Lyman- constraints and consist of more compact
soliton configurations, necessarily require the NFW part in order to reproduce
the observed Einstein radii. We then conclude that lens systems impose a
conservative lower bound and that the NFW envelope around the
soliton must be present to satisfy the observational requirements.Comment: 26 pages, 7 figures, Publishe
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