2024-03-28T21:07:26Zhttps://repositori.udl.cat/server/oai/requestoai:repositori.udl.cat:10459.1/416682020-07-14T08:39:34Zcom_10459.1_242com_10459.1_2com_10459.1_186col_10459.1_10990col_10459.1_311
Margalida, Antoni
Colomer, M. Àngels (Maria Àngels)
Sanuy i Castells, Delfí
2011-10-31T11:50:08Z
2011-10-31T11:50:08Z
2011
Background: The reduction in the amount of food available for European avian scavengers as a consequence of restrictive public health policies is a concern for managers and conservationists. Since 2002, the application of several sanitary regulations has limited the availability of feeding resources provided by domestic carcasses, but theoretical studies assessing whether the availability of food resources provided by wild ungulates are enough to cover energetic requirements are lacking.
Methodology/Findings: We assessed food provided by a wild ungulate population in two areas of NE Spain inhabited by three vulture species and developed a P System computational model to assess the effects of the carrion resources provided on their population dynamics. We compared the real population trend with to a hypothetical scenario in which only food provided by wild ungulates was available. Simulation testing of the model suggests that wild ungulates constitute an important food resource in the Pyrenees and the vulture population inhabiting this area could grow if only the food provided by wild ungulates would be available. On the contrary, in the Pre-Pyrenees there is insufficient food to cover the energy requirements of avian scavenger guilds, declining sharply if biomass from domestic animals would not be available. Conclusions/Significance: Our results suggest that public health legislation can modify scavenger population trends if a large number of domestic ungulate carcasses disappear from the mountains. In this case, food provided by wild ungulates could be not enough and supplementary feeding could be necessary if other alternative food resources are not available (i.e. the reintroduction of wild ungulates), preferably in European Mediterranean scenarios sharing similar and socio-economic conditions where there are low densities of wild ungulates. Managers should anticipate the conservation actions
required by assessing food availability and the possible scenarios in order to make the most suitable decisions.
AM was supported by the Departament of Medi Ambient i Habitatge of Generalitat de Catalunya and Ministerio de Medio Ambiente. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
https://doi.org/10.1371/journal.pone.0020248
016549
1932-6203
http://hdl.handle.net/10459.1/41668
eng
Public Library of Science (PLoS)
Reproducció del document publicat a https://doi.org/10.1371/journal.pone.0020248
PLoS ONE, 2011, vol. 6, núm. 5, e20248
cc-by, (c) Margalida, Colomer, Sanuy, 2011
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/2.5/es/deed.ca
Rapinyaires -- Europa
Ocells -- Europa
Ecosistemes -- Anàlisi
Ecosistemes -- Mètodes de simulació
Diversitat biològica -- Conservació
Can wild ungulate carcasses provide enough biomass to maintain avian scavenger populations? An empirical assessment using a bio-inspired computational model
article
publishedVersion
oai:repositori.udl.cat:10459.1/725672023-05-10T14:47:37Zcom_10459.1_186com_10459.1_2col_10459.1_311
Barrière, Lali
Comellas Padró, Francesc
Dalfó, Cristina
Fiol Mora, Miguel Ángel
2021-12-15T12:33:49Z
2021-12-15T12:33:49Z
2016-05
It has been shown that many networks associated with complex systems
are small-world (they have both a large local clustering coefficient and a small
diameter) and they are also scale-free (the degrees are distributed according
to a power law). Moreover, these networks are very often hierarchical, as they
describe the modularity of the systems that are modeled. Most of the studies
for complex networks are based on stochastic methods. However, a determin-
istic method, with an exact determination of the main relevant parameters
of the networks, has proven useful. Indeed, this approach complements and
enhances the probabilistic and simulation techniques and, therefore, it pro-
vides a better understanding of the modeled systems. In this paper we nd
the radius, diameter, clustering coefficient and degree distribution of a generic
family of deterministic hierarchical small-world scale-free networks that has
been considered for modeling real-life complex systems.
This research was supported by the Ministerio de Economía y Competitividad (Spain) and the European Regional Development Fund under project MTM2014-60127-P, and the Catalan Research Council under project 2014SGR1147.
https://doi.org/10.1088/1751-8113/49/22/225202
028002
1751-8113
http://hdl.handle.net/10459.1/72567
eng
IOP Publishing
MINECO/PN2013-2016/MTM2014-60127-P
Versió postprint del document publicat: https://doi.org/10.1088/1751-8113/49/22/225202
Journal of Physics A: Mathematical and Theoretical, vol. 49, núm. 22
© IOP Publishing Ltd, 2016
info:eu-repo/semantics/openAccess
Hierarchical network
Small-word
Scale-free
Degree
Diameter
Clustering
Deterministic hierarchical networks
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/655172019-01-17T00:23:48Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Fercec, Brigita
Giné, Jaume
2019-01-16T09:40:29Z
2019-01-16T09:40:29Z
2018
2019-01-16T09:40:29Z
In this work we provide an effective method to prove the formal integrability of the resonant saddles. The method is based on the use of a blow-up and the resolution of a recurrence differential equation using induction. Using the method some open integrability problems for certain resonant saddles are solved.
The authors are grateful to the referee for his/her valuable instructions and suggestions to improve this paper. The first author acknowledges the financial support of
the Slovenian Research Agency (core funding No. P1-0306). The second author is
partially supported by a MINECO/ FEDER grant number MTM2017-84383-P and
an AGAUR (Generalitat de Catalunya) grant number 2017SGR-1276.
application/pdf
https://doi.org/10.11948/2018.1833
027873
2156-907X
http://hdl.handle.net/10459.1/65517
eng
Shanghai Normal University & Wilmington Scientific Publisher
MINECO/PN2013-2016/MTM2017-84383-P
Reproducció del document publicat a https://doi.org/10.11948/2018.1833
Journal Of Applied Analysis And Computation, 2018, vol. 8, núm. 6, p. 1833-1850
cc-by (c) Giné et al., 2018
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Saddle constants
Formal first integral
Invariant analytic curve
A blow-up method to prove formal integrability for some planar differential systems
info:eu-repo/semantics/article
publishedVersion
oai:repositori.udl.cat:10459.1/445222020-07-14T08:39:38Zcom_10459.1_186com_10459.1_2col_10459.1_311
Chavarriga Soriano, Javier
Giacomini, Héctor
Giné, Jaume
2012-01-26T09:14:37Z
2012-01-26T09:14:37Z
1997
Let (P, Q) be a C 1 vector field defined in a open subset U ⊂ R2 . We call a null divergence factor a C 1 solution V (x, y) of the equation P ∂V + Q ∂V = ∂P + ∂Q V . In previous works ∂x ∂y ∂x ∂y it has been shown that this function plays a fundamental role in the problem of the center and in the determination of the limit cycles. In this paper we show how to construct systems with a given null divergence factor. The method presented in this paper is a generalization of the classical Darboux method to generate integrable systems.
https://doi.org/10.5565/PUBLMAT_41197_03
000688
0214-1493
http://hdl.handle.net/10459.1/44522
eng
Universitat Autònoma de Barcelona. Departament de Matemàtiques
Reproducció del document publicat a https://doi.org/10.5565/PUBLMAT_41197_03
Reproducció del document publicat a http://ddd.uab.cat/record/52?ln=ca
Publicacions matemàtiques, 1997, vol. 41, núm. 1, p. 41-56
(c) Universitat Autònoma de Barcelona. Departament de Matemàtiques, 1997
info:eu-repo/semantics/openAccess
Center-focus problem
Integrable systems in the plane
Limit cycles
Equacions diferencials
The null divergence factor
article
publishedVersion
oai:repositori.udl.cat:10459.1/728072022-01-25T00:26:17Zcom_10459.1_186com_10459.1_2col_10459.1_311
Giné, Jaume
Valls, Claudia
2022-01-24T09:19:52Z
2022-01-24T09:19:52Z
2018
In this paper we study the existence of local analytic first integrals for complex polynomial differential systems of the form ẋ = x + Pn(x, y), ẏ = −y, where Pn(x,y) is a homogeneous polynomial of degree n, called the complex homogeneous Kukles systems of degree n. We characterize all the homogeneous Kukles systems of degree n that belong to the Sibirsky ideal. Finally, we provide necessary and sufficient conditions when n = 2,...,7 in order that the complex homogeneous Kukles system has a local analytic first integral computing the saddle constants and using Gröbner bases to find the decomposition of the algebraic variety into its irreducible components.
The first author is partially supported by a MINECO/ FEDER grant number 2017-84383-P and an AGAUR (Generalitat de Catalunya) grant number 2017SGR 1276. The second author is partially supported by FCT/Portugal through UID/MAT/04459/2013.
https://doi.org/10.1080/14029251.2018.1494731
027403
1776-0852
http://hdl.handle.net/10459.1/72807
eng
Atlantis and Taylor & Francis
Reproducció del document publicat a https://doi.org/10.1080/14029251.2018.1494731
Journal of Nonlinear Mathematical Physics, 2018, vol. 25, núm. 3, p. 387-398
cc-by-nc (c) Jaume Giné, Claudia Valls, 2018
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc/4.0/
Integrability
Complex center-focus problem
Saddle constants
Kukles systems
Gröbner Basis
Integrability Conditions for Complex Homogeneous Kukles Systems
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/583702022-10-11T20:37:47Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291col_10459.1_44504
García, I. A. (Isaac A.)
Llibre, Jaume
Maza Sabido, Susanna
2016-11-03T12:45:14Z
2017-04-01T23:26:07Z
2015-01-20
2016-11-03T12:45:15Z
We consider families of planar polynomial vector fields having a singularity with purely imaginary eigenvalues for which a basis of its Bautin ideal B is known. We provide an algorithm for computing an upper bound of the Hopf cyclicity less than or equal to the Bautin depth of B. We also present a method for studying the cyclicity problem for the Hamiltonian and the time-reversible centers without the necessity of solving previously the Dulac complex center problem associated to the larger complexified family. As application we analyze the Hopf cyclicity of the quintic polynomial family written in complex notation as z = i z + zz (A z^3 + B z^2 z + C z z2 + D z3.
The first and third authors are partially supported by a MINECO
grant number MTM2011-22877 and by a CIRIT grant number 2014
SGR 1204. The second author is partially supported by a MINECO/
FEDER grants numbers MTM2008-03437 and MTM2013-40998-P, an
AGAUR grant number 2014SGR 568, ICREA Academia, two FP7-
PEOPLE-2012-IRSES numbers 316338 and 318999, and FEDER-UNAB10-
4E-378.
application/pdf
https://doi.org/10.1016/j.jde.2014.11.018
022249
0022-0396
http://hdl.handle.net/10459.1/58370
eng
Elsevier
info:eu-repo/grantAgreement/MICINN//MTM2011-22877/ES/BIFURCACIONES, INTEGRABILIDAD Y PROPIEDADES CUALITATIVAS DE FAMILIAS DE CAMPOS VECTORIALES/
info:eu-repo/grantAgreement/MICINN//MTM2008-03437/ES/ORBITAS PERIODICAS, BIFURCACIONES E INTEGRABILIDAD DE LOS SISTEMAS DINAMICOS/
info:eu-repo/grantAgreement/MINECO//MTM2013-40998-P/ES/ALGUNOS ASPECTOS DE LA DINAMICA GLOBAL DE LOS SISTEMAS DIFERENCIALES: INTEGRABILIDAD, SOLUCIONES PERIODICAS Y BIFURCACIONES/
Versió postprint del document publicat a https://doi.org/10.1016/j.jde.2014.11.018
Journal of Differential Equations, 2015, vol. 258, p. 1990-2009
info:eu-repo/grantAgreement/EC/FP7/318999
info:eu-repo/grantAgreement/EC/FP7/316338
cc-by-nc-nd (c) Elsevier, 2015
info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-nd/4.0
Center
Polynomial vector fields
Bautin ideal
Cyclicity
Limit cycle
The Hopf cyclicity of the centers of a class of quintic polynomial vector fields
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
garcia@matematica.udl.cat
García, I. A. (Isaac A.)
oai:repositori.udl.cat:10459.1/629442022-10-14T18:04:02Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
2018-03-23T15:32:40Z
2018-03-23T15:32:40Z
2017
2018-03-23T15:32:40Z
Various attempts have been made to fully explain the mechanism by which a body has inertial mass. Recently it has been proposed that this mechanism is as follows: when an object accelerates in one direction a dynamical Rindler event horizon forms in the opposite direction, suppressing Unruh radiation on that side by a Rindler-scale Casimir effect whereas the radiation in the other side is only slightly reduce by a Hubble-scale Casimir effect. This produces a net Unruh radiation pressure force that always opposes the acceleration, just like inertia, although the masses predicted are twice those expected, see \cite{Mc6}. In a later work an error was corrected so that its prediction improves to within 26\% of the Planck mass, see \cite{GM}. In this paper the expression of the inertial mass of a elementary particle is derived from the holographic scenario giving the exact value of the mass of a Planck particle when it is applied to a Planck particle.
The author thanks the referee for the comments and suggestions that helped to improve this paper. The author is partially supported by a MINECO/ FEDER grant number MTM2014-53703-P and an AGAUR (Generalitat de Catalunya)
grant number 2014SGR 1204
application/pdf
https://doi.org/10.1142/S0217751X17500439
025842
0217-751X
http://hdl.handle.net/10459.1/62944
eng
World Scientific Publishing
info:eu-repo/grantAgreement/MINECO//MTM2014-53703-P/ES/METODOS CUALITATIVOS EN SISTEMAS DIFERENCIALES CONTINUOS/
Versió postprint del document publicat a: https://doi.org/10.1142/S0217751X17500439
International Journal of Modern Physics A, 2017, vol. 32, num. 6/7, p. 1750043-1750043
(c) World Scientific Publishing, 2017
info:eu-repo/semantics/openAccess
Inertial mass
Unruh radiation
Holographic scenario
Dark matter
Dark energy
Cosmology
Inertial mass of an elementary particle from the holographic scenario
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/492572017-03-10T09:57:44Zcom_10459.1_242com_10459.1_2com_10459.1_186col_10459.1_10990col_10459.1_311
Margalida, Antoni
Colomer, M. Àngels (Maria Àngels)
Oro, Daniel
Arlettaz, Raphaël
Donázar, José A.
2015-12-11T08:44:34Z
2015-12-11T08:44:34Z
2015
The removal of eggs or chicks from wild populations to create captive populations, reinforce free-ranging populations or reintroduce species into the wild is a restoration tool that requires an assessment of potential detrimental effects upon the donor population. This is an absolute prerequisite when wild donor populations are scarce and small. Here, we forecast the population trend of the largest European population of the bearded vulture (Gypaetus barbatus) over the next 30 years under different demographic and management scenarios (removal of eggs, chicks or fledglings). Projections derived from the combination of a PDP model (Population Dynamic P-system) and a Box-Behnken design would lead to a decline in 77% of all 57 scenarios analysed. Among the 13 scenarios predicting a population increase, only 4 seem realistic in terms of growth rate (0.04%–1.01%), at least if current age at first breeding and productivity would remain constant over time. Our simulations thus suggest that most extraction scenarios would have detrimental effects on the demography of the donor population. Release of captive-born young or removal of only the second hatched chick for subsequent captive rearing and translocation into the wild appear to represent much better supplementation and reintroduction options in this threatened species.
https://doi.org/10.1038/srep16962
024807
2045-2322
http://hdl.handle.net/10459.1/49257
eng
Nature Publishing Group
Reproducció del document publicat a https://doi.org/10.1038/srep16962
Scientific Reports, 2015, vol. 5, núm. 16962, p. 1-10
cc-by, (c) Margalida et al., 2015
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/3.0/es/
Trencalòs -- Cria i desenvolupament
Assessing the impact of removal scenarios on population viability of a threatened, long-lived avian scavenger
article
publishedVersion
oai:repositori.udl.cat:10459.1/494262022-10-11T20:26:52Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
Grau Montaña, Maite
Santallusia Esvert, Xavier
2016-02-02T13:25:44Z
2014
2016-02-01T15:11:49Z
We study the center problem for the trigonometric Abel equation dρ/dθ=a1(θ)ρ2+a2(θ)ρ3,dρ/dθ=a1(θ)ρ2+a2(θ)ρ3, where a1(θ)a1(θ) and a2(θ)a2(θ) are cubic trigonometric polynomials in θθ. This problem is closely connected with the classical Poincaré center problem for planar polynomial vector fields. A particular class of centers, the so-called universal centers or composition centers, is taken into account. An example of non-universal center and a characterization of all the universal centers for such equation are provided.
The authors are partially supported by a MINECO/FEDER grant number MTM2011-22877 and by a Generalitat de Catalunya grant number 2009SGR 381
application/pdf
https://doi.org/10.14232/ejqtde.2014.1.1
020569
1417-3875
http://hdl.handle.net/10459.1/49426
eng
Bolyai Institute. University of Szeged
Hungarian Academy of Sciences
info:eu-repo/grantAgreement/MICINN//MTM2011-22877/ES/BIFURCACIONES, INTEGRABILIDAD Y PROPIEDADES CUALITATIVAS DE FAMILIAS DE CAMPOS VECTORIALES/
Reproducció del document publicat a https://doi.org/10.14232/ejqtde.2014.1.1
Electronic Journal of Qualitative Theory of Differential Equations, 2014, núm. 1, p. 1-7
cc-by (c) Giné, Jaume et al., 2014
info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by/4.0/deed.es_ES
Trigonometria
Trigonometry
Center problem
Abel differential equation
Universal center
Composition condition
Polynomial differential equations
Universal centers in the cubic trigonometric Abel equation
info:eu-repo/semantics/article
publishedVersion
oai:repositori.udl.cat:10459.1/494412022-10-11T20:29:05Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
Grau Montaña, Maite
Llibre, Jaume
2016-02-04T09:00:59Z
2016-02-04T09:00:59Z
2013-02
2016-02-04T08:47:17Z
In this work we study the existence and non-existence of finite invariant algebraic curves for a complex planar polynomial differential system having a Liouvillian first integral.
The first and the second authors are partially supported by a MICINN /FEDER grant number MTM2011-22877 and by a AGAUR (Generalitat de Catalunya) grant number 2009SGR 381. The third author is partially supported by a MICINN/FEDER grant num- ber MTM2008-03437, by a AGAUR grant number 2009SGR 410 and by ICREA Academia.
application/pdf
https://doi.org/10.1016/j.aml.2012.09.008
018102
0893-9659
http://hdl.handle.net/10459.1/49441
eng
Elsevier
info:eu-repo/grantAgreement/MICINN//MTM2011-22877/ES/BIFURCACIONES, INTEGRABILIDAD Y PROPIEDADES CUALITATIVAS DE FAMILIAS DE CAMPOS VECTORIALES/
Versió postprint del document publicat a https://doi.org/10.1016/j.aml.2012.09.008
Applied Mathematics Letters, 2013, vol. 26, num. 2, p. 285-289
cc-by-nc-nd (c) Elsevier, 2013
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/3.0/es
Liouvillian integrability
Invariant algebraic curve
Integrating factor
First integral
Equacions diferencials no lineals
A note on Liouvillian first integrals and invariant algebraic curves
article
acceptedVersion
oai:repositori.udl.cat:10459.1/657212022-09-27T14:32:14Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Estrada Roca, M. Asunción
Batanero, Carmen
Fortuny, Josep Maria
2019-02-07T12:39:07Z
2019-02-07T12:39:07Z
2006
Resumimos la tesis doctoral de Dña Assumpta Estrada Roca, dirigida por Carmen Batanero y Josep María Fortuny, y presentada en la Universidad Autónoma de Barcelona en septiembre de 2002, reflexionando sobre las implicaciones de sus resultados para la formación de profesores.
Trabajo financiado por el Proyecto SEJ2004-00789 MEC (Madrid).
012037
1132-6239
http://hdl.handle.net/10459.1/65721
spa
Universidad Autónoma de Madrid
info:eu-repo/grantAgreement/MEC//SEJ2004-00789/ES/
Reproducció del document publicat a https://revistas.uam.es/tarbiya/article/view/7201
Tarbiya, revista de Investigación e Innovación Educativa, 2006, núm. 38, p.79-90
(c) Universidad Autónoma de Madrid, 2006
info:eu-repo/semantics/openAccess
Actitudes
Formación de profesores
Estadística
Análisis de las actitudes y conocimientos estadísticos elementales en la formación del profesorado
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/4632532023-05-02T11:57:14Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Dalfó, Cristina
Fiol Mora, Miguel Ángel
Garriga, Ernest
2023-04-27T13:23:48Z
2023-04-27T13:23:48Z
2010-12-30
A graph G with diameter D and d + 1 distinct eigenvalues is said to be (ℓ, m)-walk-regular, for some integers ℓ ∈ [0, d] and m ∈
[0, D], ℓ≥ m, if the number of walks of length i ∈ [0, ℓ] between any pair of vertices at distance j ∈ [0, m] depends only on the values of
i and j. In this paper, we study some algebraic and combinatorial characterizations of (ℓ, m)-walk-regularity based on the so-called
predistance polynomials and the preintersection numbers.
Research supported by the Ministerio de Educación y Ciencia (Spain) and the European Regional Development Fund under project MTM2008-06620-C03-01, and by the Catalan Research Council under project 2009SGR1387.
https://doi.org/10.1016/j.laa.2010.06.042
028014
0024-3795
1873-1856
https://repositori.udl.cat/handle/10459.1/463253
eng
Elsevier
info:eu-repo/grantAgreement/MICINN//MTM2008-06620-C03-01/ES/PROBLEMAS EXTREMALES Y DE OPTIMIZACION EN TEORIA DE GRAFOS Y COMBINATORIA: APLICACION AL ANALISIS Y ALGORITMOS DE REDES DE COMUNICACION/
Versió postprint del document publicat a: https://doi.org/10.1016/j.laa.2010.06.042
Linear Algebra and its Applications, 2010, vol. 433, núm. 11-12, p. 1821-1826
Linear Algebra and Its Applications
cc-by-nc-nd, (c) Elsevier, 2010
Attribution-NonCommercial-NoDerivatives 4.0 International
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Distance-regular graph
Walk-regular graph
Adjacency matrix
Spectrum
Predistance polynomial
Preintersection number
Characterizing (ℓ,m)-walk-regular graphs
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/489022023-03-27T12:30:24Zcom_10459.1_186com_10459.1_2com_10459.1_239col_10459.1_311col_10459.1_10984
Galceran i Nogués, Josep
Companys Ferran, Encarnació
Puy Llorens, Jaume
Cecilia Averós, Joan
Garcés, Josep Lluís
2015-11-04T08:08:54Z
2015-11-04T08:08:54Z
2004
2015-11-04T08:08:54Z
AGNES (absence of gradients and Nernstian equilibrium stripping) is a stripping technique consisting of two conceptual steps: (i) application of a potential program (e.g. a step at a fixed potential) generating a known concentration gain between the outer and inner concentrations of the metal at the mercury electrode surface together with null gradients of the concentration profiles (inside and outside the mercury electrode) and (ii) determination of the concentration of reduced metal inside the amalgam in a stripping step. In the present implementation, the stripping step under diffusion limited conditions leads to a measured current just proportional to the free metal ion concentration. In this paper we present the basic principles of the technique, analytical expressions for a simplified model of its voltammetric implementation and a numerical study for a more refined model together with preliminary experimental results in the Cd(II)/nitrilotriacetic acid system showing how this technique can be used as an alternative to other techniques (such as ion selective electrodes) in order to determine free metal activities or concentrations in the presence of complex mixtures avoiding complications such as electrodic adsorption or complexation kinetics.
application/pdf
https://doi.org/10.1016/j.jelechem.2003.11.017
001996
1572-6657
http://hdl.handle.net/10459.1/48902
eng
Elsevier
Versió postprint del document publicat a: https://doi.org/10.1016/j.jelechem.2003.11.017
Journal of Electroanalytical Chemistry, 2004, vol. 566, num. 1, p. 95-109
(c) Elsevier, 2004
info:eu-repo/semantics/openAccess
Electroquímica
Anàlisi electroquímica
Electrochemistry
Electrochemical analysis
AGNES: a new electroanalytical technique for measuring free metal ion concentration
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/583862020-07-08T12:11:18Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
McCulloch, M. E.
2016-11-04T11:57:42Z
2017-07-01T22:29:45Z
2016
2016-11-04T11:57:42Z
It has been proposed that inertia can be explained as follows: when objects accelerate in one direction a Rindler horizon forms in the other direction, suppressing Unruh radiation on that side, and producing a net Unruh radiation pressure that always opposes the acceleration, just like inertia. So far this model has predicted masses over twice those expected. In this paper an error in this model is corrected so that its prediction improves to within 29\% of the expected Planck mass. It is also shown that inertial mass may be understood qualitatively by applying Carnot's principle and entropy to Unruh temperatures, so that the work needed for inertia comes from the difference in the Unruh temperatures seen by the accelerated object and the cosmos. This implies that highly-accelerated systems may emit heat in a new way.
The first author is partially supported by a MINECO/ FEDER grant number
MTM2014-53703-P and an AGAUR (Generalitat de Catalunya) grant
number 2014SGR 1204.
application/pdf
https://doi.org/10.1142/S0217732316501078
024515
0217-7323
http://hdl.handle.net/10459.1/58386
eng
World Scientific Publishing
MINECO/PN2013-2016/MTM2014-53703-P
Versió postprint del document publicat a https://doi.org/10.1142/S0217732316501078
Modern Physics Letters A, 2016, vol. 31, num. 17, p. 1650107-1650107
(c) World Scientific Publishing, 2016
info:eu-repo/semantics/openAccess
Cosmology
Unruh radiation
Hubble-scale Casimir effect
Inertial mass
Inertial mass from Unruh temperatures
info:eu-repo/semantics/article
acceptedVersion
gine@matematica.udl.cat
Giné, Jaume
oai:repositori.udl.cat:10459.1/653122022-10-14T18:26:02Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
García, I. A. (Isaac A.)
2018-12-13T09:24:49Z
2018-12-13T09:24:49Z
2018-01-25
2018-12-13T09:24:50Z
In this paper we show that the well-known Poincaré-Lyapunov nondegenerate analytic center problem in the plane and its higher dimensional version expressed as the 3-dimensional center problem at the zero-Hopf singularity have a lot of common properties. In both cases the existence of a neighborhood of the singularity in the phase space completely foliated by periodic orbits (including equilibria) is characterized by the fact that the system is analytically completely integrable. Hence its Poincaré-Dulac normal form is analytically orbitally linearizable. There also exists an analytic Poincar\'e return map and, when the system is polynomial and parametrized by its coefficients, the set of systems with centers corresponds to an affine variety in the parameter space of coefficients. Some quadratic polynomial families are considered.
The author is partially supported by a MINECO grant number MTM2014-53703-P and by a CIRIT grant number 2014 SGR 1204.
application/pdf
https://doi.org/10.1017/S0308210517000026
024520
0308-2105
http://hdl.handle.net/10459.1/65312
eng
info:eu-repo/grantAgreement/MINECO//MTM2014-53703-P/ES/METODOS CUALITATIVOS EN SISTEMAS DIFERENCIALES CONTINUOS/
Versió postprint del document publicat a
https://doi.org/10.1017/S0308210517000026
Proceedings of the Royal Society of Edinburgh Section A-Mathematics, 2018, vol. 148, p. 327-340
(c) Royal Society of Edinburgh , 2018
info:eu-repo/semantics/openAccess
Zero-Hopf singularity
Three-dimensional vector fields
Integrable zero-Hopf singularities and 3-dimensional centers
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/628372023-02-16T07:28:00Zcom_10459.1_56965com_10459.1_2com_10459.1_186com_10459.1_239col_10459.1_57707col_10459.1_311col_10459.1_10984col_10459.1_49291
Lamnatou, Chrysovalantou
Ezcurra Ciaurriz, F. Xavier
Chemisana Villegas, Daniel
Pla Aragonés, Lluís Miquel
2018-03-19T10:07:18Z
2018-07-11T22:15:02Z
2016-07-09
2018-03-19T10:07:18Z
Given the importance of pig-meat production in Spain, the present work (based on cumulative energy demand, global warming potential, ReCiPe method and different functional units) presents a life cycle assessment of an intensive pork-production system (growing-finishing pigs from 25 to 105 kg body weight) in North-East of Spain. Emphasis is given on animal feeding (which is separated into 3 phases) while the impact of drinking-water consumption, straw usage and transportation (for feed and straw) are also taken into account for certain scenarios. The results demonstrate that there is a cumulative energy demand of 5.6 MJprim per kg of animal feed and 14.5-35.6 MJprim per kg of meat (live or carcass weight). Moreover, global warming potential (based on a time horizon of 100 years: 100a) is 3.2-5.5 kg CO2.eq per kg of meat (live or carcass weight) and 336-460 kg CO2.eq per market pig. On the other hand, ReCiPe impact per market pig ranges from 60 to 76 Pts, depending on the scenario. Based on all the studied cases, animal feed is responsible for the greatest part of the total impact feed/drinking-water/straw/transportation and transportation is responsible for the second highest impact. A comparison with results from the literature is also provided and critical issues (about feed composition, cleaner-production solutions, etc.) are presented.
The authors would like to thank ''Ministerio de Economía y Competitividad'' of Spain for the funding (grant reference ENE2013-48325-R). Lluis M. Plà-Aragonés wishes to acknowledge the financial support of the Spanish Research ProgramTRA2013-48180-C3-P and CYTED program support to the thematic network P515RT0123.
application/pdf
https://doi.org/10.1016/j.jclepro.2016.07.051
024683
0959-6526
http://hdl.handle.net/10459.1/62837
eng
Elsevier
info:eu-repo/grantAgreement/MINECO//ENE2013-48325-R/ES/MILICONCENTRADORES DIELECTRICOS MULTIFASE PARA INTEGRACION ARQUITECTONICA EN FACHADA DE SISTEMAS SOLARES HIBRIDOS/
info:eu-repo/grantAgreement/MINECO//TRA2013-48180-C3-1-P/ES/COOPERACION HORIZONTAL Y COSTES MEDIOAMBIENTALES EN LA GESTION SOSTENIBLE DEL TRANSPORTE DE MERCANCIAS/
info:eu-repo/grantAgreement/MINECO//TRA2013-48180-C3-2-P/ES/MODELOS DE ANALITICA EMPRESARIAL Y DE COOPERACION HORIZONTAL PARA EL AREA DE LOGISTICA Y TRANSPORTE/
info:eu-repo/grantAgreement/MINECO//TRA2013-48180-C3-3-P/ES/SOLUCIONES COMPUTACIONALES PARA LA TOMA DE DECISIONES VINCULADAS A LA COOPERACION HORIZONTAL EN EL TRANSPORTE Y LA LOGISTICA/
Versió postprint del document publicat a: https://doi.org/10.1016/j.jclepro.2016.07.051
Journal of Cleaner Production, 2016, vol. 137, p. 105-115
cc-by-nc-nd, (c) Elsevier, 2016
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/3.0/es
Life Cycle Assessment (LCA)
Pig-meat production
Animal feed
Cumulative energy demand (CED)
Environmental assessment of a pork-production system in North-East of Spain focusing on life-cycle swine nutrition
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
lamnatou@macs.udl.cat
Lamnatou, Chrysovalantou
oai:repositori.udl.cat:10459.1/604702019-01-16T10:33:51Zcom_10459.1_186com_10459.1_2col_10459.1_311
Giné, Jaume
2017-11-10T14:20:46Z
2017-11-10T14:20:46Z
2011
Abstract In this short survey we discuss the narrow relation between the center problem and the Lie symmetries. It is well known that an analytic vector field X having a non–degenerate center has a non–trivial analytic Lie symmetry in a neighborhood of it, i.e. there exists an analytic vector field Y such that [X,Y] = μX. The same happens for a nilpotent center with an analytic first integral as can be seen from the recent results about nilpotent centers. From the recent results for nilpotent and degenerate centers it also can be proved that any nilpotent or degenerate center has a trivial smooth (of class C1) Lie symmetry. It remains as open problem if there always exists also a non–trivial Lie symmetry for any nilpotent and degenerate center
018130
2156-907X
2158-5644
http://hdl.handle.net/10459.1/60470
eng
Shanghai Normal University & Wilmington Scientific Publisher
Reproducció del document publicat a: http://jaac.ijournal.cn/ch/reader/issue_browser.aspx
Journal Of Applied Analysis And Computation, 2011, vol. 1, núm. 4, p. 487–496
cc-by (c) Giné, 2011
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Lie symmetries
Center problem
Vector fields
Matemàtica
Lie symmetries and the center problem
article
publishedVersion
oai:repositori.udl.cat:10459.1/445212020-07-14T08:39:38Zcom_10459.1_186com_10459.1_2col_10459.1_311
Chavarriga Soriano, Javier
Giné, Jaume
2012-01-25T13:08:55Z
2012-01-25T13:08:55Z
1996
In this work we study the integrability of a two-dimensional autonomous system in the plane with linear part of center type and non-linear part given by homogeneous polynomials of fourth degree. We give sufficient conditions for integrability in polar coordinates. Finally we establish a conjecture about the independence of the two classes of parameters which appear in the system; if this conjecture is true the integrable cases found will be the only possible ones.
https://doi.org/10.5565/PUBLMAT_40196_03
002274
0214-1493
http://hdl.handle.net/10459.1/44521
eng
Universitat Autònoma de Barcelona. Departament de Matemàtiques
Reproducció del document publicat a http://ddd.uab.cat/record/52?ln=ca
Reproducció del document publicat a https://doi.org/10.5565/PUBLMAT_40196_03
Publicacions matemàtiques, 1996, vol. 40, núm. 1, p. 21-39
(c) Universitat Autònoma de Barcelona. Departament de Matemàtiques, 1996
info:eu-repo/semantics/openAccess
Center-focus problem
Integrable systems in the plane
Equacions diferencials
Integrability of a linear center perturbed by a fourth degree homogeneous polynomial
article
publishedVersion
oai:repositori.udl.cat:10459.1/566822022-10-13T20:23:21Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
Grau Montaña, Maite
Santallusia Esvert, Xavier
2016-03-07T09:23:20Z
2018-05-31T22:18:49Z
2015
2016-02-03T13:15:27Z
The classical Poincaré center-focus problem for planar polynomial systems of ordinary differential equations can be transformed, in certain particular cases, to the center problem of a trigonometric Abel differential equation. Several research papers focused on the study of the center problem for trigonometric Abel differential equations. Polynomial Abel differential equations are also considered in the literature as a model problem. In this work we make a survey of the most important results in this context and we provide the state of the art of several related conjectures. We give two new results on these conjectures.
The authors are partially supported by a MINECO/FEDER grant number MTM2014-53703-P and by an AGAUR (Generalitat de Catalunya) grant number 2014SGR 1204
application/pdf
https://doi.org/10.1016/j.exmath.2015.12.002
024514
0723-0869
http://hdl.handle.net/10459.1/56682
eng
Elsevier
info:eu-repo/grantAgreement/MINECO//MTM2014-53703-P/ES/METODOS CUALITATIVOS EN SISTEMAS DIFERENCIALES CONTINUOS/
Versió postprint del document publicat a https://doi.org/10.1016/j.exmath.2015.12.002
Expositiones Mathematicae, 2016, vol. 34, núm. 2, p. 210-222
cc-by-nc-nd (c) Elsevier, 2015
info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ca
Abel equations
Center problem
Composition condition
Moment conditions
Composition conjecture
Equacions abelianes
The center problem and composition condition for Abel differential equations
article
acceptedVersion
mtgrau@matematica.udl.cat
Grau Montaña, Maite
oai:repositori.udl.cat:10459.1/652822023-01-27T16:44:19Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
García, I. A. (Isaac A.)
Llibre, Jaume
Maza Sabido, Susanna
2018-12-10T09:04:20Z
2018-12-10T09:04:20Z
2018-11-21
2018-12-10T09:04:20Z
In this work we consider real analytic functions $d(z,\la,\e)$, where $d : \Omega \times \mathbb{R}^p \times I \to \Omega$, $\Omega$ is a bounded open subset of $\R$, $I \subset \mathbb{R}$ is an interval containing the origin, $\lambda \in \mathbb{R}^p$ are parameters, and $\e$ is a small parameter. We study the branching of the zero-set of $d(z,\la,\e)$ at multiple points when the parameter $\e$ varies. We apply the obtained results to improve the classical averaging theory for computing $T$-periodic solutions of $\lambda$-families of analytic $T$-periodic ordinary differential equations defined on $\mathbb{R}$, using the displacement functions $d(z,\la,\e)$ defined by these equations. We call the coefficients in the Taylor expansion of $d(z,\la,\e)$ in powers of $\e$ the averaged functions. The main contribution consists in analyzing the role that have the multiple zeros $z_0 \in \Omega$ of the first non-zero averaged function. The outcome is that these multiple zeros can be of two different classes depending on whether the zeros $(z_0, \lambda)$ belong or not to the analytic set defined by the real variety associated to the ideal generated by the averaged functions in the Noetheriang ring of all the real analytic functions at $(z_0, \lambda)$. We bound the maximum number of branches of isolated zeros that can bifurcate from each multiple zero $z_0$. Sometimes these bounds depend on the cardinalities of minimal bases of the former ideal. Several examples illustrate our results and they are compared with the classical theory, branching theory and also under the light of singularity theory of smooth maps. The examples range from polynomial vector fields to Abel differential equations and perturbed linear centers.
The first and third authors are partially supported by a MINECO grant number
MTM2017-84383-P and an AGAUR grant number 2017SGR-1276. The second
author is partially supported by a MINECO grants MTM2016-77278-P and
MTM2013-40998-P, and AGAUR grant number 2014SGR 568.
application/pdf
https://doi.org/10.1088/1361-6544/aab592
027819
0951-7715
http://hdl.handle.net/10459.1/65282
eng
IOP Publishing
info:eu-repo/grantAgreement/MINECO//MTM2016-77278-P/ES/
info:eu-repo/grantAgreement/MINECO//MTM2013-40998-P/ES/ALGUNOS ASPECTOS DE LA DINAMICA GLOBAL DE LOS SISTEMAS DIFERENCIALES: INTEGRABILIDAD, SOLUCIONES PERIODICAS Y BIFURCACIONES/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-84383-P/ES/ORBITAS PERIODICAS E INTEGRABILIDAD EN SISTEMAS DIFERENCIALES CONTINUOS/
Versió postprint del document publicat a http://iopscience.iop.org/article/10.1088/1361-6544/aab592/pdf
Nonlinearity, 2018, vol. 31, p. 2666-2688
(c) IOP Publishing, 2018
info:eu-repo/semantics/openAccess
Averaging theory
Periodic orbits
Poincaré map
On the multiple zeros of a real analytic function with applications to the averaging theory of differential equations
info:eu-repo/semantics/article
acceptedVersion
oai:repositori.udl.cat:10459.1/4632232023-04-21T03:00:28Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Borges Llorens, Ricard
Sebé Feixas, Francesc
2023-04-20T08:08:28Z
2023-04-20T08:08:28Z
2021
Traditional pay-and-display ticket machines are
currently coexisting, but will probably be replaced in the
near future, with pay-by-phone applications. Such applications facilitate the payment for parking in regulated areas.
Companies providing this service collect and manage information about all the parking transactions performed by
drivers. That information is very sensitive and can be used
to generate reports on the parking history of drivers, posing
a threat on their privacy.
This paper proposes a pay-by-phone parking system in
which the service provider is prevented from being able to
track the parking transactions of drivers. The new proposal
requires drivers to be connected only at the beginning of a
parking transaction, or at the moment of indicating that a
parking transaction took less time than expected. Prototype
experiments have shown that the new proposal is much more
efficient, in terms of computational cost, than the most complete previous existing system, while providing the same
functionalities and higher security.
This study was funded by the Spanish Ministry of Science, Innovation and Universities (project number MTM2017-83271-R).
https://doi.org/10.1007/s10207-020-00527-2
030932
1615-5262
https://repositori.udl.cat/handle/10459.1/463223
eng
Springer
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-83271-R/ES/CRIPTOGRAFIA Y CODIGOS PARA APLICACIONES SEGURAS Y FIABLES/
Versió postprint del document publicat a https://doi.org/10.1007/s10207-020-00527-2
International Journal of Information Security, 2021, vol. 20, p. 715-727
(c) Springer, 2021
info:eu-repo/semantics/openAccess
Cryptography
Pay-by-phone parking
Privacy
Security
An efficient privacy-preserving pay-by-phone system for regulated parking areas
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/414842020-07-14T08:39:38Zcom_10459.1_186com_10459.1_2col_10459.1_311
Giné, Jaume
2011-06-01T12:16:55Z
2011-06-01T12:16:55Z
2009
The sameness between the inertial mass and the gravitational mass is an assumption and not a consequence of the equivalent principle is shown. In the context of the Sciama’s inertia theory, the sameness between the inertial mass and the gravitational mass is discussed and a certain condition which must be experimentally satisfied is given. The inertial force proposed by Sciama, in a simple case, is derived from the Assis’ inertia theory based in the introduction of a Weber type force. The origin
of the inertial force is totally justified taking into account that the Weber force is, in fact, an approximation of a simple retarded
potential, see [18, 19]. The way how the inertial forces are also derived from some solutions of the general relativistic equations is presented. We wonder if the theory of inertia of Assis is included in the framework of the General Relativity. In the context of the inertia developed in the present paper we establish the relation between the constant acceleration a0 , that appears in the classical Modified Newtonian Dynamics (M0ND) theory, with the Hubble constant H0 , i.e. a0 ≈ cH0 .
https://doi.org/10.1016/j.chaos.2008.07.008
014991
0960-0779
http://hdl.handle.net/10459.1/41484
eng
Elsevier
Versió preprint del document publicat a https://doi.org/10.1016/j.chaos.2008.07.008
Chaos Solitons and Fractals, 2009, vol. 41, núm. 4, p. 1651–1660
(c) Elsevier, 2009
info:eu-repo/semantics/openAccess
Gravitation theory
Gravitational fields
Mach inertia principle Particle acceleration
Gravitació
On the origin of the inertia: the modified Newtonian dynamics theory
article
submittedVersion
oai:repositori.udl.cat:10459.1/657042023-04-26T12:29:26Zcom_10459.1_186com_10459.1_2col_10459.1_311
Dalfó, Cristina
Fiol Mora, Miguel Ángel
Mitjana, Margarida
2019-02-04T08:21:08Z
2019-02-04T08:21:08Z
2015
We study a family of graphs related to the $n$-cube. The middle cube graph of parameter k is the subgraph of $Q_{2k-1}$ induced by the set of vertices whose binary representation has either $k-1$ or $k$ number of ones. The middle cube graphs can be obtained from the well-known odd graphs by doubling their vertex set. Here we study some of the properties of the middle cube graphs in the light of the theory of distance-regular graphs. In particular, we completely determine their spectra (eigenvalues and their multiplicities, and associated eigenvectors).
https://doi.org/10.5614/ejgta.2015.3.2.3
028094
2338-2287
http://hdl.handle.net/10459.1/65704
eng
Indonesian Combinatorial Society (InaCombS); Graph Theory and Applications (GTA) Research Centre; University of Newcastle, Australia; Institut Teknologi Bandung (ITB), Indonesia
Reproducció del document publicat a https://doi.org/10.5614/ejgta.2015.3.2.3
Electronic Journal of Graph Theory and Applications, vol. 3, núm 2, p. 133-145
cc-by-sa (c) C. Dalfo et al., 2015
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-sa/4.0/
Distance-regular graph
Odd graph
Spectrum
On Middle Cube Graphs
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/4648622024-01-13T03:00:23Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
2024-01-12T09:38:08Z
2024-01-12T09:38:08Z
2023
In this work, we study the existence of horizons in circular accelerated motions and its consequences. One particular case is the existence of two horizons in any uniform circular motion. The radiation of the Poincaré invariant vacuum is related to the spontaneous breakdown of the conformal symmetry in Quantum Field Theory The main consequence of the existence of these horizons is the Unruh radiation coming from such horizons. This consequence allows us to study the possible experimental detection of the Unruh radiation in such motions. The radiation of the Poincaré invariant vacuum is related to the spontaneous breakdown of the conformal symmetry in Quantum Field Theory. This radiation is associated with an effective temperature that can be detected using an Unruh–DeWitt detector. In fact, this effective temperature at the relativistic limit depends linearly with respect to the proper acceleration. However, in general, this dependence is not linear, contrary of what happens in the classical Unruh effect. In the relativistic limit and high density case, the uniform circular motion becomes a rotating black hole. This allows for future studies of pre-black hole configurations.
The author is partially supported by the Agencia Estatal de Investigación grant PID2020-113758GB-I00 and an AGAUR (Generalitat de Catalunya grant number 2021SGR 01618
https://doi.org/10.3390/sym15122193
2073-8994
https://repositori.udl.cat/handle/10459.1/464862
eng
MDPI
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-113758GB-I00/ES/ANALISIS CUALITATIVO, INTEGRABILIDAD Y BIFURCACIONES EN SISTEMAS DINAMICOS CONTINUOS/
Reproducció del document publicat a https://doi.org/10.3390/sym15122193
Symmetry, 2023, vol. 15, núm. 12, 2193
cc-by (c) Jaume Giné, 2023
Attribution 4.0 International
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Unruh radiation
Circular motions
Quantum fluctuations
Uncertainty principle
The Horizons in Circular Accelerated Motions and Its Consequences
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/715242021-07-01T00:09:22Zcom_10459.1_56965com_10459.1_2com_10459.1_242com_10459.1_186col_10459.1_57707col_10459.1_10990col_10459.1_311
Colomer, M. Àngels (Maria Àngels)
Margalida, Antoni
Alòs, Francesc
Oliva-Vidal, Pilar
Vilella, Anna
Fraile Sauce, Lorenzo José
2021-06-30T08:22:58Z
2021-06-30T08:22:58Z
2021
2021-06-30T08:22:58Z
A new bioinspired computational model was developed for the SARS-CoV-2 pandemic using the available epidemiological information, high-resolution population density data, travel patterns, and the average number of contacts between people. The effectiveness of control measures such as contact reduction measures, closure of communities (lockdown), protective measures (social distancing, face mask wearing, and hand hygiene), and vaccination were modelled to examine possibilities for control of the disease under several protective vaccination levels in the population. Lockdown and contact reduction measures only delay the spread of the virus in the population because it resumes its previous dynamics as soon as the restrictions are lifted. Nevertheless, these measures are probably useful to avoid hospitals being overwhelmed in the short term. Our model predicted that 56% of the Spanish population would have been infected and subsequently recovered over a 130 day period if no protective measures were taken but this percentage would have been only 34% if protective measures had been put in place. Moreover, this percentage would have been further reduced to 41.7, 27.7, and 13.3% if 25, 50 and 75% of the population had been vaccinated, respectively. Finally, this percentage would have been even lower at 25.5, 12.1 and 7.9% if 25, 50 and 75% of the population had been vaccinated in combination with the application of protective measures, respectively. Therefore, a combination of protective measures and vaccination would be highly efficacious in decreasing not only the number of those who become infected and subsequently recover, but also the number of people who die from infection, which falls from 0.41% of the population over a 130 day period without protective measures to 0.15, 0.08 and 0.06% if 25, 50 and 75% of the population had been vaccinated in combination with protective measures at the same time, respectively.
This study was partially funded by the University of Lleida (UdL). The comments of four anonymous reviewers improved a previous version of this article.
application/pdf
https://doi.org/10.1016/j.scitotenv.2021.147816
031302
0048-9697
http://hdl.handle.net/10459.1/71524
eng
Elsevier
Versió postprint del document publicat a: https://doi.org/10.1016/j.scitotenv.2021.147816
Science of the Total Environment, 2021, vol. 789, núm. 147816, p. 1-11
cc-by-nc-nd (c) Elsevier, 2021
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/3.0/es
COVID-19
Vaccination
Pandemic management
Pandemic control measures
Modelling the SARS-COV-2 outbreak: assessing the usefulness of protective measures to reduce the pandemic at population level
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/583532022-10-13T20:07:24Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291col_10459.1_44504
Giné, Jaume
Llibre, Jaume
Wu, Kesheng
Zhang, Xiang
2016-11-02T15:42:17Z
2018-04-01T22:14:40Z
2016
2016-11-02T15:42:17Z
In this paper we provide an arbitrary order averaging theory for higher dimensional periodic analytic differential systems. This result extends and improves results on averaging theory of periodic analytic differential systems, and it unifies many different kinds of averaging methods. Applying our theory to autonomous analytic differential systems, we obtain some conditions on the existence of limit cycles and integrability. For polynomial differential systems with a singularity at the origin having a pair of pure imaginary eigenvalues, we prove that there always exists a positive number $N$ such that if its first $N$ averaging functions vanish, then all averaging functions vanish, and consequently there exists a neighborhood of the origin filled with periodic orbits. Consequently if all averaging functions vanish, the origin is a center for $n=2$. Furthermore, in a punctured neighborhood of the origin, the system is $C^\infty$ completely integrable for $n>2$ provided that each periodic orbit has a trivial holonomy. Finally we develop an averaging theory for studying limit cycle bifurcations and the integrability of planar polynomial differential systems near a nilpotent monodromic singularity and some degenerate monodromic singularities.
The first author is partially supported by a MICINN/FEDER grant number MTM2014-53703-P and by a Generalitat de Catalunya grant number 2014SGR 1204. The second author is partially supported by a MINECO grant MTM2013-40998-P, an AGAUR grant number 2014SGR-568, the grants FP7-PEOPLE-2012-IRSES 318999 and 316338, from the recruitment program of high–end foreign experts of China. The third and fourth authors are partially supported by NNSF of China grant number 11271252, by RFDP of Higher Education of China grant number 20110073110054, and by FP7-PEOPLE-2012-IRSES-316338 of Europe. The fourth author also is supported by the innovation program of Shanghai Municipal Education Commission grant 15ZZ012
application/pdf
https://doi.org/10.1016/j.jde.2015.11.005
023779
0022-0396
http://hdl.handle.net/10459.1/58353
eng
Elsevier
info:eu-repo/grantAgreement/MINECO//MTM2014-53703-P/ES/METODOS CUALITATIVOS EN SISTEMAS DIFERENCIALES CONTINUOS/
info:eu-repo/grantAgreement/MINECO//MTM2013-40998-P/ES/ALGUNOS ASPECTOS DE LA DINAMICA GLOBAL DE LOS SISTEMAS DIFERENCIALES: INTEGRABILIDAD, SOLUCIONES PERIODICAS Y BIFURCACIONES/
Versió postprint del document publicat a: https://doi.org/10.1016/j.jde.2015.11.005
Journal of Differential Equations, 2016, vol. 260, núm. 5, p. 4130-4156
info:eu-repo/grantAgreement/EC/FP7/318999
info:eu-repo/grantAgreement/EC/FP7/316338
cc-by-nc-nd (c) Elsevier, 2016
info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ca
Differential systems
Averaging method
Limit cycle
Integrability
Polynomial differential systems
Matemàtica
Mathematics
Averaging methods of arbitrary order, periodic solutions and integrability
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
gine@matematica.udl.cat
Jaume Giné
oai:repositori.udl.cat:10459.1/584272020-05-01T00:11:26Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
García, I. A. (Isaac A.)
Shafer, Douglas S.
2016-11-08T13:57:41Z
2016-04-01
2016-11-08T13:57:42Z
In this work we extend techniques based on computational algebra for bounding the cyclicity of nondegenerate centers to nilpotent centers in a natural class of polynomial systems, those of the form $\dot x = y + P_{2m + 1}(x,y)$, $\dot y = Q_{2m + 1}(x,y)$, where $P_{2m+1}$ and $Q_{2m+1}$ are homogeneous polynomials of degree $2m + 1$ in $x$ and $y$. We use the method to obtain an upper bound (which is sharp in this case) on the cyclicity of all centers in the cubic family and all centers in a broad subclass in the quintic family.
The first author is partially supported by a MICINN grant number MTM2011-22877 and by a CIRIT grant number 2014 SGR 1204.
application/pdf
https://doi.org/10.3934/dcds.2016.36.2497
023237
1078-0947
http://hdl.handle.net/10459.1/58427
eng
American Institute of Mathematical Sciences
MICINN/PN2008-2011/MTM2011-22877
Versió postprint del document publicat a https://doi.org/10.3934/dcds.2016.36.2497
Discrete and Continuous Dynamical Systems Series A, 2016, vol. 36, núm. 5, p. 2497-2520
(c) American Institute of Mathematical Sciences, 2016
info:eu-repo/semantics/openAccess
Cyclicity
Limit cycle
Nilpotent center
Matemàtica
Mathematics
Cyclicity of a class of polynomial nilpotent center singularities
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/313292020-07-14T08:39:38Zcom_10459.1_186com_10459.1_2col_10459.1_311
Moreno Moreno, Ma. del Mar
Azcárate, Carmen
2011-03-15T12:30:48Z
2011-03-15T12:30:48Z
1997
Intending to quest about the conceptions math teachers hold about how to teach Differential Equations to chemistry
and biology students, we have devised a research tool which allows us to derive relevant information. We use different
means to collect the adequate data related to the qualitative research, targeting the exploration of what teachers «say they do» and what athey do and would like to do». The use of concept maps and a questionnaire, along with a recorded interview, has revealed itself as an accurate means for the appropriate analysis of data, as shown in the case study we hereby include.
018852
0212-4521
http://hdl.handle.net/10459.1/31329
spa
Universitat Autònoma de Barcelona. Institut de Ciències de l'Educació
Universitat de València
Reproducció del document publicat a: http://www.raco.cat/index.php/Ensenanza/article/view/21474
Enseñanza de las ciencias : revista de investigación y experiencias didácticas, 1997, vol. 15, núm. 1, p. 21-34
cc-by-nc-nd, (c) Moreno et al., 1997
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/3.0/es/deed.ca
Matemàtica -- Ensenyament
Equacions diferencials -- Ensenyament
Professors de matemàtica
Concepciones de los profesores sobre la enseñanza de las ecuaciones diferenciales a estudiantes de química y biología: estudio de casos
article
publishedVersion
oai:repositori.udl.cat:10459.1/598682017-06-16T00:28:53Zcom_10459.1_186com_10459.1_2com_10459.1_239col_10459.1_311col_10459.1_10984
Ibáñez, Manuel
Estrada Roca, M. Asunción
Barbero Sola, Iván
2017-06-15T08:04:51Z
2017-06-15T08:04:51Z
2017-03-01
2017-06-15T08:04:52Z
Este trabajo presenta el impacto de la incorporación de herramientas virtuales de simulación de libre distribución combinadas con un modelo instruccional constructivista y dialógico en la docencia de la astronomía diurna en la formación universitaria de los futuros maestros de Primaria. La implementación se evalúa mediante un diseño cuasi experimental. La evaluación consiste en pruebas individuales pre/post test y la elaboración grupal de una secuencia didáctica. El pre-test muestra la igualdad inicial entre grupos así como el desconocimiento por parte de los estudiantes de los conceptos básicos en astronomía diurna. A pesar del tamaño reducido de la muestra participante concluimos que las herramientas virtuales y el modelo instruccional han contribuido a mejorar la instrucción tradicional.
This study presents the impact of the inclusion of virtual simulation tools combined with and
dialogical constructivist instructional model in teaching Sun-earth system astronomy at university to future Primary teachers. The implementation is evaluated using a quasi-experimental design. Pre/post-test and development of a teaching sequence were used to measure change in participants understanding. The pre-test shows the initial equality between groups and ignorance in the basics of astronomy. Despite the small size of the participant we conclude that the virtual tools and the instructional model have given proper results.
Este estudio se ha realizado con el apoyo del proyecto 2014 ARMIF 00003 ‘Millora de la formació docent dels estudiants de doble grau d'educació infantil i primària mitjançant l'ús d'eines digitals’ del Departament d’Economia i Coneixement de la Generalitat de Catalunya.
application/pdf
https://doi.org/10.21556/edutec.2017.59.831
025580
1135-9250
http://hdl.handle.net/10459.1/59868
spa
Edutec. Asociación para el Desarrollo de la Tecnología Educativa
Reproducció del document publicat a: https://doi.org/10.21556/edutec.2017.59.831
EDUTEC - Revista Electrónica de Tecnología Educativa, 2017, num. 59, p. 1-14
(c) Edutec. Asociación para el Desarrollo de la Tecnología Educativa, 2017
info:eu-repo/semantics/openAccess
Ensenyament de l'astronomia
Educació primària
Mestres
Physics education
Primary education
Elementary school teachers
Herramientas virtuales de simulación en la enseñanza de la astronomía diurna en futuros maestros de Primaria
Virtual simulation tools in teaching sun-earth system astronomy in future primary teachers
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/490662017-03-10T13:02:29Zcom_10459.1_186com_10459.1_2col_10459.1_311
Giné, Jaume
Algaba, Antonio
García, Cristóbal
2015-11-26T09:22:06Z
2015-11-26T09:22:06Z
2013
We study the analytic integrability problem through the formal integrability problem and we show its connection, in some cases,
with the existence of invariant analytic (sometimes algebraic) curves. From the results obtained, we consider some families of
analytic differential systems in C2, and imposing the formal integrability we find resonant centers obviating the computation of
some necessary conditions.
https://doi.org/10.1155/2013/482305
019795
1085-3375
http://hdl.handle.net/10459.1/49066
eng
Hindawi Publishing Corporation
Reproducció del document publicat a https://doi.org/10.1155/2013/482305
Abstract And Applied Analysis, 2013, vol. 2013
cc-by (c) Algaba et al., 2013
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/3.0/es/
On the Formal Integrability Problem for Planar Differential Systems
article
publishedVersion
oai:repositori.udl.cat:10459.1/727992023-09-27T14:22:30Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Algaba, Antonio
García, Cristóbal
Giné, Jaume
Llibre, Jaume
2022-01-20T10:23:45Z
2022-01-20T10:23:45Z
2018
We say that a polynomial differential system ˙x = P(x, y), ˙y = Q(x, y) having the
origin as a singular point is Z2-symmetric if P(−x, −y) = −P(x, y) and Q(−x, −y) =
−Q(x, y).
It is known that there are nilpotent centers having a local analytic first integral, and
others which only have a C∞ first integral. But up to know there are no characterized
these two kinks of nilpotent centers.
Here we prove that the origin of any Z2-symmetric is a nilpotent center if, and
only if, there is a local analytic first integral of the form H(x, y) = y
2 + · · ·, where the
dots denote terms of degree higher than two.
The first and second authors are partially supported by a MINECO/FEDER grant number MTM2014-56272-C2-2 and by the Consejer´ıa de Educaci´on y Ciencia de la Junta de Andaluc´ıa (projects P12-FQM-1658, FQM-276). The third author is partially supported by a MINECO/FEDER grant number MTM2017-84383-P and by an AGAUR (Generalitat de Catalunya) grant number 2014SGR 1204. The fourth author is partially supported by a FEDER-MINECO grant MTM2016-77278-P, a MINECO grant MTM2013-40998-P, and an AGAUR grant number 2014SGR-568.
https://doi.org/10.1016/j.jmaa.2018.05.079
027402
0022-247X
http://hdl.handle.net/10459.1/72799
eng
Elsevier
info:eu-repo/grantAgreement/MINECO//MTM2014-56272-C2-2-P/ES/FORMAS NORMALES Y COMPORTAMIENTOS DINAMICOS/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-84383-P/ES/ORBITAS PERIODICAS E INTEGRABILIDAD EN SISTEMAS DIFERENCIALES CONTINUOS/
info:eu-repo/grantAgreement/MINECO//MTM2016-77278-P/ES/
info:eu-repo/grantAgreement/MINECO//MTM2013-40998-P/ES/ALGUNOS ASPECTOS DE LA DINAMICA GLOBAL DE LOS SISTEMAS DIFERENCIALES: INTEGRABILIDAD, SOLUCIONES PERIODICAS Y BIFURCACIONES/
Versió preprint del document publicat a https://doi.org/10.1016/j.jmaa.2018.05.079
Journal of Mathematical Analysis and Applications, 2018, vol. 466, núm. 1, p. 183-198
(c) Elsevier, 2018
info:eu-repo/semantics/openAccess
Z2-symmetric differential systems
Center problem
Nilpotent singularity
The center problem for Z_2-symmetric nilpotent vector fields
info:eu-repo/semantics/article
info:eu-repo/semantics/submittedVersion
oai:repositori.udl.cat:10459.1/663742022-09-23T20:25:19Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Garra Oronich, Ricard
Leibenger, Dominik
Miret, Josep M. (Josep Maria)
Sebé Feixas, Francesc
2019-05-23T10:55:16Z
2020-04-05T22:09:44Z
2019
2019-05-23T10:55:16Z
Smart meters inform the electricity suppliers about the consumption of their clients in short intervals. Fine-grained electricity consumption information is highly sensitive as it has been proven to permit to infer people's habits like, for instance, the time they leave or arrive home. Hence, appropriate measures have to be taken to preserve clients' privacy in smart metering systems. In this paper, we first analyze a recent proposal by Busom et al. (2016) and show how a corrupted substation is able to get the individual reading of any arbitrarily chosen smart meter without requiring the collaboration of any other party. After that, we propose a way to fix the mentioned security flaw which is based on adding an additional step in which the substation proves that it has properly followed all the protocol steps. Our solution is analyzed and shown to be computationally feasible for realistic parameter choices.
This study was funded by the European Regional Development Fund of the European Union in
the scope of the “Programa Operatiu FEDER de Catalunya
2014–2020” (project number COMRDI16-1-0060), by the Spanish Ministry of Science, Innovation and Universities (project
number MTM2017-83271-R), and by the Federal Ministry for
Economic Affairs and Energy of Germany in the SINTEG
project DESIGNETZ (project number 03SIN224)
application/pdf
https://doi.org/10.1007/s10207-019-00435-0
028587
1615-5262
http://hdl.handle.net/10459.1/66374
eng
Springer Berlin Heidelberg
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-83271-R/ES/CRIPTOGRAFIA Y CODIGOS PARA APLICACIONES SEGURAS Y FIABLES/
Versió postprint del document publicat a https://doi.org/10.1007/s10207-019-00435-0
International Journal Of Information Security, 2019, vol. 18, p. 637–646
(c) Springer Berlin Heidelberg, 2019
info:eu-repo/semantics/openAccess
Encryption
Homomorphism
Privacy
Repairing an aggregation-based smart metering system
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
fsebe@matematica.udl.cat
Sebé Feixas, Francesc
oai:repositori.udl.cat:10459.1/852542023-01-17T00:08:36Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Vanegas, Yuly Marsela
Giménez Rodríguez, Joaquim
Prat, Montserrat
Edo, Mequè
2023-01-16T10:21:21Z
2023-01-16T10:21:21Z
2021
Antecedentes: La formación de docentes en todos los niveles ha sido objeto
de estudio permanente en las últimas décadas, sin embargo, en el caso de la Educación
Infantil, se han realizado pocas investigaciones para analizar el conocimiento
matemático de futuros maestros. Para caracterizar dicho conocimiento es fundamental
organizar tareas profesionales enfocadas en reconocer cómo los futuros docentes
aprenden a mirar de manera estructurada diversas situaciones de enseñanza. Objetivo:
Nos proponemos describir el diseño y validación de una tarea profesional orientada a
que los futuros maestros observen, analicen y reflexionen sobre experiencias reales de
iniciación al razonamiento lógico-matemático en el ciclo 0-3. Diseño: La
estructuración de dicha tarea profesional contempló cinco etapas: revisión de estudios
sobre la construcción matemática en el ciclo de 0-3 años; revisión de estudios sobre el
inicio del razonamiento lógico-matemático; elección de narrativas/videos a observar y
analizar; implementación en un grupo piloto y análisis inicial de la competencia
docente, y, rediseño y construcción de la versión final de la tarea. Participantes: La
versión inicial se implementa con 37 futuras maestras del grado de Educación Infantil
de una universidad catalana. Datos y análisis: Se realiza una investigación cualitativainterpretativa, analizando las producciones escritas elaboradas por las futuras maestras,
mediante análisis del contenido. Resultados: Las observaciones del estudio piloto
permiten constatar que las futuras maestras, reconocen como los niños identifican y relacionan, pero, se observan dificultades en identificar cuando los niños están
operando. Conclusiones: Se constata que la tarea diseñada ha permitido mejorar el
conocimiento de las futuras maestras sobre el razonamiento en el ciclo 0-3 y que el uso
de narrativas resulta pertinente y enriquecedor en la estructuración de tareas
profesionales.
Este estudio se ha realizado en el marco de los proyectos: PID2019- 104964GB-I00 (MICINN) / PGC2018-098603-B-I00/ 2017-SGR-101 y 2017- SGR-1353.
https://doi.org/10.17648/acta.scientiae.6307
2178-7727
http://hdl.handle.net/10459.1/85254
spa
Universidade Luterana do Brasil
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2019-104964GB-I00/ES/USOS MATEMATICAMENTE RELEVANTES DEL HABLA DEL PROFESOR EN LA ENSEÑANZA DE CONTENIDOS DE LA MATEMATICA ESCOLAR/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PGC2018-098603-B-I00/ES/USO DEL LESSON STUDY Y LA NOCION DE IDONEIDAD DIDACTICA PARA EL DESARROLLO DE LA COMPETENCIA EN ANALISIS E INTERVENCION DIDACTICA EN LA FORMACION DE PROFESORES DE MATEMATICAS/
Reproducció del document publicat a https://doi.org/10.17648/acta.scientiae.6307
Acta Scientiae, 2021, vol. 23, núm. 7, p. 60-90
cc-by (c) Yuly Vanegas et al., 2021
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Formación de docentes
Diseño de tareas
Razonamiento
Educación infantil
Tareas profesionales en la formación de maestros de educación infantil: promoviendo el razonamiento en 0-3
Professional tasks in early childhood education teacher education: promoting reasoning at 0-3
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/577932017-03-10T13:02:18Zcom_10459.1_186com_10459.1_2col_10459.1_311
Giné, Jaume
2016-09-13T11:13:34Z
2016-09-13T11:13:34Z
2008
Action at distance in Newtonian physics is replaced by
finite propagation speeds in classical post–Newtonian physics. As
a result, the differential equations of motion in Newtonian physics
are replaced by functional differential equations, where the delay
associated with the finite propagation speed is taken into account.
Newtonian equations of motion, with post–Newtonian corrections,
are often used to approximate the functional differential equations.
In [16] a simple atomic model based on a functional differential
equation which reproduces the quantized Bohr atomic model was
presented. The unique assumption was that the electrodynamic
interaction has a finite propagation speed. In [17] a simple gravitational
model based on a functional differential equation which
gives a gravitational quantification and an explanation of the modified
Titius–Bode law is described. In [18] an explanation of the
anomalous precession of Mercury’s perihelion is given in terms of
a simple retarded potential, which, at first order, coincides with
Gerber’s potential of 1898, and which agrees with the author’s
previous works [16, 17]. In this paper, it is shown how the simple
retarded potential presented in [18] also gives the correct value of
the gravitational deflection of fast particles of General Relativity.
https://doi.org/10.1016/j.chaos.2007.06.097
012525
0960-0779
http://hdl.handle.net/10459.1/57793
eng
Elsevier
Versió preprint del document publicat a https://doi.org/10.1016/j.chaos.2007.06.097
Chaos, Solitons & Fractals, 2008, vol. 35, núm. 1, p. 1-6
http://arxiv.org/abs/arXiv:physics/0512121v3
(c) Elsevier, 2008
info:eu-repo/semantics/openAccess
Equacions diferencials
Gravitació
On the origin of the deflection of light
article
submittedVersion
oai:repositori.udl.cat:10459.1/719272023-03-06T14:54:33Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Borrajo, M.I.
Comas Rodríguez, Carles
Costafreda Aumedes, Sergi
Mateu, Jorge
2021-09-27T08:44:26Z
2021-09-27T08:44:26Z
2021
Wildlife-vehicle collisions on road networks represent a natural problem between human populations and the environment,
that affects wildlife management and raise a risk to the life and safety of car drivers. We propose a statistically principled
method for kernel smoothing of point pattern data on a linear network when the first-order intensity depends on covariates.
In particular, we present a consistent kernel estimator for the first-order intensity function that uses a convenient relationship between the intensity and the density of events location over the network, which also exploits the theoretical
relationship between the original point process on the network and its transformed process through the covariate. We derive
the asymptotic bias and variance of the estimator, and adapt some data-driven bandwidth selectors to estimate the optimal
bandwidth. The performance of the estimator is analysed through a simulation study under inhomogeneous scenarios. We
present a real data analysis on wildlife-vehicle collisions in a region of North-East of Spain.
The authors acknowledge the support of the Spanish Ministry of Economy, Industry and Competitivity through Grants MTM2016-76969P, MTM2016-78917-R and MTM2017- 86767-R. J. Mateu is also partially funded by grant UJI-B2018-04.
https://doi.org/10.1007/s00477-021-02072-3
031761
1436-3259
http://hdl.handle.net/10459.1/71927
eng
Springer
info:eu-repo/grantAgreement/MINECO//MTM2016-76969-P/ES/
info:eu-repo/grantAgreement/MINECO//MTM2016-78917-R/ES/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-86767-R/ES/NUEVAS FAMILIAS DE PROCESOS PUNTUALES ESPACIO-TEMPORALES DEFINIDAS EN ESTRUCTURAS COMPLEJAS. MODELIZACION, ESTIMACION Y PREDICCION EN NETWORKS (GRAFOS)/
Reproducció del document publicat a https://doi.org/10.1007/s00477-021-02072-3
Stochastic Environmental Research and Risk Assessment, 2021
cc-by (c) Borrajo et al., 2021
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Bandwidth selection
Covariates
First-order intensity
Kernel estimation
Stochastic smoothing of point processes for wildlife-vehicle collisions on road networks
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/654882022-10-21T17:49:59Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291col_10459.1_44504
Dalfó, Cristina
2019-01-11T08:20:10Z
2019-09-15T22:16:06Z
2017
2019-01-11T08:20:11Z
We show that the line digraph technique, when iterated, provides dense digraphs, that is, with asymptotically large order for a given diameter (or with small diameter for a given order). This is a well-known result for regular digraphs. In this note we prove that this is also true for non-regular digraphs.
This research is supported by projects MINECO MTM2014-60127-P, and 2014SGR1147 of the Catalan Government. This research has also received funding from the European Union’s
Horizon 2020 research and innovation programme under the Marie Sk lodowska-Curie grant agreement No 734922.
application/pdf
https://doi.org/10.1016/j.laa.2017.04.036
028000
0024-3795
http://hdl.handle.net/10459.1/65488
eng
Elsevier
info:eu-repo/grantAgreement/MINECO//MTM2014-60127-P/ES/TECNICAS DE OPTIMIZACION EN TEORIA DE GRAFOS, GRUPOS Y COMBINATORIA. APLICACIONES A REDES, ALGORITMOS Y PROTOCOLOS DE COMUNICACION/
Versió postprint del document publicat a https://doi.org/10.1016/j.laa.2017.04.036
Linear Algebra and its Applications, 2017, vol. 529, p. 391-396
info:eu-repo/grantAgreement/EC/H2020/734922/EU/CONNECT
cc-by-nc-nd (c) Elsevier, 2017
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Line digraph
Moore digraph
Degree/diameter problem
Iterated line digraphs are asymptotically dense
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
cristina.dalfo@matematica.udl.cat
Dalfó, Cristina
oai:repositori.udl.cat:10459.1/728512022-10-14T18:43:10Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
Valls, Claudia
2022-01-28T09:42:54Z
2022-01-28T09:42:54Z
2019
We give a complete description of the Darboux and Liouville integrability of a general Rayleigh-Duffing oscillator through the characterization of its polynomial first integrals, Darboux polynomials and exponential factors.
The authors are grateful to the referees for their valuable comments and suggestions to improve this paper. The first author is partially supported by a MINECO/ FEDER grant number MTM2017- 84383-P and an AGAUR (Generalitat de Catalunya) grant number 2017SGR-1276. The second author is supported by FCT/Portugal through UID/MAT/04459/2013.
https://doi.org/10.1080/14029251.2019.1591710
029036
1776-0852
http://hdl.handle.net/10459.1/72851
eng
Atlantis
Taylor & Francis
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-84383-P/ES/ORBITAS PERIODICAS E INTEGRABILIDAD EN SISTEMAS DIFERENCIALES CONTINUOS/
Reproducció del document publicat a https://doi.org/10.1080/14029251.2019.1591710
Journal of Nonlinear Mathematical Physics, 2019, vol. 26, núm. 2, p. 169-187
cc-by-nc (c) Jaume Giné, Claudia Valls, 2019
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc/4.0/
Liouvillian integrability
Rayleigh-Duffing oscillator
First integrals
Liouvillian integrability of a general Rayleigh-Duffing oscillator
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/489292018-02-20T00:34:09Zcom_10459.1_186com_10459.1_2com_10459.1_56939col_10459.1_311col_10459.1_56962col_10459.1_49291
Miret, Josep M. (Josep Maria)
Pujolàs Boix, Jordi
Valera Martín, Javier
2015-11-09T13:21:30Z
2015
Let E be an elliptic curve defined over a finite field Fq of odd
characteristic. Let l≠2 be a prime number different from the characteristic and dividing #E(Fq). We describe how the l-adic valuation of the number of points grows by taking finite extensions of the base field. We also investigate the group structure of the corresponding l-Sylow subgroups.
The authors would like to thank the anonymous referee, whose comments highly improved the quality of this publication. The research of the authors was supported in part by the Grants MTM2013-46949-P (Spanish Ministerio de Ciencia e Innovaci´on), 2014SGR-1666 (Generalitat de Catalunya).
https://doi.org/10.1007/s00013-015-0798-6
023216
0003-889X
http://hdl.handle.net/10459.1/48929
eng
Springer Verlag
MINECO/PN2013-2016/MTM2013-46949-P
Versió postprint del document publicat a https://doi.org/10.1007/s00013-015-0798-6
Archiv der Mathematik, 2015, vol.105, núm. 3, p. 261-269
(c) Springer Basel, 2015
info:eu-repo/semantics/openAccess
Elliptic curve
Finite field
Group order
ℓ-adic valuation
On the ℓ-adic valuation of the cardinality of elliptic curves over finite extensions of Fq
article
acceptedVersion
oai:repositori.udl.cat:10459.1/4634542024-03-12T14:05:08Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Algaba, Antonio
García, Cristóbal
Reyes, Manuel
Giné, Jaume
2023-06-05T11:14:18Z
2023-06-05T11:14:18Z
2023
For perturbations of integrable non-Hamiltonian quasi-homogeneous planar vector field whose origin is a non-degenerate singular point, orbital linearization and analytic integrability are equivalent. We show a class of analytically integrable vector fields whose origin is a degenerate singular point which is orbitally equivalent to a semi-quasi-homogeneous system, that is, it is not orbital equivalent to its lowest-degree quasi-homogeneous term.
The first three authors are partially supported by Ministerio de Economia y Competitividad, Plan Nacional I +D +I co-financed with FEDER funds, in the frame of the project PGC2018-096265-B-I00, and by Consejería de Educación y Ciencia de la Junta de Andalucía (FQM-276, P12-FQM-1658, UHU126150 and P20 00764). The last author is partially supported by the Agencia Estatal de Investigación, Spain grant PID2020-113758GB-I00 and an AGAUR (Generalitat de Catalunya) grant number 2021SGR 01618.
https://doi.org/10.1016/j.na.2023.113304
033965
0362-546X
https://repositori.udl.cat/handle/10459.1/463454
eng
Elsevier
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-113758GB-I00/ES/ANALISIS CUALITATIVO, INTEGRABILIDAD Y BIFURCACIONES EN SISTEMAS DINAMICOS CONTINUOS/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PGC2018-096265-B-I00/ES/COMPORTAMIENTO NO LINEAL Y BIFURCACIONES EN SISTEMAS DINAMICOS: APLICACIONES/
Reproducció del document publicat a https://doi.org/10.1016/j.na.2023.113304
Nonlinear Analysis, 2023, vol. 234, 113304
cc-by-nc-nd (c) Antonio Algaba et al., 2023
Attribution-NonCommercial-NoDerivatives 4.0 International
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Analytically integrability
Orbitally equivalent
Semi-quasihomogeneous system
Analytically integrable system orbitally equivalent to a semi-quasihomogeneous system
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/583922018-05-02T14:20:55Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
Valls, Claudia
2016-11-04T15:18:51Z
2018-05-01T22:20:38Z
2016
2016-11-04T15:18:51Z
Using tools of computer algebra based on the Gröbner basis theory we derive conditions for the existence of a center on a local center manifold for fifteen seven-parameter families of quadratic systems on R 3. To obtain the results we use modular arithmetics.
The authors are grateful to the referees for their valuable remarks which helped
to improve the manuscript. The first author is partially supported by a MINECO/
FEDER grant number MTM2014-53703-P and an AGAUR (Generalitat de Catalunya)
grant number 2014SGR 1204. The second author is supported by Portuguese
National Funds through FCT - Fundación para a Ciéncia e a Tecnología within the
project PEst-OE/EEI/LA0009/2013 (CAMGSD).
application/pdf
https://doi.org/10.1016/j.jsc.2015.04.001
023774
0747-7171
http://hdl.handle.net/10459.1/58392
eng
Elsevier
MINECO/PN2013-2016/MTM2014-53703-P
Versió postprint del document publicat a: https://doi.org/10.1016/j.jsc.2015.04.001
Journal of Symbolic Computation, 2016, vol. 73, p. 250-267
cc-by-nc-nd (c) Elsevier, 2016
info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ca
Center–focus problem
Center manifolds
First integrals
Modular arithmetics
Grobner basis
Matemàtica
Mathematics
Center problem in the center manifold for quadratic differential systems in R^3
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
gine@matematica.udl.cat
GINÉ MESA, JAUME
oai:repositori.udl.cat:10459.1/626672018-02-17T00:40:28Zcom_10459.1_186com_10459.1_2com_10459.1_56939col_10459.1_311col_10459.1_56962col_10459.1_49291
Fouquet, Mireille
Miret, Josep M. (Josep Maria)
Valera Martín, Javier
2018-02-16T11:20:45Z
2018-02-16T11:20:45Z
2015
International Conference on Cryptology and Information Security in Latin America
LATINCRYPT 2014: Progress in Cryptology - LATINCRYPT 2014 pp 162-175
Given an ordinary elliptic curve over a finite field located in
the floor of its volcano of ℓ-isogenies, we present an efficient procedure
to take an ascending path from the floor to the level of stability and
back to the floor. As an application for regular volcanoes, we give an
algorithm to compute all the vertices of their craters. In order to do this,
we make use of the structure and generators of the ℓ-Sylow subgroups of
the elliptic curves in the volcanoes.
The authors thank the reviewers for their valuable comments and specially Sorina Ionica for her suggestions which have improved this article. Research of the second and third authors was supported in part by grants MTM2013-46949-P (Spanish MINECO) and 2014 SGR1666 (Generalitat de Catalunya).
https://doi.org/10.1007/978-3-319-16295-9_9
022552
0302-9743
http://hdl.handle.net/10459.1/62667
eng
Springer International Publishing Switzerland
MINECO/PN2013-2016/MTM2013-46949-P
Versió postprint del document publicat a https://doi.org/10.1007/978-3-319-16295-9_9
Lecture Notes in Computer Science, 2015, vol. 8895
(c) Springer International Publishing Switzerland, 2015
info:eu-repo/semantics/openAccess
Elliptic curves
Isogeny volcanoes
Sylow subgroups
Finite fields
Isogeny volcanoes of elliptic curves and sylow subgroups
article
acceptedVersion
oai:repositori.udl.cat:10459.1/4640012024-02-16T14:26:43Zcom_10459.1_56965com_10459.1_2com_10459.1_243com_10459.1_49298com_10459.1_186col_10459.1_57707col_10459.1_3332col_10459.1_49299col_10459.1_311col_10459.1_49291
Torres-Sánchez, Jorge
Escolà i Agustí, Alexandre
de Castro, Ana I.
López-Granados, Francisca
Rosell Polo, Joan Ramon
Sebé Feixas, Francesc
Jiménez-Brenes, Francisco M.
Sanz Cortiella, Ricardo
Gregorio López, Eduard
Peña, José M.
2023-09-18T11:55:54Z
2023-09-18T11:55:54Z
2023-07-26
2023-09-18T11:55:55Z
The measurement of geometric canopy parameters in woody crops is an important task in Precision Agriculture because of their correlation with crop condition and productivity. In recent years, several technological approaches have been developed as an alternative to manual measurements, which are time- and labour-consuming. Two of the most commonly used 3D canopy characterization technologies are mobile terrestrial laser scanning (MTLS) based on light detection and ranging (LiDAR) sensors, and digital aerial photogrammetry (DAP) using imagery from uncrewed aerial vehicles (UAVs). Although both are state-of-the-art and have been fully tested and validated, a complete comparison between their geometric canopy parameter estimations in different woody crops and training systems has not been carried out. For this reason, a set of geometric parameters (canopy height, projected area, and volume) of a vineyard, an intensive peach orchard, and an intensive pear orchard were measured using UAV-DAP and MTLS-LiDAR. A comparison between both kinds of measurements was performed, accounting for the length of the sections in which the crop hedgerows were divided to extract the geometric parameters. Measurements from the UAV and the MTLS were highly correlated (R2 from 0.82 to 0.94) when considering the data from the three crops together, and the correlations were higher when analysing longer row sections. The canopy geometric parameters estimated using the MTLS-LiDAR always had higher values than those from the UAV-DAP. The results presented in this work provide useful data for a more informed selection of technological approaches for 3D crop characterization in Precision Fruticulture and high-throughput phenotyping.
This research was funded by the projects DECIMAL (PID2020-113229RB-C41), PRODIGIA (PID2020-113229RB-C44), AGVANCE (AGL2013-48297-C2-2-R), and PAgPROTECT (PID2021-126648OB-I00), from the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033). The authors also wish to thank Codorníu SA, celler Raimat and IRTA for having allowed the use of their vineyards, pear and peach orchards to conduct the trials described in this work.
application/pdf
https://doi.org/10.1016/j.compag.2023.108083
033419
0168-1699
https://repositori.udl.cat/handle/10459.1/464001
eng
Elsevier
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-113229RB-C41/ES/DESARROLLO Y VALIDACION DE NUEVAS TECNOLOGIAS DE TELEDETECCION Y APRENDIZAJE AUTOMATICO APLICADAS AL CONTROL INTELIGENTE DE MALAS HIERBAS/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-113229RB-C44/ES/AVANZANDO EN LA TRANSFORMACION DIGITAL Y LA OPTIMIZACION DE LA PRODUCTIVIDAD AGRICOLA: INTEGRACION DE INFORMACION ESPECTRAL Y ARQUITECTURA/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica, Técnica y de Innovación 2021-2023/PID2021-126648OB-I00/ES/PROTECCION DE CULTIVOS DE PRECISION PARA CONSEGUIR OBJETIVOS DEL PACTO VERDE EUROPEO EN USO EFICIENTE Y REDUCCION DE FITOSANITARIOS MEDIANTE AGRICULTURA DE PRECISION/
info:eu-repo/grantAgreement/MINECO//AGL2013-48297-C2-2-R/ES/HERRAMIENTAS DE BASE FOTONICA PARA LA GESTION AGRONOMICA Y EL USO DE PRODUCTOS FITOSANITARIOS SOSTENIBLE EN CULTIVOS ARBOREOS EN EL MARCO DE LA AGRICULTURA DE PRECISION/
Reproducció del document publicat a: https://doi.org/10.1016/j.compag.2023.108083
Computers and Electronics in Agriculture, 2023, vol. 212, 108083
cc-by-nc-nd, (c) Torres-Sánchez et al., 2023
info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-nd/4.0/
Precision agriculture
Digitalization
Vineyard
Pear
Peach
Mobile terrestrial laser scanner vs. UAV photogrammetry to estimate woody crop canopy parameters - Part 2: Comparison for different crops and training systems
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/851772023-01-05T00:08:07Zcom_10459.1_186com_10459.1_2col_10459.1_311
Eledlebi, Khouloud
Alzubaidi, Ahmed Adel
Yeun, Chan Yeob
Damiani, Ernesto
Mateu Meseguer, Víctor
Al-Hammadi, Yousof
2023-01-04T12:40:31Z
2023-01-04T12:40:31Z
2022
The evolution of 5G and 6G networks has enhanced the ability of massive IoT devices to
provide real-time monitoring and interaction with the surrounding environment. Despite recent
advances, the necessary security services, such as immediate and continuous authentication, high
scalability, and cybersecurity handling of IoT cannot be achieved in a single broadcast authentication
protocol. This paper presents a new hybrid protocol called Hybrid Two-level µ-timed-efficient stream
loss-tolerant authentication (Hybrid TLI-µTESLA) protocol, which maximizes the benefits of the
previous TESLA protocol variants, including scalability support and immediate authentication of
Multilevel-µTESLA protocol and continuous authentication with minimal computation overhead of
enhanced Inf-TESLA protocol. The inclusion of three different keychains and checking criteria of the
packets in the Hybrid TLI-µTESLA protocol enabled resistance against Masquerading, Modification,
Man-in-the-Middle, Brute-force, and DoS attacks. A solution for the authentication problem in the
first and last packets of the high-level and low-level keychains of the Multilevel-µTESLA protocol
was also proposed. The simulation analysis was performed using Java, where we compared the
Hybrid TLI-µTESLA protocol with other variants for time complexity and computation overhead at
the sender and receiver sides. We also conducted a comparative analysis between two hash functions,
SHA-2 and SHA-3, and assessed the feasibility of the proposed protocol in the forthcoming 6G
technology. The results demonstrated the superiority of the proposed protocol over other variants
in terms of immediate and continuous authentication, scalability, cybersecurity, lifetime, network
performance, and compatibility with 5G and 6G IoT generations.
This research was funded by Technology Innovation Institute under grand number 8434000386-TII-ATM-2035-2020.
https://doi.org/10.3390/s22239063
1424-8220
http://hdl.handle.net/10459.1/85177
eng
MDPI
Reproducció del document publicat a https://doi.org/10.3390/s22239063
Sensors, 2022, vol. 22, núm. 23, 9063
cc-by (c) Khouloud Eledlebi et al., 2022
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Continuous authentication
Scalability
Cybersecurity
Hash function
Immediate authentication
Low overhead
TESLA protocol
Simulation Analysis and Comparison of New Hybrid TLI-µTESLA and Variant TESLA Protocols Using SHA-2 and SHA-3 Hash Functions
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/852562023-01-17T00:08:38Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Vanegas, Yuly Marsela
Giménez Rodríguez, Joaquim
2023-01-16T10:35:53Z
2023-01-16T10:35:53Z
2021
En este artículo proponemos caracterizar las prácticas matemáticas democráticas promovidas en una clase de matemáticas con estudiantes de 12 y 13 años centrada en la enseñanza y el aprendizaje de la medida de longitud. Se muestra que la promoción de estas prácticas posibilita negociar exitosamente significados matemáticos. Se realiza un análisis donde junto con la identificación de prácticas matemáticas democráticas se observan normas, para describir e interpretar los procesos interactivos que dan forma a la participación de profesor y estudiantes en las sesiones de clase. Los resultados indican el dominio de prácticas relacionadas con la articulación y resolución de conflictos. También se constata un determinado tipo de normas en relación con cada tipo de práctica matemática democrática.
In this article we propose the characterization of the democratic mathematical practices promoted
in a mathematics classroom with 12-13-year-old students focused on the teaching and learning of the
length measurement. It is shown that the promotion of such practices makes it possible to successfully
negotiate mathematical meanings. An analysis is carried out in which, in addition to the identification of
democratic mathematical practices, we observe norms to describe and interpret the interactive
processes that shape the participation of teacher and students in the lessons. The results indicate a
predominance of practices related to the articulation and resolution of conflicts. It is also found that
each type of democratic mathematical practice relates to a certain type of norm.
Trabajo en colaboración con los equipos de PID2019-104964GB-100 y PGC2018- 098603-B-I00 (MICINN); y los equipos de SGR-2017-101 y SGR-2017-1181.
https://doi.org/10.35763/aiem.v0i19.417
2254-4313
http://hdl.handle.net/10459.1/85256
spa
Sociedad Española de Investigación en Educación Matemática
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PGC2018-098603-B-I00/ES/USO DEL LESSON STUDY Y LA NOCION DE IDONEIDAD DIDACTICA PARA EL DESARROLLO DE LA COMPETENCIA EN ANALISIS E INTERVENCION DIDACTICA EN LA FORMACION DE PROFESORES DE MATEMATICAS/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2019-104964GB-I00/ES/USOS MATEMATICAMENTE RELEVANTES DEL HABLA DEL PROFESOR EN LA ENSEÑANZA DE CONTENIDOS DE LA MATEMATICA ESCOLAR/
Reproducció del document publicat a https://doi.org/10.35763/aiem.v0i19.417
Avances De Investigación En Educación Matemática, 2021, núm. 19, p. 71-85
cc-by (c) Yuly Vanegas, Joaquín Giménez, 2021
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Prácticas matemáticas democráticas
Normas de aula
Construcción de significado
Medida de longitud
Prácticas matemáticas democráticas: Análisis de una experiencia escolar
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/4643462023-11-01T03:00:38Zcom_10459.1_186com_10459.1_2col_10459.1_311
Torreglosa Hernández, Sindy Gisela
Gonzalez Gomez, Difariney
Estrada Roca, M. Asunción
Mera-Mamián, Andry Yasmid
Contreras-Martínez, Heidy Johanna
Lizcano Cardona, Douglas
2023-10-31T15:35:25Z
2023-10-31T15:35:25Z
2023-02-20
Introducción: al considerar que, en asignaturas como la estadística, aspectos afectivos pueden determinar el logro de los objetivos de aprendizaje, este estudio se propuso establecer la validez de contenido y de constructo de la Escala de Actitudes hacia la Estadística. Métodos: estudio observacional, de corte transversal, tipo validación de escalas. Participaron 250 estudiantes de pregrado de áreas de la salud. Se analizó validez de contenido mediante juicio de expertos, validez de constructo con análisis factorial exploratorio y confirmatorio. Resultados: en la validación de contenido, todos los ítems obtuvieron calificaciones superiores a 3 (escala de 1-4), con óptimo acuerdo interjueces (> 0,5). Alfa de Cronbach de 0,865. Con el análisis factorial exploratorio, se eliminaron 6/25 ítems. Los resultados del análisis factorial confirmatorio reportaron un índice de ajuste comparativo adecuado y coeficiente de TuckerLewis aceptable. La raíz cuadrada de la media del error de aproximación (RMSEA) también fue aceptable (entre 0,05 y 0,08), la raíz cuadrada media residual estandarizada (SRMR) señaló un buen ajuste (< 0,08). Los ítems se agruparon en 3 factores: valoración positiva de la estadística, agrado y habilidades en estadística, valoración negativa de la estadística. Conclusión: la Escala de Actitudes hacia la Estadística, validada en población colombiana, es una herramienta de apoyo en el proceso enseñanza-aprendizaje de la estadística; puede ser utilizada al inicio, durante el seguimiento o al final de asignaturas que involucren la estadística.
Introduction: Considering that, in subjects such as statistics, affective aspects can determine the achievement of learning objectives, this study set out to establish the content and construct validity of the Scale of Attitudes towards Statistics. Methods: Cross-sectional observational study of scale validation type. 250 undergraduate students from health-related areas participated. Content validity was analyzed by expert judgment, construct validity with exploratory factor analysis and confirmatory. Results: In the content validation, all the items obtained scored higher than 3 (scale of 1-4), with optimal inter-judge agreement (> 0,5). Cronbach’s alpha of 0,865. With the exploratory factor analysis 6/25 items were eliminated. The results of the confirmatory factor analysis reported an adequate Comparative Fit Index and acceptable Tucker-Lewis Index. The Root Mean Square Residual Error of Approximation was also acceptable (between 0,05 and 0,08), the Standardized Root Mean Square Residual indicated a good fit (< 0,08). The items were grouped into 3 factors: positive assessment of the statistics, liking and skills in statistics, negative assessment of the statistics. Conclusion: The Scale of Attitudes towards Statistics, validated in the Colombian population, is a support tool in the teaching-learning process of statistics; it can be used at the beginning, during follow-up or at the end of subjects that involve statistics.
https://doi.org/10.18273/saluduis.54.e:22066
2145-8464
0121-0807
https://repositori.udl.cat/handle/10459.1/464346
spa
Universidad Industrial de Santander
Reproducció del document publicat a https://doi.org/10.18273/saluduis.54.e:22066
Salud UIS, 2023, vol. 55, e22066
cc-by (c) Sindy Gisela Torreglosa Hernández et al., 2023
Attribution 4.0 International
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Estudio de validación
Estadística
Actitudes
Análisis factorial
Adaptación y resultados psicométricos de una escala de actitudes hacia la estadística entre estudiantes de pregrado en salud pública
Adaptation and psychometric results of a scale of attitudes towards statistics in undergraduate public health students
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/492732022-11-28T19:30:31Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Conde Colom, Josep
Gimbert i Quintilla, Joan
Miret, Josep M. (Josep Maria)
Moreno Chiral, Ramiro
Gonzàlez, J.
2015-12-18T13:19:17Z
2015-12-18T13:19:17Z
2008
Almost Moore digraphs appear in the context of the degree/diameter problem as a class of extremal directed graphs, in the sense that their order is one less than the unattainable Moore bound M(d; k) = 1 + d + + dk, where d > 1 and k > 1 denote the maximum out-degree and diameter, respectively. So far, the problem of their existence has only been solved when d = 2; 3 or k = 2. In this paper, we prove that almost Moore digraphs of diameter k = 3 do not exist for any degree d. The enumeration of almost Moore digraphs of degree d and diameter k = 3 turns out to be equivalent to the search of binary matrices A ful lling that AJ = dJ and I+A+A2+A3 = J +P, where J denotes the all-one matrix and P is a permutation matrix . We use spectral techniques in order to show that such equation has no (0; 1)-matrix solutions. More precisely, we obtain the factorization in Q[x] of the characteristic polynomial of A, in terms of the cycle structure of P, we compute the trace of A and we derive a contradiction on some algebraic multiplicities of the eigenvalues of A. In order to get the factorization of det(xI - A) we determine when the polynomials Fn(x) = n(1 + x + x2 + x3) are irreducible in Q[x], where n(x) denotes the n-th cyclotomic polynomial, since in such case they become `big pieces' of det(xI - A). By using concepts and techniques from algebraic number theory, we prove that Fn(x) is always irreducible in Q[x], unless n = 1; 10. So, by combining tools from matrix and number theory we have been able to solve a problem of graph theory.
Partially supported by the Ministry of Science and Technology, Spain, under the projects TIC2003-
09188, MTM2006-15038-C02-02 and MTM2007-66842-C02-02.
012456
1077-8926
http://hdl.handle.net/10459.1/49273
eng
Electronic Journal of Combinatorics
info:eu-repo/grantAgreement/MICYT//TIC2003-09188/ES/
info:eu-repo/grantAgreement/MEC//MTM2006-15038-C02-02/ES/CURVAS MODULARES Y DE SHIMURA Y SUPERFICIES ABELIANAS/
info:eu-repo/grantAgreement/MEC//MTM2007-66842-C02-02/ES/ALGORITMOS Y PROTOCOLOS CRIPTOGRAFICOS CON CURVAS ELIPTICAS E HIPERELIPTICAS/
Reproducció del document publicat a http://www.combinatorics.org/ojs/index.php/eljc/article/view/v15i1r87
Electronic Journal of Combinatorics, 2008, vol. 15, núm. 1
(c) Conde et al., 2008
info:eu-repo/semantics/openAccess
Almost Moore digraph
Characteristic polynomial
Cyclotomic polynomial
Non existence of almost Moore digraphs of diameter three
article
publishedVersion
oai:repositori.udl.cat:10459.1/567922017-03-10T13:01:59Zcom_10459.1_242com_10459.1_2com_10459.1_186col_10459.1_10990col_10459.1_311
Margalida, Antoni
Colomer, M. Àngels (Maria Àngels)
2016-04-04T08:33:13Z
2016-04-04T08:33:13Z
2016
We apply a novel mistake index to assess trends in the proportion of corrections
published between 1993 and 2014 in Nature, Science and PNAS. The index revealed
a progressive increase in the proportion of corrections published in these three highquality
journals. The index appears to be independent of the journal impact factor or
the number of items published, as suggested by a comparative analyses among 16 top
scientific journals of different impact factors and disciplines. A more detailed analysis
suggests that the trend in the time-to-correction increased significantly over time and
also differed among journals (Nature 233 days; Science 136 days; PNAS 232 days). A
detailed review of 1,428 errors showed that 60% of corrections were related to figures,
authors, references or results. According to the three categories established, 34.7% of
the corrections were considered mild, 47.7% moderate and 17.6% severe, also differing
among journals. Errors occurring during the printing process were responsible for 5%
of corrections in Nature, 3% in Science and 18% in PNAS. The measurement of the
temporal trends in the quality of scientific manuscripts can assist editors and reviewers
in identifying the most common mistakes, increasing the rigor of peer-review and
improving the quality of published scientific manuscripts.
AM was supported by a research contract Ramón y Cajal from the Ministry of Economy and Competitiveness (RYC-2012-11867).
https://doi.org/10.7717/peerj.1670
024811
2167-8359
http://hdl.handle.net/10459.1/56792
eng
PeerJ
Reproducció del document publicat a https://doi.org/10.7717/peerj.1670
PeerJ, 2016, vol. 4, e1670
cc-by (c) Margalida, Antoni et al., 2016
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/3.0/es/
Bibliometric analyses
Corrections
Publishing
Improving the peer-review process and editorial quality: key errors escaping the review and editorial process in top scientific journals
article
publishedVersion
oai:repositori.udl.cat:10459.1/602072018-09-05T10:31:55Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
García, I. A. (Isaac A.)
Hernández Bermejo, Benito
2017-08-31T07:48:20Z
2018-07-14T22:21:00Z
2017-07-15
2017-08-31T07:48:21Z
Some aspects of the relationship between conservativeness of a dynamical system (namely the preservation of a finite measure) and the existence of a Poisson structure for that system are analyzed. From the local point of view, due to the Flow-Box Theorem we restrict ourselves to neighborhoods of singularities. In this sense, we characterize Poisson structures around the typical zero-Hopf singularity in dimension 3 under the assumption of having a local analytic first integral with non-vanishing first jet by connecting with the classical Poincar\'e center problem. From the global point of view, we connect the property of being strictly conservative (the invariant measure must be positive) with the existence of a Poisson structure depending on the phase space dimension. Finally, weak conservativeness in dimension two is introduced by the extension of inverse Jacobi multipliers as weak solutions of its defining partial differential equation and some of its applications are developed. Examples including Lotka-Volterra systems, quadratic isochronous centers, and non-smooth oscillators are provided.
Both authors would like to acknowledge Ministerio de Econom´ıa y Competitividad
for Project Ref. MTM2014-53703-P. In addition, I.A.G. acknowledges AGAUR
grant number 2014SGR 1204. B.H.-B. acknowledges Ministerio de Econom´ıa y Competitividad
for Project Ref. MTM2016-80276-P as well as financial support from
Universidad Rey Juan Carlos-Banco de Santander (Excellence Group QUINANOAP,
grant number 30VCPIGI14). Finally, B.H.-B. is sincerely indebted to the members
of Departament de Matemàtica, Universitat de Lleida, for their kind hospitality
application/pdf
https://doi.org/10.1088/1751-8121/aa7bda
025812
1751-8113
http://hdl.handle.net/10459.1/60207
eng
IOP Publishing
MINECO/PN2013-2016/MTM2014-53703-P
MINECO/PN2013-2016/MTM2016-80276-P
Versió postprint del document publicat a https://doi.org/10.1088/1751-8121/aa7bda
Journal of Physics A: Mathematical and Theoretical, 2017, vol. 50, p. 1-17
(c) IOP Publishing, 2017
info:eu-repo/semantics/openAccess
Matemáticas
Inverse Jacobi multipliers
Conservative systems
Poisson systems
Inverse Jacobi multiplier as a link between conservative systems and Poisson structures
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
garcia@matematica.udl.cat
García, I. A. (Isaac A.)
oai:repositori.udl.cat:10459.1/664412021-12-22T13:00:12Zcom_10459.1_186com_10459.1_2col_10459.1_311
López Masip, Susana-Clara
Muntaner Batle, Francesc Antoni
Prabu, M.
2019-06-11T08:50:57Z
2019-06-11T08:50:57Z
2017
2019-06-11T08:50:57Z
A graph G is called edge-magic if there is a bijective function f from the set of vertices and edges to the set {1,2, ,|V(G)|+|E(G)|} such that the sum f(x)+f(xy)+f(y) for any xy in E(G) is constant. Such a function is called an edge-magic labelling of G and the constant is called the valence. An edge-magic labelling with the extra property that f(V(G))={1,2, ,|V(G)|} is called super edge-magic. A graph is called perfect (super) edge-magic if all theoretical (super) edge-magic valences are possible. In this paper we continue the study of the valences for (super) edge-magic labelings of crowns Cm⊙K¯¯¯¯¯n and we prove that the crowns are perfect (super) edge-magic when m=pq where p and q are different odd primes. We also provide a lower bound for the number of different valences of Cm⊙K¯¯¯¯¯n , in terms of the prime factors of m.
The research conducted in this document by the first author has been
supported by the Spanish Research Council under project MTM2011-28800-C02-01 and symbolically by the Catalan Research Council under grant 2014SGR1147.
application/pdf
https://doi.org/10.1007/s00025-016-0643-7
028504
1422-6383
http://hdl.handle.net/10459.1/66441
eng
Springer
MICINN/PN2008-2011/MTM2011-28800-C02-01
Versió postprint del document publicat a: https://doi.org/10.1007/s00025-016-0643-7
Results in Mathematics, 2017, vol. 71, num. 3-4, p. 1459-1471
(c) Springer, 2017
info:eu-repo/semantics/openAccess
Edge-magic
Super edge-magic
Valence
Perfect (super) edge-magic
Perfect (super) Edge-Magic Crowns
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/844712023-10-26T14:21:16Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Alòs, Francesc
Colomer, M. Àngels (Maria Àngels)
Martín Cantera, Carlos
Solís Muñoz, Montserrat
Bort Roig, Judit
Saigi, Ignasi
Chirveches Pérez, Emilia
Solà Gonfaus, Mercè
Molina Aragonés, Josep Maria
Puig Ribera, Anna
2022-12-04T19:26:23Z
2022-12-04T19:26:23Z
2022
Background: Prolonged sedentary time is associated with an increased incidence of chronic disease including
type 2 diabetes mellitus (DM2). Given that occupational sedentary time contributes signifcantly to the total amount
of daily sedentariness, incorporating programmes to reduce occupational sedentary time in patients with chronic
disease would allow for physical, mental and productivity benefts. The aim of this study is to evaluate the short-,
medium- and long-term efectiveness of a mHealth programme for sitting less and moving more at work on habitual
and occupational sedentary behaviour and physical activity in ofce staf with DM2. Secondary aims. To evaluate the
efectiveness on glycaemic control and lipid profle at 6- and 12-month follow-up; anthropometric profle, blood pres‑
sure, mental well-being and work-related post-intervention outcomes at 3, 6 and 12months.
Methods: Multicentre randomized controlled trial. A sample size of 220 patients will be randomly allocated into
a control (n=110) or intervention group (n=110), with post-intervention follow-ups at 6 and 12months. Health
professionals from Spanish Primary Health Care units will randomly invite patients (18–65 years of age) diagnosed with
DM2, who have sedentary ofce desk-based jobs. The control group will receive usual healthcare and information on
the health benefts of sitting less and moving more. The intervention group will receive, through a smartphone app
and website, strategies and real-time feedback for 13weeks to change occupational sedentary behaviour. Variables:
(1) Subjective and objective habitual and occupational sedentary behaviour and physical activity (Workforce Sit‑
ting Questionnaire, Brief Physical Activity Assessment Tool, activPAL3TM); 2) Glucose, HbA1c; 3) Weight, height, waist
circumference; 4) Total, HDL and LDL cholesterol, triglycerides; (5) Systolic, diastolic blood pressure; (6) Mental well being (Warwick-Edinburgh Mental Well-being); (7) Presenteeism (Work Limitations Questionnaire); (8) Impact of work
on employees´ health, sickness absence (6th European Working Conditions Survey); (9) Job-related mental strain (Job Content Questionnaire). Diferences between groups pre- and post- intervention on the average value of the vari‑
ables will be analysed.
Discussion: If the mHealth intervention is efective in reducing sedentary time and increasing physical activity in
ofce employees with DM2, health professionals would have a low-cost tool for the control of patients with chronic
disease.
The study was funded by Fondo de Investigación Sanitaria, Instituto de Salud Carlos III (PI17/01788) and the predoctoral research grant Isabel Fernández 2020 from the Spanish Society of Family and Community Medicine (semFYC). The funders had no role in the design, analysis, data interpretation or writing of the manuscript.
https://doi.org/10.1186/s12889-022-13676-x
1471-2458
http://hdl.handle.net/10459.1/84471
eng
Springer Nature
info:eu-repo/grantAgreement/ISCIII/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016 (ISCIII)/PI17%2F01788/ES/´SENTARSE MENOS Y MOVERSE MAS` EN EL TRABAJO: IMPACTO DE UN PROGRAMA MHEALTH SOBRE EL CONTROL GLUCEMICO Y PERFIL ANTROPOMETRICO EN PERSONAL DE OFICINA CON DT2. ENSAYO CLINICO ALEATORIZADO/
Reproducció del document publicat a https://doi.org/10.1186/s12889-022-13676-x
BMC Public Health, 2022, vol. 22, art. 1269.
cc-by (c) Francesc Alòs et. al., 2022.
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Mobile applications
Smartphone
Sedentary behaviour
Physical activity
Primary healthcare
Diabetes mellitus type 2
Workplace
Effectiveness of a healthcare-based mobile intervention on sedentary patterns, physical activity, mental well-being and clinical and productivity outcomes in office employees with type 2 diabetes: study protocol for a randomized controlled trial
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/684742020-04-23T00:10:39Zcom_10459.1_186com_10459.1_2col_10459.1_311
Gea, María M.
Estrada Roca, M. Asunción
Batanero, Carmen
2020-04-22T10:51:50Z
2020-04-22T10:51:50Z
2019
The aim of this paper was to evaluate the cognitive component of Spanish prospective high school teachers about correlation and regression. The evaluation is based on the analysis of the cognitive suitability of a statistical project carried out by 65 students preparing to become mathematics teachers, after having previously worked with that project. The project is based on real data from the relationships of live expectancy with different indicators of human development, taken from the UN web server, and is intended to introduce correlation and regression in high school, The analysis of the participants’ written productions is used to assign a level in each indicator of cognitive suitability, which extends those proposed in a previous work. It also serves to identify examples of the cognitive component of teachers’ knowledge about correlation and regression.
El objetivo de este trabajo fue evaluar la componente afectiva del conocimiento didácticomatemático sobre la correlación y regresión de los futuros profesores de Educación Secundaria
Obligatoria y Bachillerato españoles. La evaluación se realiza a partir del análisis que una
muestra de 65 estudiantes que se preparan como profesores de matemáticas realizan de la
idoneidad cognitiva de un proyecto estadístico, después de haber trabajado previamente con
dicho proyecto. El proyecto está basado en datos reales sobre la relación de la esperanza de vida
con diferentes indicadores del desarrollo humano, tomados del servidor de las Naciones Unidas
y fue pensado para introducir las ideas de regresión y correlación en Bachillerato. El análisis
de las producciones escritas de los participantes permite asignarles un nivel en cada uno de los
indicadores de la idoneidad afectiva, que extienden los propuestos en un trabajo previo. También
permite mostrar ejemplos de la componente afectiva del conocimiento didáctico-matemático de
los futuros profesores sobre la correlación y regresión.
https://doi.org/10.17648/acta.scientiae.v21iss3id5092
029346
2178-7727
http://hdl.handle.net/10459.1/68474
spa
eng
Universidade Luterana do Brasil
Reproducció del document publicat a https://doi.org/10.17648/acta.scientiae.v21iss3id5092
Acta Scientiae, 2019, vol. 21, núm. 3, p. 112-130
cc-by (c) Estrada et al., 2019
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Didactic-mathematical knowledge
Cognitive component
Conocimiento didáctico-matemático
Componente cognitiva
Assessing Prospective Teachers’ Affective Component Related to Working with Statistical Projects
Evaluación de la Componente Afectiva del Trabajo con Proyectos Estadísticos por Futuros Profesores
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/571832020-05-01T00:11:34Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Rodríguez Sánchez, Sara Verónica
Albornoz Sanhueza, Victor Manuel
Pla Aragonés, Lluís Miquel
2016-06-13T08:20:26Z
2009
This paper presents a formulation and resolution of a two-stage stochastic
linear programming model with recourse for sow farms producing piglets. The
proposed model considers a medium-term planning horizon and specifically allows
optimal replacement and schedule of purchases to be obtained for the first stage. This
model takes into account sow herd dynamics, housing facilities, reproduction management,
herd size with initial and final inventory of sows and uncertain parameters
such as litter size, mortality and fertility rates. These last parameters are explicitly
incorporated via a finite set of scenarios. The proposed model is solved by using the
algebraic modelling software OPL Studio from ILOG, in combination with the solver
CPLEX to solve the linear models resulting from different instances considered. The
article also presents results obtained with previous deterministic models assessing the
suitability of the stochastic approach. Finally, the conclusions drawn from the study
including an outlook are presented.
Sara V. Rodríguez would like to thank CONACYT (Consejo Nacional de Ciencia y Tecnología, Mexico) and the Department of Universities and Information Society (autonomous government of Catalonia, Spain) for the grant received during the development of this study. Victor M. Albornoz wishes to acknowledge the Dirección General de Investigación y Postgrado of the Universidad Técnica Federico Santa María, Grant USM No. 28.08.52. Lluís M. Plà wishes to acknowledge the financial support of the Spanish Research Program (MTM2005-09362-C03-02).
https://doi.org/10.1007/s11750-009-0087-2
014166
1134-5764
http://hdl.handle.net/10459.1/57183
eng
Springer Verlag
MIECI/PN2004-2007/MTM2005-09362-C03-02
Versió postprint del document publicat a https://doi.org/10.1007/s11750-009-0087-2
Top, 2009, vol. 17, núm. 1, p. 171-189
(c) Sociedad de Estadística e Investigación Operativa, 2009
info:eu-repo/semantics/openAccess
Replacement
Planning
Stochastic programming
Sow herd management
A two-stage stochastic programming model for scheduling replacements in sow farms
article
acceptedVersion
oai:repositori.udl.cat:10459.1/626692022-10-21T17:50:20Zcom_10459.1_186com_10459.1_2com_10459.1_56939col_10459.1_311col_10459.1_56962col_10459.1_49291
Fouquet, Mireille
Miret, Josep M. (Josep Maria)
Valera Martín, Javier
2018-02-16T12:22:05Z
2019-09-28T22:21:33Z
2018
Volcanoes of ℓ–isogenies of elliptic curves are a special case of graphs
with a cycle called crater. In this paper, given an elliptic curve E of a
volcano of ℓ–isogenies, we present a condition over an endomorphism ϕ of
E in order to determine which ℓ–isogenies of E are non-descending. The
endomorphism ϕ is defined as the crater cycle of an m–volcano where E
is located, with m 6= ℓ. The condition is feasible when ϕ is a distortion
map for a subgroup of order ℓ of E. We also provide some relationships
among the crater sizes of volcanoes of m–isogenies whose elliptic curves
belong to a volcano of ℓ–isogenies.
Research of the authors was partially supported by grants MTM2013-46949-P (Spanish MINECO) and 2014 SGR1666 (Generalitat de Catalunya).
https://doi.org/10.1016/j.ffa.2017.09.006
026172
1071-5797
http://hdl.handle.net/10459.1/62669
eng
Elsevier
info:eu-repo/grantAgreement/MINECO//MTM2013-46949-P/ES/CRIPTOGRAFIA CON CURVAS ALGEBRAICAS PARA LA E-SOCIEDAD/
Versió postprint del document publicat a https://doi.org/10.1016/j.ffa.2017.09.006
Finite Fields and Their Applications, 2018, vol. 49, núm. C, p. 108-125
cc-by-nc-nd (c) Elsevier, 2018
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Finite field
Elliptic curve
Isogeny
Volcano
Distortion map
Distorting the volcano
article
acceptedVersion
jvalera@matematica.udl.cat
Javier Valera
oai:repositori.udl.cat:10459.1/4633142023-11-28T09:51:58Zcom_10459.1_186com_10459.1_2col_10459.1_311
Barrière, Lali
Comellas Padró, Francesc
Dalfó, Cristina
Fiol Mora, Miguel Ángel
2023-05-10T12:55:48Z
2023-05-10T12:55:48Z
2009-01-06
A new operation on graphs is introduced and some of its properties are studied. We call it hierarchical product, because of the strong (connectedness) hierarchy of the vertices in the resulting graphs. In fact, the obtained graphs turn out to be subgraphs of the cartesian product of the corresponding factors. Some well-known properties of the cartesian product, such as reduced mean distance and diameter, simple routing algorithms and some optimal communication protocols are inherited by the hierarchical product. We also address the study of some algebraic properties of the hierarchical product of two or more graphs. In particular, the spectrum of the binary hypertree Tm (which is the hierarchical product of several copies of the complete graph on two vertices) is fully characterized; turning out to be an interesting example of graph with all its eigenvalues distinct. Finally, some natural generalizations of the hierarchic product are proposed.
This research was supported by the Ministry of Education and Science (Spain) and the European Regional Development Fund (ERR) under projects MTM2005-08990-C02-01 and TEC2005-03575.
https://doi.org/10.1016/j.dam.2008.04.018
028053
0166-218X
1872-6771
https://repositori.udl.cat/handle/10459.1/463314
eng
Elsevier
Versió preprint del document publicat a: https://doi.org/10.1016/j.dam.2008.04.018
Discrete Applied Mathematics, 2009, vol. 157, p. 36-48
Discrete Applied Mathematics
cc-by-nc-nd, (c) Elsevier, 2009
Attribution-NonCommercial-NoDerivatives 4.0 International
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Graph operations
Hierarchical product
Diameter
Mean distance
Adjacency matrix
Eigenvalues
Characteristic polynomial
The hierarchical product of graphs
info:eu-repo/semantics/article
info:eu-repo/semantics/submittedVersion
oai:repositori.udl.cat:10459.1/590842017-01-25T01:06:17Zcom_10459.1_186com_10459.1_2col_10459.1_311
Espinola, Jesús E.
Pla Aragonés, Lluís Miquel
Montañez, Eddy J.
Leyva, Jorge W.
Cáceres, Vladimir A.
2017-01-24T11:19:59Z
2017-01-24T11:19:59Z
2017
This paper assesses the agricultural sustainability of the peasant community of Huapra, located in the Andes of Peru; this is a type of high land farming communities. The analysis has been made by applying the methodology framework for the evaluation of management systems of natural resources incorporating sustainability indicators (MESMIS). It has also been measured different performance indicators for the three dimensions considered. Among different results it has been found that Huapra community is based on a self-sufficient or peasant economy, mainly due to the low educational level of the inhabitants. On the other hand, it also has been found a high level of productive diversification. These results are similar to the results of other peasant communities like a study conducted in the peasant community of San José de Cusmapa - Nicaragua.
Los autores quieren agradecer el apoyo recibido por la Universidad Nacional Santiago Antúnez de Mayolo (UNASAM) por la financiación del proyecto “Desarrollo de un modelo matemático computacional para la evaluación de la sostenibilidad del sistema agrícola de la comunidad de Huapra”. También a la Oficina de Cooperación y Solidaridad de la Universidad de Lleida a través del proyecto titulado “Modelo de desarrollo agrario sostenible para la comunidad campesina de Huapra (PERÚ)”.
0257-4306
http://hdl.handle.net/10459.1/59084
spa
Universidad de la Habana
Reproducció del document publicat a http://rev-inv-ope.univ-paris1.fr/files/38117/38117-10.pdf
Revista de Investigación Operacional, 2017, vol. 38, núm. 1, p. 91-100
(c) Revista de Investigación Operacional, 2016
info:eu-repo/semantics/openAccess
Sustainability assessment
Performance indicators
MESMIS
Evaluación de la sustentabilidad del sistema agrícola de la Comunidad de Huapra (Perú)
article
publishedVersion
oai:repositori.udl.cat:10459.1/629792019-10-09T09:21:21Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Gasull, Armengol
Giné, Jaume
Valls, Claudia
2018-04-04T12:52:57Z
2019-10-05T22:18:35Z
2017
2018-04-04T12:52:58Z
We give a complete algebraic characterization of the non-degenerated centers for planar trigonometric Liénard systems. The main tools used in our proof are the classical results of Cherkas on planar analytic Liénard systems and the characterization of some subfields of the quotient field of the ring of trigonometric polynomials. Our results are also applied to some particular subfamilies of planar trigonometric Liénard systems. The results obtained are reminiscent of the ones for planar polynomial Liénard systems but the proofs are different.
The first author is partially supported by the MINECO MTM2013-40998-P and the
AGAUR (Generalitat de Catalunya) 2014SGR568 grants. The second author is partially
supported by the MINECO/FEDER grant number MTM2014-53703-P and the AGAUR
grant number 2014SGR 1204. The third author is partially supported by FCT/Portugal
through UID/MAT/04459/2013.
application/pdf
https://doi.org/10.1016/j.jde.2017.05.008
025850
0022-0396
http://hdl.handle.net/10459.1/62979
eng
Elsevier
MINECO/PN2013-2016/MTM2013-40998-P
MINECO/PN2013-2016/MTM2014-53703-P
Versió postprint del document publicat a https://doi.org/10.1016/j.jde.2017.05.008
Journal of Differential Equations, 2017, vol. 263, p. 3928-3942
cc-by-nc-nd (c) Elsevier, 2017
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Center problem
Trigonometric Liénard equation
Trigonometric polynomial
Center problem for trigonometric Liénard systems
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
gine@matematica.udl.cat
Giné, Jaume
oai:repositori.udl.cat:10459.1/710072023-06-06T03:00:31Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_44504
Dalfó, Cristina
Fiol Mora, Miguel Ángel
López Lorenzo, Ignacio
Martínez Pérez, Álvaro
2021-04-13T07:45:47Z
2021-06
2021-04-13T07:45:48Z
In this paper, we deal with a simple geometric problem: Is it possible to partition a rectangle into k non-congruent rectangles of equal area? This problem is motivated by the so-called 'Mondrian art problem' that asks a similar question for dissections with rectangles of integer sides. Here, we generalize the Mondrian problem by allowing rectangles of real sides. In this case, we show that the minimum value of k for a rectangle to have a 'perfect Mondrian partition' (that is, with non-congruent equal-area rectangles) is seven. Moreover, we prove that such a partition is unique (up to symmetries) and that there exist exactly two proper perfect Mondrian partitions for k=8. Finally, we also prove that any square has a perfect Mondrian decomposition for k >= 7.
The research of the first author has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 734922.
application/pdf
https://doi.org/10.1016/j.disc.2021.112389
031155
0012-365X
http://hdl.handle.net/10459.1/71007
eng
Elsevier
Reproducció del document publicat a: https://doi.org/10.1016/j.disc.2021.112389
Discrete Mathematics, 2021, vol. 344, num. 6, p. 112389
info:eu-repo/grantAgreement/EC/H2020/734922/EU/CONNECT
cc-by (c) C. Dalfó et al., 2021
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Mondrian problem
Non-congruent rectangles
Dissection
Digraph
Decompositions of a rectangle into non-congruent rectangles of equal area
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/647212023-03-27T12:56:56Zcom_10459.1_56965com_10459.1_2com_10459.1_243com_10459.1_56704com_10459.1_186col_10459.1_57707col_10459.1_3332col_10459.1_56705col_10459.1_311col_10459.1_49291
Baraibar Padró, Bàrbara
Torra Farré, Joel
Royo-Esnal, Aritz
Recasens i Guinjuan, Jordi
Comas Rodríguez, Carles
2018-09-18T07:04:51Z
2019-09-17T22:21:09Z
2018-09-17
2018-09-18T07:04:52Z
Nest densities of harvester ants (Messor barbarus) are high in rain-fed cereal fields in north-eastern Spain where the ants remove large quantities of seeds, contributing to reductions in weed populations. The distribution of harvester ant nests within a field can influence the effectiveness of ants as weed seed predators because areas with low ant nest density have lower weed seed removal rates. Tillage can disturb or even kill ant colonies and may be an important factor explaining the distribution of nests within fields. During the summers of 2011 - 2013, the number of nests in a 50 x 50 m area in 4 tilled and 3 no-till fields were counted. Tilled fields were disturbed twice a year, in November before cereal seeding and in July, after cereal harvest, whereas no-till fields had no soil disturbance. Ant nests were evenly spaced in no-till fields whereas nests were randomly distributed in tilled fields. Our results provide evidence that no-till in cereal fields promotes a more even distribution of M. barbarus nests, which should result in higher and more regular levels of weed seed predation across the field.
We would like to thank Sergi Royan and Nuria Moix for their help in locating and counting ant nests for this study. We would also like to thank the farmers Xavier Llobet, Alejandro Pollino, Jaume Ros, and Fran X. Albareda for allowing us to asses nest density in their fields. This study was partially funded by projects AGL2010-22084 and AGL2007-60828 from the Spanish National R&D program, and the Department of Agriculture, Food and environment of the Catalan Government (DAAM) (2012 AGEC 00040 Ajuts a la producción agraria ecològica).
application/pdf
https://doi.org/10.1016/j.biocontrol.2018.09.009
027939
1049-9644
http://hdl.handle.net/10459.1/64721
eng
Elsevier
info:eu-repo/grantAgreement/MICINN//AGL2010-22084-C02-01/ES/MALAS HIERBAS O DIVERSIDAD VEGETAL SU PAPEL COMO INDICADOR DE LA EFICIENCIA DE AYUDAS AGROAMBIENTALES Y DE TECNICAS DE AGRICULTURA DE CONSERVACION EN SECANOS CEREALISTAS/
info:eu-repo/grantAgreement/MEC//AGL2007-60828/ES/ANALISIS DE LA DIVERSIDAD VEGETAL EN SISTEMAS CEREALISTAS E INFLUENCIA DE LOS MARGENES EN FACILITAR LA DEPREDACION DE SEMILLAS DE MALAS HIERBAS/
Versió postprint del document publicat a: https://doi.org/10.1016/j.biocontrol.2018.09.009
Biological Control, 2019, vol. 128, p. 1-5
cc-by-nc-nd, (c) Elsevier, 2018
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Weed seed predation
Tillage
No-till
Biological weed management
Harvester ant nest distribution depends on soil disturbance regime
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
barbara.baraibar@udl.cat
Baraibar Padró, Bàrbara
oai:repositori.udl.cat:10459.1/626862019-02-11T13:50:20Zcom_10459.1_186com_10459.1_2col_10459.1_311
Estrada Roca, M. Asunción
2018-02-20T17:37:29Z
2018-02-20T17:37:29Z
2002
007895
1131-9321
2340-714X
http://hdl.handle.net/10459.1/62686
spa
Sociedad Andaluza de Educación Matemática "Thales"
Reproducció del document publicat a: http://thales.cica.es./epsilon/
Epsilon, 2002, núm. 52, p. 173-174
cc-by-nc-nd (c) Sociedad Andaluza de Educación Matemática "Thales", 2002
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Formació del professorat
Estadística matemàtica
Análisis de las actitudes y conocimientos estadísticos elementales en la formación del profesorado
article
publishedVersion
oai:repositori.udl.cat:10459.1/688342020-05-26T00:09:27Zcom_10459.1_56965com_10459.1_2com_10459.1_242com_10459.1_186col_10459.1_57707col_10459.1_10990col_10459.1_311
Colomer, M. Àngels (Maria Àngels)
Margalida, Antoni
Fraile Sauce, Lorenzo José
2020-05-25T09:33:36Z
2020-05-25T09:33:36Z
2020
2020-05-25T09:33:36Z
Aujeszky's disease is one of the main pig viral diseases and results in considerable economic losses in the pork production industry. The disease can be controlled using preventive measures such as improved stock management and vaccination throughout the pig-rearing period. We developed a stochastic model based on Population Dynamics P systems (PDP) models for a standard pig production system to differentiate between the effects of pig farm management regimes and vaccination strategies on the control of Aujeszky's disease under several different epidemiological scenarios. Our results suggest that after confirming the diagnosis, early vaccination of most of the population (>75%) is critical to decrease the spread of the virus and minimize its impact on pig productivity. The direct economic cost of an outbreak of Aujeszky's disease can be extremely high on a previously uninfected farm (from 352-792 Euros/sow/year) and highlights the positive benefits of investing in vaccination measures to control infections. We demonstrate the usefulness of computational models as tools in the evaluation of preventive medicine programs aimed at limiting the impact of disease on animal production.
This work was partially supported by FEDER project COMRDI16-1-0035-03.
application/pdf
https://doi.org/10.3390/ani10050909
029993
2076-2615
http://hdl.handle.net/10459.1/68834
eng
MDPI
Reproducció del document publicat a: https://doi.org/10.3390/ani10050909
Animals, 2020, vol. 10, num. 5, p. 909
cc-by (c) Colomer et al., 2020
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Pseudorabies
Vaccination
Control measures
Population Dynamics P system model
Vaccination is a suitable tool in the control of Aujeszky's disease outbreaks in pigs using a Population Dynamics P systems model
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/577882017-09-14T15:54:46Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giacomini, Héctor
Giné, Jaume
Grau Montaña, Maite
2016-09-13T08:10:50Z
2016-09-13T08:10:50Z
2006
In this work we consider rational ordinary
differential equations dy/dx = Q(x, y)/P(x, y), with Q(x, y)
and P(x, y) coprime polynomials with real coefficients. We
give a method to construct equations of this type for which a
first integral can be expressed from two independent solutions
of a second-order homogeneous linear differential equation.
This first integral is, in general, given by a non Liouvillian
function.
We show that all the known families of quadratic systems
with an irreducible invariant algebraic curve of arbitrarily high
degree and without a rational first integral, can be constructed
by using this method. We also present a new example of this
kind of family.
We give an analogous method for constructing rational
equations but by means of a linear differential equation of
first order.
The second and third authors are partially supported by a MCYT grant number BFM 2002-04236-C02-01. The second author is partially supported by DURSI of Government of Catalonia’s Acció Integrada ACI2002-24 and by the Distinció de la Generalitat de Catalunya per a la promoció de la recerca universitària.
https://doi.org/10.1216/rmjm/1181069462
004390
0035-7596
http://hdl.handle.net/10459.1/57788
eng
Rocky Mountain Mathematics Consortium
MICYT/PN2000-2003/ BFM2002-04236-C02-01
Versió preprint del document publicat a https://doi.org/110.1216/rmjm/1181069462
Rocky Mountain Journal of Mathematics, 2006, vol. 36, núm 2, p. 457-485
http://arxiv.org/abs/arXiv:math/0506035
(c) Rocky Mountain Mathematics Consortium, 2006
info:eu-repo/semantics/openAccess
Planar polynomial system
First integral
Invariant curves
Darboux integrability
Equacions diferencials
Integrability of planar polynomial differential systems through linear differential equations
article
submittedVersion
oai:repositori.udl.cat:10459.1/725702021-12-22T10:11:54Zcom_10459.1_186com_10459.1_2col_10459.1_311
Martins, José Alenxadre
Estrada Roca, M. Asunción
Nascimento, Maria Manuel
2021-12-15T13:19:31Z
2021-12-15T13:19:31Z
2018
Es necesario conocer las actitudes de los profesores hacia la estadística, en el sentido de entender mejor su predisposición y compromiso hacia el proceso de enseñanza-aprendizaje y su formación. Así, este estudio con 1098 profesores portugueses de 1º y 2º ciclo de educación básica se centra en la medición de las actitudes hacia la estadística y sus componentes, utilizando una escala ya probada y con buenas características psicométricas, EAEE. Los resultados obtenidos indican que la actitud hacia la Estadística de los profesores encuestados es, en general, positiva, tanto a nivel global, como a nivel de los componentes.
The need to know the attitudes of teachers in relation to Statistics is recognized. Therefore, it’s possible to know better the teachers predisposition and commitment in the teaching and learning processes and also in their training. This study with 1098 teachers of the 1st and 2nd cycle of portuguese basic education focuses on the measurement of attitudes towards Statistics and theirs components by using a tested scale with good psychometric characteristics, EAEE. A general positive attitude towards Statistics of the surveyed teachers was found, in a global level as well as in the components level.
https://doi.org/10.34624/id.v10i4.11169
029345
1647-3582
http://hdl.handle.net/10459.1/72570
por
Universidade de Aveiro
Reproducció del document publicat a https://doi.org/10.34624/id.v10i4.11169
Indagatio Didactica, 2018, vol. 10, núm. 4, p.133-146
cc-by-nc (c) José Alexandre Martins, Assumpta Estrada, Maria Manuel Nascimento, 2018
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc/4.0/
Escala
Actitudes hacia la estadística
Análisis de components
Fiabilidad
Contrariando o “velho do Restelo”: análise global e componentes das atitudes em relação à estatística em professores Portugueses
Contradicting the “oldman of Restelo”: global analysis and components of the attitudes towards statistics in Portuguese teachers
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/664602022-09-23T18:56:09Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
López Masip, Susana-Clara
Muntaner Batle, Francesc Antoni
Rius Font, Miquel
2019-06-18T07:52:04Z
2019-06-18T07:52:04Z
2014
2019-06-18T07:52:05Z
Let G be a graph of order p and size q with loops allowed. A bijective function f:V(G)∪E(G)→{i}p+qi=1 is an edge-magic labeling of G if the sum f(u)+f(uv)+f(v)=k is independent of the choice of the edge uv. The constant k is called either the valence, the magic weight or the magic sum of the labeling f. If a graph admits an edge-magic labeling, then it is called an edge-magic graph. Furthermore, if the function f meets the extra condition that f(V(G))={i}pi=1 then f is called a super edge-magic labeling and G is called a super edge-magic graph. A digraph D admits a labeling, namely l, if its underlying graph, und(D) admits l. In this paper, we introduce a new construction of super edge-magic labelings which are related to the classical jump of the knight on the chess game. We also use super edge-magic labelings of digraphs together with a generalization of the Kronecker product to get edge-magic labelings of some families of graphs.
The research conducted in this document by the first and third authors has been supported by the Spanish Research Council under project MTM2011-28800-C02-01 and by the Catalan Research Council under grant 2009SGR1387.
application/pdf
https://doi.org/10.1007/s00009-013-0360-3
028502
1660-5446
http://hdl.handle.net/10459.1/66460
eng
Springer
info:eu-repo/grantAgreement/MICINN//MTM2011-28800-C02-01/ES/OPTIMIZACION Y PROBLEMAS EXTREMALES EN TEORIA DE GRAFOS Y COMBINATORIA. APLICACIONES A LAS REDES DE COMUNICACION/
Versió postprint del document publicat a: https://doi.org/10.1007/s00009-013-0360-3
Mediterranean Journal of Mathematics, 2014, vol. 11, num. 2, p. 217-235
(c) Springer Basel, 2014
info:eu-repo/semantics/openAccess
(Super) edge-magic
Jacobsthal sequence
Dual shuffle prime
⊗h-product
The jumping knight and other (super) edge-magic constructions
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/664532022-09-23T17:30:36Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Hamidoune, Yahya Ould
Lladó, Anna
López Masip, Susana-Clara
2019-06-14T11:30:46Z
2019-06-14T11:30:46Z
2013
2019-06-14T11:30:47Z
We investigate the structure of a digraph having a transitive automorphism group where every cutset of minimal cardinality consists of all successors or all predecessors of some vertex. We give a complete characterization of vosperian arc-transitive digraphs. It states that an arc-transitive strongly connected digraph is vosperian if and only if it is irreducible. In particular, this is the case if the degree is coprime with the order of the digraph. We give also a complete characterization of vosperian Cayley digraphs and a complete characterization of irreducible superconnected Cayley digraphs. These two last characterizations extend the corresponding ones in Abelian Cayley digraphs and the ones in the undirected case.
Research supported by the Ministry of Science and Innovation, Spain under project MTM2008-06620-C03-01/MTM and the Catalan Research Council under project 2009SGR01387. Research done when the last author was visiting Université Pierre et Marie Curie, E. Combinatoire, Paris, supported by the Ministry of Science and Innovation, Spain under the National Mobility Programme of Human Resources,
Spanish National Programme I-D-I 2008–2011.
application/pdf
https://doi.org/10.1007/s00373-011-1104-4
028491
0911-0119
http://hdl.handle.net/10459.1/66453
eng
Springer
info:eu-repo/grantAgreement/MICINN//MTM2008-06620-C03-01/ES/PROBLEMAS EXTREMALES Y DE OPTIMIZACION EN TEORIA DE GRAFOS Y COMBINATORIA: APLICACION AL ANALISIS Y ALGORITMOS DE REDES DE COMUNICACION/
Versió postprint del document publicat https://doi.org/10.1007/s00373-011-1104-4
Graphs and Combinatorics, 2013, vol. 29, num. 2, p. 241-251
(c) Springer, 2013
info:eu-repo/semantics/openAccess
Arc-transitive
Cayley digraph
Isoperimetric connectivity
Superconnected
Vosperian
On Vosperian and Superconnected Vertex-Transitive Digraphs
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/664342022-09-23T17:29:02Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
López Masip, Susana-Clara
Muntaner Batle, Francesc Antoni
2019-06-10T11:37:46Z
2019-06-10T11:37:46Z
2016
2019-06-10T11:37:46Z
Skolem and Langford sequences and their many generalizations have applications in numerous areas. The -product is a generalization of the direct product of digraphs. In this paper we use the -product and super edge-magic digraphs to construct an exponential number of Langford sequences with certain order and defect. We also apply this procedure to extended Skolem sequences.
The research conducted in this document by the first author has been supported by the Spanish Research Council under project MTM2011-28800-C02-01 and symbolically by the Catalan Research Council under grant 2014SGR1147.
application/pdf
https://doi.org/10.1016/j.ejc.2015.11.004
028497
0195-6698
http://hdl.handle.net/10459.1/66434
eng
Elsevier
info:eu-repo/grantAgreement/MICINN//MTM2011-28800-C02-01/ES/OPTIMIZACION Y PROBLEMAS EXTREMALES EN TEORIA DE GRAFOS Y COMBINATORIA. APLICACIONES A LAS REDES DE COMUNICACION/
Versió postprint del document publicat a: https://doi.org/10.1016/j.ejc.2015.11.004
European Journal of Combinatorics, 2016, vol. 53, p. 86-95
cc-by-nc-nd (c) Elsevier, 2016
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/3.0/es
Teoria de grafs
Graph theory
Langford sequences and a product of digraphs
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/717772023-04-26T12:38:12Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291col_10459.1_44504
Dalfó, Cristina
Duque, F.
Fabila Monroy, R.
Fiol Mora, Miguel Ángel
Huemer, Clemens
Zaragoza Martínez, F.J.
Trujillo Negrete, A.L.
2021-09-01T08:43:54Z
2021-09-01T08:43:54Z
2021
We study the Laplacian spectrum of token graphs, also called
symmetric powers of graphs. The k-token graph Fk(G) of
a graph G is the graph whose vertices are the k-subsets of
vertices from G, two of which being adjacent whenever their
symmetric difference is a pair of adjacent vertices in G. In this
paper, we give a relationship between the Laplacian spectra of any two token graphs of a given graph. In particular, we show
that, for any integers h and k such that 1 ≤ h ≤ k ≤ n
2 , the
Laplacian spectrum of Fh(G) is contained in the Laplacian
spectrum of Fk(G). We also show that the doubled odd
graphs and doubled Johnson graphs can be obtained as token
graphs of the complete graph Kn and the star Sn = K1,n−1,
respectively. Besides, we obtain a relationship between the
spectra of the k-token graph of G and the k-token graph of
its complement G. This generalizes to tokens graphs a wellknown property stating that the Laplacian eigenvalues of G
are closely related to the Laplacian eigenvalues of G. Finally,
the doubled odd graphs and doubled Johnson graphs provide
two infinite families, together with some others, in which the
algebraic connectivities of the original graph and its token
graph coincide. Moreover, we conjecture that this is the case
for any graph G and its token graph.
This research of C. Dalfó and M.A. Fiol has been partially supported by AGAUR from the Catalan Government under project 017SGR1087 and by MICINN from the Spanish Government under project PGC2018-095471-B-I00. The research of C. Dalfó has also been supported by MICINN from the Spanish Government under project MTM2017-83271-R. The research of C. Huemer was supported by MICINN from the Spanish Government under project PID2019-104129GB-I00/AEI/10.13039/501100011033 and AGAUR from the Catalan Government under project 017SGR1336. F.J. Zaragoza Martínez acknowledges the support of the National Council of Science and Technology (Conacyt) and its National System of Researchers (SNI). This research has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 734922
https://doi.org/10.1016/j.laa.2021.05.005
031280
0024-3795
http://hdl.handle.net/10459.1/71777
eng
Elsevier
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PGC2018-095471-B-I00/ES/ESTUDIO MATEMATICO DE LOS FALLOS EN CASCADA EN SISTEMAS COMPLEJOS MEDIANTE INVARIANTES Y CENTRALIDADES EN GRAFOS. APLICACIONES A REDES REALES/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-83271-R/ES/CRIPTOGRAFIA Y CODIGOS PARA APLICACIONES SEGURAS Y FIABLES/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2019-104129GB-I00/ES/TEORIA Y APLICACIONES DE CONFIGURACIONES DE PUNTOS Y REDES/
Reproducció del document publicat a https://doi.org/10.1016/j.laa.2021.05.005
Linear Algebra and its Applications, 2021, vol. 625, p. 322-348
info:eu-repo/grantAgreement/EC/H2020/734922/EU/CONNECT
cc-by-nc-nd (c) Dalfó et al., 2021
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Token graph
Laplacian spectrum
Algebraic connectivity
Binomial matrix
Adjacency spectrum
On the Laplacian spectra of token graphs
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/595162022-10-13T20:33:15Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
2017-04-20T09:55:58Z
2017-04-20T09:55:58Z
2017
In this article we study the center problem for polynomial BiLiénard
systems of degree n. Computing the focal values and using Gröbner bases we
end the center conditions for such systems for n = 6. We also establish a
conjecture about the center conditions for polynomial BiLiénard systems of
arbitrary degree.
The author is partially supported by a MINECO/FEDER grant number MTM2014-53703-P and an AGAUR (Generalitat de Catalunya) grant number 2014SGR 1204.
1072-6691
http://hdl.handle.net/10459.1/59516
eng
Texas State University
info:eu-repo/grantAgreement/MINECO//MTM2014-53703-P/ES/METODOS CUALITATIVOS EN SISTEMAS DIFERENCIALES CONTINUOS/
Reproducció del document publicat a https://ejde.math.txstate.edu/Volumes/2017/86/gine.pdf
Electronic Journal of Differential Equations, 2017, vol. 2017, núm. 86, p. 1-5
(c) Texas State University, 2017
info:eu-repo/semantics/openAccess
Center problem
Analytic integrability
Gröbner bases
Polynomial BiLiénard diferential systems
Decomposition in prime ideals
Center conditions and limits cycles for bilienard systems
article
publishedVersion
oai:repositori.udl.cat:10459.1/3122020-07-14T08:39:38Zcom_10459.1_186com_10459.1_2col_10459.1_311
Viejo Galicia, Alexandre
Domingo i Ferrer, Josep
Sebé Feixas, Francesc
Castellà Roca, Jordi
2010-04-12T09:52:21Z
2010-04-12T09:52:21Z
2009
Wireless Sensor Networks (WSN) are formed by nodes with limited computational and power resources. WSNs are finding an increasing number of applications, both civilian and military, most of which require security for the sensed data being collected by the base station from remote sensor nodes. In addition, when many sensor nodes transmit to
the base station, the implosion problem arises. Providing security measures and implosion-resistance in a resource-limited environment is a real challenge. This article reviews the aggregation strategies proposed in the literature to handle the bandwidth and security problems related to many-to-one transmission in WSNs. Recent contributions to secure lossless many-to-one communication developed by the authors in the context of several Spanish-funded
projects are surveyed. Ongoing work on the secure lossy many-to-one communication is also sketched.
https://doi.org/10.3390/s90705324
013923
1424-8220
http://hdl.handle.net/10459.1/312
eng
Molecular Diversity Preservation International (MDPI)
Reproducció del document publicat a https://doi.org/10.3390/s90705324
Sensors, 2009, vol. 9, núm. 7, p. 5324-5338
cc-by, (c) Viejo et al., 2009
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/3.0/es/deed.ca
Many-to-one communications
Security
Sensors
WSN
Xarxes de sensors
Secure many-to-one communications in wireless sensor networks
article
publishedVersion
oai:repositori.udl.cat:10459.1/834202022-06-01T00:06:57Zcom_10459.1_186com_10459.1_2col_10459.1_311
Ricart Aranda, Maria
Estrada Roca, M. Asunción
2022-05-31T12:01:16Z
2022-05-31T12:01:16Z
2022
The development of probabilistic thinking at school requires enhancing combinatorial and proportional reasoning. For this reason, 190 sixth-grade elementary school students (11–12-year-old), without previous instruction in the topic, solve a task consisting of five questions that address both types of reasoning. This study explores the problem-solving strategies used by schoolchildren. The results obtained indicate that, in general, the students do not show strategies in the answers to the combinatorial questions. In addition, it is observed that they have difficulties in understanding the proposed statements and arguing the issues that explicitly require a justification.
Research project PID2019-105601GB-I00/AEI/10.13039/501100011033 (Ministerio de Ciencia e Innovación) and research group FQM-126 (Junta de Andalucía, Spain)
https://doi.org/10.3390/math10081340
032470
2227-7390
http://hdl.handle.net/10459.1/83420
eng
MDPI
Reproducció del document publicat a https://doi.org/10.3390/math10081340
Mathematics, 2022, vol. 10, núm. 8, 1340
cc-by (c) Maria Ricart, Assumpta Estrada, 2022
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Combinatorial reasoning
Proportional reasoning
Probabilistic thinking
Primary education
Combinatorial and Proportional Task: Looking for Intuitive Strategies in Primary Education
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/839572023-01-18T14:12:35Zcom_10459.1_242com_10459.1_2com_10459.1_186col_10459.1_10990col_10459.1_311col_10459.1_49291
Oliva-Vidal, Pilar
Hernández-Matías, Antonio
García, Diego
Colomer, M. Àngels (Maria Àngels)
Real, Joan
Margalida, Antoni
2022-10-20T08:07:08Z
2022-10-20T08:07:08Z
2022
An unexpected human-wildlife conflict between vultures and livestock has emerged in Europe during the last two decades. Farmers attributed changes in vulture behavior, due to food shortages caused by sanitary regulations, to increasing livestock interactions (‘vulture attacks’). To disentangle this conflict, we analyzed 683 farmer complaints between 1996 and 2020 in Catalonia (northeastern Spain) and investigated the eco-anthropological factors driving their frequency. We also assessed farmers' perception through 127 interviews. Most complaints (80 %) occurred during the birthing season, mainly involving cattle (76.5 %), followed by horses (14.9 %) and sheep/goats (8.6 %). From 2008 to 2020, vulture-livestock conflicts cost the government €192,000 (~22 % of claims compensated). The frequency of complaints was positively associated with extensive livestock density, griffon vulture Gyps fulvus abundance (breeding and non-breeding), shorter distances to landfill sites and, to a lesser extent, to supplementary feeding stations. In contrast, there was a negative relationship between complaints and the number of griffon vulture breeding pairs, suggesting that long-distance foraging movements by both breeding and non-breeding individuals may play a major role in determining the occurrence of conflicts. Farmers (88 %) said that vultures attack livestock and that attacks had increased in recent years because of significant vulture population increases and food shortages due to sanitary regulations. They considered government policies and compensation ineffective. We highlight the critical need for mitigation in areas with high extensive livestock numbers, particularly during birthing times. Scientific assessments and interdisciplinary awareness campaigns on the coexistence of vultures and livestock are necessary to harmonize biodiversity conservation and agro-pastoral practices in rural economies.
We thank Ferran Miralles, Ricard Casanovas and Olga Lao (Generalitat de Catalunya), Gabriel Lampreave (Cos d'Agents Rurals), Roser Costa (Unió de Pagesos) for logistical support and all farmers interviewed for accepted to be interviewed and generously sharing their knowledge. R. Baraut, M. Comas, L. Pelayo and J. Subiron helped with the survey.The comments of B. Fisher, I. Zuberogoitia and an anonymous reviewer improved an earlier draft of the manuscript. This study was partially funded by the Generalitat de Catalunya and by the projects RTI2018-099609-B-C22 and PID2020-117909RB-I00 from the I+D+I National Plan funded by the Ministry of Science, Innovation and Universities . POV and AM were funded within the framework of the project RTI2018-099609-B-C22.
https://doi.org/10.1016/j.biocon.2022.109664
0006-3207
http://hdl.handle.net/10459.1/83957
eng
Elsevier
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-117909RB-I00/ES/RETOS DE LA CONSERVACION DE LA BIODIVERSIDAD Y LA ECONOMIA CIRCULAR: EL CASO DE LAS AVES CARROÑERAS EN ESPAÑA/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/RTI2018-099609-B-C22/ES/EFECTO DE LOS CAMBIOS EN LAS PRACTICAS GANADERAS EXTESNIVAS EN LA DINAMICA POBLACIONAL Y ECOLOGIA DE FORRAJEO DE LAS AVES CARROÑERAS EN PIRINEOS/
Reproducció del document publicat a https://doi.org/10.1016/j.biocon.2022.109664
Biological conservation, 2022, vol. 272, núm. 109664, p. 1-9
cc-by-nc-nd (c) Oliva-Vidal et. al., 2022
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Farmer perception
Human-wildlife conflict
Restrictive sanitary regulations
Vulture attack
Vulture-livestock conflict
Wildlife damage compensation
Pagesos
Voltors
Agricultura--Aspectes econòmics
Griffon vultures, livestock and farmers: Unraveling a complex socio-economic ecological conflict from a conservation perspective
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/603812022-10-11T20:31:44Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291col_10459.1_44504
Giné, Jaume
Llibre, Jaume
2017-10-27T09:18:18Z
2017-10-27T09:18:18Z
2014
To characterize when a nilpotent singular point of an analytic differential system is a center is of particular interest, first for the problem of distinguishing between a focus and a center, and after for studying the bifurcation of limit cycles from it or from its period annulus. We give an effective algorithm in the search of necessary conditions for detecting nilpotent centers based in recent developments. Moreover we survey the last results on this problem and illustrate our approach by means of examples.
The first author is partially supported by a MINECO/ FEDER grant number MTM2011-22877 and an AGAUR (Generalitat de Catalunya) grant number 2009SGR 381. The second author is partially supported by a MINECO/ FEDER grant number MTM2008-03437, an AGAUR grant number 2009SGR 410, ICREA Academia and two FP7-PEOPLE-2012-IRSES numbers 316338 and 318999.
https://doi.org/10.1016/j.jmaa.2013.12.013
021522
0022-247X
http://hdl.handle.net/10459.1/60381
eng
Elsevier
info:eu-repo/grantAgreement/MICINN//MTM2011-22877/ES/BIFURCACIONES, INTEGRABILIDAD Y PROPIEDADES CUALITATIVAS DE FAMILIAS DE CAMPOS VECTORIALES/
info:eu-repo/grantAgreement/MICINN//MTM2008-03437/ES/ORBITAS PERIODICAS, BIFURCACIONES E INTEGRABILIDAD DE LOS SISTEMAS DINAMICOS/
Versió preprint del document publicat a https://doi.org/10.1016/j.jmaa.2013.12.013
Journal of Mathematical Analysis and Applications, 2014, vol. 413, p. 537-545
info:eu-repo/grantAgreement/EC/FP7/316338
info:eu-repo/grantAgreement/EC/FP7/318999
(c) Elsevier, 2014
info:eu-repo/semantics/openAccess
Nilpotent center
Degenerate center
Liapunov constants
Bautin method
A method for characterizing nilpotent centers
article
submittedVersion
oai:repositori.udl.cat:10459.1/570912018-10-23T09:12:41Zcom_10459.1_186com_10459.1_2col_10459.1_311
López Lorenzo, Ignacio
Pérez Rosés, Hebert
2016-05-24T12:00:02Z
2016-05-24T12:00:02Z
2015
The Degree/diameter problem asks for the largest graphs given diameter and maximum degree. This problem has been extensively studied both for directed and undirected graphs, ando also for special classes of graphs. In this work we present the state of art of the degree/diameter problem for mixed graphs.
https://doi.org/10.1016/j.procs.2015.12.066
1877-0509
http://hdl.handle.net/10459.1/57091
eng
Elsevier
Reproducció del document publicat a https://doi.org/10.1016/j.procs.2015.12.066
Procedia computer science, 2015, vol. 74, p. 2-9
cc-by-nc-nd (c) López et al., 2015
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Degree / diameter problem
Moore bound
Mixed Moore graph
Grafs, Teoria de
Degree/diameter problem for mixed graphs
article
publishedVersion
oai:repositori.udl.cat:10459.1/667592020-10-02T12:57:20Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_44504
Dalfó, Cristina
2019-10-10T10:29:57Z
2020-09-11T22:22:04Z
2018-09-11
2019-10-10T10:29:57Z
For a given graph G = (V, E), the degree mean rate of an edge
uv ∈ E is a half of the quotient between the geometric and arithmetic means of its end-vertex degrees d(u) and d(v). In this note, we derive tight bounds for the Randić index of G in terms of its maximum and minimum degree mean rates over its edges. As a consequence, we prove the known conjecture that the average distance is bounded above by the Randić index for graphs with order n large enough, when the minimum degree δ is greater than (approximately) ∆1/3 , where ∆ is the maximum degree. As a by-product, this proves that almost all random (Erdös-Rényi) graphs satisfy the conjecture.
This research is partially supported by the project 017SGR1087 of the Agency for the Management of University and Research Grants (AGAUR) of the Government of Catalonia. This research has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie
Sk lodowska-Curie grant agreement No 734922.
application/pdf
https://doi.org/10.1016/j.disc.2018.08.020
027995
0012-365X
http://hdl.handle.net/10459.1/66759
eng
Elsevier
Versió postprint del document publicat a: https://doi.org/10.1016/j.disc.2018.08.020
Discrete Mathematics, 2019, vol. 342, num. 10, p. 2792-2796
info:eu-repo/grantAgreement/EC/H2020/734922/EU/CONNECT
cc-by-nc-nd (c) Elsevier, 2019
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/3.0/es
Edge degree rate
Randić index
Connectivity index
Mean distance
On the Randić index of graphs
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
cristina.dalfo@matematica.udl.cat
Cristina Dalfó
oai:repositori.udl.cat:10459.1/4634942023-06-29T03:00:28Zcom_10459.1_242com_10459.1_2com_10459.1_186col_10459.1_10990col_10459.1_311col_10459.1_49291
Margalida, Antoni
Oliva-Vidal, Pilar
Llamas, Alfonso
Colomer, M. Àngels (Maria Àngels)
2023-06-13T12:29:16Z
2023-06-13T12:29:16Z
2018
The assessment of temporal and spatial availability of food resources is an important prerequisite in developing improved management tools for effective conservation action. It is especially useful in the conservation of avian scavengers inhabiting regions where livestock move on a regular basis (transhumance). Important management decisions can be taken on the basis of theoretical analyses that need to be regularly checked. In this case study, we consider models of Griffon vulture Gyps fulvus, Egyptian vulture Neophron percnopterus and bearded vulture Gypaetus barbatus populations in a part of Spain with one of the highest densities of scavenging birds, and where traditional farming practices remain. We applied bioinspired Population Dynamic P System models (PDP) to assess these species' population trends against the distribution, quantity and availability of carrion for food. We show asymmetries in the availability of food resources, which are substantially higher in summer due to transhumant movements. In the study area, a lack of food resources in winter leads to a seasonal reduction in food supplies to levels unable to meet the energetic requirements of the most abundant vulture species, the Griffon vulture. Our results suggest that regardless of active management (e.g. supplementary feeding sites) and the birds’ use of other potential food resources not included in the model, Griffon vultures are able to find important alternative food resources in more remote areas. We show the importance of variations at spatio-temporal scales in the objective forecasting of population trends, and in the correct application of management actions. Because of the importance of robust assessments for management applications, we discuss the advantages and limitations of ecological modelling for avian scavengers, highlighting the importance of transhumance processes and transboundary approaches.
A. Richford reviewed the English. A.M. was supported by a Ramón y Cajal research contract by the Ministry of Economy and Competitiveness (RYC-2012-11867). P.O-V. was supported by a research contract by the University of Lleida. This study was supported by MAGRAMA, Government of Navarra (project Necropir-EFA 130/09) and the MINECO project CGL2015-66966-C2-2-R.
https://doi.org/10.1016/j.biocon.2018.11.004
028051
0006-3207
https://repositori.udl.cat/handle/10459.1/463494
eng
Elsevier
info:eu-repo/grantAgreement/MINECO//CGL2015-66966-C2-2-R/ES/SOSTENIBILIDAD, SERVICIOS ECOSISTEMICOS Y CARROÑEROS EN SISTEMAS AGROGANADEROS: INTEGRANDO ECOLOGIA DEL MOVIMIENTO, MODELOS DE POBLACIONES Y PERCEPCION SOCIAL/
Versió postprint del document publicat a https://doi.org/10.1016/j.biocon.2018.11.004
Biological Conservation, 2018, vol. 228, p. 321-330
cc-by-nc-nd (c) Elsevier, 2018
Attribution-NonCommercial-NoDerivatives 4.0 International
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Livestock movements
Obligate scavengers
Food requirements
Simulation model
Population dynamics
PDP models
Bioinspired models for assessing the importance of transhumance and transboundary management in the conservation of European avian scavengers
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/648532020-07-08T13:04:37Zcom_10459.1_56965com_10459.1_2com_10459.1_186col_10459.1_57707col_10459.1_311
Nadal, Esteve
Pagès Bernaus, Adela
Pla Aragonés, Lluís Miquel
2018-10-10T08:31:01Z
2018-10-10T08:31:01Z
2018
This paper presents a bi-objective model for optimizing pig deliveries to the abattoir
accounting for total revenue and CO2 emissions. Fattening farms house the most important stage
in pig production, and operations on farms must be coordinated with the rest of the pig supply
chain when batch management is generally applied. The novelty of the model lies in the change of
attitude in producers towards a greener production, which is becoming one of the major concerns in
our society. In this context, we enrich the classical approach focused on revenues with the addition
of the CO2 emissions from the pigs on the fattening farms. Emissions derived from feeding and
transportation are considered since they are the most important sources of CO2 . The model is tested
using parameters representing a typical integrated Spanish fattening farm. Our findings reveal the
impact and the relationship between revenues and emissions, highlight that the break-even is reached
achieving 459 kg of CO2 per pig, which corresponds to a reduction of 6.05%. On the other hand,
the profit is slightly reduced by 4.48% in favor of the environment.
This research was partially funded by CYTED Grant Number 516RT0513. A.P.-B. and L.M.P.-A. are members of the excellence research group 2017-SGR1193 supported by the Autonomous Government of Catalonia.
https://doi.org/10.3390/su10061782
027638
2071-1050
http://hdl.handle.net/10459.1/64853
eng
MDPI
Reproducció del document publicat a https://doi.org/10.3390/su10061782
Sustainability, 2018, vol. 10, núm. 6, 1782
cc-by (c) Esteve Nadal et al., 2018
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
CO2 emissions
Deliveries to abattoir
Pig production planning
Mixed integer programming
Bi-Objective Optimization Model Based on Profit and CO2 Emissions for Pig Deliveries to the Abattoir
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/4648512024-01-11T03:00:32Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Reyes, Mònica Andrea
Dalfó, Cristina
Fiol Mora, Miguel Ángel
2024-01-10T08:16:06Z
2024-01-10T08:16:06Z
2024-01-06
Let G be a graph on n vertices. The k-token graph (or symmetric k-th power) of G, denoted by
Fk(G), has as vertices the (n/k) k-subsets of vertices from G, and two vertices are adjacent when their symmetric difference is a pair of adjacent vertices in G. In particular, Fk(Kn) is the Johnson graph J(n, k), which is a distance-regular graph used in coding theory. In this paper, we present some results concerning the (adjacency and Laplacian) spectrum of Fk(G) in terms of the spectrum of G. For instance, when G is walk-regular, an exact value for the spectral radius
(or maximum eigenvalue) of Fk(G) is obtained. When G is distance-regular, other eigenvalues of its 2-token graph are derived using the theory of equitable partitions. A generalization of Aldous’ spectral gap conjecture (which is now a theorem) is proposed.
The research of C. Dalfó and M. A. Fiol has been partially supported by AGAUR from the Catalan Government under Project 2017SGR1087 and by MICINN from the Spanish Government under Project PGC2018-095471-B-I00. The research of M. A. Fiol was also supported by a grant from the Universitat Politècnica de Catalunya with references AGRUPS-2022 and AGRUPS-2023.
http://doi.org/10.1007/s40590-023-00583-3
033819
1405-213X
2296-4495
https://repositori.udl.cat/handle/10459.1/464851
eng
Springer
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PGC2018-095471-B-I00/ES/ESTUDIO MATEMATICO DE LOS FALLOS EN CASCADA EN SISTEMAS COMPLEJOS MEDIANTE INVARIANTES Y CENTRALIDADES EN GRAFOS. APLICACIONES A REDES REALES/
Reproducció del document publicat a http://doi.org/10.1007/s40590-023-00583-3
Boletín de la Sociedad Matemática Mexicana, 2024, vol. 30, art. 11
cc-by (c) Reyes et al., 2024
Attribution 4.0 International
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Token graph
Adjacency spectrum
Local spectrum
Laplacian spectrum
Algebraic connectivity
Binomial matrix
Spectral radius
Walk-regular graph
On the spectra and spectral radii of token graphs
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/583942022-10-13T20:31:34Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
Valls, Claudia
2016-11-04T16:39:54Z
2015
2016-11-04T16:39:54Z
In this work we complete the integrability conditions (i.e. conditions for the existence of a local analytic first integral) for a family of a resonant saddle perturbed with homogeneous quintic nonlinearities studied in a previous work. In order to obtain the necessary conditions we use modular arithmetic computations.
The first author is partially supported by a MINECO/ FEDER Grant Number MTM2014-53703-P and an AGAUR (Generalitat de Catalunya) Grant Number 2014SGR 1204. The second author is supported by Portuguese national funds through FCT—Fundação para a Ciência e a Tecnologia: Project UID/MAT/04459/2013 (CAMGSD).
application/pdf
https://doi.org/10.1007/s11071-015-2122-1
023250
0924-090X
http://hdl.handle.net/10459.1/58394
spa
Springer
info:eu-repo/grantAgreement/MINECO//MTM2014-53703-P/ES/METODOS CUALITATIVOS EN SISTEMAS DIFERENCIALES CONTINUOS/
Versió postprint del document publicat a: https://doi.org/10.1007/s11071-015-2122-1
Nonlinear Dynamics, 2015, vol. 81, núm. 4, p. 2021-2030
(c) Springer, 2015
info:eu-repo/semantics/openAccess
Integrability
Resonant saddle
Quintic systems
Matemàtica
Mathematics
Integrability conditions of a resonant saddle perturbed with homogeneous quintic nonlinearities
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/494582023-07-11T14:21:01Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
Grau Montaña, Maite
Llibre, Jaume
2016-02-08T11:14:00Z
2013
2016-02-05T14:55:52Z
In this paper, we characterize the universal centres of the ordinary differential equations , where ai(θ) are trigonometric polynomials, in terms of the composition conditions. These centres are closely related with the classical Poincaré centre problem for planar analytic differential systems.
Additionally, we show that the notion of universal centre is not invariant under changes of variables, and we also provide
different families of universal centres. Finally, we characterize all the universal centres for the quadratic polynomial differential systems.
Universal centres and composition conditions.
The first and second authors are partially supported by a MICINN/FEDER grant number MTM2011-22877 and by a Generalitat de Catalunya grant number 2009SGR 381. The third author is partially supported by a MICINN/ FEDER grant number MTM2008-03437, by a Generalitat de Catalunya grant number 2009SGR 410 and by ICREA Academia.
application/pdf
https://doi.org/10.1112/plms/pds050
017898
0024-6115
http://hdl.handle.net/10459.1/49458
eng
London Mathematical Society
info:eu-repo/grantAgreement/MICINN//MTM2011-22877/ES/BIFURCACIONES, INTEGRABILIDAD Y PROPIEDADES CUALITATIVAS DE FAMILIAS DE CAMPOS VECTORIALES/
info:eu-repo/grantAgreement/MICINN//MTM2008-03437/ES/ORBITAS PERIODICAS, BIFURCACIONES E INTEGRABILIDAD DE LOS SISTEMAS DINAMICOS/
Versió preprint del document publicat a: https://doi.org/10.1112/plms/pds050
Proceedings of the London Mathematical Society, 2013, vol. 106, núm. 3, p. 481-507
(c) London Mathematical Society, 2013
info:eu-repo/semantics/openAccess
Equacions diferencials
Differential equations
Universal centers and composition conditions
info:eu-repo/semantics/article
info:eu-repo/semantics/submittedVersion
oai:repositori.udl.cat:10459.1/4632782023-11-28T09:49:50Zcom_10459.1_186com_10459.1_2col_10459.1_311
Dalfó, Cristina
Fiol Mora, Miguel Ángel
2023-05-05T07:05:36Z
2023-05-05T07:05:36Z
2023-01-01
A Moore (r; z; k)-mixed graph G has every vertex with undirected degree r, directed in and outdegree z, diameter k, and number of vertices (or order) attaining the corresponding Moore bound M(r; z; k) for mixed graphs. When the order of G is close to M(r; z; k) vertices, we refer to it as an almost Moore graph. The first part of this paper is a survey about known Moore (and almost Moore) general mixed graphs that turn out to be Cayley graphs. Then, in the second part of the paper, we give new results on the bipartite case. First, we show that Moore bipartite mixed graphs with diameter three are distance-regular, and their spectra are fully characterized. In particular, an infinity family of Moore bipartite (1; z; 3)-mixed graphs is presented, which are Cayley graphs of semidirect products of groups. Our study is based on the line digraph technique, and on some results about when the line digraph of a Cayley digraph is again a Cayley digraph.
This research has been partially supported by AGAUR from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RBI00.
https://doi.org/10.5614/ejgta.2023.11.1.15
033356
2338-2287
https://repositori.udl.cat/handle/10459.1/463278
eng
Indonesian Combinatorics Society
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-115442RB-I00/ES/
Reproducció del document publicat a https://doi.org/10.5614/ejgta.2023.11.1.15
Electronic Journal of Graph Theory and Applications, 2023, vol. 11, núm. 1, p. 183-195
Electronic Journal of Graph Theory and Applications
cc-by-sa (c) Dalfó et al., 2023
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-sa/4.0/
Cayley graph
Line digraph
Mixed graph
Moore bound
Spectrum
Moore mixed graphs from Cayley graphs
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/844632023-06-28T14:01:33Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Araujo Pardo, Martha Gabriela
López Lorenzo, Ignacio
2022-12-03T12:25:44Z
2022-12-03T12:25:44Z
2022
The modelling of interconnection networks by graphs motivated the study of several extremal problems that involve well known parameters of a graph (degree, diameter, girth and order) and optimising one of the parameters given restrictions on some of the others. Here we focus on bipartite Moore graphs, that is, bipartite graphs attaining the optimum order, fixed either the degree/diameter or degree/girth. The fact that there are very few bipartite Moore graphs suggests the relaxation of some of the constraints implied by the bipartite Moore bound. First we deal with local bipartite Moore graphs. We find in some cases those local bipartite Moore graphs with local girths as close as possible to the local girths given by a bipartite Moore graph. Second, we construct a family of (q+2)-bipartite graphs of order 2(q2+q+5) and diameter 3, for q a power of prime. These graphs attain the record value for q=9 and improve the values for q=11 and q=13.
Research of N. López was supported in part by the MCIN/AEI/10.13039/501100011033 through Grant PID2020-115442RB-I00 (Spanish Ministerio de Ciencia e Innovacion) and research of G. Araujo was supported by PASPA-DGAPA and CONACyT Sabbatical Stay 2020, CONACyT-México under Project 282280, 47510664 and PAPIIT-México under Projects IN107218, IN108121.
https://doi.org/10.1007/s00373-022-02500-3
032528
0911-0119
http://hdl.handle.net/10459.1/84463
eng
Springer Nature
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-115442RB-I00/ES/
Versió postprint del document publicat a https://doi.org/10.1007/s00373-022-02500-3
Graphs and Combinatorics, 2022, vol. 38, art. 110.
(c) Springer Nature, 2022
info:eu-repo/semantics/openAccess
Bipartite Moore bound
Bipartite graph
Girth
Local girth
On New Record Graphs Close to Bipartite Moore Graphs
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
nacho.lopez@udl.cat
Ignacio López Lorenzo
oai:repositori.udl.cat:10459.1/4632462023-11-28T09:48:12Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Dalfó, Cristina
Fiol Mora, Miguel Ángel
Garriga, Ernest
2023-04-26T13:24:31Z
2023-04-26T13:24:31Z
2013-04-01
Research supported by the Ministerio de Ciencia e Innovación (Spain) and the European Regional Development Fund under project MTM2011-28800-C02- 01, and by the Catalan Research Council under project 2009SGR1387.
https://doi.org/10.1016/j.dam.2012.10.024
028008
0166218X
1872-6771
https://repositori.udl.cat/handle/10459.1/463246
eng
Elsevier
info:eu-repo/grantAgreement/MICINN//MTM2011-28800-C02-01/ES/OPTIMIZACION Y PROBLEMAS EXTREMALES EN TEORIA DE GRAFOS Y COMBINATORIA. APLICACIONES A LAS REDES DE COMUNICACION/
Versió postprint del document publicat a: https://doi.org/10.1016/j.dam.2012.10.024
Discrete Applied Mathematics, vol. 161, núm. 6, p. 768-777
Discrete Applied Mathematics
cc-by-nc-nd, (c) Elsevier, 2013
Attribution-NonCommercial-NoDerivatives 4.0 International
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Graph
Adjacency matrix
Graft product
Moment
Topological index
Moments in graphs
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/722852023-04-26T12:31:16Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_44504
Dalfó, Cristina
Fiol Mora, Miguel Ángel
2021-11-12T13:32:56Z
2021-11-12T13:32:56Z
2021
2021-11-12T13:32:56Z
The d-Fibonacci digraphs F(d, k), introduced here, have the number of vertices following some generalized Fibonacci-like sequences. They can be defined both as digraphs on alphabets and as iterated line digraphs. Here we study some of their nice properties. For instance, F(d, k) has diameter d + k − 2 and is semi-pancyclic; that is, it has a cycle of every length between 1 and ℓ, with ℓ ∈ {2k − 2, 2k − 1}. Moreover, it turns out that several other numbers of F(d, k) (of closed l-walks, classes of vertices, etc.) also follow the same linear recurrences as the numbers of vertices of the d-Fibonacci digraphs.
The research of the first author has also received funding from the European Union’s Horizon
2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement
No 734922.
application/pdf
https://doi.org/10.5614/ejgta.2021.9.2.22
031740
2338-2287
http://hdl.handle.net/10459.1/72285
eng
Institut Teknologi Bandung (ITB) Indonesia
Indonesian Combinatorial Society (InaCombS)
GTA Research Group, University of Newcastle (Australia)
Reproducció del document publicat a: https://doi.org/10.5614/ejgta.2021.9.2.22
Electronic Journal of Graph Theory and Applications, 2021, vol. 9, num. 2, p. 527-538
info:eu-repo/grantAgreement/EC/H2020/734922/EU/CONNECT
cc-by-sa (c) Dalfó et al., 2021
info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-sa/4.0/
n-step Fibonacci number
Fibonacci graph
Digraph on alphabet
de Bruijn digraph
Line digraph
Adjacency matrix
Spectrum
On d-Fibonacci digraphs
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/494462017-03-10T09:57:44Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
Grau Montaña, Maite
Santallusia Esvert, Xavier
2016-02-04T13:05:19Z
2016-02-04T13:05:19Z
2013
2016-02-04T12:51:16Z
In this paper we deal with the center problem for the trigonometricAbel equation dρ/dρ =a1(θ)ρ^2+a2(θ)ρ^3; where a1(θ) and a2(θ)are trigonometric polynomials in θ. This problem is closely connectedwith the classical Poincar´e center problem for planar polynomial vectorfields.
The authors are partially supported by a MINECO/FEDER grant number MTM2011-22877 and by a Generalitat de Catalunya grant number 2009SGR 381
application/pdf
https://doi.org/10.11948/2013011
019633
2156-907X
http://hdl.handle.net/10459.1/49446
eng
Shanghai Normal University & Wilmington Scientific Publisher
MINECO/PN2008-2011/MTM2011-22877
Reproducció del document publicat a https://doi.org/10.11948/2013011
Journal Of Applied Analysis And Computation, 2013, vol. 3, núm. 2, p. 133-144
cc-by (c) Giné et al., 2013
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/3.0/es/
Center problem
Abel differential equation
Universal centers
Polynomial differential equations
Equacions abelianes
Composition conditions in the trigonometric Abel equation
article
publishedVersion
oai:repositori.udl.cat:10459.1/629702022-09-28T14:29:50Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
Valls, Claudia
2018-04-04T08:22:23Z
2018-04-04T08:22:23Z
2017
2018-04-04T08:22:23Z
In this paper, we provide necessary and sufficient conditions for the existence of local analytic first integrals for a seventh-parameter family of complex cubic systems called the complex Kukles systems.
The first author is partially supported by a MINECO/ FEDER [grant number MTM2014-53703-P]; an AGAUR (Generalitat de Catalunya) [grant number 2014SGR 1204]. The second author is supported by Portuguese National Funds through FCT - Fundação para a Ciência e a Tecnologia within the project PTDC/MAT/117106/2010 and by CAMGSD.
application/pdf
https://doi.org/10.1080/14689367.2016.1181715
025847
1468-9367
http://hdl.handle.net/10459.1/62970
eng
Taylor & Francis
info:eu-repo/grantAgreement/MINECO//MTM2014-53703-P/ES/METODOS CUALITATIVOS EN SISTEMAS DIFERENCIALES CONTINUOS/
Versió postprint del document publicat a https://doi.org/10.1080/14689367.2016.1181715
Dynamical Systems-An International Journal, 2017, vol. 32, núm. 2, p. 211-220
(c) Taylor & Francis, 2017
info:eu-repo/semantics/openAccess
Integrability
Complex centre-focus problem
Lyapunov constants
Integrability conditions for complex kukles systems
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/489312021-08-30T15:04:36Zcom_10459.1_186com_10459.1_2col_10459.1_311
Martínez Rodríguez, Santi
Miret, Josep M. (Josep Maria)
Valls Marsal, Magda
Tomàs, Rosana
2015-11-09T13:34:28Z
2025-01-01
2014
The amount of information stored in databases is constantly increasing. Databases contain multiple records, each of them divided in several data fields. And some of these fields may contain sensitive information, so there is a need to prevent free access to it. Traditionally, cryptography has been used to conceal this kind of information, but conventional cryptography has the problem that, for queries that need access to a specific field for all the records, it requires the decryption of the entire data field. Order preserving encryption ensures that comparing encrypted data returns the same result than comparing the original data. This permits to order encrypted data without the need of decryption. In this way, databases using this kind of cryptosystems admit encrypted record fields while still allowing searches and range queries. In this paper, we propose an order preserving symmetric encryption scheme whose encryption function is recursively constructed. Starting with the trivial order preserving encryption function, which is the identity, a function is constructed in a series of steps by making it more and more complex until the the desired security level is reached. The security of the proposed cryptosystem is also analyzed.
https://doi.org/10.12785/amis/080501
020639
2325-0399
http://hdl.handle.net/10459.1/48931
eng
Natural Sciences Publishing
Reproducció del document publicat a https://doi.org/10.12785/amis/080501
Applied Mathematics & Information Sciences, 2014, vol. 8, núm. 5, p. 2085-2094
(c) Natural Sciences Publishing, 2014
info:eu-repo/semantics/restrictedAccess
Databases
Privacy
Symmetric key
Criptografia
Bases de dades
Securing Databases by using Diagonal-based Order Preserving Symmetric Encryption
article
publishedVersion
santi@matematica.udl.cat
Martínez Rodríguez, Santi
oai:repositori.udl.cat:10459.1/655112023-02-02T12:25:26Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
García, I. A. (Isaac A.)
Maza Sabido, Susanna
2019-01-15T11:22:13Z
2019-01-15T11:22:13Z
2019-01-14
2019-01-15T11:22:13Z
In this work we prove, using averaging theory at any order in the small perturbation parameter, that the period annulus of the harmonic oscillator has cyclicity zero (no limit cycles bifurcate) when it is perturbed by any fixed homogeneous polynomial field.
The authors are partially supported by MINECO grant number MTM2017-84383-P and AGAUR
grant number 2017SGR-1276.
application/pdf
https://doi.org/10.14232/ejqtde.2019.1.3
028190
1417-3875
http://hdl.handle.net/10459.1/65511
eng
Bolyai Institute. University of Szeged
Hungarian Academy of Sciences
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y
Técnica y de Innovación 2013-2016/MTM2017-84383-P/ES/ORBITAS PERIODICAS E
INTEGRABILIDAD EN SISTEMAS DIFERENCIALES CONTINUOS/
Reproducció del document publicat a https://www.math.u-szeged.hu/ejqtde/p7044.pdf
Electronic Journal Of Qualitative Theory Of Differential Equations, 2019, vol. 3, p. 1-6
MINECO/PN2013-2016/MTM2017-84383-P
cc-by (c) García et al., 2019
info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by/4.0/deed.es_ES
Averaging theory
Periodic orbits
Poincaré map
Period annulus of the harmonic oscillator with zero cyclicity under perturbations with a homogeneous polynomial field
info:eu-repo/semantics/article
publishedVersion
oai:repositori.udl.cat:10459.1/583502022-10-11T20:36:21Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
García, I. A. (Isaac A.)
2016-11-02T11:35:00Z
2025-01-01
2015
2016-11-02T11:35:00Z
In this paper we study how are related three of the basic concepts in the rather non-generic phenomenon of integrability of analytic local vector fields X around an equilibrium in R, namely: complete integrability, orbital linearizability and number of independent normalizers (Lie symmetries). The work relates and extends several results existing in the literature of the subject.
The author is partially supported by MICINN grant number MTM2011-22877 and by
CIRIT grant number 2014 SGR 1204.
application/pdf
021209
0949-5932
http://hdl.handle.net/10459.1/58350
eng
Heldermann Verlag
info:eu-repo/grantAgreement/MICINN//MTM2011-22877/ES/BIFURCACIONES, INTEGRABILIDAD Y PROPIEDADES CUALITATIVAS DE FAMILIAS DE CAMPOS VECTORIALES/
Reproducció del document publicat a http://www.heldermann.de/JLT/JLT25/JLT251/jlt25003.htm
Journal of Lie Theory, 2015, vol. 25, p. 37-43
(c) Heldermann Verlag, 2015
info:eu-repo/semantics/restrictedAccess
Complete integrability, orbital linearizability and independent normalizers for local vector fields in R^n
info:eu-repo/semantics/article
publishedVersion
garcia@matematica.udl.cat
García, Isaac A.
oai:repositori.udl.cat:10459.1/717632021-08-28T00:09:29Zcom_10459.1_186com_10459.1_2col_10459.1_311
Pagès Bernaus, Adela
Ramalhinho-Lourenço, Helena
Juan Pérez, Ángel A.
Calvet Liñan, Laura
2021-08-27T10:27:23Z
2021-08-27T10:27:23Z
2017-07
e-Commerce activity has been increasing during recent years, and this trend is expected to continue in thenear future. e-Commerce practices are subject to uncertainty conditions and high variability in customers’demands. Considering these characteristics, we propose two facility–location models that represent alternativedistribution policies in e-commerce (one based on outsourcing and another based on in-house distribution).These models take into account stochastic demands as well as more than one regular supplier per customer.Two methodologies are then introduced to solve these stochastic versions of the well-known capacitatedfacility–location problem. The first is a two-stage stochastic-programming approach that uses an exact solver.However, we show that this approach is not appropriate for tackle large-scale instances due to the compu-tational effort required. Accordingly, we also introduce a “simheuristic” approach that is able to deal withlarge-scale instances in short computing times. An extensive set of benchmark instances contribute to illustratethe efficiency of our approach, as well as its potential utility in modern e-commerce practices.
his work has been partially supported by the Spanish Ministry of Economy and Competitive-ness and FEDER (TRA2013-48180-C3-P, TRA2015-71883-REDT) and the Erasmus+programme(2016-1-ES01-KA108-023465). We also thank the support of the UOC doctoral programme.
https://doi.org/10.1111/itor.12433
026237
0969-6016
1475-3995
http://hdl.handle.net/10459.1/71763
eng
Wiley
Versió postprint del document publicat a:https://doi.org/10.1111/itor.12433
International Transactions in Operational Research, 2017, vol. 26, núm. 2, p. 507-528
(c) Pagès Bernaus et al., 2017
(c) International Transactions in Operational Research, 2017
(c) International Federation of Operational Research Societies, 2017
info:eu-repo/semantics/openAccess
e-commerce
Supply-chain management
Capacitated facility–location problem
Stochastic combinatorial optimization
Simheuristics
Stochastic programming
Designing e-commerce supply chains: a stochastic facility–location approach
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/659742022-09-23T17:34:33Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Algaba, Antonio
García, Cristóbal
Giné, Jaume
2019-03-20T09:39:17Z
2021-06-15T22:24:16Z
2019
In this work is characterized the analytic integrability problem around a nilpotent singularity for differential systems in the plane under generic conditions. The analytic integrability problem is characterized via the existence of a formal inverse integrating factor. The relation between the analytic integrability and the existence of an algebraic inverse integrating factor is also given.
The first and second authors are partially supported by a MINECO/FEDER grant number MTM2014-56272-C2-2 and by the Consejería de Educación y Ciencia de la Junta de Andalucía (projects P12-FQM-1658, FQM-276). The third author is partially supported by a MINECO/FEDER grant number MTM2017-84383-P and by an AGAUR (Generalitat de Catalunya) grant number 2017SRG 1276.
https://doi.org/10.1016/j.cnsns.2018.09.018
029041
1878-7274
http://hdl.handle.net/10459.1/65974
eng
Elsevier
info:eu-repo/grantAgreement/MINECO//MTM2014-56272-C2-2-P/ES/FORMAS NORMALES Y COMPORTAMIENTOS DINAMICOS/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-84383-P/ES/ORBITAS PERIODICAS E INTEGRABILIDAD EN SISTEMAS DIFERENCIALES CONTINUOS/
Versió postprint del document publicat a https://doi.org/10.1016/j.cnsns.2018.09.018
Communications in Nonlinear Science and Numerical Simulation, 2019, vol. 71, p. 130-140
cc-by-nc-nd (c) Elsevier, 2019
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Analytic integrability
Nilpotent singular points
Inverse integrating factor
Integrability of planar nilpotent differential systems through the existence of an inverse integrating factor
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
gine@matematica.udl.cat
Giné, Jaume
oai:repositori.udl.cat:10459.1/664332022-09-20T15:55:46Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
López Masip, Susana-Clara
Muntaner Batle, Francesc Antoni
2019-06-10T11:18:30Z
2019-06-10T11:18:30Z
2015
2019-06-10T11:18:31Z
Figueroa-Centeno et al. [4] introduced the following product of digraphs let D be a digraph and let Γ be a family of digraphs such that V (F) = V for every F∈Γ . Consider any function h:E(D)→Γ . Then the product D⊗hΓ is the digraph with vertex set V(D)×V and ((a,x),(b,y))∈E(D⊗hΓ) if and only if (a,b)∈E(D) and (x,y)∈E(h(a,b)) . In this paper, we deal with the undirected version of the ⊗h -product, which is a generalization of the classical direct product of graphs and, motivated by the ⊗h -product, we also recover a generalization of the classical lexicographic product of graphs, namely the ∘h -product, that was introduced by Sabidussi in 1961. We provide two characterizations for the connectivity of G⊗hΓ that generalize the existing one for the direct product. For G∘hΓ , we provide exact formulas for the connectivity and the edge-connectivity, under the assumption that V (F) = V , for all F∈Γ . We also introduce some miscellaneous results about other invariants in terms of the factors of both, the ⊗h -product and the ∘h -product. Some of them are easily obtained from the corresponding product of two graphs, but many others generalize the existing ones for the direct and the lexicographic product, respectively. We end up the paper by presenting some structural properties. An interesting result in this direction is a characterization for the existence of a nontrivial decomposition of a given graph G in terms of ⊗h -product.
The research conducted in this document by the first author has been supported by the Spanish Research Council under project MTM2011-28800-C02-01 and by the Catalan Research Council under grant 2009SGR1387.
application/pdf
https://doi.org/10.1007/s10474-015-0487-8
028499
0236-5294
http://hdl.handle.net/10459.1/66433
eng
Springer
info:eu-repo/grantAgreement/MICINN//MTM2011-28800-C02-01/ES/OPTIMIZACION Y PROBLEMAS EXTREMALES EN TEORIA DE GRAFOS Y COMBINATORIA. APLICACIONES A LAS REDES DE COMUNICACION/
Versió postprint del document publicat a https://doi.org/10.1007/s10474-015-0487-8
Acta Mathematica Hungarica, 2015, vol. 145, num. 2, p. 283-303
(c) Springer, 2015
(c) Akadémiai Kiadó, Budapest, 2015
info:eu-repo/semantics/openAccess
Teoria de grafs
Graph theory
Connectivity and other invariants of generalized products of graphs
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/488972023-03-27T12:30:29Zcom_10459.1_186com_10459.1_2com_10459.1_239col_10459.1_311col_10459.1_10984
Leeuwen, Herman P. van
Puy Llorens, Jaume
Galceran i Nogués, Josep
Cecilia Averós, Joan
2015-11-03T09:06:10Z
2015-11-03T09:06:10Z
2002
2015-11-03T09:06:10Z
The voltammetric response of metal complex systems with various labilities is analyzed by rigorous numerical simulation with the Finite Element Method of the time-dependent concentration profiles of the different species. The ensuing exact fluxes and the corresponding currents are compared to those derived from the Koutecký<br>Koryta (KK) approximation which assumes a discontinuous transition in the concentration profiles from non-labile to labile behavior. The results indicate a relatively far-reaching correctness of the KK approximation in the complete kinetic range from non-labile to labile complexes, as long as the kinetic flux is computed from the effective concentration of the complex in the reaction layer. Some approximate analytical expressions for this concentration are provided. The KK approximation is shown to be applicable for any metal-to-ligand ratio, provided that the thickness of the reaction layer is expressed in terms of the ligand concentration at the electrode surface.
application/pdf
https://doi.org/10.1016/S0022-0728(02)00745-3
002955
1572-6657
http://hdl.handle.net/10459.1/48897
eng
Elsevier
Versió postprint del document publicat a: https://doi.org/10.1016/S0022-0728(02)00745-3
Journal of Electroanalytical Chemistry, 2002, vol. 526, num. 1-2, p. 10-18
(c) Elsevier, 2002
info:eu-repo/semantics/openAccess
Electroquímica
Electrochemistry
Evaluation of the Koutecký-Koryta approximation for voltammetric currents generated by metal complex systems with various labilities
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
oai:repositori.udl.cat:10459.1/623452023-01-11T19:39:07Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
López Lorenzo, Ignacio
Pérez Rosés, Hebert
Pujolàs Boix, Jordi
2018-01-12T12:17:13Z
2019-11-20T23:22:32Z
2017-11-20
2018-01-12T12:17:13Z
This paper investigates the upper bounds for the number of vertices in mixed abelian Cayley graphs with given degree and diameter. Additionally, in the case when the undirected degree is equal to one, we give a construction that provides a lower bound.
The authors have been supported in part by grants MTM2010-21580-C02-
01 and IPT-2102-0603-430000, from Ministerio Español de Economía y Competitividad,
and by grant 2009SGR-442, from the Generalitat de Catalunya.
application/pdf
https://doi.org/10.1016/j.dam.2017.04.018
026479
0166-218X
http://hdl.handle.net/10459.1/62345
eng
Elsevier
info:eu-repo/grantAgreement/MICINN//MTM2010-21580-C02-01/ES/TECNICAS CRIPTOGRAFICAS CON CURVAS ELIPTICAS E HIPERELIPTICAS/
Versió postprint del document publicat a: https://doi.org/10.1016/j.dam.2017.04.018
Discrete Applied Mathematics, 2017, vol. 231, p. 190-197
cc-by-nc-nd (c) Elsevier, 2017
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/es
Network design
Degree/Diameter Problem
Abelian Cayley graphs
The Degree/Diameter Problem for Mixed Abelian Cayley Graphs
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
nlopez@matematica.udl.cat
López Lorenzo, Ignacio
oai:repositori.udl.cat:10459.1/701262023-04-26T12:30:36Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291col_10459.1_44504
Dalfó, Cristina
Fiol Mora, Miguel Ángel
2020-12-21T09:10:14Z
2020-12-21T09:10:14Z
2020-07-12
2020-12-21T09:10:14Z
It is well known that, in general, part of the spectrum of a graph can be obtained from the adjacency matrix of its quotient graph given by a regular partition. In this paper, a method that gives all the spectrum, and also the local spectra, of a graph from the quotient matrices of some of its regular partitions, is proposed. Moreover, from such partitions, the C-local multiplicities of any class of vertices C is also determined, and some applications of these parameters in the characterization of completely regular codes and their inner distributions are described. As examples, it is shown how to find the eigenvalues and (local) multiplicities of walk-regular, distance-regular, and distance-biregular graphs.
Partially supported by AGAUR from the Catalan Government under project 2017SGR1087 and by MICINN from the Spanish Governmentunder projects PGC2018-095471-B-I00 and MTM2017-83271-R. Also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sk lodowska-Curie grant agreement no. 734922
application/pdf
https://doi.org/10.13001/ela.2020.5225
030376
1081-3810
http://hdl.handle.net/10459.1/70126
eng
International Linear Algebra Society
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PGC2018-095471-B-I00/ES/ESTUDIO MATEMATICO DE LOS FALLOS EN CASCADA EN SISTEMAS COMPLEJOS MEDIANTE INVARIANTES Y CENTRALIDADES EN GRAFOS. APLICACIONES A REDES REALES/
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-83271-R/ES/CRIPTOGRAFIA Y CODIGOS PARA APLICACIONES SEGURAS Y FIABLES/
Versió postprint del document publicat a: https://doi.org/10.13001/ela.2020.5225
Electronic Journal Of Linear Algebra, 2020, vol. 36, num. 36, p. 446-460
info:eu-repo/grantAgreement/EC/H2020/734922/EU/CONNECT
(c) Dalfó i Fiol, 2020
info:eu-repo/semantics/openAccess
Adjacency matrix
Spectrum
Eigenvalues
Local multiplicities
Walk-regular graph
C-local spectrum
Completely regular code
A general method to obtain the spectrum and local spectra of a graph from its regular partitions
info:eu-repo/semantics/article
accepted/Version
oai:repositori.udl.cat:10459.1/577862017-03-10T13:02:11Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Grau Montaña, Maite
Mañosas, Francesc
Villadelprat, Jordi
2016-09-12T10:01:10Z
2016-09-12T10:01:10Z
2010
El pdf de l'article és la versió preprint: arXiv:0805.1140
We present a criterion that provides an easy sufficient condition in order that a collection
of Abelian integrals has the Chebyshev property. This condition involves the functions in the integrand of the Abelian integrals and can be checked, in many cases, in a purely algebraic way. By using this criterion, several known results are obtained in a shorter way and some new results, which could not be tackled by the known standard methods, can also be deduced.
The first author is partially supported by the MEC/FEDER grant MTM2005-06098-C02-02. The second author by the
MEC/FEDER grants MTM2005-02139 and MTM2005-06098 and the C
IRIT grant 2005SGR-00550. The third author by the
MEC/FEDER grant MTM2005-06098-C02-01 and the CIRIT grant 2
005SGR-0055
https://arxiv.org/abs/0805.1140
https://doi.org/10.1090/S0002-9947-2010-05007-X
013240
0002-9947
http://hdl.handle.net/10459.1/57786
eng
American Mathematical Society
MIECI/PN2004-2007/MTM2005-06098-C02-02
Versió preprint del document publicat a https://doi.org/10.1090/S0002-9947-2010-05007-X
Transactions of the American Mathematical Society, 2011, vol. 363, núm. 1, p. 109-129
(c) American Mathematical Society, 2010
info:eu-repo/semantics/openAccess
Integrals
Matemàtica
A Chebyshev criterion for Abelian integrals
article
submittedVersion
oai:repositori.udl.cat:10459.1/604242023-01-27T16:42:29Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
Giné, Jaume
Llibre, Jaume
Valls, Claudia
2017-11-06T14:25:47Z
2017-11-06T14:25:47Z
2017
2017-11-06T14:25:47Z
For the polynomial differential system x˙=−y, y˙=x+Qn(x,y), where Qn(x,y) is a homogeneous polynomial of degree n there are the following two conjectures done in 1999. (1) Is it true that the previous system for n≥2 has a center at the origin if and only if its vector field is symmetric about one of the coordinate axes? (2) Is it true that the origin is an isochronous center of the previous system with the exception of the linear center only if the system has even degree? We give a step forward in the direction of proving both conjectures for all n even. More precisely, we prove both conjectures in the case n=4 and for n≥6 even under the assumption that if the system has a center or an isochronous center at the origin, then it is symmetric with respect to one of the coordinate axes, or it has a local analytic first integral which is continuous in the parameters of the system in a neighborhood of zero in the parameters space. The case of n odd was studied in [8].
The first author is partially supported by a MINECO grant number MTM2014-
53703-P and an AGAUR (Generalitat de Catalunya) grant number 2014SGR 1204. The second author is partially supported by a FEDER-MINECO grant MTM2016-77278-P, a MINECO grant MTM2013-40998-P, and an AGAUR grant number 2014SGR-568. The third author is partially supported by FCT/Portugal through the project UID/MAT/04459/2013.
application/pdf
https://doi.org/10.11948/2017093
026094
2156-907X
2158-5644
http://hdl.handle.net/10459.1/60424
eng
Shanghai Normal University & Wilmington Scientific Publisher
info:eu-repo/grantAgreement/MINECO//MTM2014-53703-P/ES/METODOS CUALITATIVOS EN SISTEMAS DIFERENCIALES CONTINUOS/
info:eu-repo/grantAgreement/MINECO//MTM2016-77278-P/ES/
info:eu-repo/grantAgreement/MINECO//MTM2013-40998-P/ES/ALGUNOS ASPECTOS DE LA DINAMICA GLOBAL DE LOS SISTEMAS DIFERENCIALES: INTEGRABILIDAD, SOLUCIONES PERIODICAS Y BIFURCACIONES/
Reproducció del document publicat a: https://doi.org/10.11948/2017093
Journal Of Applied Analysis And Computation, 2017, vol. 7, núm. 4, p. 1534-1548
cc-by (c) Giné et al., 2017
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Center-focus problem
Isochronous center
Poincaré-Liapunov constants
Gröbner basis of polynomial systems
Informàtica
Computer science
Centers for the Kukles homogeneous systems with even degree
info:eu-repo/semantics/article
publishedVersion
oai:repositori.udl.cat:10459.1/578002017-03-10T09:57:24Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
García, I. A. (Isaac A.)
Giacomini, Héctor
Grau Montaña, Maite
2016-09-14T08:25:21Z
2016-09-14T08:25:21Z
2010
This work is concerned with planar real analytic differential systems
with an analytic inverse integrating factor defined in a neighborhood of a
regular orbit. We show that the inverse integrating factor defines an ordinary
differential equation for the transition map along the orbit. When the regular
orbit is a limit cycle, we can determine its associated Poincar´e return map in
terms of the inverse integrating factor. In particular, we show that the multiplicity
of a limit cycle coincides with the vanishing multiplicity of an inverse
integrating factor over it. We also apply this result to study the homoclinic
loop bifurcation. We only consider homoclinic loops whose critical point is
a hyperbolic saddle and whose Poincar´e return map is not the identity. A
local analysis of the inverse integrating factor in a neighborhood of the saddle
allows us to determine the cyclicity of this polycycle in terms of the vanishing
multiplicity of an inverse integrating factor over it. Our result also applies in
the particular case in which the saddle of the homoclinic loop is linearizable,
that is, the case in which a bound for the cyclicity of this graphic cannot be
determined through an algebraic method.
The authors were partially supported by a DGICYT grant number MTM2005-06098-C02-02.
https://doi.org/10.1090/S0002-9947-10-05014-2
012097
0002-9947
http://hdl.handle.net/10459.1/57800
eng
American Mathematical Society
MIECI/PN2004-2007/MTM2005-06098-C02-02
Versió preprint del document publicat a https://doi.org/10.1090/S0002-9947-10-05014-2
Transactions of the American Mathematical Society, 2010, vol. 362, núm. 7, p. 3591-3612
http://arxiv.org/abs/0710.3238
(c) American Mathematical Society, 2010
info:eu-repo/semantics/openAccess
Inverse integrating factor
Poincaré map
Limit cycle
Homoclinic loop
Equacions diferencials
The inverse integrating factor and the Poincaré map
article
submittedVersion
oai:repositori.udl.cat:10459.1/681552023-01-27T16:44:46Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291col_10459.1_44504
Giné, Jaume
Llibre, Jaume
2020-03-06T09:11:31Z
2020-03-06T09:11:31Z
2020
Recently a criterion has been given for determining the weakly formal
Weierstrass non-integrability of polynomial differential systems in C2
. Here we extend this criterion for determining the strongly formal Weierstrass non-integrability
which includes the weakly formal Weierstrass non-integrability of polynomial differential systems in C2
. The criterion is based on the solutions of the form y = f(x) with
f(x) ∈ C[[x]] of the differential system whose integrability we are studying. The results
are applied to a differential system that contains the famous force-free Duffing and the
Duffing–Van der Pol oscillators.
The first author is partially supported by a MINECO/ FEDER grant number MTM2017-84383- P and an AGAUR (Generalitat de Catalunya) grant number 2017SGR-1276. The second author is partially supported by the Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación grant MTM2016-77278-P (FEDER) and grant MDM-2014-0445, the Agència de Gestió d’Ajuts Universitaris i de Recerca grant 2017SGR1617, and the H2020 European Research Council grant MSCA-RISE-2017-777911.
https://doi.org/10.14232/ejqtde.2020.1.1
030393
1417-3875
http://hdl.handle.net/10459.1/68155
eng
Bolyai Institute, University of Szeged
Hungarian Academy of Sciences
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-84383-P/ES/ORBITAS PERIODICAS E INTEGRABILIDAD EN SISTEMAS DIFERENCIALES CONTINUOS/
info:eu-repo/grantAgreement/MINECO//MTM2016-77278-P/ES/
Reproducció del document publicat a https://doi.org/10.14232/ejqtde.2020.1.1
Electronic Journal of Qualitative Theory of Differential Equations, 2020, núm. 1, p. 1-16
info:eu-repo/grantAgreement/EC/H2020/777911/EU/Dynamics
cc-by (c) Giné, Jaume et al., 2020
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Liouville integrability
Weierstrass integrability
Polynomial differential systems
Strongly formal Weierstrass non-integrability for polynomial differential systems in C2
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/675122023-04-26T12:35:19Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_44504
Dalfó, Cristina
Fiol Mora, Miguel Ángel
Sirán, Jozef
2019-11-11T12:14:53Z
2020-01-02T23:12:31Z
2019-01-02
2019-11-11T12:14:53Z
We present a method to derive the complete spectrum of the lift Γα of a base digraph Γ , with voltage assignment α on a (finite) group G. The method is based on assigning to Γ a quotient-like matrix whose entries are elements of the group algebra C[G] , which fully represents Γα . This allows us to derive the eigenvectors and eigenvalues of the lift in terms of those of the base digraph and the irreducible characters of G. Thus, our main theorem generalizes some previous results of Lovász and Babai concerning the spectra of Cayley digraphs.
The first author has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 734922. Research of the first two authors is supported by AGAUR under Project 2017SGR1087. The third author acknowledges support from the research Grants APVV 0136/12, APVV-15-0220, VEGA 1/0026/16, and VEGA 1/0142/17.
application/pdf
https://doi.org/10.1007/s10801-018-0862-y
028119
0925-9899
http://hdl.handle.net/10459.1/67512
eng
Springer
Versió postprint del document publicat a: https://doi.org/10.1007/s10801-018-0862-y
Journal of Algebraic Combinatorics, 2019, vol. 50, núm. 4, p. 419-426
info:eu-repo/grantAgreement/EC/H2020/734922/EU/CONNECT
(c) Springer Science+Business Media, LLC, part of Springer Nature, 2019
info:eu-repo/semantics/openAccess
Digraph
Adjacency matrix
Regular partition
Quotient digraph
Spectrum
Lifted digraph
The spectra of lifted digraphs
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
cristina.dalfo@matematica.udl.cat
Dalfó, Cristina
oai:repositori.udl.cat:10459.1/707892022-10-14T18:40:32Zcom_10459.1_186com_10459.1_2col_10459.1_311col_10459.1_49291
McCulloch, M. E.
Giné, Jaume
2021-03-18T08:42:53Z
2021-03-18T08:42:53Z
2020
In this paper we show that a model for inertial mass (quantised inertia) can be derived exactly and simply by assuming that the property
of inertia is caused by gradients in the energy in the Unruh radiation
field seen by a object, and that this energy is determined by the uncertainty principle, with the uncertainty in position being given by the
width of the Rindler horizons seen by the object. This is then an alternative derivation for quantised inertia which predicts galaxy rotation
without dark matter. It is also shown that quantised inertia predicts
an expression close to the simple empirical interpolation function used
in MoND.
The second author is partially supported by a MINECO/ FEDER grant number MTM2017-84383-P and an AGAUR (Generalitat de Catalunya) grant number 2017SGR-1276.
https://doi.org/10.12988/astp.2020.9416
030395
1313-1311
http://hdl.handle.net/10459.1/70789
eng
Hikari Ltd.
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MTM2017-84383-P/ES/ORBITAS PERIODICAS E INTEGRABILIDAD EN SISTEMAS DIFERENCIALES CONTINUOS/
Reproducció del document publicat a https://doi.org/10.12988/astp.2020.9416
Advanced Studies in Theoretical Physics, 2020, vol. 14, núm. 1, p. 1-8
cc-by-nc-nd (c) Hikari Ltd., 2020
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Quantised inertia
Uncertainty principle
Dark matter
Dark energy
Deriving quantised inertia using horizon-widths in the uncertainty principle
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
oai:repositori.udl.cat:10459.1/726202021-12-23T00:18:00Zcom_10459.1_186com_10459.1_2col_10459.1_311
López Masip, Susana-Clara
Muntaner Batle, Francesc Antoni
Prabu, M.
2021-12-22T09:39:30Z
2021-12-22T09:39:30Z
2020-10
A graph G is called edge-magic if there is a bijective function f from
the set of vertices and edges to the set {1, 2, . . . , |V (G)| + |E(G)|} such that the
sum f(x) + f(xy) + f(y) for any xy in E(G) is constant. Such a function is called
an edge-magic labeling of G and the constant is called the valence of f. An edgemagic
labeling with the extra property that f(V (G)) = {1, 2, . . . , |V (G)|} is called
super edge-magic. In this paper, we establish a relationship between the valences of
(super) edge-magic labelings of certain types of bipartite graphs and the existence of
a particular type of decompositions of such graphs.
The research conducted in this document by the first author has been supported symbolically by the Catalan Research Council under grant 2014SGR1147.
https://doi.org/10.1007/s40840-020-01038-y
2180-4206
0126-6705
http://hdl.handle.net/10459.1/72620
eng
Springer
Versió postprint del document publicat a https://doi.org/10.1007/s40840-020-01038-y
Bulletin of the Malaysian Mathematical Sciences Society, 2021, vol. 44, p. 1881–1892
© Malaysian Mathematical Sciences Society and Penerbit Universiti Sains Malaysia, 2020
info:eu-repo/semantics/openAccess
Edge-magic
Super edge-magic
Magic sum
Decompositions
(Di)graph decompositions and magic type labelings: a dual relation
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
dim///col_10459.1_311/100