Departament de Matemàtiques
http://hdl.handle.net/2117/3917
2016-10-22T06:03:52ZCombinatorial recurrences and linear difference equations
http://hdl.handle.net/2117/90923
Combinatorial recurrences and linear difference equations
Jiménez Jiménez, M. Jose; Encinas Bachiller, Andrés Marcos
In this work we introduce the triangular arrays of depth greater than 1 given by linear recurrences, that generalize some well known recurrences that appear in enumerative combinatorics. In particular, we focussed on triangular arrays of depth 2, since they are closely related with the solution of linear three–terms recurrences. We show through some simple examples how this triangular arrays appear as essential components in the expression of some classical orthogonal polynomials and combinatorial numbers
2016-10-20T11:43:50ZJiménez Jiménez, M. JoseEncinas Bachiller, Andrés MarcosIn this work we introduce the triangular arrays of depth greater than 1 given by linear recurrences, that generalize some well known recurrences that appear in enumerative combinatorics. In particular, we focussed on triangular arrays of depth 2, since they are closely related with the solution of linear three–terms recurrences. We show through some simple examples how this triangular arrays appear as essential components in the expression of some classical orthogonal polynomials and combinatorial numbersStability of Markov jump systems with quadratic terms and its application to RLC circuits
http://hdl.handle.net/2117/90847
Stability of Markov jump systems with quadratic terms and its application to RLC circuits
Vargas, Alessandro; Pujol Vázquez, Gisela; Acho Zuppa, Leonardo
The paper presents results for the second moment stability of continuous-time Markov jump systems with quadratic terms, aiming for engineering applications. Quadratic terms stem from physical constraints in applications, as in electronic circuits based on resistor (R), inductor (L), and capacitor (C). In the paper, an RLC circuit supplied a load driven by jumps produced by a Markov chain—the RLC circuit used sensors that measured the quadratic of electrical currents and voltages. Our result was then used to design a stabilizing controller for the RLC circuit with measurements based on that quadratic terms. The experimental data confirm the usefulness of our approach.
2016-10-18T11:55:38ZVargas, AlessandroPujol Vázquez, GiselaAcho Zuppa, LeonardoThe paper presents results for the second moment stability of continuous-time Markov jump systems with quadratic terms, aiming for engineering applications. Quadratic terms stem from physical constraints in applications, as in electronic circuits based on resistor (R), inductor (L), and capacitor (C). In the paper, an RLC circuit supplied a load driven by jumps produced by a Markov chain—the RLC circuit used sensors that measured the quadratic of electrical currents and voltages. Our result was then used to design a stabilizing controller for the RLC circuit with measurements based on that quadratic terms. The experimental data confirm the usefulness of our approach.Effects of thermoregulation on human sleep patterns: A mathematical model of sleep-wake cycles with REM-NREM subcircuit
http://hdl.handle.net/2117/90841
Effects of thermoregulation on human sleep patterns: A mathematical model of sleep-wake cycles with REM-NREM subcircuit
Bañuelos, Selenne; Best, Janet; Huguet Casades, Gemma; Prieto-Langarica, Alicia; Pyzza, Pamela; Schmidt, Markus; Wilson, Shelby
In this paper we construct a mathematical model of human sleep/wake regulation with thermoregulation and temperature e ects. Simulations of this model show features previously presented in experimental data such as elongation of duration and number of REM bouts across the night as well as the appearance of awakenings due to deviations in body temperature from thermoneutrality. This model helps to demonstrate the importance of temperature in the sleep cycle. Further modi cations of the model to include more temperature e ects on other aspects of sleep regulation such as sleep and REM latency are discussed
2016-10-18T10:52:04ZBañuelos, SelenneBest, JanetHuguet Casades, GemmaPrieto-Langarica, AliciaPyzza, PamelaSchmidt, MarkusWilson, ShelbyIn this paper we construct a mathematical model of human sleep/wake regulation with thermoregulation and temperature e ects. Simulations of this model show features previously presented in experimental data such as elongation of duration and number of REM bouts across the night as well as the appearance of awakenings due to deviations in body temperature from thermoneutrality. This model helps to demonstrate the importance of temperature in the sleep cycle. Further modi cations of the model to include more temperature e ects on other aspects of sleep regulation such as sleep and REM latency are discussedHybrid cell centred/vertex model for large tissue deformations
http://hdl.handle.net/2117/90839
Hybrid cell centred/vertex model for large tissue deformations
Muñoz Romero, José; Mosafa, Payman; Mao, Yanlan; Tetley, Rob; Asadipour, Nina; Rodríguez Ferran, Antonio
Macroscopic deformations in embryonic soft tissues are due to the intra-cellular remodelling
and cell intercalation. We here present a computational approach that can handle the
two types of deformations, and also take into account the active cell response. The model resorts
to cell-centred techniques, where particles represent cell nuclei, and to vertex models, where the
vertices represent cell boundaries. This hybrid approach allows to consider separately intracellular
and inter-cellular forces, and at the same time impose cell incompressibility.
In the proposed model, the cell boundaries (defined by vertices) and cell nuclei (or cellcentres)
networks are coupled through an interpolation scheme, which is eventually relaxed in
order to smooth the cell boundaries. We show that this coupling between the two networks
modifies the equilibrium equations and stabilises the vertex network. Incompressibility is implemented
through a penalty method. The resulting model can be implemented in two- and
three-dimensions, and is complemented with active rheological models.
We apply the model to simulate the stretching and relaxation of cell monolayers, and to
simulate wound healing process in the wing disc of Drosophila fly embryo. We show that the
numerical results agree with the experimental measurements.
2016-10-18T10:43:30ZMuñoz Romero, JoséMosafa, PaymanMao, YanlanTetley, RobAsadipour, NinaRodríguez Ferran, AntonioMacroscopic deformations in embryonic soft tissues are due to the intra-cellular remodelling
and cell intercalation. We here present a computational approach that can handle the
two types of deformations, and also take into account the active cell response. The model resorts
to cell-centred techniques, where particles represent cell nuclei, and to vertex models, where the
vertices represent cell boundaries. This hybrid approach allows to consider separately intracellular
and inter-cellular forces, and at the same time impose cell incompressibility.
In the proposed model, the cell boundaries (defined by vertices) and cell nuclei (or cellcentres)
networks are coupled through an interpolation scheme, which is eventually relaxed in
order to smooth the cell boundaries. We show that this coupling between the two networks
modifies the equilibrium equations and stabilises the vertex network. Incompressibility is implemented
through a penalty method. The resulting model can be implemented in two- and
three-dimensions, and is complemented with active rheological models.
We apply the model to simulate the stretching and relaxation of cell monolayers, and to
simulate wound healing process in the wing disc of Drosophila fly embryo. We show that the
numerical results agree with the experimental measurements.On the Caginalp phase-field systems with two temperatures and the Maxwell–Cattaneo law
http://hdl.handle.net/2117/90781
On the Caginalp phase-field systems with two temperatures and the Maxwell–Cattaneo law
Miranville, Alain; Quintanilla de Latorre, Ramón
Our aim in this paper is to study generalizations of the nonconserved and conserved Caginalp phase-¿eld systems based on the Maxwell–Cattaneo law with two temperatures for heat conduction. In particular, we obtain well-posedness results and study the dissipativity of the associated solution operators.
This is the peer reviewed version of the following article: Miranville, A., and Quintanilla, R. (2016) On the Caginalp phase-field systems with two temperatures and the Maxwell–Cattaneo law. Math. Meth. Appl. Sci., 39: 4385–4397, which has been published in final form at http://dx.doi.org/10.1002/mma.3867. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving
2016-10-14T10:40:07ZMiranville, AlainQuintanilla de Latorre, RamónOur aim in this paper is to study generalizations of the nonconserved and conserved Caginalp phase-¿eld systems based on the Maxwell–Cattaneo law with two temperatures for heat conduction. In particular, we obtain well-posedness results and study the dissipativity of the associated solution operators.Continua of periodic points for planar integrable rational maps
http://hdl.handle.net/2117/90779
Continua of periodic points for planar integrable rational maps
Gasull Embid, Armengol; Llorens, Mireia; Mañosa Fernández, Víctor
We present three alternative methodologies to find continua of periodic points with a prescribed period for rational maps having rational first integrals. The first two have been already used by other authors and apply when the maps are birational and the generic level sets of the corresponding first integrals have either genus 0 or 1. As far as we know, the third one is new and it works for rational maps without imposing topological properties to the invariant level sets. It is based on a computational point of view, and relies on the use of resultants in a suitable setting. We apply them to several examples, including the 2-periodic Lyness composition maps and some of the celebrated McMillan–Gumovski–Mira maps
2016-10-14T08:39:04ZGasull Embid, ArmengolLlorens, MireiaMañosa Fernández, VíctorWe present three alternative methodologies to find continua of periodic points with a prescribed period for rational maps having rational first integrals. The first two have been already used by other authors and apply when the maps are birational and the generic level sets of the corresponding first integrals have either genus 0 or 1. As far as we know, the third one is new and it works for rational maps without imposing topological properties to the invariant level sets. It is based on a computational point of view, and relies on the use of resultants in a suitable setting. We apply them to several examples, including the 2-periodic Lyness composition maps and some of the celebrated McMillan–Gumovski–Mira mapsAveraged dynamics of a coupled-inductor boost converter under sliding mode control using a piecewise linear complementarity model
http://hdl.handle.net/2117/90749
Averaged dynamics of a coupled-inductor boost converter under sliding mode control using a piecewise linear complementarity model
Carrero Candelas, Niliana Andreina; Batlle Arnau, Carles; Fossas Colet, Enric
An averaged model of a coupled-inductor boost converter using the piecewise complementarity model of the converter under sliding motions is obtained. The model takes into account the idealized voltage–current characteristic of passive switches (diodes) present in the converter. Because of its lower complexity, the averaged model is more suitable for control design purposes when compared with the linear complementarity systems (LCS) model of the converter. The dynamic performance of the LCS model and the averaged models of the converter are validated through computer simulations using Matlab.
2016-10-13T13:52:49ZCarrero Candelas, Niliana AndreinaBatlle Arnau, CarlesFossas Colet, EnricAn averaged model of a coupled-inductor boost converter using the piecewise complementarity model of the converter under sliding motions is obtained. The model takes into account the idealized voltage–current characteristic of passive switches (diodes) present in the converter. Because of its lower complexity, the averaged model is more suitable for control design purposes when compared with the linear complementarity systems (LCS) model of the converter. The dynamic performance of the LCS model and the averaged models of the converter are validated through computer simulations using Matlab.Adaptividade e estimativas de erro orientadas por metas aplicadas a um benchmark test de propagação de onda
http://hdl.handle.net/2117/90741
Adaptividade e estimativas de erro orientadas por metas aplicadas a um benchmark test de propagação de onda
Steffens, Lindaura; Díez, Pedro; Parés Mariné, Núria; Alves, Marcelo Krajnc
O objetivo deste artigo é estudar a eficiência e a robustez de técnicas adaptativas e estimativas de erro orientadas por metas para um benchmark test. As técnicas utilizadas aqui são baseadas em um simples pós-processo das aproximacções de elementos finitos. As estimativas de erro orientadas por metas são obtidas por analisar o problema direto e um problema auxiliar, o qual está relacionado com a quantidade de interesse específico. O procedimento proposto é válido para quantidades lineares e não-lineares. Além disso, são discutidas diferentes representacções para o erro e é analisada a influência do erro de dispersão. Os resultados numéricos mostram que as estimativas de erro fornecem boas aproximações ao erro real e que a técnica de refino adaptativo proposta conduz a uma redução mais rápida do erro.
2016-10-13T12:42:25ZSteffens, LindauraDíez, PedroParés Mariné, NúriaAlves, Marcelo KrajncO objetivo deste artigo é estudar a eficiência e a robustez de técnicas adaptativas e estimativas de erro orientadas por metas para um benchmark test. As técnicas utilizadas aqui são baseadas em um simples pós-processo das aproximacções de elementos finitos. As estimativas de erro orientadas por metas são obtidas por analisar o problema direto e um problema auxiliar, o qual está relacionado com a quantidade de interesse específico. O procedimento proposto é válido para quantidades lineares e não-lineares. Além disso, são discutidas diferentes representacções para o erro e é analisada a influência do erro de dispersão. Os resultados numéricos mostram que as estimativas de erro fornecem boas aproximações ao erro real e que a técnica de refino adaptativo proposta conduz a uma redução mais rápida do erro.Lie Symmetries and non-integrability of maps: the Cohen map case.
http://hdl.handle.net/2117/90740
Lie Symmetries and non-integrability of maps: the Cohen map case.
Mañosa Fernández, Víctor
Slides of the invited lecture at IV Symposium on Planar Vector Fields, Lleida 2016
2016-10-13T12:40:07ZMañosa Fernández, VíctorExact consensus controllability of multi-agent linear systems
http://hdl.handle.net/2117/90633
Exact consensus controllability of multi-agent linear systems
García Planas, María Isabel
In this paper we study the exact controllability of multi-agent linear systems, in which all agents have an identical linear dynamic mode that can be in any order.; In this paper we study the exact controllability of multi-agent linear systems, in which all agents have an identical linear dynamic mode that can be in any order
Multi-agent systems, consensus, controllability, exact consensus controllability.
2016-10-10T12:17:40ZGarcía Planas, María IsabelIn this paper we study the exact controllability of multi-agent linear systems, in which all agents have an identical linear dynamic mode that can be in any order.
In this paper we study the exact controllability of multi-agent linear systems, in which all agents have an identical linear dynamic mode that can be in any order