Departament de Matemàtiques
http://hdl.handle.net/2117/3917
Thu, 25 May 2017 12:02:54 GMT2017-05-25T12:02:54ZOn Noether's rationality problem for cyclic groups over Q
http://hdl.handle.net/2117/104804
On Noether's rationality problem for cyclic groups over Q
Plans Berenguer, Bernat
Let p be a prime number. Let C p , the cyclic group of order p , permute transitively a set of indeterminates f x 1 ;:::;x p g . We prove that the invariant eld Q ( x 1 ;:::;x p ) C p is rational over Q if and only if the ( p
Wed, 24 May 2017 08:11:05 GMThttp://hdl.handle.net/2117/1048042017-05-24T08:11:05ZPlans Berenguer, BernatLet p be a prime number. Let C p , the cyclic group of order p , permute transitively a set of indeterminates f x 1 ;:::;x p g . We prove that the invariant eld Q ( x 1 ;:::;x p ) C p is rational over Q if and only if the ( pAnalizing exact controllability of l-order linear ystems
http://hdl.handle.net/2117/104800
Analizing exact controllability of l-order linear ystems
García Planas, María Isabel
In recent years there has been growing interest in the descriptive analysis of l -order time invariant linear dynamical system x l = A l system x l = A l where A i are square complex matrices and x i denotes the i-th derivative of x. We are interested to mesure the minimum number of controls B that are needed in order to make
the system
Wed, 24 May 2017 06:07:45 GMThttp://hdl.handle.net/2117/1048002017-05-24T06:07:45ZGarcía Planas, María IsabelIn recent years there has been growing interest in the descriptive analysis of l -order time invariant linear dynamical system x l = A l system x l = A l where A i are square complex matrices and x i denotes the i-th derivative of x. We are interested to mesure the minimum number of controls B that are needed in order to make
the systemInfluence of admission marks on the academic performance of technical architecture students
http://hdl.handle.net/2117/104739
Influence of admission marks on the academic performance of technical architecture students
Gaspar Fàbregas, Kàtia; Núñez Andrés, María Amparo; Rodríguez Jordana, Juan; Jordana Riba, Francisco de Paula
Traditionally, students from higher training cycle and upper secondary school education access higher technical education
with a wide range of access marks in each group. The purpose of this article is to analyse how students’ backgrounds and
access marks really influence their success in the first academic year and further evolution to obtain the degree of Technical
Architecture.
To achieve this aim, the progress of students from different backgrounds was analysed for three academic years from
2002/2003 to 2004/2005 prior to the implementation of a curriculum adapted to the European Higher Education Area
(EHEA), so that the curriculum change does not introduce noise in the data. That involves 983 students in this study.
Moreover, most students in the new curriculum have not completed all the courses.
It was found that, once students had completed the first semester, a selection stage in the studies that were analysed, their
background did not influence their performance. However, it was also found that the access mark influenced both the mark
for the selection stage and academic performance until completion of the degree.
Tue, 23 May 2017 08:51:38 GMThttp://hdl.handle.net/2117/1047392017-05-23T08:51:38ZGaspar Fàbregas, KàtiaNúñez Andrés, María AmparoRodríguez Jordana, JuanJordana Riba, Francisco de PaulaTraditionally, students from higher training cycle and upper secondary school education access higher technical education
with a wide range of access marks in each group. The purpose of this article is to analyse how students’ backgrounds and
access marks really influence their success in the first academic year and further evolution to obtain the degree of Technical
Architecture.
To achieve this aim, the progress of students from different backgrounds was analysed for three academic years from
2002/2003 to 2004/2005 prior to the implementation of a curriculum adapted to the European Higher Education Area
(EHEA), so that the curriculum change does not introduce noise in the data. That involves 983 students in this study.
Moreover, most students in the new curriculum have not completed all the courses.
It was found that, once students had completed the first semester, a selection stage in the studies that were analysed, their
background did not influence their performance. However, it was also found that the access mark influenced both the mark
for the selection stage and academic performance until completion of the degree.A Classroom activity to work with real data and diverse strategies in order to build models with the help of the computer
http://hdl.handle.net/2117/104633
A Classroom activity to work with real data and diverse strategies in order to build models with the help of the computer
Ginovart Gisbert, Marta
Dealing with pseudo-mechanistic models, which are continuous and
empirical models where the parameters involved have a meaning according to the context where they are applied, has an added value. The aim of this study was to design a set of tasks to be performed with the help of the computer and implement them in the classroom in order to investigate a real data set with empirical models
and pseudo-mechanistic models. A framework showing different strategies to tackle these data, and how they generate a variety of plausible responses to the problem, was configured. The sequence and structure of these tasks jointly with the help of appropriate computer resources, according to the students ’perceptions, enhanced the understanding of the construction and use of these models
Fri, 19 May 2017 08:04:24 GMThttp://hdl.handle.net/2117/1046332017-05-19T08:04:24ZGinovart Gisbert, MartaDealing with pseudo-mechanistic models, which are continuous and
empirical models where the parameters involved have a meaning according to the context where they are applied, has an added value. The aim of this study was to design a set of tasks to be performed with the help of the computer and implement them in the classroom in order to investigate a real data set with empirical models
and pseudo-mechanistic models. A framework showing different strategies to tackle these data, and how they generate a variety of plausible responses to the problem, was configured. The sequence and structure of these tasks jointly with the help of appropriate computer resources, according to the students ’perceptions, enhanced the understanding of the construction and use of these modelsA new labeling construction from the -product
http://hdl.handle.net/2117/104632
A new labeling construction from the -product
López Masip, Susana Clara; Muntaner Batle, Francesc Antoni; Prabu, M.
The ¿h-product that is referred in the title was introduced in 2008 as a generalization of the Kronecker product of digraphs. Many relations among labelings have been obtained since then, always using as a second factor a family of super edge-magic graphs with equal order and size. In this paper, we introduce a new labeling construction by changing the role of the factors. Using this new construction the range of applications grows up considerably. In particular, we can increase the information about magic sums of cycles and crowns.
Fri, 19 May 2017 07:50:07 GMThttp://hdl.handle.net/2117/1046322017-05-19T07:50:07ZLópez Masip, Susana ClaraMuntaner Batle, Francesc AntoniPrabu, M.The ¿h-product that is referred in the title was introduced in 2008 as a generalization of the Kronecker product of digraphs. Many relations among labelings have been obtained since then, always using as a second factor a family of super edge-magic graphs with equal order and size. In this paper, we introduce a new labeling construction by changing the role of the factors. Using this new construction the range of applications grows up considerably. In particular, we can increase the information about magic sums of cycles and crowns.Using the multilinear extension to study some probabilistic power indices
http://hdl.handle.net/2117/104580
Using the multilinear extension to study some probabilistic power indices
Freixas Bosch, Josep; Pons Vallès, Montserrat
We consider binary voting systems modeled by a simple game, in which voters vote independently of each other, and the probability distribution over coalitions is known. The Owen’s multilinear extension of the simple game is used to improve the use and the computation of three indices defined in this model: the decisiveness index, which is an extension of the Banzhaf index, the success index, which is an extension of the Rae index, and the luckiness index. This approach leads us to prove new properties and inter-relations between these indices. In particular it is proved that the ordinal equivalence between success and decisiveness indices is achieved in any game if and only if the probability distribution is anonymous. In the anonymous case, the egalitarianism of the three indices is compared, and it is also proved that, for these distributions, decisiveness and success indices respect the strength of the seats, whereas luckiness reverses this order.
The final publication is available at Springer via http://dx.doi.org/10.1007/s10726-016-9514-6
Wed, 17 May 2017 14:32:45 GMThttp://hdl.handle.net/2117/1045802017-05-17T14:32:45ZFreixas Bosch, JosepPons Vallès, MontserratWe consider binary voting systems modeled by a simple game, in which voters vote independently of each other, and the probability distribution over coalitions is known. The Owen’s multilinear extension of the simple game is used to improve the use and the computation of three indices defined in this model: the decisiveness index, which is an extension of the Banzhaf index, the success index, which is an extension of the Rae index, and the luckiness index. This approach leads us to prove new properties and inter-relations between these indices. In particular it is proved that the ordinal equivalence between success and decisiveness indices is achieved in any game if and only if the probability distribution is anonymous. In the anonymous case, the egalitarianism of the three indices is compared, and it is also proved that, for these distributions, decisiveness and success indices respect the strength of the seats, whereas luckiness reverses this order.Arnold diffusion for a complete family of perturbations
http://hdl.handle.net/2117/104532
Arnold diffusion for a complete family of perturbations
Delshams Valdés, Amadeu; Gonçalves Schaefer, Rodrigo
In this work we illustrate the Arnold diffusion in a concrete example — the a priori unstable Hamiltonian system of 2 + 1/2 degrees of freedom H(p, q, I, f, s) = p2/2+ cos q - 1 + I2/2 + h(q, f, s; e) — proving that for any small periodic perturbation of the form h(q, f, s; e) = e cos q (a00 + a10 cosf + a01 cos s) (a10a01 ¿ 0) there is global instability for the action. For the proof we apply a geometrical mechanism based on the so-called scattering map. This work has the following structure: In the first stage, for a more restricted case (I* ~ p/2µ, µ = a10/a01), we use only one scattering map, with a special property: the existence of simple paths of diffusion called highways. Later, in the general case we combine a scattering map with the inner map (inner dynamics) to prove the more general result (the existence of instability for any µ). The bifurcations of the scattering map are also studied as a function of µ. Finally, we give an estimate for the time of diffusion, and we show that this time is primarily the time spent under the scattering map.
Wed, 17 May 2017 07:57:57 GMThttp://hdl.handle.net/2117/1045322017-05-17T07:57:57ZDelshams Valdés, AmadeuGonçalves Schaefer, RodrigoIn this work we illustrate the Arnold diffusion in a concrete example — the a priori unstable Hamiltonian system of 2 + 1/2 degrees of freedom H(p, q, I, f, s) = p2/2+ cos q - 1 + I2/2 + h(q, f, s; e) — proving that for any small periodic perturbation of the form h(q, f, s; e) = e cos q (a00 + a10 cosf + a01 cos s) (a10a01 ¿ 0) there is global instability for the action. For the proof we apply a geometrical mechanism based on the so-called scattering map. This work has the following structure: In the first stage, for a more restricted case (I* ~ p/2µ, µ = a10/a01), we use only one scattering map, with a special property: the existence of simple paths of diffusion called highways. Later, in the general case we combine a scattering map with the inner map (inner dynamics) to prove the more general result (the existence of instability for any µ). The bifurcations of the scattering map are also studied as a function of µ. Finally, we give an estimate for the time of diffusion, and we show that this time is primarily the time spent under the scattering map.A well-posed problem for the three-dual-phase-lag heat conduction
http://hdl.handle.net/2117/104492
A well-posed problem for the three-dual-phase-lag heat conduction
Quintanilla de Latorre, Ramón
Tue, 16 May 2017 10:32:21 GMThttp://hdl.handle.net/2117/1044922017-05-16T10:32:21ZQuintanilla de Latorre, RamónReal time global ionospheric maps: a low latency alternative to traditional GIMs
http://hdl.handle.net/2117/104472
Real time global ionospheric maps: a low latency alternative to traditional GIMs
Roma Dollase, David; Hernández Pajares, Manuel; García Rigo, Alberto; Laurichesse, Denis; Schmidt, Michael; Erdogan, Eren; Yuan, Yunbin; Li, Zishen; Gómez-Cama, José Ma.; Krankowski, Andrzej
Since the late nineties different entities have been generating and distributing Global Ionospheric Maps (GIMs). In this time, multiple new application have arisen from the determination of electron content distribution and time evolution at global scale: from the more direct correction used by GNSS users up to measurement of solar EUV flux rate during solar flares, at global scale (Singh et al 2015). Moreover specific applications requiring precise real-time positioning and potential detection of tsunamis at regional and continental scales (Galvan et al 2011) are also active fields of work. However, the latency to access the GNSS data and the computational time was too high to make real time GIMs. Nowadays thanks to the internet, which allows having real time access to permanent GNSS receiver’s raw data, the maturity of
the ionospheric modelling techniques and the computational power of modern computers we are able to compute different real-time ionospheric products. In this poster we compare six different products: three real-time from CAS (aoeg), CNES (cnsg) and UPC (urtg); one near real time from TUM (dgfi) and two traditional GIMs for reference, from UPC (uqrg) and IGS (igs).
Tue, 16 May 2017 08:11:54 GMThttp://hdl.handle.net/2117/1044722017-05-16T08:11:54ZRoma Dollase, DavidHernández Pajares, ManuelGarcía Rigo, AlbertoLaurichesse, DenisSchmidt, MichaelErdogan, ErenYuan, YunbinLi, ZishenGómez-Cama, José Ma.Krankowski, AndrzejSince the late nineties different entities have been generating and distributing Global Ionospheric Maps (GIMs). In this time, multiple new application have arisen from the determination of electron content distribution and time evolution at global scale: from the more direct correction used by GNSS users up to measurement of solar EUV flux rate during solar flares, at global scale (Singh et al 2015). Moreover specific applications requiring precise real-time positioning and potential detection of tsunamis at regional and continental scales (Galvan et al 2011) are also active fields of work. However, the latency to access the GNSS data and the computational time was too high to make real time GIMs. Nowadays thanks to the internet, which allows having real time access to permanent GNSS receiver’s raw data, the maturity of
the ionospheric modelling techniques and the computational power of modern computers we are able to compute different real-time ionospheric products. In this poster we compare six different products: three real-time from CAS (aoeg), CNES (cnsg) and UPC (urtg); one near real time from TUM (dgfi) and two traditional GIMs for reference, from UPC (uqrg) and IGS (igs).Locating-dominating partitions in graphs
http://hdl.handle.net/2117/104422
Locating-dominating partitions in graphs
Pelayo Melero, Ignacio Manuel; Hernando Martín, María del Carmen; Mora Giné, Mercè
Let G = (V, E) be a connected graph of order n. Let ¿ = {S1, . . . , Sk} be
a partition of V . Let r(u|¿) denote the vector of distances between a vertex
v ¿ V and the elements of ¿, that is, r(v, ¿) = (d(v, S1), . . . , d(v, Sk)). The
partition ¿ is called a locating partition of G if, for every pair of distinct
vertices u, v ¿ V , r(u, ¿) 6= r(v, ¿). A locating partition ¿ is called metriclocating-dominating partition (an MLD-partition for short) of G if it is also dominating,
Mon, 15 May 2017 12:02:03 GMThttp://hdl.handle.net/2117/1044222017-05-15T12:02:03ZPelayo Melero, Ignacio ManuelHernando Martín, María del CarmenMora Giné, MercèLet G = (V, E) be a connected graph of order n. Let ¿ = {S1, . . . , Sk} be
a partition of V . Let r(u|¿) denote the vector of distances between a vertex
v ¿ V and the elements of ¿, that is, r(v, ¿) = (d(v, S1), . . . , d(v, Sk)). The
partition ¿ is called a locating partition of G if, for every pair of distinct
vertices u, v ¿ V , r(u, ¿) 6= r(v, ¿). A locating partition ¿ is called metriclocating-dominating partition (an MLD-partition for short) of G if it is also dominating,