Note on improvement precision of recursive function simulation in floating point standard

An improvement on precision of recursive function simulation in IEEE floating point standard is presented. It is shown that the average of rounding towards negative infinite and rounding towards positive infinite yields a better result than the usual standard rounding to the nearest in the simulation of recursive functions. In general, the method improves one digit of precision and it has also been useful to avoid divergence from a correct stationary regime in the logistic map. Numerical studies are presented to illustrate the method.Comment: DINCON 2017 - Conferencia Brasileira de Dinamica, Controle e Aplicacoes - Sao Jose do Rio Preto - Brazil. 8 page

Strong evidences for a nonextensive behavior of the rotation period in Open Clusters

Time-dependent nonextensivity in a stellar astrophysical scenario combines nonextensive entropic indices $q_{K}$ derived from the modified Kawaler's parametrization, and $q$, obtained from rotational velocity distribution. These $q$'s are related through a heuristic single relation given by $q\approx q_{0}(1-\Delta t/q_{K})$, where $t$ is the cluster age. In a nonextensive scenario, these indices are quantities that measure the degree of nonextensivity present in the system. Recent studies reveal that the index $q$ is correlated to the formation rate of high-energy tails present in the distribution of rotation velocity. On the other hand, the index $q_{K}$ is determined by the stellar rotation-age relationship. This depends on the magnetic field configuration through the expression $q_{K}=1+4aN/3$, where $a$ and $N$ denote the saturation level of the star magnetic field and its topology, respectively. In the present study, we show that the connection $q-q_{K}$ is also consistent with 548 rotation period data for single main-sequence stars in 11 Open Clusters aged less than 1 Gyr. The value of $q_{K}\sim$ 2.5 from our unsaturated model shows that the mean magnetic field topology of these stars is slightly more complex than a purely radial field. Our results also suggest that stellar rotational braking behavior affects the degree of anti-correlation between $q$ and cluster age $t$. Finally, we suggest that stellar magnetic braking can be scaled by the entropic index $q$.Comment: 6 pages and 2 figures, accepted to EPL on October 17, 201

A nonextensive insight to the stellar initial mass function

the present paper, we propose that the stellar initial mass distributions as known as IMF are best fitted by $q$-Weibulls that emerge within nonextensive statistical mechanics. As a result, we show that the Salpeter's slope of $\sim$2.35 is replaced when a $q$-Weibull distribution is used. Our results point out that the nonextensive entropic index $q$ represents a new approach for understanding the process of the star-forming and evolution of massive stars.Comment: 5 pages, 2 figures, Accepted to EP

Metodología de evaluación continua en la asignatura de Fundamentos de Programación: un cambio de evaluación enfocado al desarrollo de competencias

El marco del Espacio Europeo de Educación Superior (EEES) y la implantación del Sistema de Crédito Europeo (ECTS) han motivado un cambio en el modelo educativo. De un modelo basado en clases magistrales se ha evolucionado hacia un modelo basado en el aprendizaje por competencias del alumnado. Esto implica un cambio en el sistema de evaluación. Este trabajo expone la experiencia negativa vivida el primer año de la asignatura de Fundamentos de la Programación (FP) en los nuevos Grados de Ingeniería Informática de la Escuela Técnica Superior de Ingeniería Informática (ETSII) de la Universidad de Sevilla (US). La experiencia negativa se produjo por una sobre-evaluación del alumnado fruto de una planificación de evaluación un tanto excesiva. Como consecuencia de esta experiencia negativa, se decidió realizar una nueva planificación de evaluación continua de competencias adquiridas. Esta planificación se está llevando a cabo en la actualidad y en este artículo presentamos las conclusiones parciales.SUMMARY -- The European Higher Education Area and the implantation of the European Credit Transfer System have promoted a change in the educational model and, hence, a change in the evaluation system. This paper describes the negative experience in the first year of the course Fundamentals of Programming in the new Computer Science Degrees at University of Seville. The negative experience has been an overevaluation of the students caused by an excessive evaluation planning. To overcome this negative experience, a new plan of continuous assessment of skills is planned. This plan is being implemented at present and the partial conclusions obtained are described in this paper.Peer Reviewe

Simulation of Chua's Circuit by Means of Interval Analysis

The Chua's circuit is a paradigm for nonlinear scientific studies. It is usually simulated by means of numerical methods under IEEE 754-2008 standard. Although the error propagation problem is well known, little attention has been given to the relationship between this error and inequalities presented in Chua's circuit model. Taking the average of round mode towards $+\infty$ and $-\infty$, we showed a qualitative change on the dynamics of Chua's circuit.Comment: 6th International Conference on Nonlinear Science and Complexity - S\~ao Jos\'e dos Campos, 2016, p. 1-