Proxy dynamic delegation in grid gateway

Nowadays one of the main obstacles the research comes up against is the difficulty in accessing the required computational resources. Grid is able to offer the user a wide set of resources, even if they are often too hard to exploit for non expert end user. Use simplification has today become a common practice in the access and utilization of Cloud, Grid, and data center resources. With the launch of L-GRID gateway, we introduced a new way to deal with Grid portals. L-GRID is an extremely light portal developed in order to access the EGI Grid infrastructure via Web, allowing users to submit their jobs from whatever Web browser in a few minutes, without any knowledge about the underlying Grid infrastructure.Comment: 6 page

Cohomology of D-complex manifolds

In order to look for a well-behaved counterpart to Dolbeault cohomology in D-complex geometry, we study the de Rham cohomology of an almost D-complex manifold and its subgroups made up of the classes admitting invariant, respectively anti-invariant, representatives with respect to the almost D-complex structure, miming the theory introduced by Li and Zhang (2009) in [20] for almost complex manifolds. In particular, we prove that, on a 4-dimensional D-complex nilmanifold, such subgroups provide a decomposition at the level of the real second de Rham cohomology group. Moreover, we study deformations of D-complex structures, showing in particular that admitting D-Kähler structures is not a stable property under small deformations

Harmonic analysis of oscillators through standard numerical continuation tools

In this paper, we describe a numerical continuation method that enables harmonic analysis of nonlinear periodic oscillators. This method is formulated as a boundary value problem that can be readily implemented by resorting to a standard continuation package - without modification - such as AUTO, which we used. Our technique works for any kind of oscillator, including electronic, mechanical and biochemical systems. We provide two case studies. The first study concerns itself with the autonomous electronic oscillator known as the Colpitts oscillator, and the second one with a nonlinear damped oscillator, a non-autonomous mechanical oscillator. As shown in the case studies, the proposed technique can aid both the analysis and the design of the oscillators, by following curves for which a certain constraint, related to harmonic analysis, is fulfilled.Comment: 20 pages, 4 figure

Degree of non-K\"ahlerianity for 6-dimensional nilmanifolds

We use Bott-Chern cohomology to measure the non-K\"ahlerianity of 6-dimensional nilmanifolds endowed with the invariant complex structures in M. Ceballos, A. Otal, L. Ugarte, and R. Villacampa's classification, [Invariant Complex Structures on 6-Nilmanifolds: Classification, Fr\"olicher Spectral Sequence and Special Hermitian Metrics, J. Geom. Anal. (2014)]. We investigate the existence of pluriclosed metric in connection with such a classification

Triggering magnetar outbursts in 3D force-free simulations

In this letter, we present the first 3D force-free general relativity simulations of the magnetosphere dynamics related to the magnetar outburst/flare phenomenology. Starting from an initial dipole configuration, we adiabatically increase the helicity by twisting the footprints of a spot on the stellar surface and follow the succession of quasi-equilibrium states until a critical twist is reached. Twisting beyond that point triggers instabilities that results in the rapid expansion of magnetic field lines, followed by reconnection, as observed in previous axi-symmetric simulations. If the injection of magnetic helicity goes on, the process is recurrent, periodically releasing a similar amount of energy, of the order of a few % of the total magnetic energy. From our current distribution, we estimate the local temperature assuming that dissipation occurs mainly in the highly resistive outermost layer of the neutron star. We find that the temperature smoothly increases with injected twist, being larger for spots located in the tropical regions than in polar regions, and rather independent of their sizes. After the injection of helicity ceases, the magnetosphere relaxes to a new stable state, in which the persistent currents maintain the footprints area slightly hotter than before the onset of the instability.Comment: 6 pages, 5 figure

The surgical point of view about persistent air leaks: prevention first

No abstract availabl

Inbound open innovation and firm performance

A number of studies focus on the effects of open innovation on firm performance. However, in our view, previous contributions suffer from two main limitations: at first, there is still no homogeneity in the proposition of what "firm performance" is, according to extant literature. In addition, we see a heterogeneity of implications for the relationship between openness and performance, since there is still no consensus among authors on whether the relationship between openness and firm performance is positive, negative or non-linear.We address this issue through an empirical analysis of a cross-national unbalanced panel data of European firms listed in the five major European markets in the years 2008–2013. We seek to sort the impact of the level of inbound openness, derived by the amount invested in internal development versus the external acquisition of intangible assets on firm performance according to three dimensions: economic performance, measured as the amount of firm turnover; firm financial performance, measured with shares value; and human resources performance, measured as the level of employment.Results of panel data regression show that the effects of both internal development and external acquisition are positive and significant across different dimensions, but their output varies in terms in magnitude and distribution both variables are positively and significantly correlated with firm turnover, and that their effect on the latter is almost equal. In addition, we find that only internal development is positively and significantly correlated with the other two dimensions of performance, once we control for firm-specific time trends. Once we control for relative size of firms in the sample, we see that the effect of openness is more spread out across different class sizes, while the effect of internal development of intangibles influences the economic performance only for larger firms, and increases employment only for relatively smaller firms, while it has no effect on the financial side of performance. Resumen: Una serie de estudios centrados en los efectos de la innovación abierta en el desempeño de la empresa. Sin embargo, en nuestra opinión, las contribuciones anteriores sufren sobretodo de dos limitaciones principales: en principio, todavía, no tenemos ninguna homogeneidad en lo que podemos definir como "desempeño de la empresa" basándonos en los escritos existentes. Además, notamos una heterogeneidad de conceptos y opiniones distintas sobre la relación entre apertura y rendimiento, ya que todavía no hay ningún consenso entre los autores sobre si la relación entre la apertura y el desempeño de la empresa pueda ser algo positivo, negativo o discontinuo.Vamos así profundizando este tema a través de un análisis empírico basado en la comparación de los datos de las empresas europeas que figuran en los cinco principales mercados europeos en los años 2008-2013. Intentamos así de clasificar el impacto del nivel de apertura entrante, derivado del monto invertido para el desarrollo interno -por un lado- y la adquisición externa de bienes intangibles en el rendimiento de la empresa -en el otro- de acuerdo con tres dimensiones: Desempeño económico, medido como la cantidad de rotación de la empresa; desempeño financiero de la empresa, medido con el valor de las acciones; desempeño de los recursos humanos, medido como el nivel de empleo.Los resultados de la elaboración de los datos de nuestro panel muestran que los efectos tanto del desarrollo interno como de la adquisición externa son positivos y significativos en varias y distintas dimensiones, pero su producción puede variar en términos de cantidad y distribución. Ambas las variables se correlacionan positivamente y significativamente en cuanto a la rotación de la empresa y su efecto sobre el último es casi lo mismo. Además, encontramos que solo el desarrollo interno se correlaciona positivamente y significativamente con las otras dos dimensiones del desempeño de la empresa una vez que controlamos las tendencias de tiempo específicas de la empresa misma. Una vez que controlamos el tamaño relativo de las empresas consideradas, nos damos cuenta que el efecto de la apertura está más extendido en diferentes tamaños de clase, mientras que el efecto del desarrollo interno de intangibles influye en el rendimiento económico solo para las empresas más grandes y aumenta el empleo solo para las empresas relativamente más pequeñas; mientras que no tiene ningún efecto en el lado financiero de ningún tipo empresa. JEL classification: O320, O390, Códigos JEL: O320, O390, Keywords: Open innovation, Outside-in, Inbound, Performance, Palabras clave: Innovación abierta, "Afuera/Adentro", Entrante, Rendimient

Reti complesse e resistenze ai guasti

No abstract availabl