948 resultados para embedded linux, ISO 14443


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En aquests últims anys, són moltes les empreses que han optat per la utilització de sistemes de gestió normalitzats, per a garantir la rendibilitat i fiabilitat dels resultats de la implantació del sistema de gestió en qüestió. A la dècada dels 90 va ser quan la implantació de sistemes de gestió va començar a ser important en la majoria de sectors econòmics. L’evolució en els sistemes de gestió a trets generals va iniciar-se primerament en l’àmbit de la qualitat, seguidament en la gestió ambiental i en última instància en la prevenció de riscos laborals. Aquests tres tipus de sistemes de gestió, en els últims anys s’han anat integrant, de manera que s’han reduït els recursos i els esforços emprats en la gestió, millorant significativament l’eficàcia i l’eficiència d’aquests sistemes. L’objectiu principal que persegueix aquest projecte, és definir un sistema de gestió que permeti a l’empresa conduir les seves activitats de forma simplificada i ordenada, i que alhora faciliti la informació necessària per a corregir i millorar les activitats. Un altre objectiu que pretén aconseguir aquest projecte, és el de dissenyar un SGI que aprofiti les sinèrgies generades en els diferents àmbits de la pròpia empresa i fomenti les interaccions entre els diferents nivells de l’organització. En conseqüència, millorarà de forma important els fluxos d’informació dins de l’empresa minimitzant els esforços i la pèrdua d’informació. El mètode escollit per a la implantació del SGI, ha estat la Gestió per Processos, la qual es basa en la definició i seguiment dels processos de l’empresa, partint de les necessitats del client i acabant quan aquestes estan satisfetes. En conclusió, a la finalització del present projecte s’obtindrà un SGI, amb tots els processos de l’empresa definits i implantats, que doni compliment a les normes UNEEN-ISO 9001:00, UNE-EN-ISO 14001:04 i OHSAS 18001:07. Aquest SGI, que s’ha realitzat des d’un punt de vista documental i teòric, suposarà una millora de l’eficàcia operativa dels processos i una important millora competitiva de l’empresa.

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El presente trabajo permite conocer el proceso de implantación de un sistema de gestión de seguridad de la información SGSI en una organización perteneciente al sector financiero y los resultados asociados a dicha implantación.

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El proyecto trata sobre la migración de sistemas a plataformas GNU/Linux de la empresa Desarrollos inteligentes, dedicada a la creación de software.

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[eng] ISO standard 9001 is one of a set of management tools that libraries have adopted in recent years. This article focuses on libraries in higher education institutions that have received ISO certification of their quality management systems (ISO standard 9001:2000). We examine their reasons for seeking certification and the advantages and difficulties they have encountered in applying this ISO standard. Finally, we consider the future prospects of ISO standard 9001 in university libraries.

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[eng] ISO standard 9001 is one of a set of management tools that libraries have adopted in recent years. This article focuses on libraries in higher education institutions that have received ISO certification of their quality management systems (ISO standard 9001:2000). We examine their reasons for seeking certification and the advantages and difficulties they have encountered in applying this ISO standard. Finally, we consider the future prospects of ISO standard 9001 in university libraries.

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[eng] ISO standard 9001 is one of a set of management tools that libraries have adopted in recent years. This article focuses on libraries in higher education institutions that have received ISO certification of their quality management systems (ISO standard 9001:2000). We examine their reasons for seeking certification and the advantages and difficulties they have encountered in applying this ISO standard. Finally, we consider the future prospects of ISO standard 9001 in university libraries.

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Tractography algorithms provide us with the ability to non-invasively reconstruct fiber pathways in the white matter (WM) by exploiting the directional information described with diffusion magnetic resonance. These methods could be divided into two major classes, local and global. Local methods reconstruct each fiber tract iteratively by considering only directional information at the voxel level and its neighborhood. Global methods, on the other hand, reconstruct all the fiber tracts of the whole brain simultaneously by solving a global energy minimization problem. The latter have shown improvements compared to previous techniques but these algorithms still suffer from an important shortcoming that is crucial in the context of brain connectivity analyses. As no anatomical priors are usually considered during the reconstruction process, the recovered fiber tracts are not guaranteed to connect cortical regions and, as a matter of fact, most of them stop prematurely in the WM; this violates important properties of neural connections, which are known to originate in the gray matter (GM) and develop in the WM. Hence, this shortcoming poses serious limitations for the use of these techniques for the assessment of the structural connectivity between brain regions and, de facto, it can potentially bias any subsequent analysis. Moreover, the estimated tracts are not quantitative, every fiber contributes with the same weight toward the predicted diffusion signal. In this work, we propose a novel approach for global tractography that is specifically designed for connectivity analysis applications which: (i) explicitly enforces anatomical priors of the tracts in the optimization and (ii) considers the effective contribution of each of them, i.e., volume, to the acquired diffusion magnetic resonance imaging (MRI) image. We evaluated our approach on both a realistic diffusion MRI phantom and in vivo data, and also compared its performance to existing tractography algorithms.

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We report on the study and modeling of the structural and optical properties of rib-loaded waveguides working in the 600-900-nm spectral range. A Si nanocrystal (Si-nc) rich SiO2 layer with nominal Si excess ranging from 10% to 20% was produced by quadrupole ion implantation of Si into thermal SiO2 formed on a silicon substrate. Si-ncs were precipitated by annealing at 1100°C, forming a 0.4-um-thick core layer in the waveguide. The Si content, the Si-nc density and size, the Si-nc emission, and the active layer effective refractive index were determined by dedicated experiments using x-ray photoelectron spectroscopy, Raman spectroscopy, energy-filtered transmission electron microscopy, photoluminescence and m-lines spectroscopy. Rib-loaded waveguides were fabricated by photolithographic and reactive ion etching processes, with patterned rib widths ranging from 1¿to¿8¿¿m. Light propagation in the waveguide was observed and losses of 11dB/cm at 633 and 780 nm were measured, modeled and interpreted.

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he complex refractive index of SiO2 layers containing Si nanoclusters (Si-nc) has been measured by spectroscopic ellipsometry in the range from 1.5 to 5.0 eV. It has been correlated with the amount of Si excess accurately measured by x-ray photoelectron spectroscopy and the nanocluster size determined by energy-filtered transmission electron microscopy. The Si-nc embedded in SiO2 have been produced by a fourfold Si+ ion implantation, providing uniform Si excess aimed at a reliable ellipsometric modeling. The complex refractive index of the Si-nc phase has been calculated by the application of the Bruggeman effective-medium approximation to the composite media. The characteristic resonances of the refractive index and extinction coefficient of bulk Si vanish out in Si-nc. In agreement with theoretical simulations, a significant reduction of the refractive index of Si-nc is observed, in comparison with bulk and amorphous silicon. The knowledge of the optical properties of these composite layers is crucial for the realization of Si-based waveguides and light-emitting devices.

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We demonstrate that thickness, optical constants, and details of the multilayer stack, together with the detection setting, strongly influence the photoluminescence spectra of Si nanocrystals embedded in SiO2. Due to multiple reflections of the visible light against the opaque silicon substrate, an interference pattern is built inside the oxide layer, which is responsible for the modifications in the measured spectra. This interference effect is complicated by the depth dependence of (i) the intensity of the excitation laser and (ii) the concentration of the emitting nanocrystals. These variations can give rise to apparent features in the recorded spectra, such as peak shifts, satellite shoulders, and even splittings, which can be mistaken as intrinsic material features. Thus, they can give rise to an erroneous attribution of optical bands or estimate of the average particle size, while they are only optical-geometrical artifacts. We have analyzed these effects as a function of material composition (Si excess fraction) and thickness, and also evaluated how the geometry of the detection setup affects the measurements. To correct the experimental photoluminescence spectra and extract the true spectral shape of the emission from Si nanocrystals, we have developed an algorithm based on a modulation function, which depends on both the multilayer sequence and the experimental configuration. This procedure can be easily extended to other heterogeneous systems.

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The correlation between the structural (average size and density) and optoelectronic properties [band gap and photoluminescence (PL)] of Si nanocrystals embedded in SiO2 is among the essential factors in understanding their emission mechanism. This correlation has been difficult to establish in the past due to the lack of reliable methods for measuring the size distribution of nanocrystals from electron microscopy, mainly because of the insufficient contrast between Si and SiO2. With this aim, we have recently developed a successful method for imaging Si nanocrystals in SiO2 matrices. This is done by using high-resolution electron microscopy in conjunction with conventional electron microscopy in dark field conditions. Then, by varying the time of annealing in a large time scale we have been able to track the nucleation, pure growth, and ripening stages of the nanocrystal population. The nucleation and pure growth stages are almost completed after a few minutes of annealing time at 1100°C in N2 and afterward the ensemble undergoes an asymptotic ripening process. In contrast, the PL intensity steadily increases and reaches saturation after 3-4 h of annealing at 1100°C. Forming gas postannealing considerably enhances the PL intensity but only for samples annealed previously in less time than that needed for PL saturation. The effects of forming gas are reversible and do not modify the spectral shape of the PL emission. The PL intensity shows at all times an inverse correlation with the amount of Pb paramagnetic centers at the Si-SiO2 nanocrystal-matrix interfaces, which have been measured by electron spin resonance. Consequently, the Pb centers or other centers associated with them are interfacial nonradiative channels for recombination and the emission yield largely depends on the interface passivation. We have correlated as well the average size of the nanocrystals with their optical band gap and PL emission energy. The band gap and emission energy shift to the blue as the nanocrystal size shrinks, in agreement with models based on quantum confinement. As a main result, we have found that the Stokes shift is independent of the average size of nanocrystals and has a constant value of 0.26±0.03 eV, which is almost twice the energy of the Si¿O vibration. This finding suggests that among the possible channels for radiative recombination, the dominant one for Si nanocrystals embedded in SiO2 is a fundamental transition spatially located at the Si¿SiO2 interface with the assistance of a local Si-O vibration.

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We present computational approaches as alternatives to a recent microwave cavity experiment by S. Sridhar and A. Kudrolli [Phys. Rev. Lett. 72, 2175 (1994)] on isospectral cavities built from triangles. A straightforward proof of isospectrality is given, based on the mode-matching method. Our results show that the experiment is accurate to 0.3% for the first 25 states. The level statistics resemble those of a Gaussian orthogonal ensemble when the integrable part of the spectrum is removed.

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