223 research outputs found

    The Fog Makes Sense: Enabling Social Sensing Services With Limited Internet Connectivity

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    Social sensing services use humans as sensor carriers, sensor operators and sensors themselves in order to provide situation-awareness to applications. This promises to provide a multitude of benefits to the users, for example in the management of natural disasters or in community empowerment. However, current social sensing services depend on Internet connectivity since the services are deployed on central Cloud platforms. In many circumstances, Internet connectivity is constrained, for instance when a natural disaster causes Internet outages or when people do not have Internet access due to economical reasons. In this paper, we propose the emerging Fog Computing infrastructure to become a key-enabler of social sensing services in situations of constrained Internet connectivity. To this end, we develop a generic architecture and API of Fog-enabled social sensing services. We exemplify the usage of the proposed social sensing architecture on a number of concrete use cases from two different scenarios.Comment: Ruben Mayer, Harshit Gupta, Enrique Saurez, and Umakishore Ramachandran. 2017. The Fog Makes Sense: Enabling Social Sensing Services With Limited Internet Connectivity. In Proceedings of The 2nd International Workshop on Social Sensing, Pittsburgh, PA, USA, April 21 2017 (SocialSens'17), 6 page

    PEASE G.Y., Franklin (ed.) Collaquas 1, PontificiaUniversidad Católica del Perú. FondoEditorial, Lima 1977, 487 págs.

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    Formación de la capacidad cognitiva en México: impactos económicos y de políticas públicas

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    A stochastic frontier model is used to make a comparative estimate of the production of cognitive capacity and stature in the family, using data from the Mexican survey ENNVIH 2002. We find that child cognitive capacity is associated with the economic status of the family, public policy variables and descriptors of the local economy. Economic and public policy inputs intervene more efficiently for the formation of cognitive capacity that for stature. The application of public programs with the objective of promoting cognitive capacity could be effective.cognitive ability, intergenerational inequality, poverty, public policy.

    Low-mass galaxy formation in cosmological AMR simulations: the effects of varying the sub-grid physics parameters

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    We present numerical simulations aimed at exploring the effects of varying the sub-grid physics parameters on the evolution and the properties of the galaxy formed in a low-mass dark matter halo (~7 times 10^10 Msun/h at redshift z=0). The simulations are run within a cosmological setting with a nominal resolution of 218 pc comoving and are stopped at z = 0.43. In all of our simulations, an extended old/intermediate-age stellar halo and a more compact younger stellar disk are formed. We found that a non negligible fraction of the halo stars are formed in situ in a spheroidal distribution. Changes in the sub-grid physics parameters affect significantly and in a complex way the evolution and properties of the galaxy: (i) Lower threshold densities nsf produce larger stellar effective radii Re, less peaked circular velocity curves V_c(R), and greater amounts of low-density and hot gas in the disk mid-plane; (ii) When stellar feedback is modeled by temporarily switching off radiative cooling in the star forming regions, Re increases (by a factor of ~ 2 in our particular model), the circular velocity curve becomes flatter, and a complex multi-phase gaseous disk structure develops; (iii) A more efficient local conversion of gas mass to stars, measured by a stellar particle mass distribution biased toward larger values, increases the strength of the feedback energy injection -driving outflows and inducing burstier SF histories; iv) If feedback is too strong, gas loss by galactic outflows -which are easier to produce in low-mass galaxies- interrupts SF, whose history becomes episodic. The simulations exhibit two important shortcomings: the baryon fractions are higher, and the specific SF rates are much smaller, than observationally inferred values for redshifts ~ 0.4-1.Comment: Accepted by ApJ after referee's revision (abstract abridged

    Dynamical trust and reputation computation model for B2C E-Commerce

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    Trust is one of the most important factors that influence the successful application of network service environments, such as e-commerce, wireless sensor networks, and online social networks. Computation models associated with trust and reputation have been paid special attention in both computer societies and service science in recent years. In this paper, a dynamical computation model of reputation for B2C e-commerce is proposed. Firstly, conceptions associated with trust and reputation are introduced, and the mathematical formula of trust for B2C e-commerce is given. Then a dynamical computation model of reputation is further proposed based on the conception of trust and the relationship between trust and reputation. In the proposed model, classical varying processes of reputation of B2C e-commerce are discussed. Furthermore, the iterative trust and reputation computation models are formulated via a set of difference equations based on the closed-loop feedback mechanism. Finally, a group of numerical simulation experiments are performed to illustrate the proposed model of trust and reputation. Experimental results show that the proposed model is effective in simulating the dynamical processes of trust and reputation for B2C e-commerce

    Oligodendroglioma anaplásico primario de la médula espinal

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    El oligodendroglioma de la médula espinal es una neoplasia extremadamente rara y solo se han reportado 52 casos en la literatura. Se reporta el caso de un paciente varón de 52 años, con paraplejia y un tumor en la medula espinal a nivel de C7 a T4. El diagnóstico final fue oligodendroglioma anaplásico con deleción del cromosoma 1p

    Non-Volatile Resistive Switching of Polymer Residues in 2D Material Memristors

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    Two-dimensional (2D) materials are popular candidates for emerging nanoscale devices, including memristors. Resistive switching (RS) in such 2D material memristors has been attributed to the formation and dissolution of conductive filaments created by the diffusion of metal ions between the electrodes. However, the area-scalable fabrication of patterned devices involves polymers that are difficult to remove from the 2D material interfaces without damage. Remaining polymer residues are often overlooked when interpreting the RS characteristics of 2D material memristors. Here, we demonstrate that the parasitic residues themselves can be the origin of RS. We emphasize the necessity to fabricate appropriate reference structures and employ atomic-scale material characterization techniques to properly evaluate the potential of 2D materials as the switching layer in vertical memristors. Our polymer-residue-based memristors exhibit RS typical for a filamentary mechanism with metal ion migration, and their performance parameters are strikingly similar to commonly reported 2D material memristors. This reveals that the exclusive consideration of electrical data without a thorough verification of material interfaces can easily lead to misinterpretations about the potential of 2D materials for memristor applications.Comment: 30 page

    Historia de la Santa A. M. Iglesia de Santiago de Compostela

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    Todos los volúmenes, excepto el T.I, tienen apéndices documentales.En algunos vóls. las fechas de portada no coinciden con las de cubierta: vol. VII (1904/1905), vol. VIII (1905/1906), vol. XI (1909/1911)Contiene: I. Orígenes de la iglesia compostelana.-- II-III. Los tres primeros siglos de la Iglesia Compostelana. -- IV-V. Los dos siglos de oro de la Iglesia compostelana. -- VI-VII. Los dos siglos de decadencia. -- VIII. La iglesia compostelana en el siglo XVI. -- IX. La iglesia compostelana en el siglo XVII. -- X. La iglesia compostelana en el siglo XVIII. -- XI. Vicisitudes de la iglesia compostelana desde mediados del siglo XVII
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