90,226 research outputs found

    Poemas de Kim Keun

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    Kim Keun (1973). Gochang, Corea del Sur. Ganador del premio Munhakdongne de Nuevo Escritor. Publicó el libro de poemas Las excursiones del niño serpiente, y Nos vemos en el cine nube. La poesía de Kim surge, en buena medida, del trabajo que el autor hace a partir del dialecto de la provincia de Gochang, de la que es originario. La obra de Kim emerge de un imaginario en ocasiones sórdido e irónico; su plasticidad y ambigüedad en el lenguaje son dos de los rasgos más evidentes en su obra

    Remarks on non-linear noise excitability of some stochastic heat equations

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    We consider nonlinear parabolic SPDEs of the form tu=Δu+λσ(u)w˙\partial_t u=\Delta u + \lambda \sigma(u)\dot w on the interval (0,L)(0, L), where w˙\dot w denotes space-time white noise, σ\sigma is Lipschitz continuous. Under Dirichlet boundary conditions and a linear growth condition on σ\sigma, we show that the expected L2L^2-energy is of order exp[const×λ4]\exp[\text{const}\times\lambda^4] as λ\lambda\rightarrow \infty. This significantly improves a recent result of Khoshnevisan and Kim. Our method is very different from theirs and it allows us to arrive at the same conclusion for the same equation but with Neumann boundary condition. This improves over another result of Khoshnevisan and Kim

    Optimal circular flight of multiple UAVs for target tracking in urban areas

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    This work is an extension of our previous result in which a novel single-target tracking algorithm for fixed-wing UAVs (Unmanned Air Vehicles) was proposed. Our previous algorithm firstly finds the centre of a circular flight path, rc, over the interested ground target which maximises the total chance of keeping the target inside the camera field of view of UAVs, , while the UAVs fly along the circular path. All the UAVs keep their maximum allowed altitude and fly along the same circle centred at rc with the possible minimum turn radius of UAVs. As discussed in [1,4], these circular flights are highly recommended for various target tracking applications especially in urban areas, as for each UAV the maximum altitude flight ensures the maximum visibility and the minimum radius turn keeps the minimum distance to the target at the maximum altitude. Assuming a known probability distribution for the target location, one can quantify , which is incurred by the travel of a single UAV along an arbitrary circle, using line-of-sight vectors. From this observation, (the centre of) an optimal circle among numerous feasible ones can be obtained by a gradient-based search combined with random sampling, as suggested in [1]. This optimal circle is then used by the other UAVs jointly tracking the same target. As the introduction of multiple UAVs may minimise further, the optimal spacing between the UAVs can be naturally considered. In [1], a typical line search method is suggested for this optimal spacing problem. However, as one can easily expect, the computational complexity of this search method may undesirably increase as the number of UAVs increases. The present work suggests a remedy for this seemingly complex optimal spacing problem. Instead of depending on time-consuming search techniques, we develop the following algorithm, which is computationally much more efficient. Firstly, We calculate the distribution (x), where x is an element of , which is the chance of capturing the target by one camera along . Secondly, based on the distribution function, (x), find separation angles between UAVs such that the target can be always tracked by at least one UAV with a guaranteed probabilistic measure. Here, the guaranteed probabilistic measure is chosen by taking into account practical constraints, e.g. required tracking accuracy and UAVs' minimum and maximum speeds. Our proposed spacing scheme and its guaranteed performance are demonstrated via numerical simulations

    Review of The Politics of War: Canada’s Afghanistan Mission, 2001-14 by Jean-Christophe Boucher and Kim Richard Nossal

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    Review of The Politics of War: Canada’s Afghanistan Mission, 2001-14 by Jean-Christophe Boucher and Kim Richard Nossal

    Management of Prediabetes

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    Nurses have a key role in promoting the patient's self-management and fostering motivation for lifestyle change, writes Nicky Kim

    Enhanced quantum tunnelling induced by disorder

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    We reconsider the problem of the enhancement of tunnelling of a quantum particle induced by disorder of a one-dimensional tunnel barrier of length LL, using two different approximate analytic solutions of the invariant imbedding equations of wave propagation for weak disorder. The two solutions are complementary for the detailed understanding of important aspects of numerical results on disorder-enhanced tunnelling obtained recently by Kim et al. (Phys. rev. B{\bf 77}, 024203 (2008)). In particular, we derive analytically the scaled wavenumber (kL)(kL)-threshold where disorder-enhanced tunnelling of an incident electron first occurs, as well as the rate of variation of the transmittance in the limit of vanishing disorder. Both quantities are in good agreement with the numerical results of Kim et al. Our non-perturbative solution of the invariant imbedding equations allows us to show that the disorder enhances both the mean conductance and the mean resistance of the barrier.Comment: 10 page
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