284,620 research outputs found

    U-health expert system with statistical neural network

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    Ubiquitous Health(U-Health) system witch focuses on automated applications that can provide healthcare to human anywhere and anytime using wired and wireless mobile technologies is becoming increasingly important. This system consists of a network system to collect data and a sensor module which measures pulse, blood pressure, diabetes, blood sugar, body fat diet with management and measurement of stress etc, by both wired and wireless and further portable mobile connections. In this paper, we propose an expert system using back-propagation to support the diagnosis of citizens in U-Health system

    Optimal Estimates for the Electric Field in Two-Dimensions

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    The purpose of this paper is to set out optimal gradient estimates for solutions to the isotropic conductivity problem in the presence of adjacent conductivity inclusions as the distance between the inclusions goes to zero and their conductivities degenerate. This difficult question arises in the study of composite media. Frequently in composites, the inclusions are very closely spaced and may even touch. It is quite important from a practical point of view to know whether the electric field (the gradient of the potential) can be arbitrarily large as the inclusions get closer to each other or to the boundary of the background medium. In this paper, we establish both upper and lower bounds on the electric field in the case where two circular conductivity inclusions are very close but not touching. We also obtain such bounds when a circular inclusion is very close to the boundary of a circular domain which contains the inclusion. The novelty of these estimates, which improve and make complete our earlier results published in Math. Ann., is that they give an optimal information about the blow-up of the electric field as the conductivities of the inclusions degenerate.Comment: 26 page

    Critical self-organization of astrophysical shocks

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    There are two distinct regimes of the first order Fermi acceleration at shocks. The first is a linear (test particle) regime in which most of the shock energy goes into thermal and bulk motion of the plasma. The second is an efficient regime when it goes into accelerated particles. Although the transition region between them is narrow, we identify the factors that drive the system to a {\it self-organized critical state} between those two. Using an analytic solution, we determine this critical state and calculate the spectra and maximum energy of accelerated particles.Comment: To appear in ApJL, Sec.3 extensively rewritten, 4 pages, Latex, emulateapj.sty, eps

    Evidence for an incommensurate magnetic resonance in La(2-x)Sr(x)CuO(4)

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    We study the effect of a magnetic field (applied along the c-axis) on the low-energy, incommensurate magnetic fluctuations in superconducting La(1.82)Sr(0.18)CuO(4). The incommensurate peaks at 9 meV, which in zero-field were previously shown to sharpen in q on cooling below T_c [T. E. Mason et al., Phys. Rev. Lett. 77, 1604 (1996)], are found to broaden in q when a field of 10 T is applied. The applied field also causes scattered intensity to shift into the spin gap. We point out that the response at 9 meV, though occurring at incommensurate wave vectors, is comparable to the commensurate magnetic resonance observed at higher energies in other cuprate superconductors.Comment: 8 pages, including 4 figure

    Radio/X-ray Offsets of Large Scale Jets Caused by Synchrotron Time Lags

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    In the internal shock scenario, we argue that electrons in most kpc (or even larger) scale jets can be accelerated to energies high enough to emit synchrotron X-rays, if shocks exist on these scales. These high energy electrons emit synchrotron radiation at high frequencies and cool as they propagate downstream along the jet, emitting at progressively lower frequencies and resulting in time lags and hence radio/X-ray (and optical/X-ray if the optical knot is detectable) offsets at bright knots, with the centroids of X-ray knots being closer to the core. Taking into account strong effects of jet expansion, the behaviour of radio/X-ray and optical/X-ray offsets at bright knots in M87, Cen A, 3C 66B, 3C 31, 3C 273, and PKS 1127-145 is consistent with that of synchrotron time lags due to radiative losses. This suggests that the large scale X-ray and optical jets in these sources are due to synchrotron emission.Comment: 4 pages, Accepted for publication in ApJ Letter

    Young tableaux and crystal B(∞)B(\infty) for finite simple Lie algebras

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    We study the crystal base of the negative part of a quantum group. An explicit realization of the crystal is given in terms of Young tableaux for types AnA_n, BnB_n, CnC_n, DnD_n, and G2G_2. Connection between our realization and a previous realization of Cliff is also given
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