Results 11 to 20 of about 63,022 (99)

Discrete structures in gravity [PDF]

, 2000
Discrete approaches to gravity, both classical and quantum, are reviewed briefly, with emphasis on the method using piecewise-linear spaces. Models of 3-dimensional quantum gravity involving 6j-symbols are then described, and progress in generalising ...
Ambjørn J., Archer F. J., Baez J., Baez J., Barrett J. W., Barrett J. W., Barrett J. W., Barrett J. W., Barrett J. W., Barrett J. W., Barrett J. W., Birmingham D., Birmingham D., Brewin L., Brewin L., Carfora M., Caselle M., Correia da Silva C. L. B., Correia da Silva C. L. B., Franzosi R., Franzosi R., Freidel L., Freidel L., Gott J. R., Hamber H. W., Hamber H. W., Hartle J. B., Hasslacher B., Hollmann H. R., Immirzi G., Ionicioiu R., Ionicioiu R., Iwasaki J., Kauffman L. H., Mannion C. L., Markopoulou F., Markopoulou F., Menotti P., Ooguri H., Reisenberger M., Reisenberger M., Reisenberger M., Riedler J., Roberts J. D., Roček M., Ruth M. Williams, Schleich K., Schleich K., Tullio Regge, Turaev V. G., Waelbroeck H., Welling M., Williams R. M., ’t Hooft G., ’t Hooft G.   +54 more
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Analysis of a class of boundary value problems depending on left and right Caputo fractional derivatives [PDF]

, 2017
In this work we study boundary value problems associated to a nonlinear fractional ordinary differential equation involving left and right Caputo derivatives.
Antunes, Pedro R. S., Ferreira, Rui A. C.   +1 more
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Continuous and Discrete Adjoints to the Euler Equations for Fluids

, 2011
Adjoints are used in optimization to speed-up computations, simplify optimality conditions or compute sensitivities. Because time is reversed in adjoint equations with first order time derivatives, boundary conditions and transmission conditions through ...
Alauzet, Frederic, Pironneau, Olivier
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Calculation of the Stability Index in Parameter-Dependent Calculus of Variations Problems: Buckling of a Twisted Elastic Strut [PDF]

, 2002
We consider the problem of minimizing the energy of an inextensible elastic strut with length 1 subject to an imposed twist angle and force. In a standard calculus of variations approach, one first locates equilibria by solving the Euler--Lagrange ODE ...
Hoffman, Kathleen A., Manning, Robert S., Paffenroth, Randy C.   +2 more
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The Variable-Order Fractional Calculus of Variations

, 2018
This book intends to deepen the study of the fractional calculus, giving special emphasis to variable-order operators. It is organized in two parts, as follows. In the first part, we review the basic concepts of fractional calculus (Chapter 1) and of the
Almeida, Ricardo, Tavares, Dina, Torres, Delfim F. M.   +2 more
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A survey on fractional order control techniques for unmanned aerial and ground vehicles [PDF]

, 2019
In recent years, numerous applications of science and engineering for modeling and control of unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs) systems based on fractional calculus have been realized.
Cajo Diaz, Ricardo Alfredo, Copot, Cosmin, De Keyser, Robain, Ionescu, Clara-Mihaela, Mac Thi, Thoa, Plaza Guingla, Douglas Antonio   +5 more
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Fractional Order Version of the HJB Equation

, 2018
We consider an extension of the well-known Hamilton-Jacobi-Bellman (HJB) equation for fractional order dynamical systems in which a generalized performance index is considered for the related optimal control problem.
AsadiZadehShiraz, Mehdi, Razminia, Abolhassan, Torres, Delfim F. M.   +2 more
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Hydrodynamic Flows on Curved Surfaces: Spectral Numerical Methods for Radial Manifold Shapes

, 2018
We formulate hydrodynamic equations and spectrally accurate numerical methods for investigating the role of geometry in flows within two-dimensional fluid interfaces.
Atzberger, Paul J., Gross, Ben J.
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Fast algorithms for computing defects and their derivatives in the Regge calculus

, 2010
Any practical attempt to solve the Regge equations, these being a large system of non-linear algebraic equations, will almost certainly employ a Newton-Raphson like scheme.
Brewin L, Christiansen S H, Gentle A P, Leo Brewin, Miller M A, Wheeler J A, Williams R M   +6 more
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Optimal control of a fractional order epidemic model with application to human respiratory syncytial virus infection [PDF]

, 2018
A human respiratory syncytial virus surveillance system was implemented in Florida in 1999, to support clinical decision-making for prophylaxis of premature newborns. Recently, a local periodic SEIRS mathematical model was proposed in [Stat. Optim.
Rosa, Silverio, Torres, Delfim F. M.
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