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Pedro García

Publications and source records attributed to Pedro García.

4 recordsLinked to original sources

In silico evaluation of pramlintide dosing algorithms in artificial pancreas systems

Pramlintide's capability to delay gastric emptying has motivated its use in artificial pancreas systems, accompanying insulin as a control action. Due to the scarcity of pramlintide simulation models in the literature, in silico testing of insulin-plus-pramlintide strategies is not widely used. This work incorporates a recent pramlintide pharmacokinetics/pharmacodynamics model into the T1DM UVA/Padova simulator to adjust and validate four insulin-plus-pramlintide control algorithms. The proposals are based on an existing insulin controller and administer pramlintide either as independent boluses or as a ratio of the insulin infusion. The results of the insulin-pramlintide algorithms are compared against their insulin-alone counterparts, showing an improvement in the time in range between 3.00\% and 10.53\%, consistent with results reported in clinical trials in the literature. Future work will focus on individualizing the pramlintide model to the patients' characteristics and evaluating the implemented strategies under more challenging scenarios.

eess.SY

Q-ball-like solitons on the M2-brane with worldvolume fluxes

In this paper we obtain a family of analytic solutions to the nonlinear partial differential equations that describe the dynamics of the bosonic part of the mass operator of a M2-brane compactified on $M_9\times T^2$ in the LCG with worldvolume fluxes. Those fluxes can be induced by a constant and quantized supergravity 3-form. This sector of the theory, at supersymmetric level, has the interesting property of having a discrete spectrum. We have focused on the characterization of Q-ball-like (QBL) solitons on the M2-brane with worldvolume fluxes. Two scenarios are analysed: one in which the system is isotropic and the other anisotropic. In the isotropic case, we obtain analytic families of string-like solutions to the membrane equations of motion in the presence of a non-vanishing symplectic gauge field that satisfy all constraints. We explicitly show a localised family of QBL solutions. It is demonstrated that although the solutions generally exhibit dispersion, they also allow for dispersion-free solutions. In the non-isotropic case, we obtain full-fledged membrane QBL solutions by numerical methods. We characterize some other properties of the solutions found. The dynamics of the QBL solutions are also encountered. We analyze the Lorentz boosts and Galilean transformations. Since we work in the Light Cone Gauge, the Lorentz transformed solutions are not automatically solutions, rather some extra conditions must be imposed. Only a subset of the solutions remain. We discuss some examples. The QBL solitons of the M2-brane that have been discovered contain an interaction term between the Noether charge of the Q-ball and the topological monopole charge associated with the worldvolume flux. The monopole charge increases the stability of the analytic solutions against fission...

hep-th

Spinning solutions for the bosonic M2-brane with $C_{\pm}$ fluxes

In this work we obtain classical solutions of the bosonic sector of the supermembrane theory with two-form fluxes associated to a quantized constant $C_{\pm}$ background. This theory satisfies a flux condition on the worldvolume that induces monopoles over it. Classically it is stable as it does not contain string-like spikes with zero energy in distinction with the general case. At quantum level the bosonic membrane has a purely discrete spectrum but the relevance is that the same property holds for its supersymmetric spectrum. We find for this theory spinning membrane solutions, some of them including the presence of a non-vanishing symplectic gauge connection defined on its worldvolume in different approximations. By using the duality found between this theory and the so-called supermembrane with central charges, rotating membrane solutions found in that case, are also solutions of the M2-brane with $C_{\pm}$ fluxes. We generalize this result to other embeddings. We find new distinctive rotating membrane solutions, some of them including the presence of a non-vanishing symplectic gauge connection defined on its worldvolume. We obtain numerical and analytical solutions in different approximations characterizing the dynamics of the membrane with fluxes $C_{\pm}$ for different ansätze of the dynamical degrees of freedom. Finally we discuss the physical admissibility of some of these ansätze to model the components of the symplectic gauge field.

hep-th

A machine learning based control of complex systems

In this work, inspired in the symbolic dynamic of chaotic systems and using machine learning techniques, a control strategy for complex systems is designed. Unlike the usual methodologies based on modeling, where the control signal is obtained from an approximation of the dynamic rule, here the strategy rest upon an approach of a function, that from the current state of the system, give the necessary perturbation to bring the system closer to a homoclinic orbit that naturally goes to the target. The proposed methodology is data-driven or can be developed in a based-model context and is illustrated with computer simulations of chaotic systems given by discrete maps, ordinary differential equations and coupled maps networks. Results shows the usefulness of the design of control techniques based on machine learning and numerical approach of homoclinic orbits.

nlin.CD