Artículos de conferencia

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https://repositorio.uc.cl/handle/11534/23156

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Browsing Artículos de conferencia by browse.metadata.categoria "Matemática física y química"

Now showing 1 - 4 of 4
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    Algebraic Reconstruction of Source and Attenuation in SPECT Using First Scattering Measurements
    (Springer, 2018) Cueva, Evelyn; Osses Alvarado, Axel Esteban; Quintana Fresno, Juan Carlos; Tejos Núñez, Cristián Andrés; Courdurier Bettancourt Matias Alejandro; Irarrazaval Mena, Pablo
    Here we present an Algebraic Reconstruction Technique (ART) for solving the identification problem in Single Photon Emission Computed Tomography (SPECT). Traditional reconstruction for SPECT is done by finding the radiation source, nevertheless the attenuation of the surrounding tissue affects the data. In this context, ballistic and first scattering information are used to recover source and attenuation simultaneously. Both measurements are related with the Attenuated Radon Transform and a Klein-Nishina angular type dependency is considered for the scattering. The proposed ART algorithm allow us to obtain good reconstructions of both objects in a few number of iterations.
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    Equilibrium Dynamics in Market Games with Exchangeable and Divisible Resources
    (2024) Correa, José; Harks, Tobias; Schedel, Anja; Verschae Tannenbaum Jose Claudio
    We study a market game with n ≥ 2 players competing over m ≥ 1 divisible resources of different finite capacities. Resources are traded via the proportional sharing mechanism, where players are price-anticipating, meaning that they can influence the prices with their bids. Additionally, each player has an initial endowment of the resources which are sold at market prices. Although the players’ total profit functions may be discontinuous in the bids, we prove existence and uniqueness of pure Nash equilibria of the resulting market game. Then, we study a discrete dynamic arising from repeatedly taking the (unique) equilibrium resource allocation as initial endowments for the next market game. We prove that the total utility value of the dynamic converges to either an optimal allocation value (maximizing total utility over the allocation space) or to a restricted optimal allocation value, where the restriction is defined by fixing some tight resources which are exclusively allocated to a single player. As a corollary, it follows that for strictly concave utility functions, the aggregated allocation vector of the dynamic converges to the unique (possibly restricted) optimal aggregated allocation, and for linear utility functions, we even get convergence of the dynamic to a (possibly restricted) optimal solution in the (non-aggregated) original allocation space.
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    Formation and Morphology of Single Phospholipid Bilayers Formed by Velocity-Controlled Dip-Coating
    (2018) Cisternas Fruns, Marcelo Andrés; Soto Arriaza, Marco Antonio; Retamal Ponce, Maria Jose; Moraga Alarcón, Nicolás Hernán; Catalán Lopez, Rodrigo Esteban; Volkmann, Ulrich Georg; Diaz, Diego; Corrales, Tomas P.
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    Quantum transport across a slab of a type I Weyl Semimetal with a uniform concentration of torsion dislocation defects
    (2023) Bonilla Moreno, Daniel; Muñoz, Enrique
    In this work, we study the electronic transport in a Type I Weyl Semimetal slab with a uniform and diluted concentration of torsional dislocation defects. The defects have cylindrical geometry and are modeled as a pseudo-gauge field accounting for torsional strain and a repulsive delta-shell potential for the lattice mismatch effect. We give explicit forms for the retarded Green function in the presence of uniformly distributed scattering centers and the spectral density in terms of the relaxation time (imaginary part of the self-energy). The relaxation time is computed from the known scattering cross-section as a function of the phase shifts for the single-defect scattering problem. Finally, we use the Kubo formula to calculate electrical conductivity.