227 research outputs found
Mixing of the Averaging process and its discrete dual on finite-dimensional geometries
We analyze the -mixing of a generalization of the Averaging process
introduced by Aldous. The process takes place on a growing sequence of graphs
which we assume to be finite-dimensional, in the sense that the random walk on
those geometries satisfies a family of Nash inequalities. As a byproduct of our
analysis, we provide a complete picture of the total variation mixing of a
discrete dual of the Averaging process, which we call Binomial Splitting
process. A single particle of this process is essentially the random walk on
the underlying graph. When several particles evolve together, they interact by
synchronizing their jumps when placed on neighboring sites. We show that, given
the number of particles and the (growing) size of the underlying graph,
the system exhibits cutoff in total variation if and .
Finally, we exploit the duality between the two processes to show that the
Binomial Splitting satisfies a version of Aldous' spectral gap identity,
namely, the relaxation time of the process is independent of the number of
particles.Comment: 30 pages. Typos fixe
Spectral gap of the symmetric inclusion process
We consider the symmetric inclusion process on a general finite graph. Our
main result establishes universal upper and lower bounds for the spectral gap
of this interacting particle system in terms of the spectral gap of the random
walk on the same graph. In the regime in which the gamma-like reversible
measures of the particle systems are log-concave, our bounds match, yielding a
version for the symmetric inclusion process of the celebrated Aldous' spectral
gap conjecture originally formulated for the interchange process. Finally, by
means of duality techniques, we draw analogous conclusions for an interacting
diffusion-like unbounded conservative spin system known as Brownian energy
process.Comment: 16 page
Stochastic duality and eigenfunctions
We start from the observation that, anytime two Markov generators share an
eigenvalue, the function constructed from the product of the two eigenfunctions
associated to this common eigenvalue is a duality function. We push further
this observation and provide a full characterization of duality relations in
terms of spectral decompositions of the generators for finite state space
Markov processes. Moreover, we study and revisit some well-known instances of
duality, such as Siegmund duality, and extract spectral information from it.
Next, we use the same formalism to construct all duality functions for some
solvable examples, i.e., processes for which the eigenfunctions of the
generator are explicitly known
Productividad de la rotación anual raigrás- maÃz en galicia: evaluación durante cinco años en regadÃo y secano y bajo dos sistemas de siembra
Es un estudio sobre la productividad de la rotación anual raigrás- maÃz en galicia: evaluación durante cinco años en regadÃo y secano y bajo dos sistemas de siembr
Higher order hydrodynamics and equilibrium fluctuations of interacting particle systems
Motivated by the recent preprint [arXiv:2004.08412] by Ayala, Carinci, and
Redig, we first provide a general framework for the study of scaling limits of
higher order fields. Then, by considering the same class of infinite
interacting particle systems as in [arXiv:2004.08412], namely symmetric simple
exclusion and inclusion processes in the d-dimensional Euclidean lattice, we
prove the hydrodynamic limit, and convergence for the equilibrium fluctuations,
of higher order fields. In particular, the limit fields exhibit a tensor
structure. Our fluctuation result differs from that in [arXiv:2004.08412],
since we consider a different notion of higher order fluctuation fields.Comment: 29 pages, to appear in Markov Process. Related Field
Predicción de la fenologÃa de vicia faba l.: estimación de parámetros con el modelo cropgro- faba bean usando experimentos de múltiples fechas de siembra.
Entre los modelos de leguminosas más mecanicistas se puede destacar el modelo CROPGRO. Boote et al. (2002) adaptaron el CROPGRO para simular el crecimiento del haba (Vicia faba L.), naciendo asÃ, CROPGRO-faba bean (incluido en el paquete DSSAT V4) en el que la tasa de desarrollo se expresa como dÃa fisiológico (DF) transcurrido por dÃa del calendario (dÃa) (Ec. 1) y es una función multiplicativa de la temperatura (T) y fotoperÃodo (P). Cada una de estas funciones adopta valores comprendidos entre 0 y
Predicting phenology of Vicia faba: Parameter estimation with CROPGRO-fababean model using multiple sowing date experiments.
Crop models have become valuable tools for designing efficient cropping systems, particularly once model reliability is documented for a given environment. For this use, the timing of crop phenology has to be accurately simulated to predict life cycle and the correct allocation of assimilates to yield components. The CROPGRO-Fababean model was developed based on adaptation of the generic CROPGRO legume model to simulate faba bean grown in Cordoba, Spain (Boote et al., 2002) but the model has not been tested extensively in other environments. Therefore, the model needs to be tested for additional environments, and may need to be modified to improve its reliability under a wide range of field conditions. For the initial model version, phase durations were calibrated against field data collected at Córdoba; however, the cardinal temperatures that affect phenology were derived from the literature. Because our goal was to use these parameters to make reliable predictions in new field environments, we propose that the best way to solve the coefficients is through a calibration process based on field data obtained under varying daily and seasonal temperature and daylength, similar to the method used successfully to calibrate the SOYGRO model phenology. The objective of this work was to determine quantitatively the effects of temperature and daylength on rate of vegetative node expression, time to flowering, time to beginning pod, time to beginning seed, and time to physiological maturity with the ultimate goal of making the CROPGRO-Faba bean model more reliable over a wide range of sowing date environments
Hydrodynamics for the partial exclusion process in random environment
In this paper, we introduce a random environment for the exclusion process in
obtained by assigning a maximal occupancy to each site. This maximal
occupancy is allowed to randomly vary among sites, and partial exclusion
occurs. Under the assumption of ergodicity under translation and uniform
ellipticity of the environment, we derive a quenched hydrodynamic limit in path
space by strengthening the mild solution approach initiated in
\cite{nagy_symmetric_2002} and \cite{faggionato_bulk_2007}. To this purpose, we
prove, employing the technology developed for the random conductance model, a
homogenization result in the form of an arbitrary starting point quenched
invariance principle for a single particle in the same environment, which is a
result of independent interest. The self-duality property of the partial
exclusion process allows us to transfer this homogenization result to the
particle system and, then, apply the tightness criterion in
\cite{redig_symmetric_2018}
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