203 research outputs found
A Nash-Moser theorem for singular evolution equations. Application to the Serre and Green-Naghdi equations
We study the well-posedness of the initial value problem for a wide class of
singular evolution equations. We prove a general well-posedness theorem under
three assumptions easy to check: the first controls the singular part of the
equation, the second the behavior of the nonlinearities, and the third one
assumes that an energy estimate can be found for the linearized system. We
allow losses of derivatives in this energy estimate and therefore construct a
solution by a Nash-Moser iterative scheme. As an application to this general
theorem, we prove the well-posedness of the Serre and Green-Naghdi equation and
discuss the problem of their validity as asymptotic models for the water-waves
equations
Existence of travelling-wave solutions and local well-posedness of the Fowler equation
We study the existence of travelling-waves and local well-posedness in a
subspace of for a nonlinear evolution equation recently
proposed by Andrew C. Fowler to study the dynamics of dunes.Comment: 21 page
Variable depth KDV equations and generalizations to more nonlinear regimes
We study here the water-waves problem for uneven bottoms in a highly
nonlinear regime where the small amplitude assumption of the Korteweg-de Vries
(KdV) equation is enforced. It is known, that for such regimes, a
generalization of the KdV equation (somehow linked to the Camassa-Holm
equation) can be derived and justified by A. Constantin, D. Lannes "The
hydrodynamical relevance of the Camassa-Holm and Degasperis-Processi equations"
when the bottom is flat. We generalize here this result with a new class of
equations taking into account variable bottom topographies. Of course, the many
variable depth KdV equations existing in the literature are recovered as
particular cases. Various regimes for the topography regimes are investigated
and we prove consistency of these models, as well as a full justification for
some of them. We also study the problem of wave breaking for our new variable
depth and highly nonlinear generalizations of the KDV equations
Impacto de un Sistema Web para Optimizar Insumos en Negocio de Comida
Los avances tecnológicos han contribuido a que las empresas alcancen ventajas competitivas, tal como, la implementación de sistemas informáticos, los cuales aportan y cubren falencias de procesos de información. Si se habla de negocios de comida, uno de los principales objetivos es la gestión de los insumos y su inventario, con los cuales se busca reducir costos sin afectar la calidad de los productos. Por lo anteriormente expuesto, éste artículo tiene como objetivo analizar el impacto de una aplicación web desarrollada con metodología ágil Scrum, enfocándose en la optimización de los insumos de un local de comida. Para lograr esto, se consideraron tres etapas para la implementación: definición del producto, diseño de la solución y el desarrollo de la aplicación web; obteniendo como resultado, un sistema informático que permite mejorar el control de los inventarios; así como la planificación de adquisición y distribución de los insumos
Blow-up and global existence for a general class of nonlocal nonlinear coupled wave equations
We study the initial-value problem for a general class of nonlinear nonlocal
coupled wave equations. The problem involves convolution operators with kernel
functions whose Fourier transforms are nonnegative. Some well-known examples of
nonlinear wave equations, such as coupled Boussinesq-type equations arising in
elasticity and in quasi-continuum approximation of dense lattices, follow from
the present model for suitable choices of the kernel functions. We establish
local existence and sufficient conditions for finite time blow-up and as well
as global existence of solutions of the problem.Comment: 11 pages. Minor changes and added reference
El urbanismo táctico y la participación ciudadana en el distrito de Comas 2021
Al pasar de los años se han presentado muchos problemas sociales en diversas partes del
mundo, afectando las actividades del día a día. Esto es causado por los factores que se
interponen entre la misma población, debido a la falta de desinterés hacia el espacioque lo
rodea, sin tener en cuenta que la opinión del usuario es parte importante del lugar social;
ya que, al dar importancia al espacio y al usuario en conjunto se va a generar un
crecimiento social y cultural. El presente artículo pretende determinar, a través de una
metodología de tipo aplicada, con nivel descriptiva-causal, enfoque mixto, diseño no
experimental y método hipotético- deductivo, qué relación existe entre el urbanismo tacto
y participación ciudadana. El urbanismo táctico es un instrumento provisional, que con
apoyo del ciudadano se desarrolla comunitariamentegenerando cambios a su entorno, ese
contiende estrategias para crear sociedad el cual requiere participación ciudadana de
manera fundamental. La relación que ambas poseen es de importancia para el desarrollo
positivo urbano
Simultaneous denoising and enhancement of signals by a fractal conservation law
In this paper, a new filtering method is presented for simultaneous noise
reduction and enhancement of signals using a fractal scalar conservation law
which is simply the forward heat equation modified by a fractional
anti-diffusive term of lower order. This kind of equation has been first
introduced by physicists to describe morphodynamics of sand dunes. To evaluate
the performance of this new filter, we perform a number of numerical tests on
various signals. Numerical simulations are based on finite difference schemes
or Fast and Fourier Transform. We used two well-known measuring metrics in
signal processing for the comparison. The results indicate that the proposed
method outperforms the well-known Savitzky-Golay filter in signal denoising.
Interesting multi-scale properties w.r.t. signal frequencies are exhibited
allowing to control both denoising and contrast enhancement
Large time wellposdness to the 3-D Capillary-Gravity Waves in the long wave regime
In the regime of weakly transverse long waves, given long-wave initial data,
we prove that the nondimensionalized water wave system in an infinite strip
under influence of gravity and surface tension on the upper free interface has
a unique solution on [0,{T}/\eps] for some \eps independent of constant
We shall prove in the subsequent paper \cite{MZZ2} that on the same time
interval, these solutions can be accurately approximated by sums of solutions
of two decoupled Kadomtsev-Petviashvili (KP) equations.Comment: Split the original paper(The long wave approximation to the 3-D
capillary-gravity waves) into two parts, this is the first on
- …