4,853 research outputs found
WENO schemes applied to the quasi-relativistic Vlasov--Maxwell model for laser-plasma interaction
In this paper we focus on WENO-based methods for the simulation of the 1D
Quasi-Relativistic Vlasov--Maxwell (QRVM) model used to describe how a laser
wave interacts with and heats a plasma by penetrating into it. We propose
several non-oscillatory methods based on either Runge--Kutta (explicit) or
Time-Splitting (implicit) time discretizations. We then show preliminary
numerical experiments
Estimating the size of the solution space of metabolic networks
In this work we propose a novel algorithmic strategy that allows for an
efficient characterization of the whole set of stable fluxes compatible with
the metabolic constraints. The algorithm, based on the well-known Bethe
approximation, allows the computation in polynomial time of the volume of a non
full-dimensional convex polytope in high dimensions. The result of our
algorithm match closely the prediction of Monte Carlo based estimations of the
flux distributions of the Red Blood Cell metabolic network but in incomparably
shorter time. We also analyze the statistical properties of the average fluxes
of the reactions in the E-Coli metabolic network and finally to test the effect
of gene knock-outs on the size of the solution space of the E-Coli central
metabolism.Comment: 8 pages, 7 pdf figure
A Statistical Theory of Designed Quantum Transport Across Disordered Networks
We explain how centrosymmetry, together with a dominant doublet in the local
density of states, can guarantee interference-assisted, strongly enhanced,
strictly coherent quantum excitation transport between two predefined sites of
a random network of two-level systems. Starting from a generalisation of the
chaos assisted tunnelling mechanism, we formulate a random matrix theoretical
framework for the analytical prediction of the transfer time distribution, of
lower bounds of the transfer efficiency, and of the scaling behaviour of
characteristic statistical properties with the size of the network.Comment: 23 pages, 8 figure
Message passing and Monte Carlo algorithms: connecting fixed points with metastable states
Mean field-like approximations (including naive mean field, Bethe and Kikuchi
and more general Cluster Variational Methods) are known to stabilize ordered
phases at temperatures higher than the thermodynamical transition. For example,
in the Edwards-Anderson model in 2-dimensions these approximations predict a
spin glass transition at finite . Here we show that the spin glass solutions
of the Cluster Variational Method (CVM) at plaquette level do describe well
actual metastable states of the system. Moreover, we prove that these states
can be used to predict non trivial statistical quantities, like the
distribution of the overlap between two replicas. Our results support the idea
that message passing algorithms can be helpful to accelerate Monte Carlo
simulations in finite dimensional systems.Comment: 6 pages, 6 figure
Estudio preliminar de la aplicación de varias técnicas de comunicación en diseños circulares
Comunicació presentada al 23rd International Congress on Project Management and Engineering (Málaga, 10-12 July 2019).An effective Circular Economy strategy comprises demonstrate practical application, by including real life examples and emphasizing with data and facts. The communication strategy is addressed during the design process and designers have to think about the product/service and about how communicating it. To reach a broader impact, techniques like creative storytelling or educational messages are needed. This work aims to know the ease or difficulty for industrial design engineering students in the application of these techniques to effectively communicate the advantages of a design based in the Circular Economy. To address this, a workshop has been done to explain basic notions about circular economy and consumptions patterns and trends. Then, communication techniques were explained, using examples. The workshop proceeded asking the students to apply these techniques for emphasizing the advantages of a circular product, working in groups. Finally, a questionnaire was passed to evaluate their opinion about the communication techniques applied. At the end, a debate was conducted about their perception about the importance of communication in designs based in circular economy.Una estrategia de Economía Circular efectiva requiere mostrar aplicación práctica, incluyendo ejemplos de la vida real y enfatizando con datos y hechos. La estrategia de comunicación se aborda durante el proceso de diseño y los diseñadores deben pensar en el producto/servicio y en cómo comunicarlo. Para conseguir un mayor impacto, es necesaria la aplicación de técnicas como narración creativa de historias o los mensajes educativos. Este trabajo pretende conocer la facilidad o dificultad que tienen estudiantes de ingeniería en diseño industrial en aplicar estas técnicas para comunicar de forma efectiva las ventajas de un diseño basado en la economía circular. Para ello, se ha programado un taller en el que se introdujo la economía circular y los patrones de consumo y tendencias de mercado relacionados con ésta. Después se les explicaron las técnicas de comunicación, mostrando un ejemplo. A continuación, se les ha pedido que apliquen, trabajando en grupo, cada técnica de comunicación para enfatizar las ventajas de un producto circular. Finalmente, se les pasó un cuestionario de evaluación sobre su opinión acerca de las técnicas de comunicación aplicadas. También se debatió sobre su percepción en cuanto a la importancia de la comunicación en diseños basados en la economía circular
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