Homogenization of the discrete diffusive coagulation-fragmentation equations in perforated domains

The asymptotic behavior of the solution of an infinite set of Smoluchowski's discrete coagulation-fragmentation-diffusion equations with non-homogeneous Neumann boundary conditions, defined in a periodically perforated domain, is analyzed. Our homogenization result, based on Nguetseng-Allaire two-scale convergence, is meant to pass from a microscopic model (where the physical processes are properly described) to a macroscopic one (which takes into account only the effective or averaged properties of the system). When the characteristic size of the perforations vanishes, the information given on the microscale by the non-homogeneous Neumann boundary condition is transferred into a global source term appearing in the limiting (homogenized) equations. Furthermore, on the macroscale, the geometric structure of the perforated domain induces a correction in the diffusion coefficients

Variational approach to gas flows in microchannels on the basis of the Boltzmann equation for hard-sphere molecules

This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.The objective of the present paper is to provide an analytic expression for the first- and second-order velocity slip coefficients. Therefore, gas flow rates in microchannels have been rigorously evaluated in the near-continuum limit by means of a variational technique which applies to the integrodifferential form of the Boltzmann equation based on the true linearized collision operator. The diffuse-specular reflection condition of Maxwell’s type has been considered in order to take into account the influence of the accommodation coefficient on the slip parameters. The polynomial form of Knudsen number obtained for the Poiseuille mass flow rate and the values of the second order velocity slip coefficients found on the basis of our variational solution of the linearized Boltzmann equation for hardsphere molecules are analyzed in the frame of potential applications of classical continuum numerical tools (as lattice Boltzmann methods) in simulations of microscale flows

The Data Processing Pipeline for the Herschel-HIFI Instrument

The HIFI data processing pipeline was developed to systematically process diagnostic, calibration and astronomical observations taken with the HIFI science instrumentas part of the Herschel mission. The HIFI pipeline processed data from all HIFI observing modes within the Herschel automated processing environment, as well as, within an interactive environment. A common software framework was developed to best support the use cases required by the instrument teams and by the general astronomers. The HIFI pipeline was built on top of that and was designed with a high degree of modularity. This modular design provided the necessary flexibility and extensibility to deal with the complexity of batch-processing eighteen different observing modes, to support the astronomers in the interactive analysis and to cope with adjustments necessary to improve the pipeline and the quality of the end-products. This approach to the software development and data processing effort was arrived at by coalescing the lessons learned from similar research based projects with the understanding that a degree of foresight was required given the overall length of the project. In this article, both the successes and challenges of the HIFI software development process are presented. To support future similar projects and retain experience gained lessons learned are extracted.Comment: 18 pages, 5 figure

A Mathematical model for Alzheimer's disease: An approach via stochastic homogenization of the Smoluchowski equation

In this note, we apply the theory of stochastic homogenization to find the asymptotic behavior of the solution of a set of Smoluchowski's coagulation-diffusion equations with non-homogeneous Neumann boundary conditions. This system is meant to model the aggregation and diffusion of β-amyloid peptide (Aβ) in the cerebral tissue, a process associated with the development of Alzheimer's disease. In contrast to the approach used in our previous works, in the present paper we account for the non-periodicity of the cellular structure of the brain by assuming a stochastic model for the spatial distribution of neurons. Further, we consider non-periodic random diffusion coefficients for the amyloid aggregates and a random production of Aβ in the monomeric form at the level of neuronal membranes

A Mathematical model for Alzheimer's disease: An approach via stochastic homogenization of the Smoluchowski equation

In this note, we apply the theory of stochastic homogenization to find the asymptotic behavior of the solution of a set of Smoluchowski's coagulation-diffusion equations with non-homogeneous Neumann boundary conditions. This system is meant to model the aggregation and diffusion of β-amyloid peptide (Aβ) in the cerebral tissue, a process associated with the development of Alzheimer's disease. In contrast to the approach used in our previous works, in the present paper we account for the non-periodicity of the cellular structure of the brain by assuming a stochastic model for the spatial distribution of neurons. Further, we consider non-periodic random diffusion coefficients for the amyloid aggregates and a random production of Aβ in the monomeric form at the level of neuronal membranes

L'industrie du Lobbying. Les stratégies d'influence des groupements de consommateurs en Europe, à l'heure d'Internet

The research focuses on how in Europe consumer groups attempt to increase their power by developing their influence strategies within the lobbying industry. We also try to assess the impact of the Internet on their level of competitiveness and their ability to influence. We have made use of theoretical reflections relevant to analysing the lobbying, such as the concept of influence, various concepts of the industrial economy, and consumer groups. We conclude from our review that lobbying consumer groups are fully-fledged stakeholders (Freeman, 1984). We propose our own definition of lobbying as well as an improved view of the lobbying-mix in conjunction with Internet usages. We observe the emergence of a new force (Porter, 1979, 2008) : the one of lobbying, which innervates in a concealed way the whole structure of any industry. The lobbying industry lives on its highly added value offer of services and has a double tradable asset. Our strategy to confront reality is twofold. We have conducted two case studies as well as a qualitative survey with a population of consumer associations representing 31 European countries, thus enabling us to offer a complete overview of the existing landscape. Our theoretical and methodological contributions include a description and a definition of the lobbying industry. They are also related to the very notion of influence strategy and research on consumer groups. Operational contributions concern the analysis and understanding of the role and strategies of consumer associations at the European level, interactions between actors of the lobbying industry, and the impact of the Internet on the influence strategies of consumer associations.Notre recherche porte sur la façon dont en Europe les groupements des consommateurs cherchent à gagner en pouvoir en développant leurs stratégies d’influence au sein de l’industrie du lobbying. Nous avons aussi cherché à évaluer l’incidence d’Internet sur leur degré de compétitivité et leur capacité d’influence. Nous avons mobilisé des éléments de réflexion théorique utiles à l’analyse du lobbying, tels que le concept d’influence, divers concepts de l’économie industrielle et les groupements de consommateurs. Nous concluons que les groupements de consommateurs lobbyistes sont des stakeholders (Freeman, 1984) à part entière et nous proposons notre propre définition du lobbying, ainsi qu’un enrichissement du lobbying-mix en lien avec Internet. Nous faisons le constat de l’émergence d’une nouvelle force (Porter, 1979, 2008), celle du lobbying, qui innerve de façon larvée l’ensemble de la structure de toute industrie. Notre stratégie d’accès au réel s’est construite autour de deux études de cas et d’une enquête qualitative auprès d’une population d’associations de consommateurs de 31 pays d’Europe, permettant de faire une synthèse exhaustive de l’existant. Nos apports théoriques et méthodologiques comprennent une description et une définition de l’industrie du lobbying. Ils concernent aussi la notion de stratégie d’influence et la recherche sur les groupements de consommateurs. Les apports opérationnels concernent l’analyse et la compréhension du rôle et des stratégies des associations de consommateurs à l’échelle européenne, des interactions entre acteurs de l’industrie du lobbying et de l’impact d’Internet sur les stratégies d’influence des associations de consommateurs

A mathematical model for Alzheimer's disease: An approach via stochastic homogenization of the Smoluchowski equation

In this note, we apply the theory of stochastic homogenization to find the asymptotic behavior of the solution of a set of Smoluchowski's coagulation-diffusion equations with non-homogeneous Neumann boundary conditions. This system is meant to model the aggregation and diffusion of β-amyloid peptide (Aβ) in the cerebral tissue, a process associated with the development of Alzheimer's disease. In contrast to the approach used in our previous works, in the present paper we account for the non-periodicity of the cellular structure of the brain by assuming a stochastic model for the spatial distribution of neurons. Further, we consider non-periodic random diffusion coefficients for the amyloid aggregates and a random production of Aβ in the monomeric form at the level of neuronal membranes

A mathematical model for Alzheimer's disease: An approach via stochastic homogenization of the Smoluchowski equation

In this note, we apply the theory of stochastic homogenization to find the asymptotic behavior of the solution of a set of Smoluchowski's coagulation-diffusion equations with non-homogeneous Neumann boundary conditions. This system is meant to model the aggregation and diffusion of β-amyloid peptide (Aβ) in the cerebral tissue, a process associated with the development of Alzheimer's disease. In contrast to the approach used in our previous works, in the present paper we account for the non-periodicity of the cellular structure of the brain by assuming a stochastic model for the spatial distribution of neurons. Further, we consider non-periodic random diffusion coefficients for the amyloid aggregates and a random production of Aβ in the monomeric form at the level of neuronal membranes

Traduzione automatica di descrizioni di servizi Web

La tesi presenta uno schema di traduzione basato su pattern che permette di tradurre processi BPEL4WS (Business Process Execution Language 4 WS) in workflow YAWL (Yet Another Workflow Language). Viene quindi descritta una realizzazione in Java di tale traduzion