Towards a Tool-based Development Methodology for Pervasive Computing Applications

Despite much progress, developing a pervasive computing application remains a challenge because of a lack of conceptual frameworks and supporting tools. This challenge involves coping with heterogeneous devices, overcoming the intricacies of distributed systems technologies, working out an architecture for the application, encoding it in a program, writing specific code to test the application, and finally deploying it. This paper presents a design language and a tool suite covering the development life-cycle of a pervasive computing application. The design language allows to define a taxonomy of area-specific building-blocks, abstracting over their heterogeneity. This language also includes a layer to define the architecture of an application, following an architectural pattern commonly used in the pervasive computing domain. Our underlying methodology assigns roles to the stakeholders, providing separation of concerns. Our tool suite includes a compiler that takes design artifacts written in our language as input and generates a programming framework that supports the subsequent development stages, namely implementation, testing, and deployment. Our methodology has been applied on a wide spectrum of areas. Based on these experiments, we assess our approach through three criteria: expressiveness, usability, and productivity

Non-linear oscillatory rheological properties of a generic continuum foam model: comparison with experiments and shear-banding predictions

The occurence of shear bands in a complex fluid is generally understood as resulting from a structural evolution of the material under shear, which leads (from a theoretical perspective) to a non-monotonic stationnary flow curve related to the coexistence of different states of the material under shear. In this paper we present a scenario for shear-banding in a particular class of complex fluids, namely foams and concentrated emulsions, which differs from other scenarii in two important ways. First, the appearance of shear bands is shown to be possible both without any intrinsic physical evolution of the material (e.g. via a parameter coupled to the flow such as concentration or entanglements) and without any finite critical shear rate below which the flow does not remain stationary and homogeneous. Secondly, the appearance of shear bands depends on the initial conditions, i.e., the preparation of the material. In other words, it is history dependent. This behaviour relies on the tensorial character of the underlying model (2D or 3D) and is triggered by an initially inhomogeneous strain distribution in the material. The shear rate displays a discontinuity at the band boundary, whose amplitude is history dependent and thus depends on the sample preparation.Comment: 18 pages - 17 figure

A Tool Suite to Prototype Pervasive Computing Applications (Demo)

International audienceDespite much progress, developing a pervasive computing application remains a challenge because of a lack of conceptual frameworks and supporting tools. This challenge involves coping with heterogeneous entities, overcoming the intricacies of distributed systems technologies, working out an architecture for the application, encoding it in a program, writing specific code to test the application, and finally deploying it. We present DiaSuite, a tool suite covering the development life-cycle of a pervasive computing system. This tool suite comprises a domain-specific design language, a compiler for this language, which produces a Java programming framework, an editor to define simulation scenarios, and a 2D-renderer to simulate pervasive computing applications. We have validated our tool suite on a variety of comprehensive applications in areas including telecommunications, building automation, and health-care

DiaSim: A Parameterized Simulator for Pervasive Computing Applications

International audiencePervasive computing applications involve both soft- ware concerns, like any software system, and integration con- cerns, for the constituent networked devices of the pervasive computing environment. This situation is problematic for testing because it requires acquiring, testing and interfacing a variety of software and hardware entities. This process can rapidly become costly and time-consuming when the target environment involves many entities. In this demonstration, we present DiaSim, a simulator for per- vasive computing applications. To cope with widely heterogeneous entities, DiaSim is parameterized with respect to a description of a target pervasive computing environment. This description is used to generate both a programming framework to develop the simulation logic and an emulation layer to execute applications. Furthermore, a simulation renderer is coupled to DiaSim to allow a simulated pervasive system to be visually monitored and debugged

DiaSim: A Parameterized Simulator for Pervasive Computing Applications

International audiencePervasive computing applications involve both software concerns, like any software system, and integration concerns, for the constituent networked devices of the pervasive computing environment. This situation is problematic for testing because it requires acquiring, testing and interfacing a variety of software and hardware entities. This process can rapidly become costly and time-consuming when the target environment involves many entities. In this demonstration, we present DiaSim, a simulator for pervasive computing applications. To cope with widely heterogeneous entities, DiaSim is parameterized with respect to a description of a target pervasive computing environment. This description is used to generate both a programming framework to develop the simulation logic and an emulation layer to execute applications. Furthermore, a simulation renderer is coupled to DiaSim to allow a simulated pervasive system to be visually monitored and debugged

Stabilité d'écoulements bifluides dans un microcanal

L'instabilité de Plateau-Rayleigh est une instabilité classique, liée aux effets interfaciaux, qui concerne les écoulements de cylindres de fluides. Afin d'abaisser son énergie de surface, le cylindre va se fragmenter et former des gouttes. En microfluidique, les phénomènes de tension de surface prédominent. Par conséquent, lorsque l'on considère l'écoulement de deux fluides dans un microcanal cylindrique, suivant les conditions de la manipulation, on peut observer le morcellement du fluide interne. Les expériences montrent qu'il y a trois types de configurations: la formation de gouttes, bouchons ou la persistance du jet. Ces arrangements résultent de la compétition entre le confinement, la vitesse du jet et le gain d'énergie à faire des gouttes. Partant des constatations expérimentales, le travail consiste à réaliser numériquement une étude paramétrique afin de comprendre le rôle des variables physiques en présence (vitesses d'injections des fluides, viscosité, tension de surfac

Pore-scale numerical simulation of two phase flow of newtonian and viscoelastic fluids

This work is motivated by the need for better understanding the Polymer Enhanced Oil Recovery technique at the pore-scale. We consider two phase immiscible and incompressible fluids in a microchannel network. The newtonian fluid is governed by incompressible Stokes equations. The Oldroyd-B rheological model is used to capture viscoelastic behavior. To trace the interface between the two fluids, we use the Level-Set method. We will present simulations in a two and three dimensional microfluidic pore network, then we will compare numerical results with experimental results

Enablers for robust POD models

International audienceThis paper focuses on improving the stability as well as the approximation properties of Reduced Order Models (ROM) based on Proper Orthogonal Decomposition (POD). The ROM is obtained by seeking a solution belonging to the POD subspace and that at the same time minimizes the Navier-Stokes residuals. We propose a modified ROM that directly incorporates the pressure term in the model. The ROM is then stabilized making use of a method based on the fine scale equations. An improvement of the POD solution subspace is performed thanks to an hybrid method that couples direct numerical simulations and reduced order model simulations. The methods proposed are tested on the two-dimensional confined square cylinder wake flow in laminar regime

A numerical study of two dimensional flows past a bluff body for dilute polymer solutions

International audienceIn this paper, we use a simple Oldroyd B constitutive model to study the role of the viscoelasticity of dilute polymer solutions in two-dimensional flows past a bluff body using numerical simulations. This investigation is motivated by the numerous experimental results obtained in quasi two dimensional systems such as soap film channels. The numerical modeling is novel for this case and therefore a comprehensive comparison is carried out to validate the present penalization method and artificial boundary conditions. In particular we focus on flow past a circular object for various values of the Reynolds number, Weissenberg number, and polymer viscosity ratio. Drag enhancement and drag reduction regimes are discussed in detail along with their flow features such as the pattern of vortex-shedding, the variation of lift as well as changes in pressure, elongational rates, and polymer stress profiles. A comprehensive study of the flow behavior and energy balance are carefully carried out for high Reynolds numbers. Flow instabilities in both numerical and experimental results are discussed for high Weissenberg number

Preliminary Results in Virtual Testing for Smart Buildings (Poster)

International audienceSmart buildings promise to revolutionize the way we live. Applications ranging from climate control to fire management can have significant impact on the quality and cost of these services. However, a smart building and any technology with direct effect on the safety of its occupants must undergo extensive testing. Virtual testing by means of computer simulation can significantly reduce the cost of testing and, as a result, accelerate the development of novel applications. Unfortunately, building physically-accurate simulation codes can be labor intensive. To address this problem, we propose a framework for rapid, physically-accurate virtual testing of smart building systems. The proposed framework supports analytical modeling and simulation of both a discrete distributed system as well as the physical environment that hosts it