COLLABORATIVE CONSUMPTION THROUGH NEW TECHNOLOGIES

The goal of the present paper is to present the raise of collaborative consumption through new technologies, and find out the impact of this new economic system on the contemporary society. In a first place the theoretical part provide an overview of the collaborative consumption in general, with definitions, consideration of the levels of sharing economy, and main success of the collaborative organizations in the 21th century. Then a part highlighting the key role of new technologies and internet for the development of this concept is mentioned, with a notion of access, trust and role played by communities in this system. Nonetheless the reasons of involvement to this sharing economy are given and explanations about how sharing economy is giving answered to issues of this century, followed by the problems concerning the impact on traditional businesses. The experiment, survey and interview were aimed at testing the knowledge of the respondents on the concept, discover which reasons influence the involvement and find out which place do they give to sharing economy as a change of the consuming behaviors. Data for the research were collected from 108 respondents, through an online survey. Subjects were randomly selected. The interview was conduct with a Finnish user of couch surfing, a collaborative lifestyle. This study support the view that collaborative consumption implies modification in the economic system nowadays, and that it could redefine the relation of ownership of the hyper-consumption times. Respondents seemed mainly willing to try and adopt more regular collaborative behaviors. In addition developments of new technologies, synchronized with new reputation systems building the trust are going to empower users and give strength to collaborative consumption. Nevertheless the study questions the boundaries of collaborative economy, and the relation with capitalism model. Also it will have to face a good management of data to promote trust, the essence of this new system. To succeed collaborative economy should work and balance with traditional businesses and states’ institutions to manage a good transition

SimGrid: a Sustained Effort for the Versatile Simulation of Large Scale Distributed Systems

In this paper we present Simgrid, a toolkit for the versatile simulation of large scale distributed systems, whose development effort has been sustained for the last fifteen years. Over this time period SimGrid has evolved from a one-laboratory project in the U.S. into a scientific instrument developed by an international collaboration. The keys to making this evolution possible have been securing of funding, improving the quality of the software, and increasing the user base. In this paper we describe how we have been able to make advances on all three fronts, on which we plan to intensify our efforts over the upcoming years.Comment: 4 pages, submission to WSSSPE'1

Application of ab initio calculations to collagen and brome mosaic virus

Title from PDF of title page, viewed on July 16, 2014VitaThesis advisor: Wai-Yim ChingIncludes bibliographic references (pages 85-91)In bio-related research, large proteins are of important interest. We study two such proteins. Collagen contains one such protein, the collagen triple-helix, which forms part of the structural matrix for animals, such as in their bones and teeth. 1JS9 is another protein that is a component of the protein shell of the brome mosaic virus (BMV). And BMV is important for drug delivery and imaging. To better understand the properties of these proteins, quantum mechanically (QM) based results are needed, however computationally feasible methods are also necessary. The Orthogonalized Linear Combination of Atomic Orbitals (OLCAO) method is wellsuited for application to such large proteins. However, a new approach to reduce the computational cost and increase the computational feasibility is required and this extension to the method we call the Amino-Acid Based Method (AAPM) of OLCAO. In brief, the AAPM calculates electronic, self-consistent fi eld (scf) potentials for individual amino-acids with their neighboring amino-acids included as a boundary condition. This allows the costly scf part of the calculation to be skipped out. Additionally, the number of potentials used to describe the 1JS9 protein is also minimized. Results for e ective charge and bond order are obtained and analyzed for Collagen and preliminary eff ective charge results are obtained for 1JS9. The e ffective charge results of the AAPM represent well those already obtained with the scf OLCAO result, but with reduced cost and preserved accuracy. The bond order results for Collagen also represent well the hydrogen bonding based on bond distances observed in experimentally-dervied images between the individual chains of the collagen triple-helix as well as the observed hydrogen bonding networkAbstract -- List of illustrations -- List of tables -- Acknowledgments -- Introduction -- Theoretical background -- Method -- Models for collagen and the amino acid potential method -- Collagen results -- Brome mosaic virus results -- Future work -- Initial input file for AAPM -- AAPM programs and potential reduction method -- Reference

Dynamic Performance Forecasting for Network-Enabled Servers in a Heterogeneous Environment

This paper presents a tool for dynamic forecasting of Network-Enabled Servers performance. FAST (Fast Agent's System Timer}) is a software package allowing client applications to get an accurate forecast of communicat- ion and computation times and memory use in a heterogeneous environment. It relies on low level software packages, i.e., network and host monitoring tools, and some of our developments in computation routines modeling. The FAST internals and user interface are presented and a comparison between the execution time predicted by FAST and the measured time of complex matrix multiplication executed on an heterogeneous platform is given

GRAS: a Research and Development framework for Grid services

Grid platforms federate large numbers of resources across several organizations. While their promises are great, these platforms have proven challenging to use because of inherent heterogeneity and dynamic characteristics. Therefore, grid application development is possible only if robust distributed services infrastructures, e.g. for resource and data discovery, resource monitoring or application deployment, are available. These infrastructures, which are large-scaled distributed loosely-coupled applications, are very difficult to design, develop and tune.This paper presents the Grid Reality And Simulation (GRAS) framework that allows grid developers to first implement and experiment with such an infrastructure in simulation, benefiting from a controlled and fast environment. The infrastructure can then be deployed in situ without code modification. We first detail the design goals and the implementation of GRAS, and contrast them to the state of the art. We then present a case study to highlight the fundamentals of GRAS and illustrate its ease-of-use. In addition, we quantify the complexity of a code example using either GRAS or several other communication solutions. We also conduct tests over LAN and WAN networks to assess the performance. We find that the code using GRAS is simpler and shorter than any other solution while achieving better performance than most of the other solutions

SimGrid: a Generic Framework for Large-Scale Distributed Experiments

International audienceIn this paper we describe a comprehensive simulation framework, SimGrid, for the simulation of distributed applications on distributed platforms. Our goal is to describe the salient capabilities of SimGrid and explain how they allow users to perform simulations for a wide range of applications and platforms

A Simple Model of Communication APIs – Application to Dynamic Partial-order Reduction

We are interested in the verification, using model checking, of distributed programs that communicate asynchronously over standard communication APIs such as MPI. This is feasible only if the set of executions that the model checker explores is aggressively reduced to a subset of representative executions, using techniques such as dynamic partial-order reduction. We propose a small set of core primitives in terms of which such APIs can be defined and formally specify these primitives in TLA+. From this specification we derive theorems about the (in)dependence of invocations of the primitives, and use them in a DPOR-based verifier that runs within SimGrid, a simulation framework for distributed programming. Our preliminary experimental results indicate that we obtain good reductions, even though complex network operations are implemented in terms of the core commu nication primitives

Assessing the Performance of MPI Applications Through Time-Independent Trace Replay

International audienceSimulation is a popular approach to obtain objective performance indicators platforms that are not at one's disposal. It may help the dimensioning of compute clusters in large computing centers. In this work we present a framework for the off-line simulation of MPI applications. Its main originality with regard to the literature is to rely on time-independent execution traces. This allows us to completely decouple the acquisition process from the actual replay of the traces in a simulation context. Then we are able to acquire traces for large application instances without being limited to an execution on a single compute cluster. Finally our framework is built on top of a scalable, fast, and validated simulation kernel. In this paper, we present the used time-independent trace format, investigate several acquisition strategies, detail the developed trace replay tool, and assess the quality of our simulation framework in terms of accuracy, acquisition time, simulation time, and trace size.La simulation est une approche très populaire pour obtenir des indicateurs de performances objectifs sur des plates-formes qui ne sont pas disponibles. Cela peut permettre le dimensionnement de grappes de calculs au sein de grands centres de calcul. Dans cet article nous présentons un outil de simulation post-mortem d'applications MPI. Sa principale originalité au regard de la littérature est d'utiliser des traces d'exécution indépendantes du temps. Cela permet de découpler intégralement le processus d'acquisition des traces de celui de rejeu dans un contexte de simulation. Il est ainsi possible d'obtenir des traces pour de grandes instances de problèmes sans être limité à des exécutions au sein d'une unique grappe. Enfin notre outil est développé au dessus d'un noyau de simulation scalable, rapide et validé. Cet article présente le format de traces indépendantes du temps utilisé, étudie plusieurs stratégies d'acquisition, détaille l'outil de rejeu que nous avons dévelopé, et evalué la qualité de nos simulations en termes de précision, temps d'acuisition, temps de simulation et tailles de traces

On the electro-oxidation of small organic molecules: Towards a fuel cell catalyst testing platform based on gas diffusion electrode setups

The electrocatalytic oxidation of small organic compounds such as methanol or formic acid has been the subject of numerous investigations in the last decades. The motivation for these studies is often their use as fuel in so-called direct methanol or direct formic acid fuel cells, promising alternatives to hydrogen-fueled proton exchange membrane fuel cells. The fundamental research spans from screening studies to identify the best performing catalyst materials to detailed mechanistic investigations of the reaction pathway. These investigations are commonly performed at conditions quite different to fuel cell devices, where no liquid electrolyte will be present. We previously developed a gas diffusion electrode setup to mimic “real-life” reaction conditions and study electrocatalysts for oxygen gas reduction or water splitting. It is here demonstrated that the setup is also suitable to investigate the properties of catalysts for the electro-oxidation of small organic molecules simulating conditions of low temperature proton exchange membrane fuel cells

GRAS: a Research and Development Framework for Grid and P2P Infrastructures

International audienceDistributed service architectures are mandatory to handle the platform scale and dynamicity hindering the development of grid and P2P applications. These large-scaled distributed applications are difficult to design, develop and tune because of both theoretical and practical issues. This paper presents the GRAS framework that allows developers to first implement and experiment with such an infrastructure in simulation, benefiting from a controlled environment. The infrastructure can then be deployed in-situ without code modification. We detail our design goals, and contrast them with the state of the art. We study the exchange of a message (from the Pastry protocol) using either GRAS or several other solutions. We quantify both the code complexity and the performance and find that GRAS performs better according to both metrics