Building upon Fast Multipole Methods to Detect and Model Organizations

Many models in natural and social sciences are comprised of sets of inter-acting entities whose intensity of interaction decreases with distance. This often leads to structures of interest in these models composed of dense packs of entities. Fast Multipole Methods are a family of methods developed to help with the calculation of a number of computable models such as described above. We propose a method that builds upon FMM to detect and model the dense structures of these systems

GraphStream: A Tool for bridging the gap between Complex Systems and Dynamic Graphs

The notion of complex systems is common to many domains, from Biology to Economy, Computer Science, Physics, etc. Often, these systems are made of sets of entities moving in an evolving environment. One of their major characteristics is the emergence of some global properties stemmed from local interactions between the entities themselves and between the entities and the environment. The structure of these systems as sets of interacting entities leads researchers to model them as graphs. However, their understanding requires most often to consider the dynamics of their evolution. It is indeed not relevant to study some properties out of any temporal consideration. Thus, dynamic graphs seem to be a very suitable model for investigating the emergence and the conservation of some properties. GraphStream is a Java-based library whose main purpose is to help researchers and developers in their daily tasks of dynamic problem modeling and of classical graph management tasks: creation, processing, display, etc. It may also be used, and is indeed already used, for teaching purpose. GraphStream relies on an event-based engine allowing several event sources. Events may be included in the core of the application, read from a file or received from an event handler

Challenges in technology transfer: an actor perspective in a quadruple helix environment

© 2016, Springer Science+Business Media New York. This article presents and tests a knowledge and technology transfer framework in a quadruple helix environment, from an actor perspective. The Canadian forest products industry provides a unique opportunity for data collection through case studies as it is an industry built on a triple bottom line, which is managed for sustainable progress. By confronting the new framework to 31 professionals, we highlight the role and challenges faced by each helix. Several factors such as culture, time horizon management and the adaption of theory to practice appear to be determinant to improve technology transfer. We see in our work an important contribution to the generalization of knowledge and technology transfer processes in a quadruple helix environment

Assessment of high (diurnal) to low (seasonal) frequency variations of isoprene emission rates using a neural network approach

Using a statistical approach based on artificial neural networks, an emission algorithm (ISO-LF) accounting for high to low frequency variations was developed for isoprene emission rates. ISO-LF was optimised using a data base (ISO-DB) specifically designed for this work, which consists of 1321 emission rates collected in the literature and 34 environmental variables, measured or assessed using National Climatic Data Center or National Centers for Environmental Predictions meteorological databases. ISO-DB covers a large variety of emitters (25 species) and environmental conditions (10° S to 60° N). When only instantaneous environmental regressors (instantaneous air temperature <i>T0</i> and photosynthetic photon flux density <i>L0</i>) were used, a maximum of 60% of the overall isoprene variability was assessed with the highest emissions being strongly underestimated. ISO-LF includes a total of 9 high (instantaneous) to low (up to 3 weeks) frequency regressors and accounts for up to 91% of the isoprene emission variability, whatever the emission range, species or climate investigated. ISO-LF was found to be mainly sensitive to air temperature cumulated over 3 weeks (<i>T21</i>) and to <i>L0</i> and <i>T0</i> variations. <i>T21</i>, <i>T0</i> and <i>L0</i> only accounts for 76% of the overall variability

Communication models insights meet simulations

International audienceIt is well-known that taking into account communications while scheduling jobs in large scale parallel computing platforms is a crucial issue. In modern hierarchical platforms, communication times are highly different when occurring inside a cluster or between clusters. Thus, allocating the jobs taking into account locality constraints is a key factor for reaching good performances. However, several theoretical results prove that imposing such constraints reduces the solution space and thus, possibly degrades the performances. In practice, such constraints simplify implementations and most often lead to better results. Our aim in this work is to bridge theoretical and practical intuitions, and check the differences between constrained and unconstrained schedules (namely with respect to locality and node contiguity) through simulations. We have developped a generic tool, using SimGrid as the base simulator, enabling interactions with external batch schedulers to evaluate their scheduling policies. The results confirm that insights gained through theoretical models are ill-suited to current architectures and should be reevaluated

Alignement des capacités TI sur les besoins en information et performance des PME internationales

Cette recherche vise à expliquer l'effet de l'alignement entre les capacités Tl et les besoins en information sur la performance des PME internationales1. Elle cherche simultanément à comprendre l'effet des facteurs environnementaux et stratégiques sur le développement des capacités Tl et des besoins en information. Pour atteindre ce but, la recherche se divise en deux phases. La première phase consiste en une recherche qualitative avec études de cas alors que la seconde phase est une recherche quantitative par enquête. La recherche qualitative désire valider la pertinence des construits de recherche que sont l'environnement (mesuré par l'intensité informationnelle et l'incertitude environnementale), les besoins en information (communication, contrôle et collaboration), la stratégie internationale, les capacités Tl et la performance. Elle vise également à valider des liens attendus entre ceux-ci (l'environnement et les besoins en information comme variables exogènes, agissant comme antécédents des capacités Tl, et la performance comme variable endogène). La deuxième phase est la réalisation d'une recherche quantitative appuyée par un questionnaire d'enquête. Ce questionnaire (français et anglais) a été envoyé à 885 directeurs de PME internationales, 174 réponses ont été obtenues (pour un taux de réponse de 19,6 %), permettant par PLS de confirmer ou non nos hypothèses de recherche. Le modèle de recherche est vérifié à l'aide de la technique des moindres carrés partiels (Partial Least Squares, PLS). On constate tout d'abord que les facteurs influençant le développement des capacités Tl pour une PME internationale sont l'environnement et la stratégie internationale retenue. Les résultats montrent également l'influence directe des capacités Tl sur la performance de la PME et enfin qu'un alignement entre les besoins en information (collaboration et contrôle) et les capacités Tl de l'organisation permet à la PME d'être plus performante.2 Cette recherche présente un modèle de réussite pour une PME dans un contexte d'internationalisation. Celle-ci passe par le déploiement de capacités Tl en lien avec des besoins en information ciblés (communication et contrôle). Les capacités Tl doivent être choisies et mises en place en prenant en considération l'environnement et la stratégie organisationnelle. Les résultats de cette thèse constituent de nouvelles orientations d'études pour les recherches sur l'alignement stratégique et sur les capacités Tl. Elle offre d'importantes contributions pratiques et théoriques de par ses résultats (alignement entre des besoins et des capacités Tl, développement des capacités Tl, influence sur la performance) et de par son contexte (PME internationales).1 Par internationales, nous entendons des PME déjà internationalisées ou en phase d'internationalisation.2 Dans cette recherche, les termes organisation, PME, firme et entreprise sont considérés indifféremment

A 24-h forecast of ozone peaks and exceedance levels using neural classifiers and weather predictions

A neural network combined to a neural classifier is used in a real time forecasting of hourly maximum ozone in the centre of France, in an urban atmosphere. This neural model is based on the MultiLayer Perceptron (MLP) structure. The inputs of the statistical network are model output statistics of the weather predictions from the French National Weather Service. With this neural classifier, the Success Index of forecasting is 78% whereas it is from 65% to 72% with the classical MLPs. During the validation phase, in the Summer of 2003, six ozone peaks above the threshold were detected. They actually were seven

Using oracles for the design of efficient approximation algorithms

International audienceWe are interested here in oracle techniques for the design of approximation algo- rithms. Following the classical definition, an oracle is a black box capable of answering correctly and instantaneously any question. Several classical approximation scheme de- sign techniques (typically PTAS) can be revisited using oracle. Our objective in this work is to show that, conversely, oracle techniques are not limited to the design of PTAS. In particular, interactivity (using queries to oracle) may also lead to parameterized algorithm (whose complexity is exponential in a parameter, supposed to be "small"), that can be more practical than classical P T AS. Moreover, we aim at showing how it is possible to "degenerate" questions asked to the oracle to derive fast implementations of these interactive algorithms. These ideas will be illustrated on the classical makespan minimization on uniform machines problem (QCmax )

Batsim: a Realistic Language-Independent Resources and Jobs Management Systems Simulator

International audienceAs large scale computation systems are growing to exascale, Resources and Jobs Management Systems (RJMS) need to evolve to manage this scale modification. However, their study is problematic since they are critical production systems, where experimenting is extremely costly due to downtime and energy costs. Meanwhile, many scheduling algorithms emerging from theoretical studies have not been transferred to production tools for lack of realistic experimental validation. To tackle these problems we propose Batsim, an extendable, language-independent and scalable RJMS simulator. It allows researchers and engineers to test and compare any scheduling algorithm, using a simple event-based communication interface, which allows different levels of realism. In this paper we show that Batsim's behaviour matches the one of the real RJMS OAR. Our evaluation process was made with reproducibility in mind and all the experiment material is freely available

Lorraine Dumenil, Artaud et le cinéma

Après Breton, Duras ou Ponge, c’est Artaud qui est l’objet d’un essai monographique de la collection « Le cinéma des poètes ». Après avoir organisé en 2011 à la Villa Médicis une rétrospective des apparitions d’Artaud dans le cinéma des années 1920 et 1930, Lorraine Dumenil, professeure d’histoire et de théorie des arts, interroge dans Artaud et le cinéma la façon paradoxale dont l’auteur du Théâtre et son double aborde le septième art. Dans cet ouvrage synthétique, elle divise son étude en t..