Le cyberactivisme à l'heure de la révolution tunisienne

In this paper, we examine the contribution of the social Web in the events that led to the fall of the regime of Ben Ali in January 14, 2011. We take an interest in cyberactivism during the revolution for thinking about the ways of writing and archiving of the collective memory of Tunisia. In addition, the role played by cyberactivists through censored social platforms and websites is especially surprising in the sequence of events leading to the collapse considering how strong was the repression. We study the tools, methods and procedures of the actions carried out by cyberactivists to bypass repression, highlighting how in social events the Web acted as a relay of information, a catalyst of contestation and, since January 15, 2011, an outlet of the trauma of Ben Ali's fall. We also investigate about how coordination between the Web and the street took place in the mobilization of the protest. Finally, we reflect on the changing role of online activists in post-revolutionary Tunisia and the need to redefine their roles, their speeches and their goals. The debate about reclaiming the public sphere, a watermark of our analysis, permits to observe how the reconstruction process is at work. The learning of democratic public debate takes place in a context charged with conflict, tension and disagreements of various kinds.Nous examinons la contribution du Web social dans l'enchaînement des évènements qui vont mener à la chute du régime de Ben Ali le 14 janvier 2011. L'intérêt porté au cyberactivisme à l'heure de la révolution engage notre réflexion sur l'écriture et l'archivage de la mémoire collective tunisienne. Par ailleurs, le rôle joué par les cyberactivistes à travers les plates-formes sociales et les sites Web pourtant censurés, a été pour le moins surprenant dans l'enchaînement des évènements menant à la chute du régime tant la répression était forte. Nous étudions donc les outils, les modalités et les procédures d'action engagés par les cyberactivistes afin de contourner cette répression. Cette analyse permet de mettre en évidence la fonction de relais de l'information que le Web social a joué durant les évènements, de catalyseur d'une partie de la contestation et, à partir du 15 janvier 2011, d'exutoire du traumatisme Ben Ali. Nous nous interrogeons également sur l'étendue de la coordination entre le Web et la rue dans la mobilisation de la contestation. Enfin, nous réfléchissons sur l'évolution du rôle des cyberactivistes dans la Tunisie post-révolutionnaire et sur la nécessité de redéfinir leurs rôles, leurs discours et leurs objectifs. Le débat sur la réappropriation de la sphère publique, en filigrane de cette analyse, permet d'observer un processus de reconstruction qui est à l'œuvre. L'apprentissage du débat public démocratique s'effectue dans un contexte porteur de conflits, de tensions et de divergences multiples

Crise d'identité arabo-islamique ; rapports à l'Occident et enjeux du discours radical

Dans la mémoire collective arabo-islamique, l'Occident renvoie à une image ambiguë et porteuse de tensions multiples. Il est, en effet, curieux de constater qu'il existe un rapport de rejet et en même temps de fascination envers cet ensemble . Ce rapport oscillant entre le “moi” arabo-islamique et les “autres” (les Occidentaux) traduit un malaise de perception de l'Occident en tant qu'interlocuteur. Pourtant, cette ambivalence ainsi que ces tensions ne représentent qu'un aspect de la crise identitaire qui traverse l'ensemble arabo-islamique. Car, en dehors du rapport complexe avec l'Occident, il existe une crise de reconnaissance et de définition de ce même “moi” face à sa propre culture-religion et face au monde qui l'entoure. Par ailleurs, l'on sait que les retombées de la domination coloniale se ressentent encore aujourd'hui. Seulement, elles sont aussi présentes au sein même du discours identitaire arabo-islamique en ce sens où l'on se définit comme étant le monde vaincu et opprimé. De l'opposition d'un passé islamique sujet de fierté et d'un présent porteur d'auto-dépréciation, naît le malaise identitaire. C'est dans ce climat qu'est apparu un discours qui trouve une forte résonance : le discours radical. Il est fort intéressant de se pencher sur le rôle de ce discours dans l'appropriation même du moi arabo-islamique et de la culture-religion régnant dans cette sphère. En ce sens, le discours fondamentaliste s'érige au milieu de ces tensions en tant que “sauveur” au sens weberien du terme. Il se propose, tout en essayant de le remplir, de délimiter l'espace public et de donner une issue à la crise en définissant par-là même l'identité arabo-islamique. Il se base sur une stratégie argumentative fondée sur le référencement à une mémoire collective historique partagée par l'ensemble des nations qui constituent cette sphère

COCO: A Platform for Comparing Continuous Optimizers in a Black-Box Setting

We introduce COCO, an open source platform for Comparing Continuous Optimizers in a black-box setting. COCO aims at automatizing the tedious and repetitive task of benchmarking numerical optimization algorithms to the greatest possible extent. The platform and the underlying methodology allow to benchmark in the same framework deterministic and stochastic solvers for both single and multiobjective optimization. We present the rationales behind the (decade-long) development of the platform as a general proposition for guidelines towards better benchmarking. We detail underlying fundamental concepts of COCO such as the definition of a problem as a function instance, the underlying idea of instances, the use of target values, and runtime defined by the number of function calls as the central performance measure. Finally, we give a quick overview of the basic code structure and the currently available test suites.Comment: Optimization Methods and Software, Taylor & Francis, In press, pp.1-3

Modeling Perception-Action Loops: Comparing Sequential Models with Frame-Based Classifiers

International audienceModeling multimodal perception-action loops in face-to-face interactions is a crucial step in the process of building sensory-motor behaviors for social robots or users-aware Embodied Conversational Agents (ECA). In this paper, we compare trainable behavioral models based on sequential models (HMMs) and classifiers (SVMs and Decision Trees) inherently inappropriate to model sequential aspects. These models aim at giving pertinent perception/action skills for robots in order to generate optimal actions given the perceived actions of others and joint goals. We applied these models to parallel speech and gaze data collected from interacting dyads. The challenge was to predict the gaze of one subject given the gaze of the interlocutor and the voice activity of both. We show that Incremental Discrete HMM (IDHMM) generally outperforms classifiers and that injecting input context in the modeling process significantly improves the performances of all algorithms

Graphical models for social behavior modeling in face-to face interaction

International audienceThe goal of this paper is to model the coverbal behavior of a subject involved in face-to-face social interactions. For this end, we present a multimodal behavioral model based on a Dynamic Bayesian Network (DBN). The model was inferred from multimodal data of interacting dyads in a specific scenario designed to foster mutual attention and multimodal deixis of objects and places in a collaborative task. The challenge for this behavioral model is to generate coverbal actions (gaze, hand gestures) for the subject given his verbal productions, the current phase of the interaction and the perceived actions of the partner. In our work, the structure of the DBN was learned from data, which revealed an interesting causality graph describing precisely how verbal and coverbal human behaviors are coordinated during the studied interactions. Using this structure, DBN exhibits better performances compared to classical baseline models such as Hidden Markov Models (HMMs) and Hidden Semi-Markov Models (HSMMs). We outperform the baseline in both measures of performance, i.e. interaction unit recognition and behavior generation. DBN also reproduces more faithfully the coordination patterns between modalities observed in ground truth compared to the baseline models

Self-adaptive hybrid genetic algorithm using an ant-based algorithm

The pheromone trail metaphor is a simple and effective way to accumulate the experience of the past solutions in solving discrete optimization problems. Ant-based optimization algorithms have been successfully employed to solve hard optimization problems. The problem of achieving an optimal utilization of a hybrid genetic algorithm search time is actually a problem of finding its optimal set of control parameters. In this paper, a novel form of hybridization between an ant-based algorithm and a genetic-local hybrid algorithm is proposed. An ant colony optimization algorithm is used to monitor the behavior of a genetic-local hybrid algorithm and dynamically adjust its control parameters to optimize the exploitation-exploration balance according to the fitness landscape

Accelerating genetic schema processing through local search

peer reviewedAchieving a balance between the exploration and exploitation capabilities of genetic algorithms is a key factor for their success in solving complicated search problems. Incorporating a local search method within a genetic algorithm can enhance the exploitation of local knowledge but it risks decelerating the schema building process. This paper defines some features of a local search method that might improve the balance between exploration and exploitation of genetic algorithms. Based on these features a probabilistic local search method is proposed. The proposed search method has been tested as a secondary method within a staged hybrid genetic algorithm and as a standalone method. The experiments conducted showed that the proposed method can speed up the search without affecting the schema processing of genetic algorithms. The experiments also showed that the proposed algorithm as a standalone algorithm can, in some cases, outperform a pure genetic algorithm

Setting temporal baselines for biodiversity : the limits of available monitoring data for capturing the full impact of anthropogenic pressures

Temporal baselines are needed for biodiversity, in order for the change in biodiversity to be measured over time, the targets for biodiversity conservation to be defined and conservation progress to be evaluated. Limited biodiversity information is widely recognized as a major barrier for identifying temporal baselines, although a comprehensive quantitative assessment of this is lacking. Here, we report on the temporal baselines that could be drawn from biodiversity monitoring schemes in Europe and compare those with the rise of important anthropogenic pressures. Most biodiversity monitoring schemes were initiated late in the 20th century, well after anthropogenic pressures had already reached half of their current magnitude. Setting temporal baselines from biodiversity monitoring data would therefore underestimate the full range of impacts of major anthropogenic pressures. In addition, biases among taxa and organization levels provide a truncated picture of biodiversity over time. These limitations need to be explicitly acknowledged when designing management strategies and policies as they seriously constrain our ability to identify relevant conservation targets aimed at restoring or reversing biodiversity losses. We discuss the need for additional research efforts beyond standard biodiversity monitoring to reconstruct the impacts of major anthropogenic pressures and to identify meaningful temporal baselines for biodiversity

Master of Science

thesisThis work studies the removal of arsenic (V), arsenate, and arsenic (III), arsenite, from aqueous solution using calcined Quintinite-3T (Al/Mg mixed oxides) and calcined La-LDHs (La/Mg mixed oxides). The two adsorbents Quintinite-3T and La-LDHs were prepared, calcined at different temperatures, and characterized by XRD, BET, and SEM. The surface area of the calcined Quintinite-3T was 193.4 m2/g, while the surface area of the calcined La-LDHs was 112.4 m2/g. The particles size ranged from 12 to 56 nm for the uncalcined Quintinite-3T and from 24 to 42 nm for the calcined Quintinite-3T. The particle size ranged from 27 to 56 nm for as-synthesized La-LDHs and from 18 to 35 nm for the calcined La-LDHs. Also, new hybrid adsorbent was synthesized and characterized as well. Kinetic analysis, adsorption isotherm, and factors affecting the adsorption were investigated. Calcined Quintinite-3T retained As(v) and did not release it back to water even after an entire month. The adsorption of As(V) and As(III) by calcined La-LDHs increased with time up to 2 weeks and 1 month, respectively