Économie mixte | EPFL Graph Search

En théorie, une économie mixte est une économie dans laquelle le secteur privé et le secteur public coexistent en parts relativement équivalentes. Une illustration très emblématique de ce mélange d'économie de marché et d'économie planifiée est la politique économique française d'après la Seconde Guerre mondiale, qui était largement inspirée par le Programme du Conseil national de la Résistance. En Allemagne de nos jours, on parle également d'économie sociale de marché. En pratique, tous les systèmes économiques sont mixtes mais se distinguent par les parts relatives des secteurs privé et public. Le démantèlement de l'Union soviétique à la fin des années 1980 a marqué le début d'une période de « libéralisation » à l'échelle mondiale, notamment par la privatisation d'entreprises publiques et de services publics. La crise des subprimes de 2008 pourrait cependant inciter certains gouvernements à mettre un terme à cette tendance, voire à l'inverser. En France, l'économie mixte dite «

Decoding urban development dynamics through actor-network methodological approach

Jean-Claude Bolay, Marija Cvetinovic

Due to growing social and physical transformations, contemporary cities reveal the profound necessity of proper scientific approaches that are adjusted to conditions of global complexity and dynamic patterns of development. Predominance of an overall market economy, sporadic deregulations of administrative powers and a lack of local investment or resources, dominate urban reality. Incongruous urban decision-making procedures result in contextually inappropriate and incoherent urban management. We will explore these operational elements in Savamala neighbourhood in Belgrade. The actor-network theory.(ANT) is applied to analyse the hyper dynamic circumstances of transition in Serbia. An unclear regulatory framework, powerful,financial means for investment and limited institutional influence of citizen participation, deploy unstable urban development modalities at the neighbourhood level. ANT offers an insight into how urban norms, projections and structures unfold and how associations and translations of urban elements develop. Plausible yet complex collisions in Savamala constitute a challenge for ANT in mapping urban development processes and visualizing actors and networks through diagrams. Based on the presented results, the illustrative perspective of ANT minimalizes both the importance and the influence of the permanence of urban structures across time and space. Instead, ANT deals with a city as a contingent, fragmentary and heterogeneous, yet persistent product of actors, their roles, associations, agencies and networks. Possible adaptations of ANT should respond to the needs of non-scientific actors and practitioners for an interpretive tool that addresses undercover processes and mechanisms or provides explanations, recommendations or operational diagnoses on how to absorb urban development dynamics.

2017

Bidirectional interactions facilitate the integration of a robot into a shoal of zebrafish Danio rerio

Frank Bonnet, Bertrand Eric Collignon, Francesco Mondada, Vaios Papaspyros

Many studies on collective animal behavior seek to identify the individual rules that underlie collective patterns. However, it was not until the recent advancements of micro-electronic and embedded systems that scientists were able to create mixed groups of sensor-rich robots and animals and study collective interactions from the within a bio-hybrid group. In recent work, scientists showed that a robot-controlled lure is capable of influencing the collective decisions of zebrafish Danio rerio shoals moving in a ring and a two-room setup. Here, we study a closely related topic, that is, the collective behavior patterns that emerge when different behavioral models are reproduced through the use of a robotic lure. We design a behavioral model that alternates between obeying and disobeying the collective motion decisions in order to become socially accepted by the shoal members. Subsequently, we compare it against two extreme cases: a reactive and an imposing decision model. For this, we use spatial, directional and information theoretic metrics to measure the degree of integration of the robotic agent. We show that our model leads to similar information flow as in freely roaming shoals of zebrafish and exhibits leadership skills more often than the open-loop models. Thus, in order for the robot to achieve higher degrees of integration in the zebrafish shoal, it must, like any other shoal member, be bidirectionally involved in the decision making process. These findings provide insight on the ability to form mixed societies of animals and robots and yield promising results on the degree to which a robot can influence the collective decision making.

2019

Shoaling with fish: using miniature robotic agents to close the interaction loop with groups of zebrafish Danio rerio

Frank Bonnet

Robotic animals are nowadays developed for various types of research, such as bio-inspired robotics, biomimetics and animal behavior studies. The miniaturization of technologies and the increase in performance of embedded systems allowed engineers to develop more powerful, sophisticated and miniature devices. The case of robotic fish is a typical example of such challenging design: the fish locomotion and body movements are difficult to reproduce and the device has to move autonomously underwater. More specifically, in the case of collective animal behavior research, the robotic device has to interact with animals by generating and exploiting signals relevant for social behavior. Once perceived by the animal society as conspecific, these robots can become powerful tools to study the animal behaviors, as they can at the same time monitor the changes in behavior and influence the collective choices of the animal society. In this work, we present novel robotized tools that can integrate shoals of fish in order to study their collective behaviors. This robotic platform is composed of two subsystems: a miniature wheeled mobile robot that can achieve dynamic movements and multi-robot long-duration experiments, and a robotic fish lure that is able to beat its tail to generate fish-like body movements. The two subsystems are coupled with magnets which allows the wheeled mobile robot to steer the robotic fish lure so that it reaches very high speeds and accelerations while achieving shoaling. An experimental setup to conduct studies on mixed societies of artificial and living fish was designed to facilitate the experiments for biologists. A software framework was also implemented to control the robots in a closed-loop using data extracted from visual tracking that retrieved the position of the robots and the fish. We selected the zebrafish Danio rerio as a model to perform experiments to qualify our system. We used the current state of the art on the zebrafish social behavior to define the specifications of the robots, and we performed stimuli analysis to improve their developments. Bio-inspired controllers were designed based on data extracted from experiments with zebrafish for the robots to mimic the zebrafish locomotion underwater. Experiments involving a robot with a shoal of fish in a constrained environment showed that the locomotion of the robot was one of the main factor to affect the collective behavior of zebrafish. We also shown that the body movements and the biomimetic appearance of the lure could increase its acceptance by fish. Finally, an experiment involving a mixed society of fish and robots qualified the robotic system to be integrated among a zebrafish shoal and to be able to influence the collective decisions of the fish. These results are very promising for the field of fish-robot interaction studies, as we showed the effect of the robots in long-duration experiments and repetitively, with the same order of response from the animals.

EPFL2017

Shoaling with fish: using miniature robotic agents to close the interaction loop with groups of zebrafish Danio rerio

Frank Bonnet

EPFL2017