Multi-agent planning and scheduling, execution monitoring and incremental rescheduling: Application to motorway traffic

This article describes a planning method applicable to agents with great perception and decision-making capabilities and the ability to communicate with other agents. Each agent has a task to fulfill allowing for the actions of other agents in its vicinity. Certain simultaneous actions may cause conflicts because they require the same resource. The agent plans each of its actions and simultaneously transmits these to its neighbors. In a similar way, it receives plans from the other agents and must take account of these plans. The planning method allows us to build a distributed scheduling system. Here, these agents are robot vehicles on a highway communicating by radio. In this environment, conflicts between agents concern the allocation of space in time and are connected with the inertia of the vehicles. Each vehicle made a temporal, spatial, and situated reasoning in order to drive without collision. The flexibility and reactivity of the method presented here allows the agent to generate its plan based on assumptions concerning the other agents and then check these assumptions progressively as plans are received from the other agents. A multi-agent execution monitoring of these plans can be done, using data generated during planning and the multi-agent decision-making algorithm described here. A selective backtrack allows us to perform incremental rescheduling

The determinants of innovation adoption

Using a sample of 46 000 EU firms from the Community Innovation Survey, this paper analyses the drivers of innovation adoption. In contrast to most empirical studies on innovation diffusion in which a specific technology is analyzed, this study covers several countries and industries in the European Union. Following Van de Ven and Van Praag (1981), Heckman's method is applied in a context of binary endogenous variable to explain the choices made by firms regarding innovation. Distinctions are made between the internal generation of innovation and the adoption of innovation produced by others, as well as between different types of adoption (product vs. process and cooperation-based adoption vs. isolated adoption). The study is focused on the impact of users' features and their cooperation with suppliers on the adoption choices. The results point out that cooperation is a key driver of adoption choices. Usual determinants such as firm size, absorptive capability or exports would foster generation of innovation instead of adoption.Innovation adoption; Innovation diffusion; Community Innovation Survey; Process adoption; Product adoption

THE IMPACT OF PRICES ON SEAFOOD TRADE: A PANEL DATA ANALYSIS OF THE FRENCH SEAFOOD MARKET

In the early 1990s, two major crises affected the French fish market. Low import prices were suspected to have affected import levels of fish. Therefore, this paper looks at the empirical economic factors of fish imports in France. Most economic papers related to this field use a demand function of imports for a single product and focus only on trade relations between two countries. In this research, a panel data trade model is used at the multilateral level with many trade partners and products over several years. Results are presented by product groups at both aggregated and disaggregated levels. French imports appear to be very sensitive to internal price competitiveness and nominal exchange rates, with a differentiated impact according to the degree of processing. From that model, simulations show the consequences of the implementation of a single European currency on seafood trade.International Relations/Trade, Resource /Energy Economics and Policy,

Numerical study of solid particle axial mixing in a fixed cylindrical drum with rotating paddles

Axial mixture characterization is a wide spread problem in granular particle blending processes such as in an horizontal drum mixer. The homogeneous mixture of particles is obtained by blending the particles via rotating paddles in a fixed cylindrical drum. This problem, common to many technological devices, is crucial in the manufacture of a broad variety of industrial products, such as polypropylene. The granular flow behavior in these systems is still poorly understood and the numerical study of such configurations receives increasing academic and industrial attention. In this paper, a study is conducted to investigate the effects of different aspects of the reactor design on the axial transport of monodisperse, uniform density and spherical polypropylene particles. Results show that principally the shape of the paddles is the important design consideration to enhance the axial transport of particles

Longitudinal Electrical Near-field generated by a Tapered Coax and studied with a Piezoelectric Film coupled with an Optical Probe

International audienceWe investigated the influence of using a conical end on the longitudinal electrical near-field generated by a coaxial cable. Simulations with Finite Integration Technique show that this influence greatly varies along the longitudinal axis. Experimental measurements were also carried out. To that purpose, we designed a new set-up to measure the electrical field in one direction with a spatial resolution of 100 microns in this direction, with nearly no perturbation by the other components of the field. This set-up uses a piezoelectric sintered PZT film and a heterodyne laser probe

Institutional entrepreneurs as translators : a comparative study in an emerging activity.

This paper analyzes the reasons why some institutional entrepreneurship strategies failed to translate an institution while other succeeded, by paying a specific attention to the interaction between material and discursive dimensions in the translation process. A theoretical framework integrating both dimensions of translation is first proposed in order to study strategies of competing entrepreneurs. Then a comparative study of three entrepreneurs translating practices of corporate social evaluation in the French context is used to investigate the processes through which competing translators achieved their objective more or less successfully.neo-institutionalisme; translation; corporate social responsibility;

One way to design the control law of a mini-UAV.

International audienceThis paper deals with a method used to design the control law of the μDrone MAV. This vehicle uses six propellers to fly and the dynamic model approximation for the motion is a MIMO linear time-invariant system. As we want to design a linear regulator, it is necessary to build a robust feedback control law. The LQ state feedback regulator design is applied to a standard model, tacking into account some perturbations. This is why the model is augmented with a perturbation vector and an observable subsystem is extracted in order to build a state estimator whose gain is the solution of a LQ problem. The subsystem is then decomposed into a controllable set and an uncontrollable one. The use of an asymptotic rejection strategy of the influence of uncontrollable modes gives the possibility to find a state feedback applied only to the controllable ones. Here again feedback matrix is chosen as the solution of a LQ problem. To compute the weighting matrices of quadratic criterions we use a “partial observability gramian”. The great advantage of this method is due to the use of only three scalars to synthesize the control law

Imperata cylindrica

Imperata cylindrica est une espèce adventice pérenne agressive par ses rhizomes vigoureux et ses semences fortement disséminées par le vent. Le désherbage est difficile, soit par un travail du sol avec un labour profond, soit à l'aide d'herbicide