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Exploring the impact of industrial environment uncertainty on export sophistication
No full textInternational audienceA favorable industrial environment is important for increasing the sophistication and competitiveness of a country’s exports. However, a country’s industrial environment is bound to change dynamically. Therefore, this study explores the impact of industrial environment uncertainty on export complexity. Through an empirical analysis of panel data from 76 countries from 2010 to 2020, we find that political and social uncertainty significantly inhibits exports, while an uncertain economic environment significantly complicates exports. Moreover, uncertainty in the industrial environment affects high- and middle-income countries more than low-income countries. Furthermore, the analysis of regulatory effects shows that political uncertainty and social uncertainty have a substitution relationship in inhibiting export complexity. This study affirms the impact of industrial environment uncertainty on a country’s export capabilities and provides a reference for countries with different incomes to formulate and modify their industrial environment policies
Collective responses of flocking sheep (Ovis aries) to a herding dog (border collie)
No full textInternational audienceGroup-living organisms commonly exhibit collective escape responses, yet how information flows among group members in these events remains an open question. Here, we study the collective responses of a sheep flock (Ovis aries) to a shepherd dog (border collie) in a driving task between two well-defined target points. We collected high-resolution spatiotemporal data from 14 sheep and the dog, using Ultra-Wide-Band tags attached to each individual. We find that the spatial positions of sheep along the front-back axis of the group’s velocity strongly correlate with their impact on the collective movement. Our analyses reveal that, even though the dog chases the sheep flock from behind, directional information on shorter time scales propagates from the front of the group towards the rear; further, the dog adjusts its movement in response to the flock’s dynamics. We introduce an agent-based model that captures key data features. Specifically, in response to chasing, the sheep change their spatial relative positions less frequently and exhibit a transfer of directional information flow from front to back; this pattern disappears in the absence of chasing. Our study reveals some general insights into how directional information propagates in escaping animal groups
Complex Pulse Profile Optimization by Chromatic Dispersion Management in Coupled Opto Electronic Oscillator based on Semiconductor Optical Amplifier
No full textInternational audienceAn Ikeda map iterative numerical model completed with an analytical Gaussian analysis and experimental measurements of complex pulse profile and phase noise performance at 10 GHz are proposed. This work aims to study and optimize the chromatic dispersion of a fibered mode-locked laser (MLL) based on a semiconductor optical amplifier (SOA) as part of a coupled optoelectronic oscillator (COEO). We will demonstrate that a close to zero anomalous dispersion regime is preferred as it allows the generation of optical picosecond pulses with minimum full width at half maximum (FWHM) and maximizes the absolute value of chirp and peak power. This guarantees the generation of narrow and diffraction-limited optical pulses after the chromatic dispersion compensating stage prior photodetection in order to lower the phase noise of the microwave signal generated at 10 GHz but also for high-order microwave harmonics synthesis
First Steps of Designing Adaptable User Interfaces to Mediate Human-Robot Interaction
No full textInternational audienceThere is a wide diversity of platforms for teleoperating robots. Every robot, use case, and type of user brings a unique set of expectations. We propose that human-robot interaction should consider the opportunity to use an external device (such as a smartphone) to not only teleoperate but also mediate the interaction with a robot, either in telepresence or in co-presence. In this paper, we present first steps and ideas towards the development of this media. It involves, as first end-users, the members of the robotics department of our laboratory and considers all robotic platforms which are hosted there (assistance robots, terrestrial robots, robots humanoids, quadrupeds, etc.). We describe our user-centred design methodology, detailing the needs analysis and brainstorming sessions conducted. Following this, we outline the design and prototyping phases, showcasing the iterative development of our interface. Finally, we discuss the results from our evaluations and the implications for future work in creating flexible and inclusive interfaces for diverse user groups
Influence des modes de résonateur dans les VCSEL pour la mesure de absolue par réinjection optique
No full textNational audienceLa réinjection optique dans une diode laser est une méthode interférométrique pouvant être utilisée pour de la mesure de distance absolue. Nous démontrons que lorsque la source est un laser à cavité verticale émettant par la surface (VCSEL), le caractère multimode/monomode de la source laser a un impact direct sur la précision de la mesure
Integrate-and-Reset Feedback and Feedforward for a Solenoid With Unknown Parameters
No full textInternational audienceWe propose a hybrid feedback-feedforward control scheme for output current tracking in a solenoid, based on an integrate-and-reset paradigm. The feedback, based on a First-Order Reset Element, produces stabilizing inputs comprising diverging exponentials, inducing an aggressive feedback correction. The feedforward uses a hybrid recursive leastsquares method with directional forgetting. The hybrid nature of the control loop allows using non-exponentially stable filters, which preserve the past information, as opposed to the stable filters typically used in the adaptive control literature. We prove stability of both the estimation and the tracking error, also using a novel result on forward invariance of a desirable set where the information matrix evolves. Experimental results confirm the effectiveness of the proposed hybrid control scheme.</div
Monitoring of Ammonium and Nitrate Ions in Soil Using Ion-Sensitive Potentiometric Microsensors
No full textInternational audienceFocusing on the ChemFET (chemical field-effect transistor) technology, the development of a multi-microsensor platform for soil analysis is described in this work. Thus, different FET-based microdevices (i.e., pH-ChemFET pNH4-ISFET and pNO3-ISFET sensors) were realized with the aim of monitoring nitrogen-based ionic species in soil, evidencing quasi-Nernstian detection properties (>50 mV/decade) in appropriate concentration ranges for agricultural applications. Using a specific test bench adapted to important earth samples (mass: ~50 kg), first experiments were done in a lab, mimicking rainy periods as well as nitrogen-based fertilizer inputs. By monitoring pH, pNH4, and pNO3 in an acidic (pH ≈ 4.7) clay-silt soil matrix, different processes associated to the nitrogen cycle were characterized over a fortnight, demonstrating comprehensive results for ammonium nitrate NH4NO3 inputs at different concentrations, water additions, nitrification phenomena, and ammonium NH4+ ion trapping. Even if the ChemFET-based measurement system should be improved according to the soil(electrolyte)/sensor contact, such realizations and results show the ChemFET technology potentials for long-term analysis in soil, paving the way for future “in situ” approaches in the frame of modern farming
On the Complexity of Proving Polyhedral Reductions
No full textInternational audienceWe propose an automated procedure to prove polyhedral abstractions (also known as polyhedral reductions) for Petri nets. Polyhedral abstraction is a new type of state space equivalence, between Petri nets, based on the use of linear integer constraints between the marking of places. In addition to defining an automated proof method, this paper aims to better characterize polyhedral reductions, and to give an overview of their application to reachability problems. Our approach relies on encoding the equivalence problem into a set of SMT formulas whose satisfaction implies that the equivalence holds. The difficulty, in this context, arises from the fact that we need to handle infinite-state systems. For completeness, we exploit a connection with a class of Petri nets, called flat nets, that have Presburger-definable reachability sets. We have implemented our procedure, and we illustrate its use on several examples
Static anti-windup with shifted equilibria applied to a Segway-like vehicle
No full textInternational audienceLeveraging recent results on bounded stabilization of linear plants using shifted equilibria, we propose a novel anti-windup scheme for linear input-saturated plants with (asymmetric) saturation limits. We show that, with open-loop plants involving a continuum of equilibria, the proposed anti-windup solution provides an unbounded estimate of the basin of attraction, thereby overcoming typical limits of classical solutions. We also report on experiments performed on a segway-like vehicle, where the controller effectively displaces the segway between any two locations, due to unboundedness of the basin of attraction