Scheduler-oriented algorithms to improve human-machine cooperation in transportation scheduling support systems

International audienceA decision support system designed to enhance human-machine interaction in transportation scheduling is proposed. We aim to integrate human factors and ergonomics from the beginning of the design phase and to propose a system fitted with enough flexibility to be able to deal with the characteristics of a dynamic context such as transportation scheduling. In this interdisciplinary approach, a link is done between problem solving methods (operations research techniques and data classification algorithms) and human-machine interaction (solving control modes). A set of scheduler-oriented algorithms favouring human-machine cooperation for problem solving is proposed. Some of these algorithms have been efficiently tested on instances of the literature. Finally, an original framework aiming to assist scheduler in constraint relaxation when the problem becomes infeasible is proposed and evaluated

Implications of technological changes in vehicle routing interfaces for planners' constraint processing

International audienceThis study sought to assess the consequences of technological changes in vehicle routing interfaces for planners' constraint processing during route selection. We began by developing a model of domain constraints for the generic vehicle routing problem, in order to characterize planners' constraint processing and assess the visibility of constraints on different routing interfaces. An experiment featuring vehicle routing problems was then designed to test interfaces reflecting technological changes, including automation leading to simplified interfaces and the display of multiple routes computed by algorithms. Twelve participants who had worked for a small transport company for nine months were exposed to all these interfaces. Mental workload, performance and decision-making times were measured. Results revealed that automation decreases mental workload and decision times, attributable to the abridged (vs. unabridged) display of constraints on the interface. Results also showed that the perceptual (vs. analytical) display of routes greatly decreases decision times and enhances performances

Analyse du domaine de travail pour les problèmes de tournées de véhicules

Cet article s'inscrit dans une démarche de proposition d'une approche interdisciplinaire appliquée à la logistique des transports. On s'intéresse plus particulièrement à la conception d'une architecture générique pour le problème de tournées de véhicules (VRP). On propose ainsi une articulation entre des méthodes de recherche opérationnelle (principalement la programmation par contraintes) et une analyse du domaine de travail issue de l'ergonomie cognitive

An interdisciplinary method for a generic vehicle routing problem decision support system

International audienceIn this paper, we propose an interdisciplinary method for the logistics of transportation. It focuses on the design of a generic architecture for the vehicle routing problem (VRP). We highlight that human factors and dynamics aspects are generally ignored in the classical approaches to solve the vehicle routing problem. In our study, a link is done between methods of operations research (specific methods to solve vehicle routing problems and constraint programming techniques) and a work domain analysis technique coming from cognitive ergonomics. The proposed architecture allows to consider and to process the constraints identified by the work domain analysis during the problem resolution. It is also well adapted to the consideration of the Human as a main actor in the decision-making process

Work domain analysis and ecological interface for the vehicle routing problem

International audienceIn this paper, we propose a work domain analysis for the vehicle routing problem. This analysis facilitates the identification of the problem constraints. The analysis is done through an abstraction hierarchy which facilitates an ecological user-interface design. The proposed decision support system and the ecological interfaces are presented. Finally, we propose an experimental study in order to evaluate the influence on the user for one of these interfaces

A decision support system for vehicle routing based on model inversion and data analysis

International audienceIn this paper, we present a three-phase solving mechanism for the vehicle routing problem. The solving mechanism is part of a decision support system architecture deduced from an interdisciplinary study. We highlight that human factors and dynamic aspects are generally ignored in the classical approaches to solve the problem. In our approach, a link is done between methods of operations research and an ecological interface design coming from cognitive ergonomics. We focus our study in how to manage the constraint relaxation if the problem is not satisfiable. We propose and evaluate model inversion techniques and data classification based methods in order to determine the most suitable constraints to relax in priority

Agile low phase noise radio-frequency sine wave generator applied to experiments on ultracold atoms

We report on the frequency performance of a low cost (~500$) radio-frequency sine wave generator, using direct digital synthesis (DDS) and a field-programmable gate array (FPGA). The output frequency of the device may be changed dynamically to any arbitrary value ranging from DC to 10 MHz without any phase slip. Sampling effects are substantially reduced by a high sample rate, up to 1 MHz, and by a large memory length, more than 2.10^5 samples. By using a low noise external oscillator to clock the DDS, we demonstrate a phase noise as low as that of the master clock, that is at the level of -113 dB.rad^2/Hz at 1 Hz from the carrier for an output frequency of 3.75 MHz. The device is successfully used to confine an ultracold atomic cloud of rubidium 87 in a RF-based trap, and there is no extra heating from the RF source.Comment: 10 pages, 6 figure

Accompanying Symptoms Overlap during Attacks in Menière’s Disease and Vestibular Migraine

Journal Article;Menière's disease and vestibular migraine (VM) are the most common causes of spontaneous recurrent vertigo. The current diagnostic criteria for the two disorders are mainly based on patients' symptoms, and no biological marker is available. When applying these criteria, an overlap of the two disorders is occasionally observed in clinical practice. Therefore, the present prospective multicenter study aimed to identify accompanying symptoms that may help to differentiate between MD, VM, and probable vestibular migraine (pVM). Two hundred and sixty-eight patients were included in the study (MD: n = 119, VM: n = 84, pVM: n = 65). Patients with MD suffered mainly from accompanying auditory symptoms (tinnitus, fullness of ear, and hearing loss), while accompanying migraine symptoms (migraine-type headache, photo-/phonophobia, visual aura), anxiety, and palpitations were more common during attacks of VM. However, it has to be noted that a subset of MD patients also experienced (migraine-type) headache during the attacks. On the other hand, some VM/pVM patients reported accompanying auditory symptoms. The female/male ratio was statistically higher in VM/pVM as compared to MD, while the age of onset was significantly lower in the former two. The frequency of migraine-type headache was significantly higher in VM as compared to both pVM and MD. Accompanying headache of any type was observed in declining order in VM, pVM, and MD. In conclusion, the present study confirms a considerable overlap of symptoms in MD, VM, and pVM. In particular, we could not identify any highly specific symptom for one of the three entities. It is rather the combination of symptoms that should guide diagnostic reasoning. The identification of common symptom patterns in VM and MD may help to refine future diagnostic criteria for the two disorders.This study was supported by a grant from CRP Santé and the Ministère de l’Enseignement Supérieur et de la Recherche, Grand-Duché de Luxembourg.Ye

Characterization of nanostructured SnO2 films deposited by reactive DC-magnetron sputtering

Nanostructured tin oxide thin films were deposited on silicon and glass slides substrates by reactive DC-Magnetron sputtering using a tin target in a mixture of argon and oxygen gases. The substrate temperature was varied in the range from 53 to 243 oC, keeping the other deposition parameters constant. The tin oxide films were characterized by: Scanning Electron Microscopy, Energy Dispersive Spectrometry, X Ray Diffraction, microRaman spectroscopy and UV-VIS spectroscopy. It was found that the substrate temperature has an effect mainly on the structural, morphological and optical properties of the thin films. At 53 and 90 oC the tetragonal crystalline phase was obtained while a mixture of crystalline phases (o-SnO2 and t-SnO2) was obtained at 148, 185 and 243 oC