A Multi-Agent System framework to support the decision-making in complex real-world domains

The aim of this work was to develop a framework capable of supporting the decision-making process in complex real-world domains, such as environmental, industrial or medical domains using a Multi-Agent approach with Rule-based Reasoning. The validation of the framework was done in the environmental domain, particularly in the area of river basins

State dependency of inhibitory control performance: an electrical neuroimaging study

Behavioral and brain responses to stimuli not only depend on their physical features but also on the individuals' neurocognitive states before stimuli onsets. While the influence of pre-stimulus fluctuations in brain activity on low-level perceptive processes is well established, the state dependency of high-order executive processes remains unclear. Using a classical inhibitory control Go/NoGo task, we examined whether and how fluctuations in the brain activity during the period preceding the stimuli triggering inhibition influenced inhibitory control performance. Seventeen participants completed the Go/NoGo task while 64-channel electroencephalogram was recorded. We compared the event-related potentials preceding the onset of the NoGo stimuli associated with inhibition failures false alarms (FA) vs. successful inhibition correct rejections (CR) with data-driven statistical analyses of global measures of the topography and strength of the scalp electric field. Distributed electrical source estimations were used to localize the origin of the event-related potentials modulations. We observed differences in the global field power of the event-related potentials (FA > CR) without concomitant topographic modulations over the 40 ms period immediately preceding NoGo stimuli. This result indicates that the same brain networks were engaged in the two conditions, but more strongly before FA than CR. Source estimations revealed that this effect followed from a higher activity before FA than CR within bilateral inferior frontal gyri and the right inferior parietal lobule. These findings suggest that uncontrolled quantitative variations in pre-stimulus activity within attentional and control brain networks influence inhibition performance. The present data thereby demonstrate the state dependency of cognitive processes of up to high- order executive levels

State dependency of inhibitory control performance: an electrical neuroimaging study

Behavioral and brain responses to stimuli not only depend on their physical features but also on the individuals' neurocognitive states before stimuli onsets. While the influence of pre-stimulus fluctuations in brain activity on low-level perceptive processes is well established, the state dependency of high-order executive processes remains unclear. Using a classical inhibitory control Go/NoGo task, we examined whether and how fluctuations in the brain activity during the period preceding the stimuli triggering inhibition influenced inhibitory control performance. Seventeen participants completed the Go/NoGo task while 64-channel electroencephalogram was recorded. We compared the event-related potentials preceding the onset of the NoGo stimuli associated with inhibition failures false alarms (FA) vs. successful inhibition correct rejections (CR) with data-driven statistical analyses of global measures of the topography and strength of the scalp electric field. Distributed electrical source estimations were used to localize the origin of the event-related potentials modulations. We observed differences in the global field power of the event-related potentials (FA > CR) without concomitant topographic modulations over the 40 ms period immediately preceding NoGo stimuli. This result indicates that the same brain networks were engaged in the two conditions, but more strongly before FA than CR. Source estimations revealed that this effect followed from a higher activity before FA than CR within bilateral inferior frontal gyri and the right inferior parietal lobule. These findings suggest that uncontrolled quantitative variations in pre-stimulus activity within attentional and control brain networks influence inhibition performance. The present data thereby demonstrate the state dependency of cognitive processes of up to high- order executive levels

Évaluation de l’effet de la piézo-corticision et des ostéoperforations sur le mouvement dentaire orthodontique chez le rat

Objectifs : Comparer l’effet de la piezo-corticision (PC) et de l’ostéoperforation (OP) sur le taux de mouvement dentaire orthodontique (MDO), la morphométrie osseuse et la cicatrisation parodontale chez le rat. Matériel et méthodes : Trente-six rats mâles de type Wistar ont été divisés en 3 groupes (n=12 chacun) : MDO; MDO + PC et MDO + OP. Le MDO a été réalisé à l’aide d’un ressort collé entre la première molaire maxillaire et l’incisive maxillaire droite. La PC a été réalisée au mésio-palatin de la crête alvéolaire de la première molaire supérieure. Deux OPs ont été éffectués en antéro-palatin et mésio-palatin de la première molaire supérieure. Les animaux ont été euthanasiés à 3 et 7 jours suivant la chirurgie. Les échantillons ont été analysés au micro-CT et préparé pour l’analyse histologique. Le MDO, la morphométrie osseuse, ainsi que la cicatrisation parodontale ont été étudiés. Résultats : À 3 jours, le MDO a été significativement plus élevé dans le groupe MDO + PC (219.68 ± 53.6 μm) comparativement au groupe MDO (154.90 ± 35.6 μm ; p=0.051). Aucune différence significative dans le MDO n’a été détectée entre le groupe MDO + OP et le groupe MDO, et entre le groupe MDO + OP et MDO + PC. De plus, le groupe MDO + PC présentait une diminution significativement plus grande des volumes tissulaires (VT; 22.06 ± 2.62 μm) et osseux (VO; 15.55 μm ± 2.65) comparativement au groupe MDO + OP (VT = 23.36 ± 1.40 μm; p=0,001) (VO = 19.03 ± 1.54 μm ; p=0,020). La hauteur de l’os alvéolaire à la furcation était significativement plus réduite dans le groupe MDO + OP (684.2 ± 73.4 μm) comparé au groupe contrôle MDO (559.4 ± 93.5 μm; p= 0.041) et la cicatrisation parodontale était significativement plus avancée dans le groupe MDO + OP comparativement au groupe MDO + PC. À 7 jours, le groupe MDO + PC a démontré une réduction significativement plus élevée du pourcentage de volume osseux (%VO; 67.63 ± 4.49 μm) et une augmentation significativement plus grande du modèle trabéculaire (MT; -29.66 ± 5.22 μm), de la densité de connectivité (DC; 1405.03 ± 519.82 μm) et de la porosité totale ( PT; 32.37 ± 4.49 μm) comparativement au groupe contrôle MDO (%VO= 72.64 ± 2.82 μm ; p=0,051), (MT= -20.97 ± 4.98 μm; p=0,008), (DC= 765.17 ± 165.81 μm; p=0,022), (PT= 27.36 ± 2.82 μm; p=0,051). Conclusion : La PC augmente le taux de MDO à court terme et a plus d’impact sur la morphométrie osseuse. L’OP est associée à une résorption osseuse plus grande à la furcation. La cicatrisation parodontale est retardée avec la PC.Objectives: To compare the effect of piezo-corticision (PC) and osteoperforation (OP) on the rate of orthodontic tooth movement (OTM), bone morphometry and periodontal healing in a rat model. Material and methods: Thirty-six male Wistar rats were divided into 3 groups (n=12 each): OTM; OTM + PC; OTM + OP. OTM was performed by using a NiTi coil bonded between the maxillary first molar and the maxillary right incisor. PC was performed at the mesio-palatal aspect of the maxillary first molar. Two OPs were performed at the antero-palatal and the mesio-palatal aspects of the maxillary first molar. The animals were euthanized three and seven days after surgery. Samples were analyzed with micro-CT and prepared for histological analysis. The OTM, bone morphometry and periodontal healing were evaluated. Results: At day 3, OTM was significantly increased in the OTM+PC group (219.68 ± 53.6 μm) compared to the OTM only group (154.90 ± 35.6 μm; p=0.051). No significant differences in OTM were detected between OTM+OP and OTM only group, and between OTM+OP and OTM+PC groups. Additionally, the OTM + PC group showed a significantly higher reduction in tissue (TV; 22.06 ± 2.62 μm) and bone volume (BV; 15.55 μm ± 2.65) when compared to the OTM + OP group (TV= 23.36 ± 1.40 μm; p=0,001) (BV= 19.03 ± 1.54 μm; p=0,020). The OTM + OP group showed a significantly higher reduction in bone height in the furcation areas (684.2 ± 73.4 μm) compared to the OTM group (559.4 ± 93.5 μm; p= 0.041) and an earlier periodontal healing compared to the OTM + PC group. At day 7, the OTM + PC group showed a significantly higher reduction in bone volume percentage (BV%; 67.63 ± 4.49 μm) and a significantly higher trabecular pattern factor (TPF; -29.66 ± 5.22 μm), connectivity density (CD; 1405.03 ± 519.82 μm) and total porosity (TP; 32.37 ± 4.49 μm) compared to the OTM group. (BV%= 72.64 ± 2.82 μm; p=0,051), (TPF= -20.97 ± 4.98 μm; p=0,008), (CD= 765.17 ± 165.81 μm; p=0,022), (TP= 27.36 ± 2.82 μm; p=0,051). Conclusion: PC accelerated the amount of OTM in the short term and has more impact on bone morphometry. OP was associated with more bone resorption in the furcation area. The periodontal healing was delayed with PC

Multi-agent prototype for simulating scenarios for decision-making in river basin systems

Environmental systems are usually extremely difficult to be undertaken by traditional software systems. This is due to the complexity of the environmental domain. Particularly, river catchment systems are very intricate to manage in order to achieve a good quality and quantity of water at the river. Multi-Agent systems (MAS) are able to cope with this complexity by integrating all the water systems involved at catchment scale through several agents who model real environmental situations. This work presents the development of our MAS prototype made in the agent platform Jadex. The design was made using the methodology Prometheus. The aim of our prototype is to provide feasible solutions at catchment scale throughout modelling and simulation of different scenarios in a river basin system.Postprint (published version

Spatiotemporal brain dynamics underlying attentional bias modifications

Exaggerated attentional biases toward specific elements of the environment contribute to the maintenance of several psychiatric conditions, such as biases to threatening faces in social anxiety. Although recent literature indicates that attentional bias modification may constitute an effective approach for psychiatric remediation, the underlying neurophysiological mechanisms remain unclear. We addressed this question by recording EEG in 24 healthy participants performing a modified dot-probe task in which pairs of neutral cues (colored shapes) were replaced by probe stimuli requiring a discrimination judgment. To induce an attentional bias toward or away from the cues, the probes were systematically presented either at the same or at the opposite position of a specific cue color. This paradigm enabled participants to spontaneously develop biases to initially unbiased, neutral cues, as measured by the response speed to the probe presented after the cues. Behavioral result indicated that the ABM procedure induced approach and avoidance biases. The influence of ABM on inhibitory control was assessed in a separated Go/NoGo task: changes in AB did not influence participants' capacity to inhibit their responses to the cues. Attentional bias modification was associated with a topographic modulation of event-related potentials already 50–84 ms following the onset of the cues. Statistical analyses of distributed electrical source estimations revealed that the development of attentional biases was associated with decreased activity in the left temporo-parieto-occipital junction. These findings suggest that attentional bias modification affects early sensory processing phases related to the extraction of information based on stimulus saliency

Détection et localisation de défauts en échographie ultrasonore

L'interprétation des images ultrasonores est un problème délicat. La durée temporelle de l'onde émise par le traducteur, sa déformation au cours de sa propagation et la largeur du faisceau rendent difficile la détection et la localisation des défauts. Afin d'accroître la résolution des images ultrasonores, nous présentons un traitement en deux étapes. Chaque signal composant l'image est déconvolué séparément par rapport à un même signal. On augmente ainsi la résolution axiale et on met en forme les données pour le second traitement. L'image est ensuite reconstruite grâce à un algorithme de type SAFT (Synthetic Aperture Focusing Technique) dont les lois de reconstruction sont calculées à partir d'une simulation numérique du champ rayonné

Bimodal mesoporous titanium dioxide anatase films templated by a block polymer and an ionic liquid: influence of the porosity on the permeability

In the present paper, we report the synthesis of bimodal mesoporous anatase TiO2 films by the EISA (Evaporation-Induced Self-Assembly) method using sol-gel chemistry combining two porogen agents, a low molecular weight ionic template and a neutral block copolymer. The surfactant template (C(16)mimCl) generates non-oriented worm-like pores (8 to 10 nm) which connect the regularly packed ellipsoidal mesopores (15 to 20 nm diameter) formed by an amphiphilic block copolymer of the type poly(isobutylene)-b-poly(ethylene oxide) (PIB-PEO). The surfactant template can also significantly influence the size and packing of the ellipsoidal mesopores. The mesostructural organization and mesoporosity of the films are studied by Environmental Ellipsometry-Porosimetry (EEP), Grazing-Incidence Small-Angle X-ray Scattering (GISAXS) and electron microscopy techniques. Electrochemical characterization is performed to study the permeability of the films to liquid solutions, using two types of probe moieties (K3FeIII(CN)(6) and Ru(bpy)(3)(2+)) by the wall-jet technique. An optimum ratio of C(16)mimCl/PIB-PEO provides anatase films with a continuous bimodal mesopore structure, possessing a permeability up to two times higher than that of the mesoporous films templated by PIB-PEO only (with partially isolated mesopores). When C(16)mimCl is used in large quantities, up to 20% weight vs. PIB-PEO, large overall porous volume and surface area are obtained, but the mesostructure is increasingly disrupted, leading to a severe loss of permeability of the bimodal films. A dye-sensitized solar cell set-up is used with anatase films as the photoelectrode. The photosensitizer loading and the total energy conversion efficiency of the solar cells using the mesoporous films templated by an optimal ratio of the two porogen agents C(16)mimCl and PIB-PEO can be substantially increased in comparison with the solar cells using mesoporous films templated by PIB-PEO only.DFG/SM 199/6-1DFG/OE 420/5-1BMBF/SOHyb/03X3525

Age-related changes in the bimanual advantage and in brain oscillatory activity during tapping movements suggest a decline in processing sensory reafference

Deficits in the processing of sensory reafferences have been suggested as accounting for age-related decline in motor coordination. Whether sensory reafferences are accurately processed can be assessed based on the bimanual advantage in tapping: because of tapping with an additional hand increases kinesthetic reafferences, bimanual tapping is characterized by a reduced inter-tap interval variability than unimanual tapping. A suppression of the bimanual advantage would thus indicate a deficit in sensory reafference. We tested whether elderly indeed show a reduced bimanual advantage by measuring unimanual (UM) and bimanual (BM) self-paced tapping performance in groups of young (n=29) and old (n=27) healthy adults. Electroencephalogram was recorded to assess the underlying patterns of oscillatory activity, a neurophysiological mechanism advanced to support the integration of sensory reafferences. Behaviorally, there was a significant interaction between the factors tapping condition and age group at the level of the inter-tap interval variability, driven by a lower variability in BM than UM tapping in the young, but not in the elderly group. This result indicates that in self-paced tapping, the bimanual advantage is absent in elderly. Electrophysiological results revealed an interaction between tapping conditionand age group on low beta band (14-20Hz) activity. Beta activity varied depending on the tapping condition in the elderly but not in the young group. Source estimations localized this effect within left superior parietal and left occipital areas. We interpret our results in terms of engagement of different mechanisms in the elderly depending on the tapping mode: a ‘kinesthetic' mechanism for UM and a ‘visual imagery' mechanism for BM tapping movement

Stimulus reward value interacts with training-induced plasticity in inhibitory control

Training inhibitory control, the ability to suppress motor or cognitive processes, not only enhances inhibition processes, but also reduces the perceived value and behaviors toward the stimuli associated with the inhibition goals during the practice. While these findings suggest that inhibitory control training interacts with the aversive and reward systems, the underlying spatio-temporal brain mechanisms remain unclear. We used electrical neuroimaging analyses of event-related potentials to examine the plastic brain modulations induced by training healthy participants to inhibit their responses to rewarding (pleasant chocolate) versus aversive food pictures (unpleasant vegetables) with Go/NoGo tasks. Behaviorally, the training resulted in a larger improvement in the aversive than in the rewarding NoGo stimuli condition, suggesting that reward responses impede inhibitory control learning. The electrophysiological results also revealed an interaction between reward responses and inhibitory control plasticity: we observed different effects of practice on the rewarding vs. aversive NoGo stimuli at 200 ms post-stimulus onset, when the conflicts between automatic response tendency and task demands for response inhibition are processed. Electrical source analyses revealed that this effect was driven by an increase in right orbito-cingulate and a decrease in temporo-parietal activity to the rewarding NoGo stimuli and the reverse pattern to the aversive stimuli. Our collective results provide direct neurophysiological evidence for interactions between stimulus reward value and executive control training, and suggest that changes in the assessment of stimuli with repeated motoric inhibition likely follow from associative learning and behavior-stimulus conflicts reduction mechanisms