Subtle interactions for distress regulation: efficiency of a haptic wearable according to personality

The incorporation of empathic systems in everyday life draws a lot of attention from society. Specifically, the use of wearables to perform stress regulation is a growing field of research. Among techniques explored, the haptic emulation of lowered physiological signals has been suggested to be promising. However, some discrepancies remain in empirical research focusing on such biofeedback (BF) regarding their efficacy, and the mechanisms underlying the effects of these wearables remains unclear. Moreover, the influence of individual traits on the efficiency of BF has been marginally studied, while it has been shown that personality could impact both stress and its regulation. The aim of this study is to investigate the outcome of interactions with these technologies from a psycho-physiological standpoint, but also to explore whether personality may influence its efficiency when other interaction devices are present. Participants had to play a challenging game while a lowered haptic BF of their heart rate was induced on their wrist. Results showed variable efficiency of the wearable among the participants: a subjective relaxation was evident for the participants exhibiting the highest neurotic and extraverted traits score. Our results highlight the plurality of the modes of action of these techniques, depending on the individual and on the level of stress to regulate. This study also suggests that tailoring these regulation methods to individual characteristics, such as personality traits, is important to consider, and proposes perspectives regarding the investigation of stress and regulation systems embedded in wearables

Determination of cognitive workload variation in driving from ECG derived respiratory signal and heart rate

2nd International Neuroergonomics Conference, PHILADELPHIE, ETATS-UNIS, 27-/06/2018 - 29/06/2018Research works on operator monitoring underline the benefit of taking into consideration several signal modalities to improve accuracy for an objective mental state diagnosis. Heart rate (HR) is one of the most utilized systemic measures to assess cognitive workload (CW), whereas respiration parameters are hardly utilized. This study aims at verifying the contribution of analyzing respiratory signals to extract features to evaluate driver's activity and CW variations in driving with regard to cardiac activity. Eighteen subjects participated in the study. The participants carried out two different cognitive tasks requiring different CW demands, a single task as well as a competing cognitive task realized while driving in a simulator. Our results confirm that both HR and breathing rate (BR) increase in driving and are sensitive to CW. However, HR and BR are differently modulated by the CW variations in driving. Specifically, BR is suitable to evidence a variation of CW when driving is not required. On the other hand, spectral features characterizing respiratory signal could be also used similarly to HR variability indices to detect high CW episodes. These results hint the use of respiration to monitor the driver mental state in autonomic vehicles in order to predict the available cognitive resources if the user has to take over the vehicle

A database of whole-body action videos for the study of action, emotion, and untrustworthiness

We present a database of high-definition (HD) videos for the study of traits inferred from whole-body actions. Twenty-nine actors (19 female) were filmed performing different actions—walking, picking up a box, putting down a box, jumping, sitting down, and standing and acting—while conveying different traits, including four emotions (anger, fear, happiness, sadness), untrustworthiness, and neutral, where no specific trait was conveyed. For the actions conveying the four emotions and untrustworthiness, the actions were filmed multiple times, with the actor conveying the traits with different levels of intensity. In total, we made 2,783 action videos (in both two-dimensional and three-dimensional format), each lasting 7 s with a frame rate of 50 fps. All videos were filmed in a green-screen studio in order to isolate the action information from all contextual detail and to provide a flexible stimulus set for future use. In order to validate the traits conveyed by each action, we asked participants to rate each of the actions corresponding to the trait that the actor portrayed in the two-dimensional videos. To provide a useful database of stimuli of multiple actions conveying multiple traits, each video name contains information on the gender of the actor, the action executed, the trait conveyed, and the rating of its perceived intensity. All videos can be downloaded free at the following address: http://www-users.york.ac.uk/~neb506/databases.html. We discuss potential uses for the database in the analysis of the perception of whole-body actions

Respiration and Heart Rate Modulation Due to Competing Cognitive Tasks While Driving

Research works on operator monitoring underline the benefit of taking into consideration several signal modalities to improve accuracy for an objective mental state diagnosis. Heart rate (HR) is one of the most utilized systemic measures to assess cognitive workload (CW), whereas, respiration parameters are hardly utilized. This study aims at verifying the contribution of analyzing respiratory signals to extract features to evaluate driver’s activity and CW variations in driving. Eighteen subjects participated in the study. The participants carried out two different cognitive tasks requiring different CW demands, a single task as well as a competing cognitive task realized while driving in a simulator. Our results confirm that both HR and breathing rate (BR) increase in driving and are sensitive to CW. However, HR and BR are differently modulated by the CW variations in driving. Specifically, HR is affected by both driving activity and CW, whereas, BR is suitable to evidence a variation of CW only when driving is not required. On the other hand, spectral features characterizing respiratory signal could be also used similarly to HR variability indices to detect high CW episodes. These results hint the use of respiration as an alternative to HR to monitor the driver mental state in autonomic vehicles in order to predict the available cognitive resources if the user has to take over the vehicle

Phase control and measurement in digital microscopy

The ongoing merger of the digital and optical components of the modern microscope is creating opportunities for new measurement techniques, along with new challenges for optical modelling. This thesis investigates several such opportunities and challenges which are particularly relevant to biomedical imaging. Fourier optics is used throughout the thesis as the underlying conceptual model, with a particular emphasis on three--dimensional Fourier optics. A new challenge for optical modelling provided by digital microscopy is the relaxation of traditional symmetry constraints on optical design. An extension of optical transfer function theory to deal with arbitrary lens pupil functions is presented in this thesis. This is used to chart the 3D vectorial structure of the spatial frequency spectrum of the intensity in the focal region of a high aperture lens when illuminated by linearly polarised beam. Wavefront coding has been used successfully in paraxial imaging systems to extend the depth of field. This is achieved by controlling the pupil phase with a cubic phase mask, and thereby balancing optical behaviour with digital processing. In this thesis I present a high aperture vectorial model for focusing with a cubic phase mask, and compare it with results calculated using the paraxial approximation. The effect of a refractive index change is also explored. High aperture measurements of the point spread function are reported, along with experimental confirmation of high aperture extended depth of field imaging of a biological specimen. Differential interference contrast is a popular method for imaging phase changes in otherwise transparent biological specimens. In this thesis I report on a new isotropic algorithm for retrieving the phase from differential interference contrast images of the phase gradient, using phase shifting, two directions of shear, and non--iterative Fourier phase integration incorporating a modified spiral phase transform. This method does not assume that the specimen has a constant amplitude. A simulation is presented which demonstrates good agreement between the retrieved phase and the phase of the simulated object, with excellent immunity to imaging noise

Les voies de recherche en distribution

International audienceCet article passe en revue les travaux récents consacrés à trois axes de recherche en distribution: l'analyse des canaux, et notamment la problématique des relations entre producteurs et distributeurs, la stratégie de la firme de distribution, et enfin la relation du consommateur avec le point de vente

Les voies de recherche en distribution

International audienceCet article passe en revue les travaux récents consacrés à trois axes de recherche en distribution: l'analyse des canaux, et notamment la problématique des relations entre producteurs et distributeurs, la stratégie de la firme de distribution, et enfin la relation du consommateur avec le point de vente

Influence de la température sur le perçage à sec du laiton et de l'aluminum

Les différents stades du perçage à sec des laitons et des alliages d'aluminium ont été identifiés. En particulier l'effet du contenu en plomb et de la température ont été examinés. Il a été montré que : à basse température, en dessous de 0 °C, la force normale (axiale) aussi bien que le moment (couple) sont peu sensibles à une variation de la vitesse de coupe et de la température ; à vitesses plus élevées (de 0 °C à 200 °C), la température joue un rôle important : les forces de coupe augmentent ; à plus hautes vitesses (au-delà de 250 °C), les forces commencent à décroître. De plus, les alliages de cuivre subissent une perte en zinc. Une explication de ces phénomènes est proposée. Une analyse plus qualitative tente de décrire les phénomènes observés, qui tient compte de la variation des propriétés des métaux. La notion d'énergie spécifique de coupe est utilisée. Il est ainsi montré que la chute des forces de coupe est attribuable à la variation de l'énergie spécifique de coupe, causée par les chutes des propriétés mécaniques