La fatigue cognitive représente un phénomène auquel nous sommes tous familiers. Nous en faisons quotidiennement l'expérience, celle-ci étant associée à une réduction de productivité, une augmentation de risques professionnels et une diminution de notre qualité de vie. Malgré l’importance sociétale de ces implications, qui ont fait de l'étude de la fatigue cognitive une de plus investiguées dans le domaine des sciences cognitives, il subsiste un manque de vision commune ainsi qu'une théorie unifiée de la fatigue cognitive, déterminant son origine et ses fonctions, tandis que son caractère stochastique continue à diviser le milieu scientifique. La présente dissertation présente une approche multimodale combinant des données comportementaux et de neuroimagerie spectroscopie proche infrarouge (fNIRS) pour investiguer les facteurs à l’origine du déclenchement du phénomène ainsi que les dynamiques cérébrales associées. Nos résultats suggèrent que la fatigue cognitive ressentie associée à la chute de performance est une fonction de la charge cognitive définie par le Time Based Shared Resources Model (TBRS). Au niveau neural, nous discutons la présence des systèmes de compensation et les changements de connectivité cérébrale dans ce déclenchement. et comment les possibles mécanismes responsables de la maintenance de performance durant des demandes attentionnelles soutenues y sont associées. / Doctorat en Sciences psychologiques et de l'éducation / info:eu-repo/semantics/nonPublished

Dans des systèmes de communication sans fil modernes, la demande de débit de transmission des données par utilisateur est en croissance constante. Pour soutenir la forte demande de débit de données des utilisateurs une solution possible est de rapprocher l'utilisateur de la station de base émettrice et donc déployer une infrastructure réseau très dense. Dans cette configuration nous obtenons de fortes interférences. L’interférence a été souvent identifiée comme le principal obstacle des systèmes modernes de communications sans fil cellulaires. Cette considération a conduit à d'intenses activités de recherche qui a récemment poussé les opérateurs de réseaux et les fabricants à inclure de manière plus proactive et efficace pour supprimer/contrôler les interférences. D'un point de vue théorie de l'information, ce problème peut être mathématiquement étudié comme, ce qui est appelé, un canal d'interférence. Dans la première partie de cette thèse, nous concentrons notre attention à la conception de l'émetteur pour le canal d'interférence avec des terminaux avec antennes multiples. Nous proposons l'optimisation conjointe de l'émetteur et du récepteur en fonction de deux critères: l'alignement des interférences et la maximisation la somme pondérée des débits. La deuxième partie de la thèse est consacrée au problème de conception de l'émetteur dans le scénario de la radio cognitive. Nous commençons à considérer un scénario Underlay, ensuite, nous passons au scénario Interweave. L'objectif est de concevoir les émetteurs et les récepteurs, au niveau du réseau secondaire, telle que l'interférence, générée à chaque récepteur principal, est égal à zéro. / In modern wireless communication systems, the per-user data rate demand is constantly growing. To sustain the heavy user data rate demand, network operators try to deploy cellular system with more cells and applying more efficient spectrum reuse techniques. One possible solution to increase system throughput is to get the user closer to the transmitting base station and hence deploy very dense network infrastructure. In this setup strong interference situations will result. Interference has been identified as the main bottleneck of modern wireless cellular communication systems. With small dense cells this is more the case. This consideration has led to intense research activities that has recently pushed network operators and manufacturers to include more proactive and efficient way to suppress/control interference. From an information theoretic point of view this problem can be mathematically studied as an interference channel. In the first part of this thesis, we focus our attention on the beamforming design for the interference channel with particular focus on the MIMO case. There we propose the joint optimization of linear transmitter and receiver according to two criteria : Interference Alignment and weighted sum rate maximization. The second part of the thesis is devoted to the beamforming design problem in cognitive radio settings. We start considering an underlay scenario where the secondary network is modeled as a MISO interference channel. Then we move to the MIMO interweave cognitive radio. There the objective is to design the transmitters and receivers, at the secondary network, such that the interference, generated at each primary receiver, is zero.

A critical element in the development of interpersonal skills is the ability to recognize facial expressions. However, in persons with mild mental retardation (PMR), social interactions based on the recognition of others' emotional states may be compromised. Guided by the theory of mind, which allows one to make inferences on someone's mental states, differentiate facts from friction, and process others' beliefs and intentions, this study determined if emotion training impacted future emotion recognition scores in a PMR population and whether the variables of gender, age, and baseline Facial Expression of Emotions Stimuli and Test (FEEST) scores predicted changes in emotion recognition. Secondary data from a group of trainees identified as having mild mental retardation who participated in an emotion recognition training program (n = 31) were assessed. A paired samples t test revealed no differences between the pre-and post- assessments as a function of training, and the multiple regression analysis revealed that gender, age, and baseline FEEST score did not predict changes in emotional recognition. These findings, despite their non significance, offer a unique contribution to the field of mental retardation and contribute to theory of mind research in PMR populations. Positive social change implications include the potential ability to identify ways to improve social skills and effective training models to foster social inclusion in PMR population.

<p> Psycho-physiological trauma theory postulates that trauma can cause nervous system dysregulation, which has not been considered with evidence-based treatments. Other models, including the community resiliency model, have focused on reducing nervous system dysregulation. This study used a comparison group in a pre-test post-test model to examine the difference between participants with post-traumatic stress disorder symptoms who did and did not receive model training. Eighteen adult subjects were non-randomly assigned to control and treatment groups. The frequency and severity of intrusive symptoms, avoidance/numbing symptoms, and hyperarousal symptoms were measured by the Davidson Trauma Scale. Data were collected at pre-treatment, immediately following treatment, and one week after treatment. Three separate mixed ANOVAs were run to assess the effect of CRM treatment over time. The dependent variables were derived from the Davidson Trauma Scale&rsquo;s three subscales, Intrusive, Avoidance/Numbing, and Hyperarousal. Initial analyses revealed a significant main effect of time, but no main effect of treatment, across all three variables. However, a significant interaction was evident for all three subscales, warranting follow-up analyses. For all three dependent variables, the pretest means were significantly greater for the treatment group than for the control group. These differences may reflect the non-random assignment of participants to the control group.</p>

<p> Due to high implementation costs of the Next Generation Air Transportation System (NextGen) in the near-term, Air Traffic Controllers (ATCos) will have to manage mixed equipped airspace. Previous studies have evaluated different methods for training ATCos to use current-day tools and NextGen tools. More specifically, recent studies investigated how ATCo performance, workload, and situation awareness were affected by part-task and whole-task training. The current study builds on this research by examining ATCos' communication complexity as a function of these training types. Communication complexity is related to the number of commands ATCos incorporate in a single transmission, and it has been cited as a major contributor to incidents in aviation. The main finding of this investigation indicated that the largest differences in communication complexity between training groups occurred during the 100% NextGen equipped scenarios, with the whole-task group transmitting more complex communications than the part-task group.</p>

No description available.

<p> This dissertation presents two studies that examined how goal-management abilities are associated with procrastination. The first study was a two-part intervention study designed to (a) examine whether individuals could reduce their academic procrastination, and (b) examine the association between procrastination and the accomplishment of academic goals. In the second study, data from a longitudinal twin study were analyzed to (a) examine whether procrastination in adulthood could be predicted by three cognitive abilities in early childhood, and (b) further understand how procrastination is associated with intelligence. </p><p> In the first study, 221 subjects completed an experiment in which they set academic goals and identified the temptations that often cause them to procrastinate. Some subjects also completed interventions in addition to these goal-setting exercises, which focused on elaborative goal-setting (i.e., setting SMART goals) and/or prepared subjects with strategies to resist their temptations (by forming implementation intentions). Results indicated that procrastination was predictive of the success of the goals generated during the exercises, but there were no effects of either intervention on the reduction in academic procrastination (or the accomplishment of academic goals), even when examining relevant moderating variables. </p><p> In the second study, I analyzed data from 954 twins who completed measures of self-restraint, attentional control, and IQ in early childhood (ages 1-3 years) and returned for measures of procrastination, goal management, impulsivity, and IQ at age 23. Results indicated that neither self-restraint, attentional control, nor IQ in early childhood were associated with procrastination at the phenotypic or genetic levels, and that procrastination was not associated with IQ even when examining IQ in adolescence or early adulthood. </p><p> Together, these findings provided additional, albeit limited, evidence for the association between goal management abilities and procrastination, most strongly with regard to the accomplishment of academic goals. These studies were also the first to directly test the effectiveness of goal-related interventions on procrastination and examine early life correlates of procrastination. Given the lack of conclusive evidence observed here for both of these topics, further research is needed to understand what interventions are effective at reducing procrastination and identify which factors in childhood can predict later life procrastination.</p>

<p>"Cognitive control" describes endogenous guidance of behavior in situations where routine stimulus-response associations are suboptimal for achieving a desired goal. The computational and neural mechanisms underlying this capacity remain poorly understood. The present dissertation examines recent advances stemming from the application of a statistical, Bayesian learner perspective on control processes. An important limitation in current models consists of a lack of a plausible mechanism for the flexible adjustment of control over variable environments. I propose that flexible cognitive control can be achieved by a Bayesian model with a self-adapting, volatility-driven learning scheme, which modulates dynamically the relative dependence on recent (short-term) and remote (long-term) experiences in its prediction of future control demand. Using simulation data, human behavioral data and human brain imaging data, I demonstrate that this Bayesian model does not only account for several classic behavioral phenomena observed from the cognitive control literature, but also facilitates a principled, model-guided investigation of the neural substrates underlying the flexible adjustment of cognitive control. Based on the results, I conclude that the proposed Bayesian model provides a feasible solution for modeling the flexible adjustment of cognitive control.</p> / Dissertation

The congruency sequence effect literature is inconsistent when it comes to the issue of the boundaries of this phenomenon. Some have argued that control is implemented at the level of a stimulus dimension while other have claimed that control operates across dimensions and tasks. Flexible control boundaries defined by task sets might explain the inconsistent findings. Response set manipulations have been shown to influence control boundaries. Unitary response sets can produce cross-dimension congruency sequence effects but applying separate response sets to a task can lead to the absence of the congruency sequence effect on dimension switch trials. This thesis is concerned with the extension of these findings. The study applied response set manipulations to a paradigm (Stroop Trajectory Task) that has exhibited robust crossdimension congruency sequence effects. In addition, the influence of switching routine on congruency sequence effects was tested. It was expected that separate response sets for different stimulus dimensions would eliminate the congruency sequence effect on switch trials. Switching routine was anticipated to act as a weaker boundary marker but nevertheless it was expected that systematic switching routines should have at least attenuated the congruency sequence effect on switch trials. Contrary to expectations it was found that the congruency sequence effect was present in switch trials across all conditions.

No description available.