There is plenty of research on effects of negative stereotypes on performance, but less is known about effects of positive stereotypes. Research examining effects of positive stereotypes on performance has found mixed, often competing, results; positive stereotypes have been shown to lead to performance decrements, performance boosts, both boosts and decrements, or neither. One goal of the current study was to examine how domain identification, mode of stereotype activation, group membership of social referents, and valence of performance feedback (i.e. threat salience antecedents) influence whether positive stereotypes harm or benefit performance. I asserted that different combinations of the aforementioned variables would result in differential levels of threat salience, which I define as feelings of stress or pressure that arise from a dynamic interplay between performance motivation, anxiety and self-efficacy. Furthermore, as threat salience increased performance boosts from the positively stereotyped identity were expected to decrease and eventually lead to performance decrements. I also aimed to pinpoint the exact condition, or level of threat salience, that would lead to the switch from performance boosts to performance decrements (i.e. a tipping point). The threat salience antecedents of social referent’s group membership and feedback valence were combined to create a 2 (male/negative feedback vs female/positive feedback) X 2 (implicit activation vs explicit activation) design with a measured causal antecedent (domain identification). Participants took part in a laboratory study utilizing the positive stereotype that females are better than males at verbal ability tasks. Before arriving to the lab, participants were required to complete measures of verbal ability domain identification. Upon arrival to the lab, participants completed one trial of verbal ability items before being exposed to one of the four combinations of threat salience antecedents; following the manipulations, participants completed a subsequent trial of verbal ability items. The results of the study did not support the hypotheses; greater threat salience was not found to lead to worse performance nor was there support for a tipping point whereby performance boosts shifted to performance decrements. Possible reasons for null findings are discussed along with implications of exploratory analyses. / Master of Science / Research on the impact of positive stereotypes on performance has often resulted in mixed conclusions, with some research finding evidence for performance boosts, some finding evidence for performance decrements, and some finding both or neither. The current study sought to demonstrate that certain variables (i.e. domain identification, mode of stereotype activation, group membership of social referents, and valence of performance feedback) impact whether positive stereotypes lead to increases or decreases in performance outcomes through presenting differential threat salience. Threat salience essentially being feelings of pressure or worry about contradicting a positive stereotype; said feelings are believed to be the result of a dynamic interplay between motivation, self-efficacy, and anxiety about performance outcomes. I hypothesized that as threat salience increased then performance would decrease, eventually causing performance boosts from positive stereotypes to switch to performance decrements. Furthermore, I aimed to identify the exact level of threat salience that resulted in a switch from performance boosts to performance decrements (i.e. a tipping point). The study results did not provide support for the hypotheses, nor was I able to identify a tipping point whereby performance switched from boosts to decrements. Implications of exploratory analyses are discussed, along with possible explanations for null findings.

Pour répondre au contexte d’exploitation des énergies renouvelables marines où l’accès aux systèmes de production d’énergie électrique est délicat, cette thèse porte sur l’étude d’une chaîne de conversion d’énergie tolérante aux défauts. Trois volets sont investigués : l’analyse comportementale de la topologie, le contrôle de la puissance produite ainsi que la détection et la localisation des défauts. La chaîne est constituée d’une MSAP pentaphasée, d’un redresseur à diodes à 5 bras et de 3 convertisseurs DC-DC de type Boost entrelacés. Pour la stratégie de contrôle de la puissance de sortie, un double asservissement est appliqué au bloc DC-DC. Des modèles dynamiques petits signaux sont établis. La boucle interne est dédiée à l’asservissement du courant d'entrée de l’étage Boost et la boucle externe au contrôle de la puissance. Trois types de régulateurs en courant sont étudiés et comparés. Des approches de synchronisation des commandes des 3 Boosts sont proposées. Il ressort que le régulateur non linéaire, dit MRC, satisfait complètement aux performances désirées. Le contrôle de puissance, intégré ensuite dans la chaîne complète de production d’énergie et testé pour différents modes de fonctionnement sains et dégradés, est de très bon niveau. Des méthodes de détection et de localisation des défauts au niveau de l’entrée et de la sortie du redresseur ont été développées. En se basant sur la mesure des courants de phase ou sur la mesure de la tension en sortie du redresseur, les défauts côté AC sont détectés et localisés. La détection côté continu est de faible complexité. Cette méthode est ensuite étendue aux défauts de l’étage DC-DC en utilisant son courant d’entrée. / To answer the context of marine renewable energy exploitation where the access of energy production system is difficult, this thesis deals with the study of a fault tolerant energy conversion chain. Three aspects are investigated: behavior analysis of the topology; output power control; detection and location of faults. The chain involves a five-phase PMSG, a five-leg diode rectifier and a three-interleaved DC-DC Boost converter. Concerning the output power control strategy, a double-loop control is applied on the DC-DC block. Small-signal dynamic models are established. The inner loop is used for controlling the input current of the Boost stage. The outer loop is for the output power. Three types of current controllers are studied and compared. Methods of synchronization for the three-interleaved Boost converter control are proposed. It results that the nonlinear controller, called in French version, the MRC, totally satisfies the desired performances. The control of power, which is then used for the full conversion chain, is tested under different operating modes (health and fault) and is of high performances. Several methods for detecting and locating rectifier’s AC and DC side faults have been developed. Based on the measurements of phase currents or the measurement of the output voltage of the rectifier, AC side faults can be detected and located. DC measurement based fault detection is of low complexity. This method is then extended to the faults of DC-DC block by using its input current.

This thesis explores boosting to improve decision-making in the context of the COVID-19 pandemic using a structured introspection. Structured introspection is an intervention where individuals are prompted with and are asked to estimate the importance of a set of attributes relevant to the decision in order to limit the prevalence of potential cognitive biases. To test the intervention, 281 participants divided into an intervention and control group answered an online survey with a dilemma about COVID-19. The dilemma was whether Sweden should shut down the economy or keep it open during the COVID-19 pandemic. The intervention group was asked to rate how important the attributes “saving lives”, “saving the economy”, “concern for the health of the elderly and risk groups”, and “concern for the quality of life and well-being of all citizens” should be for their decision. The control group was only prompted with the question and asked to think carefully. All participants were asked a set of control variables such as risk perception for self and others and emotions when thinking about COVID-19. The results did not show a significant influence on choice on decisions based on the intervention. They did however show a significant correlation with choice on risk perception as well as a correlation between choice on the dependent variable and the attributes in the intervention group.             The conclusion of the thesis is that structured introspection may not be suitable on a contemporary issue affecting participants directly, as they may already have strong opinions about the issue. Further and broader research needs to be conducted to determine in which circumstances this boost can be effective.

The aim of this thesis is to design a step-up DC/AC converter, an inverter from 12 V to 120 Vrms, with a sinus output signal. The converter should deliver a continuous performance of 300 W and a double peak power output of 600 W. The supposed usage of this inverter would be as a back-up power source for the circulatory pump of the central heating in the case of power outage. The inverter is consisting of a T-type power section.