Les ambiguïtés de phrases sont au cœur de la recherche sur la compréhension du langage depuis un certain temps. Pour les sémanticiens, ces ambigüités ont été utilisées pour suggérer l’existence de différents mécanismes abstraits qui pourraient s’appliquer à une même structure syntaxique au stade de l’interprétation. Pour les psycholinguistes, les ambiguïtés sémantiques ont offert un outil d’étude de la dynamique du traitement de phrases : puisque les ambiguïtés tendent à être résolues incrémentalement (c’est-à-dire avant la fin de la phrase), le schéma de traitement des phrases ambiguës peut permettre d’identifier les facteurs linguistiques et non linguistiques qui jouent un rôle dans la compréhension online. Cette dissertation traite des théories de la compréhension du langage en explorant deux questions complémentaires : (1) comment différents sens peuvent-ils être associés à une seule tournure de phrase, et (2) comment sommes-nous capables d’accéder à ces interprétations alternatives et de les traiter pendant l’analyse syntaxique. Pour répondre à ces questions, la présente étude se focalise principalement sur ce qu’on appelle les ambiguïtés de pluriel, qui surgissent par l’interaction entre certains prédicats et leurs arguments pluriels. Par exemple, la phrase Amir et Milica ont construit un château de sable a une interprétation non distributive, collective (c’est-à-dire qu’Amir et Milica ont construit ensemble un château de sable) mais aussi une interprétation distributive (c’est-à-dire qu’Amir et Milica ont chacun construit un château de sable). La plupart des approches linguistiques partent du principe que les lectures distributives dérivent d’interprétations non distributives, plus élémentaires, par l’application d’un opérateur de « distributivité » phonologiquement nul (Link, 1987 ; Champollion, 2014). La première partie de cette dissertation présente deux études qui visent à identifier les mécanismes abstraits qui sous-tendent le contraste distributif/non distributif à travers un paradigme d’amorçage. Cette méthode d’amorçage est ensuite étendue à d’autres phénomènes sémantiques (c’est-à-dire des ambiguïtés de portée) dans la deuxième partie de la dissertation, dans laquelle des interactions entre pluralité et phénomène de portée sont aussi testées expérimentalement. Pour évaluer la dynamique de la résolution des ambiguïtés, la troisième partie de cette dissertation présente une étude de suivi des mouvements de souris, conçue pour établir les caractéristiques de trajectoires de souris qui se corrèlent avec la prise de décision et la désambiguïsation. La méthodologie développée dans cette étude est ensuite utilisée pour analyser des données préliminaires relatives au traitement de phrases à ambiguïtés de pluriel. / Sentence ambiguities have been at the center of the research on language comprehension for some time. For semanticists, these ambiguities have been taken to suggest the existence of different abstract mechanisms that may apply to the same syntactic structure at the interpretation stage. For psycholinguists, semantic ambiguities have provided a tool to analyze the dynamics of sentence parsing: since ambiguities tend to be solved incrementally (i.e. before the end of the sentence), the processing pattern of ambiguous sentences might allow identifying the linguistic and non-linguistic factors that play a role during online comprehension. This dissertation informs theories of language comprehension by exploring two complementary questions: (1) how are different meanings associated to a single sentence form, and (2) how are we able to access and compute these alternative interpretations during parsing. To address these questions, the present work mainly focuses on the so-called plural ambiguities, which arise by the interaction between certain predicates and their plural arguments. For instance, the sentence Amir and Milica built a sandcastle has a non-distributive, collective, interpretation (i.e. Amir and Milica together built a sandcastle) as well as a distributive one (i.e. Amir and Milica each built a sandcastle). Most linguistic approaches assume that distributive readings are derived from more basic non-distributive interpretations by the application of a covert “distributivity” operator (Link, 1987; Champollion, 2014) . The first part of this dissertation presents two studies that aim to identify the abstract mechanisms underlying the distributive/non-distributive contrast through a priming paradigm. This priming method is then extended to other semantic phenomena (i.e. scope ambiguities) in the second part of the dissertation, where some interactions between plurality and scope phenomena are also tested experimentally. To assess the dynamics of ambiguity resolution, the third part of this work presents a mouse-tracking study designed to establish the features of mouse-trajectories that correlate with decision making and disambiguation. The methodology developed in this study is then used to analyze preliminary data on the processing of plural ambiguous sentences.

In this dissertation, I address a range of topics in the context of mutual fund performance and high frequency trading. The first chapter provides novel evidence on the role of ambiguity aversion in determining the response of mutual fund investors to historical fund performance information. It presents a model of ambiguity averse investors who receive multiple performance-based signals of uncertain precision about manager skill. A key implication of the model is that when investors receive multiple signals of uncertain quality, they place a greater weight on the worst signal. There is strong empirical support for this prediction in the data. Fund flows display significantly higher sensitivity to the worst performance measure even after controlling for fund performance at multiple horizons, performance volatility, flow-performance convexity, and a host of other relevant explanatory variables. This effect is particularly pronounced in the case of retail funds in contrast to institutional funds. The results suggest that fund investor behavior is best characterized as reflecting both Bayesian learning and ambiguity aversion. The second chapter combines data on high frequency trading (HFT) activities of a randomly selected sample of 120 stocks and data on institutional trades, I find that HFT increases the trading costs of traditional institutional investors. An increase of one standard deviation in the intensity of HFT activities increases institutional execution shortfall costs by a third. Further analysis suggests that HFT represents an opportunistic and extra-expensive source of liquidity when demand and supply among institutional investors are imbalanced. Moreover, the impact on institutional trading costs is most pronounced when high frequency (HF) traders engage in directional strategies (e.g., momentum ignition and order anticipation). I perform various analyses to rule out an alternative explanation that HF traders are attracted to stocks that have high trading costs. First, HFT is most prevalent in liquid stocks. Second, the results are robust to controls for stable stock liquidity characteristics and events that might jointly affect HFT and trading costs. Third, an analysis of the HFT behavior around the temporary short selling ban in September 2008 highlights the opportunistic nature of liquidity provision by HF traders. Finally, Granger causality tests show that intensive HFT activity significantly contributes to institutional trading costs, but not vice versa. The third chapter analyzes the implications of the tournament-like competition in the mutual fund industry using a framework that addresses the risk-taking incentives facing fund managers. The theoretical model presented in this chapter suggests that the increase in the \emph{activeness} of the interim loser manager's portfolio is directly related to the magnitude of the performance gap at the interim stage, and to the strength of the investor (cash flow) response to the relative performance rankings of the funds (i.e., the strength of the tournament effect). The empirical evidence based on quarterly Active Share data for a sample of domestic stock funds, is consistent with the key predictions of the model.

One important issue in mechanism design theory is to model agents’ behaviors under uncertainty. The classical approach assumes that agents hold commonly known probability assessments towards uncertainty, which has been challenged by economists in many fields. My thesis adopts alternative methods to model agents’ behaviors. The new findings contribute to understanding how the mechanism designer can benefit from agents’ uncertainty aversion and how she should respond to the lack of information on agents’ probability assessments. Chapter 1 of this thesis allows the mechanism designer to introduce ambiguity to the mechanism. Instead of informing agents of the precise payment rule that she commits to, the mechanism designer can tell agents multiple payment rules that she may have committed to. The multiple payment rules are called ambiguous transfers. As agents do not know which rule is chosen by the designer, they are assumed to make decisions based on the worst-case scenario. Under this assumption, this chapter characterizes when the mechanism designer can obtain the first-best outcomes by introducing ambiguous transfers. Compared to the standard approach where the payment rule is unambiguous, first-best mechanism design becomes possible under a broader information structure. Hence, there are cases when the mechanism designer can benefit from introducing ambiguity. Chapter 2 assumes that the mechanism designer does not know agents’ probability assessments about others’ private information. The mechanisms designed to implement the social choice function thus should not depend on the probability assessments, which are called robust mechanisms. Different from the existing robust mechanism design literature where agents are always assumed to act non-cooperatively, this chapter allows them to communicate and form coalitions. This chapter provides necessary and almost sufficient conditions for robustly implementing a social choice function as an equilibrium that is immune to all coalitional deviations. As there are social choice functions that are only implementable with coalitional structures, this chapter provides insights on when agents should be allowed to communicate. As an extension, when the mechanism designer has no information on which coalitions can be formed, this chapter also provides conditions for robust implementation under all coalition patterns. Chapter 3 assumes that agents are not probabilistic about others’ private information. Instead, when they hold ambiguous assessments about others’ information, they make decisions based on the worst-case belief. This chapter provides necessary and almost sufficient conditions on when a social choice goal is implementable under such a behavioral assumption. As there are social choice goals that are only implementable under ambiguous assessments, this chapter provides insights on what information structure is desirable to the mechanism designer.

Creative ambiguity as a negotiation strategy is used often in peace agreements and refers to when ambiguities are used in agreements to serve as a positive motivation to get over obstacles. While it has many positive impacts, the use of creative ambiguity also often times shifts the burden of the negotiation phase to the implementations phase, and thus can result into agreements that are not implemented as well as plummeting the relations between the parties affected. This thesis aims to understand how the use of creative ambiguity in the Brussels Agreement between Kosovo and Serbia had an impact on the heightened conflict between the countries. This thesis is a single instrumental case study that illustrates the issue of creative ambiguity through the case of the Brussels Agreement. Through analysing interferences from material mainly collected from both countries’ government websites, this study conducted that the use of creative ambiguity had a harmful impact not only on the relations between Kosovo and Serbia, but also on the implementation of the agreement.

A major focus of many U.S. higher-education institutions is to increase internationalization of their campus through, in part, the promotion of study abroad experiences among domestic students and to recruit and retain international students to their institution. This study explored the effects of certain factors on various domains of the Global Engagement Measurement Scale (GEMS) – Cultural Engagement, Ambiguity Tolerance, Knowledge of Host Site, and Diversity Openness – among U.S. students who have studied abroad and international exchange students who have studied in the U.S. There was a particular focus, on determining whether U.S. study abroad students, compared to international students, rate differently on GEMS scales, after controlling for other possible confounding variables. Participants were recruited from three Southeastern, public, 4-year universities and were eligible if they were enrolled at any of those universities in the last five years. A hierarchical regression analysis revealed several factors significantly affected each of the various outcomes on the GEMS. Cultural Engagement and Ambiguity Tolerance were both predicted by the institution of study and the type of student (U.S. study abroad versus international exchange). Knowledge of Host Site was predicted by whether or not the trip was government sponsored, pre-trip familiarity with the host culture, and type of student. The overall regression model for Diversity Openness was not significant. These results provide insights into key factors that affect the overall global engagement of college students and can be used to inform university faculty and staff about features they can add to improve campus internationalization efforts.

Different types of ambiguous student contributions occur in mathematics classrooms. In this study I identified (1) different types of ambiguous student contributions and (2) the different ways teachers respond to one particular kind of ambiguous contribution, clarifiable ambiguity. Note that clarifiable ambiguity is ambiguity that stems from a student who uses an unclear referent in their contribution and can be clarified in the moment by the particular student. Literature has focused only on ambiguity that has the potential to further the development of mathematical concepts and has only theorized about teacher responses to this specific type of ambiguity. This study identified an additional three types of ambiguous student contributions: Student Appropriation of Teacher Ambiguity, Irrelevant Ambiguity, and General Ambiguity. It was important to identify all the different types of ambiguous student contributions because teacher responses should likely be different to the different types of ambiguity. In addition, through analyzing the teacher responses to the clarifiably ambiguous student contributions, this study found that teachers addressed the clarifiably ambiguous student contributions about half the time. When the teachers did address the clarifiable ambiguity, the majority of the time the teacher clarified the ambiguity themselves with the most common response being the teacher honed in on the clarifiably ambiguity and asked for confirmation from the student on the accuracy of the clarification.

Philosophiae Doctor - PhD / The purpose of the present study is to enrich academic knowledge, the understanding of management theory, and professional management practice for leaders in a South African Higher Education Institution (HEI) under volatile, uncertain, complex, and ambiguous (VUCA) conditions. Due to increased globalisation and rapid changes in the technological, social, economic, and political spheres, the environment in which organisations function has become increasingly VUCA. These factors create a unique set of challenges for the leaders of these organisations. Traditionally tested and proven methods of leading organisations no longer guarantee high performance. The dynamic environment is challenging leaders to find new ways to be successful. To further complicate matters, the speed, frequency, and intensity with which the organisational environment is changing are ascending in nature. The field of Higher Education in South Africa demonstrates the challenges and opportunities VUCA imposes on organisational leadership.

This study attempted to relate service orientation discrepancy between employees and managers to employees’ affective reactions in the restaurant industry. To fulfill this purpose, this study developed a new model and tested it by conducting an empirical analysis of restaurant employees. Specifically, this study examined the relationships among service orientation discrepancy (SOD), service employees’ role conflict (RC), role ambiguity (RA), job satisfaction (JS), and organizational commitment (OC). In addition, using path analysis, this study further scrutinized the causal relationships among the above variables. The key findings of this study indicate that there is an SOD between managers and employees. Employees saw themselves as more enthusiastic and less bureaucratic than managers and this SOD was correlated with employee outcomes such as RC, RA, JS, and OC. When the proposed model of the study was tested, the results indicated that SOD had a positive, direct effect on RC and direct, negative effects on JS and OC. SOD also had negative, indirect effects on JS and OC through RC and RA. RC had a negative, direct effect on JS and a negative, indirect effect on OC. RA had a negative, direct effect on JS. Finally, JS had a negative, direct effect on OC. The contribution of this study lies in attempting to explore the possibility of synthesizing service management and organizational behavior literature in the restaurant industry setting. By introducing the concept of SOD, this study showed the relationship between SOD and its impact on affective reactions of restaurant employees. Further, this study contributed to the existing literature by demonstrating the causal relationships among the variables examined. With these efforts, this study also laid the foundation for future empirical research. From the industry point of view, the findings of this study will provide substantive information that restaurant chains can use to design training, communication, and motivational programs and other human resource management programs for their employees. The study holds promise for reducing employee turnover and for improving customer service in the hospitality industry. / Ph. D.

The aim of this thesis is to estimate parameters of the moving target using different radar configurations. First the Doppler effect and the time delay of the received signal is examined. The investigation of these phenomenons is made for radial and non-radial movement of simple monostatic radar configuration and after that for the bistatic and multistatic MIMO configuration. The ambiguity function is presented for all these configurations. The ambiguity function is then used to estimate target parameters from the received signal. The received signal model and ambiguity function for the monostatic radar configuration is developed using Matlab software. Finally the practical use of these implementations is presented and compared.

Cette thèse porte sur les conséquences de l’aversion à l’ambiguïté dans des contextes dynamiques en économie. En particulier, elle s’intéresse aux conséquences de l’aversion à l’ambiguïté dans les décisions d’investissement irréversibles, ainsi que dans un problème d’aléa moral dynamique, modélisé en temps continu. Le premier chapitre propose une revue de la littérature traitant de l’aversion à l’ambiguïté en contexte dynamique. Nous y passons en revue les modèles existants ainsi que leurs applications en économie et en finance. Le second chapitre s’intéresse aux décisions d’investissement irréversible d’un monopole et de firmes en compétition parfaite, en présence d’ambiguïté à propos de la volatilité du processus stochastique gouvernant la demande. Cette notion particulière d’ambiguïté nécessite de mobiliser les outils récents de la théorie des espérances non linéaires. On y montre qu’en présence d’aversion à l’ambiguïté, la stratégie optimale d’un monopole implique d’investir plus rapidement que dans un marché en concurrence parfaite. Le troisième chapitre s’appuie sur les résultats du second chapitre pour traiter le cas d’une concurrence imparfaite entre deux firmes. Le quatrième chapitre traite d’un problème d’aléa moral dynamique en temps continu et on y introduit la notion plus classique d’ambiguïté à propos de la dérive du processus gouvernant l’incertitude. On y montre que sous certaines restrictions semblables au cas standard, le contrat optimal est linéaire par rapport à la production finale. Ce résultat nous permet ensuite de discuter l’effet de l’aversion à l’ambiguïté sur les incitations et l’utilisation de l’information. / This thesis focuses on the consequences of ambiguity aversion in dynamic contexts in economics. In particular, we focus on the consequences of ambiguity aversion in irreversible investment problems, and in dynamic moral hazard problems in continuous-time. The first chapter reviews the literature on ambiguity in dynamic contexts, and reviews existing models as well as their applications in economics and finance. The second chapter deals with irreversible investment in the monopoly case and under perfect competition, under ambiguous volatility. The notion of ambiguous volatility requires the use of recent tools in non linear expectation theory. We show that the optimal entry strategy of a monopoly under ambiguous volatility implies investing sooner than the perfectly competitive equilibrium under volatility ambiguity. The third chapter builds on the results of the second chapter and treats a special case of imperfect competition. The last chapter deals with a dynamic principal-agent problem under moral in continuous-time, in which agents perceive ambiguity about the drift of the relevant process. We show that under certain conditions, the optimal contract is linear in final output. We then use this result to discuss the effect of ambiguity aversion on the incentive power of the optimal contract and the informativeness principle.