Дисертації з теми "Ambiguity attitudes"

This investigation considered the relationship among attitudes toward interracial relationships, tolerance of ambiguity, and mindfulness using a correlational design. The exploratory research question was: Does a tolerance of ambiguity plays a role in the acceptance of interracial relationships? Adult participants (N = 253) between the ages of 18 and 78 included male, female, and genderqueer adult individuals in the United States. Participants were recruited through online advertisements. They responded to items on a demographic questionnaire, along with four assessment instruments measuring mindfulness (MAAS), tolerance for ambiguity (MSTAT-II), attitudes toward interracial relationships (ATID), and cognitive load (WPM). The key finding in this study was that level of mindfulness was positively related to the level of tolerance for ambiguity (p < .001). However, no significant relationships among mindfulness, cognitive load, or attitudes toward interracial relationships were found. Results for the variable measuring attitudes toward interracial relationships was heavily skewed in the negative direction, indicating a very accepting group, which influenced the nature of data analysis.

The premise of this thesis is that Western thought is characterised by the need to enforce binary classification in order to structure the world. Classifications of sexuality and gender both embody this tendency, which has been largely influenced by Judeo-Christian tradition. Thus, it is argued that attitudes to sexuality, particularly homosexuality are, in part, a function of the way in which we seek to impose structure on the world. From this view, it is (partly) the ambiguity, inherent in gender and sexual variation, which evokes negative responses. The thesis presents a series of inter-linked studies examining attitudes to various aspects of human sexuality, including the human body, non-procreative sex acts (anal an oral sex) and patterns of sexuality that depart from the hetero-homo dichotomy. The findings support the view that attitudes to sexuality are significantly informed by gender-role stereotypes, with negative attitudes linked to intolerance of ambiguity. Male participants show large differences in their evaluations of male and female bodies, and of male and female sexual actors, than do female participants. Male participants also show a greater negativity to gay male sexual activity than do female participants, but males perceive lesbian sexuality similarly to heterosexuality. Male bodies are rated as being less 'permeable' than female bodies and male actors are more frequently identified as being the instigators of sexual acts. Crucial to the concept of heterosexism is the assumption that 'femininity' is considered inherently inferior to 'masculinity'. Hence, the findings provide an empirical basis for making connections between heterosexism and sexism, and therefore between the psychology of women, and gay and lesbian psychology.

Cette thèse appartient au domaine de la théorie de la décision en situation d'incertitude. Elle vise à comprendre, décrire, et représenter les choix individuels dans différents contextes de décision. Notre travail se concentre sur le fait que le comportement économique est souvent influencé par la structure et le déroulement de la résolution de l'incertitude. Dans une première expérience nous avons confronté nos sujets à différents types d'incertitude – à savoir du risque (probabilités connues), de l'incertain (probabilités inconnues), du risque composé et de l'incertain composé – en utilisant des mécanismes aléatoires particuliers. Le chapitre 1 analyse l'hétérogénéité des attitudes individuelles face à l'ambiguïté, au risque composé et à l'incertain composé alors que dans le chapitre 2, le modèle d'espérance d'utilité à dépendance du rang est utilisé comme outil de mesure afin d'étudier en détails ces attitudes au niveau individuel. Le chapitre 3 confronte à l'expérience l'interprétation de l'ambiguïté en terme de croyances de second ordre et propose une méthode d'élicitation de la fonction qui caractérise l'attitude face à l'ambiguïté dans les modèles « récursifs » de décision face à l'incertain. La seconde partie de la thèse s'intéresse aux comportements de décision individuelle dans un contexte dynamique et est composée de deux études expérimentales indépendantes. Néanmoins, elles reposent toutes deux sur la décomposition de l'axiome d'indépendance en trois axiomes dynamiques: conséquentialisme, cohérence dynamique et réduction des loteries composées. Le chapitre 4 rapporte les résultats d'une expérience de décision individuelle sur les facteurs de violations de chacun de ces axiomes. Le chapitre 5 présente une catégorisation conceptuelle des comportements individuels dans des problèmes de décision séquentiels face au risque. Le cas des agents ne se conformant pas à l'axiome d'indépendance y est étudié de façon systématique et les résultats d'une expérience spécialement conçue pour tester cette catégorisation sont présentés
This thesis belongs to the domain of decision theory under uncertainty and aims to understand, describe and represent individual choices in various decision contexts. Our work focuses on the fact that economic behavior is often influenced by the structure and the timing of resolution of uncertainty. In a first experimental part, we confronted subjects with different types of uncertainty, namely risk (known probabilities), uncertainty (unknown probabilities), compound risk and compound uncertainty, which were generated using special random devices. In chapter 1 we analyze the heterogeneity of attitudes towards ambiguity, compound risk and compound uncertainty whereas in chapter 2, we use rank dependent expected utility as a measuring tool in order to individually investigate these attitudes. Chapter 3 confronts the interpretation of ambiguity in term of second order beliefs with the experimental data and proposes a method for eliciting the function that encapsulates attitudes toward ambiguity in the “recursive” or multistage models of decision under uncertainty. The second part of the thesis deals with individual decision making under risk in a dynamic context and is composed of two independent experimental studies. Both of them rely on the decomposition of the independence axiom into three dynamic axioms: consequentialism, dynamic consistency and reduction of compound lotteries. Chapter 4 reports experimental data about violations of each of the three axioms. Chapter 5 presents a conceptual categorization of individual behavior in sequential decision problems under risk, especially those which do not conform to the independence axiom. We propose an experiment specially designed to test the predictions of this categorization

Purpose: The purpose of this study was to explain whether the conceptualized model of consumer confusion regarding the multiple number of brands and products also applies to the increasing number of eco-labels. The study also examined how the attitudes were affected if confusion occurred amongst the consumers. More specifically, whether consumer confusion leads to negative attitudes. Theoretical Framework: The conceptualized model of consumer confusion, including the three dimensions of ambiguity, information overload and similarity was used in this research.In addition, theories regarding attitudes and indicators that affect consumer’s attitudes werepresented and used for the analysis. Methodological Framework: This research took an explanatory and deductive approach. The research was carried out with a quantitative method including three hypotheses derived from the literature. Data was collected through a questionnaire that was spread online on social media. The gathered data was coded accordingly in order to get the results from the frequencies, descriptive statistics, correlation and the regression analysis. Empirical Results: It was discovered that the respondents were confused by eco-labels and eco-labelled products regarding all the three dimensions of the conceptualized model of consumer confusion. However, the fact that the attitudes towards eco-labels and eco-labelled products were very positive, led to a rejection of all the three hypotheses. Consequently, supportive questions from the questionnaire and the demographic details of the sample served as additional support to further discuss the results of the study. Conclusions: This study showed that the conceptualized model of consumer confusion also applies to eco-labels. However, the consumers still had positive attitudes towards eco-labels and eco-labelled products which could be seen as contradictory. Nevertheless, positive beliefs about eco-labels and its effects and demographic details were found to have an impact on the positive attitudes.

This thesis contains four empirical chapters which together contribute to behavioural economics in the area of fish production in a developing country context. The key thread connecting all the empirical studies is the behavioural characteristic of farmers (risk and ambiguity attitudes) elicited through incentivised field experiments and general survey questions. The first empirical chapter seeks to answer the questions: What is the risk attitude of a typical smallholder fish farmer in a developing country? Do risk attitudes of fish farmers remain stable across different elicitation methods and contexts of validation? Risk attitude measures are known to be sensitive to the method of elicitation and context (Bauermeister and Mushoff, 2016). The purpose of this chapter is three-fold. 1. It elicits and compares the risk attitudes of within-subject sample of smallholder fish farmers in southern Ghana using three of the frontier methods used to elicit risk attitudes in the literature. The risk attitudes elicited from these methods are employed in the subsequent chapters of this thesis to investigate how risk preferences affect production efficiency and technology adoption. 2. It investigates how the risk attitude measures correlate with each other, and how they vary with farmer characteristics. 3. It assesses whether the risk attitude measures can predict farmer responses to questions on hypothetical economic choices. The results show that a typical smallholder fish farmer is risk preferring in the gains-only lottery experiment, risk averse in the gains-and-losses lottery experiment but is risk neutral from the self-reported risk attitude scale. However, the risk attitude measures from the two lottery experiments are positively correlated, consistent with the assumption that the two experiments capture similar traits of the same farmer. This confirms that risk attitude measures are influenced by the method of elicitation and the context being examined. Some personal characteristics of the farmers influence their risk attitudes. Finally, while risk preferences from the lottery experiments failed to explain hypothetical economic choices, the stated risk preferences were significantly correlated with some hypothetical economic choices, perhaps due to hypothetical bias. These results indicate that care should be taken to tailor the elicitation of risk attitudes to contexts and domains farmers are familiar with. The second empirical analysis attempts to answer the question: to what extent does a fish farmer's risk attitude affect his/her level of economic efficiency? This is predicated on the assumption that the types, levels and frequency of application of inputs could be influenced by the risk attitudes of farmers. Data on the units of inputs, outputs and prices are collated from the farmers in an earlier survey, and their risk attitudes obtained from the previous chapter are then juxtaposed on their production data. The economic efficiency of the farmers is assessed with both the Stochastic Frontier Analysis (SFA) and the Corrected Ordinary Least Squares (COLS) techniques. While the former assumes that all deviations from the cost frontier are due to farmer-specific factors (including risk attitudes) and stochastic factors, the latter, a deterministic procedure, attributes all deviations from the frontier to farmer-specific factors. The evidence from this chapter suggests that over 80% of the total deviation from the cost frontier results from stochastic factors beyond the control of the farmers. It is also found that risk attitudes play no significant role in the economic efficiency of fish production in the study area. Based on the findings, it is concluded that stochastic factors, such as government policies, may have a greater impact on economic efficiency rather than risk attitudes of farmers. The third empirical study assesses how risk attitudes of fish farmers affect the speed of technology adoption; adoption decisions are modelled with duration models. This study focuses on the adoption of Floating Cages, Extruded Feed and Akosombo Strain of Tilapia (AST) technologies in the fish farming sector in southern Ghana. Contrary to most existing literature on speed of adoption of technologies (e.g. Liu, 2013), the results from this chapter show that risk averse farmers have a higher proclivity to adopt the AST, Extruded Feed and Floating Cage technologies at a point in time. This novel outcome is due to the nature of the technologies in question, as perceived by the farmers. Liu's (2013) study, for instance, focuses on the adoption of cotton seeds modified genetically with Bacillus thuringiensis (Bt) bacteria, which enables cotton plants to produce phytotoxins to kill pests. The subjective risks posed by these phytotoxins to the farmers themselves may be an additional source of uncertainty and a likely reason for the delayed adoption by risk averse farmers. However, in this chapter, even though the AST is also genetically modified, it produces no toxins and yet it is more disease-resistant than the local breeds, therefore it may be perceived by the farmers as risk-reducing and hence it may not be surprising that risk averse farmers adopt this technology earlier. In the final empirical study, attention is on how ambiguity attitudes affect the farming decisions of smallholder fish farmers, using the speed of adopting the AST technology as an example of such decisions. The speed of technology adoption is analysed with the hazard/survival model. Additionally, this chapter introduces and interacts the number of previous adopters in the same village with ambiguity attitude as a better test of the effect of ambiguity aversion on farmers' decisions. Where a farmer cannot predict with certainty the yield to be obtained from the new technology, an ambiguity averse farmer is expected to adopt the technology late. Ambiguity attitudes are elicited with Ellsberg's (1961) two-colour urn experiment. The results from this chapter show that the average fish farmer is ambiguity averse. However, risk aversion, but not ambiguity aversion, has a significant effect on the speed of adopting the AST technology in the study area, confirming the robustness of the finding in the previous chapter. I also find that the speed of adopting this technology increases with the number of prior adopters in the same village. The lack of any significant impact of ambiguity attitudes in determining the speed of adopting this technology suggests that there are other important determinants of adopting this technology, rather than lack of information about it, that affect other technology adoption decisions. Overall, this thesis demonstrates and presents the elicitation of risk and ambiguity preferences outside the usual laboratory setting by engaging fish farmers in a field experiment involving real cash incentives, as well as field surveys. The experiments and methods employed are at the frontier of research in the field of development economics. The results of the analysis presented in this thesis indicate that that risk preferences are sensitive to the method of elicitation, as well as the context or domain in which it is elicited. While contrary to findings from other studies, risk averse farmers are more prone to adopt improved fish farming technologies earlier than farmers who are not risk averse. This conclusion is plausible because the technologies may be perceived as risk-reducing by the farmers. This outcome remains robust when ambiguity aversion is introduced into the analysis of the technology adoption decision. Therefore, research on farmer production choices should take their risk attitudes into account, and such risk attitude measures should be elicited in a manner that is compatible with the context of operation of the farmers.

Police are increasingly responding to incidents involving persons with mental illness (PMIs). This is an important area of research considering the well-documented challenges these types of interventions represent for police officers and police agencies more broadly. Yet, to date, there remains limited empirical knowledge about the extent of police involvement with PMIs, particularly in the Australian context. Similarly, little is known about police officers’ perception of the role they perform with PMIs and the influences that shape their role performance, despite evidence of the challenges modern-day police are facing in the attempt to consolidate the ‘law enforcer’ and ‘service’ elements of the police role. The overarching objective of this research program is to gain a better understanding of the role of police in responding to PMIs. Within this objective, three more specific aims are derived, each targeting a distinct, yet complementary, component of police roles with PMIs: 1) To examine the frequency, distribution and outcomes of police involvement with persons with mental illness in Queensland, Australia; 2) To examine police officers’ attitudes towards their role in responding to persons with mental illness; and 3) To use the role episode model to examine the perceptions and experiences of police officers in responding to persons with mental illness. The role episode model was chosen as a theoretical framework that guided this research program. This model allows for a comprehensive exploration of police officers’ perceptions of this element of police role through an identification of the members of their role set, analysis of the expectations held by each role sender, and finally by studying the presence and outcomes of role-related stress. Two research studies were conducted, addressing a total of 15 research questions. In Study 1, Queensland Police Service (QPS) administrative data from two selected police regions in Queensland were analysed for the frequency, distribution and the outcomes of police-PMI encounters. In Study 2, an online survey with 242 sworn QPS officers was undertaken to examine their perceptions of the role of police in responding to mental health related calls for service. In Study 1, 12,415 mental health related calls for service were identified, accounting for 2.6% of all calls for service. Significant temporal and spatial variation of these calls was noted. Socio-demographic characteristics identified as increasing the rate of police-PMI contacts included: younger median age, smaller population size, low percent of Indigenous population, high percent of population with severed disability, and a greater degree of socioeconomic disadvantage. An analysis of the outcomes of mental health calls showed frequent utilisation of health-related pathways, predominantly by initiating transfers to a mental health facility, and a very low incidence of arrests. The likelihood of a health-related outcomes was increased when the call was initiated by an ambulance officer or other professional agencies, when the incident occurred in a public location (rather than in a private residence), when there was a risk to PMIs’ life, or any indications of violence or aggression. In Study 2, police officers reported that on average, a quarter of their time is taken up by engagements with PMIs, and most of them felt that this is too much. Overall, officers accepted their involvement with PMIs as part of their role, though a considerable number continued to feel that the extent of their work with PMIs is excessive and reflective of the failings of the mental health system. Participating police officers identified on average four persons or groups as having an important influence on how they perform their work with PMIs: these were most commonly themselves, colleagues, their immediate supervisor and PMIs. Officers described their personal expectations regarding their work with PMIs as requiring an equal application of the ‘law enforcement’ and ‘service’ aspects of their role. Their expectations were aligned with those perceived to be held by other members of the police service, however, for the majority of officers, they were incongruent with the more service-oriented expectations attributed to the broader community and the mental health sector. The study results revelated moderate levels of role conflict and low levels of role ambiguity resulting from police work with PMIs. Various organisational and personal factors were found to predict the likelihood of experiencing high levels of these role-related stresses. Of particular interest is a positive association between the officers’ identification with the ‘crime control’ aspects of their role and high levels of role-related stress. Finally, results showed that role ambiguity, but not role conflict, increases the likelihood of officers reporting poor job satisfaction. The theoretical contribution of this research is through an innovative application of the role episode model to research on mental health policing. It offers a confirmation to the previously debated, but never empirically investigated, argument that engagements with PMI place police within a complex network of stakeholders and exposes them to role expectations from disciplines that are characterised by different expectations about provision of care to vulnerable members of society. There are also several practical implications of the findings of this research program. Most notably, information about spatial and temporal distribution of mental health calls for service can be used to guide the data-driven, targeted allocation of police resources using the principles of hot-spot policing. The information about the extent of police involvement with PMIs can also help improved police officers’ awareness of the realities of mental health policing. Finally, several recommendations for future research are highlighted, particularly around the need to examine the role of occupational socialisation on the development of police officers’ perception of their role as first responders to mental health related incidents. It is hoped that continued research into these topics can continue to support police in providing safe and effective responses to people experiencing mental health crises.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Crim & Crim Justice
Arts, Education and Law
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This thesis contributes to the theoretical work on decision and game theory when decision makers or players perceive ambiguity. The first article introduces a new axiomatic framework for ambiguity aversion and provides axiomatic characterizations for important preference classes that thus far had lacked characterizations. The second article introduces a new axiom called Weak Monotonicity which is shown to play a crucial role in the multiple prior model. It is shown that for many important preference classes, the assumption of monotonic preferences is a consequence of the other axioms and does not have to be assumed. The third article introduces an intuitive definition of perceived ambiguity in the multiple prior model. It is shown that the approach allows an application to games where players perceive strategic ambiguity. A very general equilibrium existence result is given. The modelling capabilities of the approach are highlighted through the analysis of examples. The fourth article applies the model from the previous article to a specific class of games with a lattice-structure. We perform comparative statics on perceived ambiguity and ambiguity attitude. We show that more optimism does not necessarily lead to higher equilibria when players have Alpha-Maxmin preferences. We present necessary and sufficient conditions on the structure of the prior sets for this comparative statics result to hold. The introductory chapter provides the basis of the four articles in this thesis. An overview of axiomatic decision theory, decision-making under ambiguity and ambiguous games is given. It introduces and discusses the most relevant results from the literature.

This paper analyzes some forms of linguistic manipulation in Japanese in newspapers when reporting on North Korea and its nuclear tests. The focus lies on lexical ambiguity in headlines and journalist’s voices in the body of the articles, that results in manipulation of the minds of the readers. The study is based on a corpus of nine articles from two of Japan’s largest newspapers Yomiuri Online and Asahi Shimbun Digital. The linguistic phenomenon that contribute to create manipulation are divided into Short Term Memory impact or Long Term Memory impact and examples will be discussed under each of the categories.The main results of the study are that headlines in Japanese newspapers do not make use of an ambiguous, double grounded structure. However, the articles are filled with explicit and implied attitudes as well as attributed material from people of a high social status, which suggests that manipulation of the long term memory is a tool used in Japanese media.
この論文は日本語の新聞中の北朝鮮と核実験に関する報告記事の曖昧さと操作的な態度についてである。この研究は特に北朝鮮について新聞の記事中の計画的で無意識に言語的な操作態度についてである。記事の見出しと読者の心意を関わる曖昧さについてである。全部の記事は読売新聞と朝日新聞に取ったが、全部の中に、多大態度がある。調査は日本の最大の新聞読売オンラインと朝日新聞デジタルの九の記事のコーパスに基づいてである。研究の主な結果は、日本の新聞の見出しがあいまいな構造を利用していないことだが、記事は明示的な態度だけでなく、多大な引用文で満たされている

This thesis is concerned with determining the orientation of small Unmanned Aerial Vehicles(UAVs). To make commercial use of these aircraft in aerial surveying markets their attitude needs to be determined accurately and precisely throughout a survey flight. Traditionally inertial sensors have been used on larger aircraft to estimate both position and orientation in combination with Global Navigation Satellite Systems (GNSS). High quality inertial sensors have many downsides when used on the small UAV. They are expensive, power hungry and often heavy. Inertial sensors are vulnerable to vibration, high acceleration, high rotation rate and jerk. All of these are present on the small UAV. This thesis identifies GNSS attitude determination as a potentially suitable alternative to inertial techniques. Carrier phase GNSS attitude determination uses three or more GNSS receivers with antennas separated by a short baseline to estimate the orientation of the UAV. This technique offers low cost, high accuracy and drift-free attitude estimates. To be successfully used it requires removal of the biases present in the received GNSS signals and estimation of the integer cycle ambiguity present in the carrier phase measurement. This thesis presents and examines the state of the art techniques for removing these biases and estimating an integer cycle ambiguity using a priori measurement of the interantenna distance. In this work a novel method is developed which uses this a priori baseline measurement to validate estimates of the carrier phase ambiguities. In order to test these methods data has been gathered using low cost, commercially available GNSS receivers and antennas. This is the first work in which modern, low cost, GNSS equipment has been tested for use in attitude determination. It is found that the state of the art carrier phase GNSS attitude determination methods can provide an accurate attitude estimate for every set of measurements from the GNSS receivers. However, a real UAV flight indicates that the low cost GNSS equipment does not track the GNSS signals throughout the flight. Signal outages, cycle slips and half cycle ambiguous carrier phase measurements occur due to rapid UAV manoeuvres. Having identified this problem this work goes on to replicate and quantify it through the use of a GNSS hardware simulator. Algorithms are then devised to increase the availability of the GNSS attitude solution throughout the tracking difficulties. Complete GNSS signal tracking failures are overcome through the innovative use of kinematic and dynamic attitude models. Both types of model give an attitude solution throughout GNSS signal tracking problems without adding significant cost or weight to the system. When tracking of the GNSS carrier phase signal is possible, novel use of the carrier phase triple difference observable allows the attitude rate to be estimated even when the carrier phase measurements are half cycle ambiguous. It is shown that integer and half integer cycle slips can be removed from the measurement through the combination of the modelling and triple difference techniques. The attitude output of both modelling and triple difference methods is used to resolve half cycle ambiguities and make full use of half cycle ambiguous data where previously it could not have been used. Success rates of up to 99.6% have been achieved for half cycle ambiguity resolution. As a result precise and accurate GNSS attitude solutions are available at nearly every epoch for which a carrier phase measurement is output by the GNSS receivers. When no measurement is available the attitude solution gracefully degrades over time. This work makes reliable, accurate, low cost attitude determination possible on mini-UAVs.

Pour les entreprises concernées par le phénomène du vieillissement, le rapport entre la structure par âge de la main d’œuvre, les profils des salaires et de productivité est un élément clé abordé dans cette thèse. Le premier chapitre passe en revue divers concepts théoriques et décrit les résultats empiriques en ce qui concerne le profil des salaires et de productivité en fonction de l’âge. L’étude empirique présentée dans le chapitre deux évalue le profil de productivité marginale selon l'âge. Nous considérons la main d'œuvre à la fois par qualification (peu qualifiés, hautement qualifiés) et par âge (jeunes, âge moyen, âgés). Nous estimons, sur des données françaises d'entreprises, une fonction de production de type CES emboîtée qui autorise une substitution imparfaite entre les différentes catégories de travailleurs. Parmi les résultats principaux, nous avons trouvé que la productivité du travail par l’âge dépend étroitement de la catégorie de qualification et du secteur d’activité des travailleurs. Le chapitre trois analyse le comportement des juniors et des seniors, en particulier leurs attitudes face au risque, la confiance en soi et la propension à entrer en compétition. Pour cela, nous avons organisé une expérience avec des banquiers suisse. Nous trouvons que, bien que les deux générations ne présentent ni des différences considérables quant à leurs attitudes face au risque, ni face à l’ambiguïté, les seniors font preuve d’une propension plus élevée à entrer en compétition. Cette décision est clairement influencée par l’information sur l’âge des autres participants. De plus, les deux générations maximisent leurs profits dans les groupes équilibrés en termes d’âge
The relationship between the age structure of workforce, earnings and productivity profiles is a key issue for the enterprises facing the phenomenon of ageing. The present thesis addresses these issues in the following order. The first chapter reviews different theoretical concepts and recent empirical findings concerning the profile of earnings and productivity by age. The empirical study presented in the chapter two aims at estimating the actual profile of labour productivity across different age groups. In this purpose, we differentiate the workforce simultaneously by skills (low-skilled, high-skilled) and by age (young, middle-aged, old). Using French firm-level data, we estimate a production function with a nested constant-elasticity-of-substitution (CES) specification in labour, which allows the imperfect substitution between different age and skill categories of workers. Among the main findings, labour productivity by age highly depends on skill category of workers and the sector of activity. The third chapter involves the behavioural analysis of the workforce composed of juniors and seniors. In particular, we study workers’ risk attitudes, self-confidence and propensity to enter the competition. In this purpose, we perform an artefactual field experiment with the employees of a Swiss bank. We find that, although there are no significant differences in attitudes towards risk and ambiguity between both generations, seniors have higher propensity to enter the competition. The information on age of others players clearly has an impact on this decision. Moreover, the profits of both generations are maximised, when a pool of competitors is balanced in terms of age

Finding the correct integers is the key to high precision range measurements. This has been an issue of investigation since the early 1980’s and many different techniques have been developed, none of them can guarantee to resolve the correct integers in 100% of the cases(Kim & Langley, 2000) though. This thesis focuses on a new approach for Integer Ambiguity Resolution (IAR), using a geometric approach and Interval Analysis (IA). The new method can guarantee that if all measurement errors are bounded by the interval bands the correct integers will always be found. Depending on the width of the interval bands though, there may be more than one solution. The research objective of the thesis is to determine if the Interval Based Integer Am-biguity Resolution (IBIAR) method can be used for accurate attitude determination with only one remaining (correct) solution. Earlier results using the Bounded integer ambiguity resolution using interval analysis (BOUNDS) algorithm (van Kampen, 2010) have shown that one solution can not be obtained for all epochs when applied to flight data from a Cessna Citation II research airplane equipped with three antennas. The analysis did not make use of two frequencies, comparing the baseline orientations and adding an extra antenna though. These aspects are added to the BOUNDS algorithm in order to potentially reduce the number of solutions. Further the effects of the noise on both the carrier phase measurements and baseline lengths are investigated. All simulations are done off line as no real flight data is available for the test configurations. The simulations are loosely based on the Cessna Citation II research airplane belonging to the Dutch National Aerospace Laboratory (NLR) and Delft University of Technology (DUT). For all simulations the correct solution is bounded by the noise levels, which means that the BOUNDS algorithm theoretically always finds the correct solution. Further it is assumed that there are no multipath effects, no restrictions on the attitude angles the airplane can fly with, that the antennas always have a clear view of the satellites and the cut off angle is zero degrees. The conclusion of the thesis is that the IBIAR method can be used for attitude determination where one (correct) solution remains but the accuracy of the solution is low. The thesis gives recommendations on how to improve the accuracy of the attitude angles.

Les informations négatives sur les produits et les entreprises auxquelles les consommateurs ont accès ne sont pas toujours fiables et claires. Cette thèse étudie comment l'orientation régulatrice des consommateurs influe sur leur réaction par rapport aux informations négatives comme une fonction de l'ambiguïté des informations. Nous suggérons que lorsque les informations négatives sont ambigües, les consommateurs avec une orientation prévention, par rapport à ceux avec une orientation promotion, seront beaucoup plus influencés par les informations et susceptibles de changer en conséquence vers le bas leur attitude envers la marque. En revanche, lorsque les informations négatives sont claires, à la fois les consommateurs orientés promotion et ceux orientés prévention seront très influencés et susceptibles de revoir leur attitude à la baisse par rapport à la marque en question. De plus, nous alléguons que la diagnosticité perçue des informations exerce un rôle médiateur sur les effets proposés. Plus particulièrement, en présence des informations négatives ambiguës, l'orientation prévention (par rapport à l'orientation promotion) a tendance à amplifier la diagnosticité perçue des informations qui, en retour, accentue les effets que les informations négatives auront sur la révision de l'attitude. Quatre études expérimentales ont testé et confirmé ces hypothèses à travers trois scénarios ambigus différents : (1) quand les informations négatives proviennent d'une source dont la crédibilité est incertaine (étude 1), (2) quand la raison pour laquelle un produit défectueux est ambiguë (étude 2) et (3) quand les évaluations de produit sont très contradictoires (études 3a et 3b)
Negative information about products or companies that consumers encounter in the marketplace is not always certain and clear-cut. This dissertation explores how consumers' regulatory focus orientation affects their response to negative information as a function of information ambiguity. We propose that under the situations where ambiguity is present in the negative information, prevention-focused compared to promotion-focused consumers will be more strongly persuaded and exhibit a large downward revision of their attitude toward the brand. In contrast, under the situations where the negative information is unambiguous, both promotion and prevention-focused consumers will be strongly persuaded and revise accordingly their attitude toward the brand. Moreover, we argue that perceived diagnosticity of the information mediates the proposed effect. Specifically, in the presence of ambiguity in negative information, a prevention focus (vs. a promotion focus) leads to an inflated perceived information diagnosticity, which, in turn, accentuates the impact of negative information on judgment revision. Four experimental studies tested and confirmed these propositions in three different ambiguous scenarios: (1) when negative product information comes from a source with uncertain credibility(Study 1); (2) when the cause of a reported product failure is ambiguous(Study2), and (3) when product reviews are highly conflicting (Study 3a and Study 3b)

This thesis consists in three essays that study the linkages between real and financial factors from different perspectives. Chapter 1, co-authored with Ester Faia and Valeria Patella, introduces a full set of ambiguity attitudes, which endogenously induces agents' optimism in booms and pessimism in recessions, in a model where borrowers face occasionally binding collateral constraints. We use GMM techniques with latent value functions to estimate the ambiguity attitudes process, showing that agents update their belief over the credit cycle in a way coherent with our preferences specification. By simulating a crisis scenario, we show that optimism in booms is responsible for strong leverage build-up before the crises while pessimism in recessions implies sharper de-leveraging and asset price bursts. Analytically and numerically, using global non-linear methods, we show that our ambiguity attitudes coupled with the collateral constraints help to explain relevant asset price and leverage cycle facts around the unfolding of financial crises. Chapter 2, co-authored with Carmelo Salleo, studies the strategic interactions between monetary and macroprudential authorities through the lens of an open-economy monetary model featuring trade and financial ows between two symmetric countries. Characterizing a set of Within-Country Cooperative and Nash Equilibria for different degrees of trade and financial integration, the analysis identifies large costs associated to the strategic interaction between the domestic authorities. Moreover, the gains from cooperation are strongly affected by the degree of cross-country integration and by the channel through which the integration is realized: larger trade ows reduce the gains, while higher financial globalization makes cooperation more valuable. Then, moving to a Between-Countries Cooperative and Nash Equilibria analysis, we confirm that cooperation is beneficial from both the country-specific and the global perspective. Chapter 3, co-authored with Javier Ojea Ferreiro and Elena Rancoita proposes an innovative methodology for the design of adverse scenarios for macroprudential policies calibration and impact assessment. Our methodology allows building tailored scenarios characterized by two main features. First, there is a stable and transparent mapping of the cyclical systemic risk level into the path of the scenario's target variables, which are those variables that determine the overall scenario's severity. Second, the path of the other complementary variables is calibrates with a multivariate copula model estimated with macro and financial data (MacroFin Copula). Simulating the model for Euro Area countries, we show that our methodology is able to calibrate adverse scenarios that properly replicate the global financial crises dynamics in terms of severity and co-movement between the key macroeconomic and financial variables.

Объектом исследования явилась жизнестойкость личности. Предметом исследования стала связь жизнестойкости и ее показателей с толерантностью к неопределенности и показателями профессионального самоотношения. Магистерская диссертация состоит из введения, двух глав, заключения, списка литературы (80 источников) и приложений, включающего в себя бланки применявшихся методик и результаты статистической обработки данных. Объем магистерской диссертации 86 страниц, на которых размещены 12 рисунков и 8 таблиц. Во введении раскрывается актуальность проблемы исследования, разработанность проблематики, ставятся цель и задачи исследования, определяются объект и предмет исследования, формулируются основная и дополнительные гипотезы, указываются методы и эмпирическая база, а также этапы проведения исследования, научная новизна, теоретическая и практическая значимость работы. Первая глава включает в себя обзор иностранной и отечественной литературы по темам жизнестойкости, толерантности к неопределенности и профессионального самоотношения. Представлены разделы, посвященные анализу специфики профессиональной деятельности практического психолога. Выводы по первой главе представляют собой итоги по изучению теоретического материала. Вторая глава посвящена эмпирической части исследования. В ней представлено описание организации и методов проведенного исследования и результатов, полученных по всем использованным методикам: теста жизнестойкости С. Мадди (в адаптации Д.А. Леонтьева и Е.И. Рассказовой), методики определения толерантности к неопределенности С. Баднера (в адаптации А.Г. Солдатовой), а также опросника профессионального самоотношения К.В. Карпинского и А.М. Колышко. Также в главе представлен корреляционный и регрессионный анализ результатов исследования. Выводы по главе 2 включают в себя основные результаты эмпирического исследования. В заключении в обобщенном виде изложены результаты теоретической и эмпирической частей работы, а также выводы по выдвинутым гипотезам, обоснована практическая значимость исследования и описаны возможные перспективы дальнейшей разработки данной проблематики.
The object of the study was the resilience of the individual. The subject of the study was the relationship of hardiness and its indicators with tolerance to uncertainty and indicators of professional self-attitude. The master's thesis consists of an introduction, two chapters, a conclusion, a list of references (80 sources) and appendices, including forms of the applied methods and the results of statistical data processing. The volume of the master's thesis is 86 pages, which contain 12 figures and 8 tables. The introduction reveals the relevance of the research problem, study problem, put the goal and objectives of the study, defines the object and subject of research, formulates the main and additional hypotheses that specifies the methods and empirical base, as well as the stages of the study, scientific novelty, theoretical and practical significance of the work. The first chapter includes a review of foreign and domestic literature on the topics of hardiness, tolerance to uncertainty and professional self-attitude. The sections devoted to the analysis of the specifics of the professional activity of a practical psychologist are presented. The conclusions of the first chapter are the results of the study of the theoretical material. The second chapter is devoted to the empirical part of the study. It describes the organization and methods of the study and the results obtained by all the methods used: the test of hardiness of S. Maddi (in the adaptation of D. A. Leontiev and E. I. Rasskazova), the method of determining tolerance to uncertainty of S. Badner (in the adaptation of A. G. Soldatova), as well as the questionnaire of professional self-attitude of K. V. Karpinsky and A. M. Kolyshko. The chapter also presents a correlation and regression analysis of the results of the study. The conclusions of chapter 2 include the main results of the empirical study. In conclusion, the results of the theoretical and empirical parts of the work, as well as conclusions on the hypotheses put forward, are summarized, the practical significance of the study is justified and possible prospects for further development of this problem are described.

碩士
國立中山大學
經濟學研究所
100
Two different types of games are used to measure subjects’ attitudes towards risk and ambiguity in this paper. In GAME 1, subjects are provided with a series of binary choices and a fill-in question for every set of tasks. In GAME 2, subjects are asked to play an auction game. Gains and losses stimulate subjects’ different attitudes toward risk. It also happens when we measure subjects’ attitude toward ambiguity. However, the results of Game 1 and Game 2 lack strong correlation with each other. While answering the series of binary choices in Game 1, subjects are risk averse/ambiguity averse over gains, and risk seeking/ambiguity seeking over losses. While answering the fill-in question in Game 1, subjects are risk neutral/ambiguity neutral over gains, and risk seeking/ambiguity seeking over losses. In GAME 2, we measure the attitude toward risk or attitude by the deviation from the case of neutrality or by risk indexes/ambiguity indexes. Analyzing the deviation, we conclude: (1) In the gains domain with high average probabilities to win, subjects are risk averse/ambiguity averse, but in the case of low average probabilities to win, subjects are risk seeking/ambiguity seeking. On the other hand, in the losses domain with high average probabilities to loss, subjects are risk seeking/ambiguity seeking, but when with low average probabilities to loss, subjects are risk aversion/ambiguity aversion. (2) The correlation between the attitudes toward risk and ambiguity gains is significantly greater than that over losses. (3) In the gains domain, the level of ambiguity aversion of subjects significantly increases with the ambiguous ranges of games. However, in the losses domain, the relation between those two is weak or non-significant. Analyzing the data with the risk indexes and the ambiguity indexes, we have two conclusions identical to the above. However, in the gains domain, the level of ambiguity aversion of subjects significantly increases with the ambiguity range of the games while we have the opposite result in the losses domain.

Available theory suggests that both issue and context related factors as well as individual factors influence the ethical decision-making process. This study used an experimental design to investigate whether the issue-related construct reward consequences, an extension of Jones’ (1991) issue-related factor, magnitude of consequences, is a strong predictor of attitude of business stakeholders towards the ethicality of a morally ambiguous action, in this case, a strategic competitor bluff. The study also investigated the predictive capability of the personal moral philosophy dimensions of relativism and idealism in the presence of differential reward consequences in a morally ambiguous context. The study found clear support for the predictive capability of the issue-related factor, reward consequences, for the moral decision-maker, however, the personal factor of business stakeholders’ a priori personal moral philosophy, measured using Forsyth’s (1980) Ethics Position Questionnaire (EPQ), was not found to predict their attitudes towards the morally ambiguous action. These findings were consistent across four different business stakeholder roles considered. The findings did indicate, however, that the relativism dimension of the EPQ moderates the relationship between reward consequences and attitude towards the morally ambiguous action. The contributions of the findings to theory bearing on ethical decision-making in the context of morally ambiguous circumstances and stakeholder management are discussed, as are their implications for business management.
Thesis (Ph.D.)--Gordon Institute of Business Science, 2013
pagibs2014
Gordon Institute of Business Science (GIBS)
unrestricted

The objective of the study was to examine the effect of cognitive moral development on ethical attitudes, in the presence of reward consequences, under conditions of moral ambiguity. The study is based on business stakeholders under conditions of strategic business competition. The intention of the study is to explore and understand the predictors of ethical behaviour. The participants of the experimental study were 2012/13 GIBS MBA business students with real managerial experience. They were randomly assigned to different stakeholder roles in a controlled business simulation game called the Execugame, with varying treatments of reward consequences and a strategic competitor bluff. The study sought to determine whether Reward Consequences (RC) will be a stronger predictor of Attitude towards the Ethicality of Competitor Bluffing (ATECB) amongst Stakeholder Role Players (SRPs) than their Level Cognitive Moral Development as a predictor of Attitude towards the Ethicality of Competitor Bluffing (ATECB). Overall the results didn’t find evidence to support the research hypotheses. Hence the research failed to prove a relationship and did not find evidence to support a relationship.
Dissertation (MBA)--University of Pretoria, 2013.
lmgibs2014
Gordon Institute of Business Science (GIBS)
MBA
Unrestricted

碩士
銘傳大學
觀光事業學系碩士在職專班
100
In recent years, the focus of research on the visual elements in printed advertising has shifted from the presence of pictorial element to the way of presentation. Images also can convey semantically meaningful, descriptive concepts via their stylistic properties, which are a variety of factors that affect the manner in which visual material is displayed, such as the orientation (e.g., vertical, diagonal) of objects displayed in a scene and various production elements (e.g., camera angle). In this research, the author focuses on an important but not explored stylistic property, the depth of field, and argues that shallow depth of field can lead to better attitude toward advertising. The reason behind this effect is based on relevant literature which suggests that an individual will obtain more pleasure from figuring out an ambiguous object. This procedure, named relief of ambiguity, plays the primary psychological mechanism in the effects of depth of field on advertising attitude. The author executed three experiments to verify proposed hypotheses. Experiment one investigated the influences of depth of field on advertising attitude and positive affect. This experiment also inquired the role of self-construal. The author argues that consumers with interdependent self-construal will have better responses toward advertising using shallow depth of field. The empirical evidences indicated that, as hypothesized, shallow depth of field lead to better advertising attitude and higher positive affect. Moreover, positive affect mediated the relationship between depth of field and advertising attitude. Experiment one also found that consumer’s self-construal played a moderating role. Experiment two integrated another important consumer characteristic, the need for cognition. The author argues that the effect observed in the first experiment will only sustain for high need for cognition consumers. The results of experiment two confirmed this hypothesis. This research provides theoretical and practical implications for marketers and researchers.

碩士
國立交通大學
運輸與物流管理學系
107
With the rapid development of information and communication technology (ICT), airports and airlines are trying to provide passengers with the personalized boarding experience using mobile devices and automation equipment. Therefore, the deeper the understanding of the passengers' boarding behavior by the airport or airline, the more they can provide the most appropriate information and personalized services that passengers need. In addition, boarding passengers are increasingly paying attention to the waiting time of unnecessary waste, and begin to pursue the acquisition of real-time information and self-control of the boarding process. Based on the above reasons, this study is aim to explore the risk attitude and ambiguity attitude of airport boarding passengers due to the lack of important information on travel time uncertainty. Most of the previous studies only considered boarding passengers' choice of airport arrival behaviors, ignoring the possible link between the airport arrival behavior and the activity arrangement in the terminal. The main contribution of this study is to consider the risk attitude and ambiguity attitude of air passengers on the travel time uncertainty, and to obtain the composition and characteristics of air passengers with different time preferences. The concept of the trip chain is used to link the airport arrival behavior and terminal activities of boarding passengers. Based on the time and space trajectory data of the boarding passengers in the terminal activities, the analysis of passengers' time preference and terminal activities time allocation is carried out to avoid the passengers' perception errors in recalling individual behaviors. This study used Taipei Songshan Airport and Taiwan Taoyuan International Airport as research samples. First, a one-on-one interview was conducted on passengers using questionnaires and scenario design. Then, the risk attitude model and the ambiguity attitude model of the air passengers with travel time uncertainty are built by using the Ordered probit model and the α-maxmin model. Finally, minutes before the departure time of the flight is used as the explanatory variable, and the regression analysis model is used to analyze the impact of time allocation of mandatory activities in the terminal and the degree of risk aversion and the degree of ambiguity pessimism that obtained from the risk attitude model and the ambiguity attitude model.

碩士
國立臺灣海洋大學
航運管理學系
93
Abstract In order to improve the operation efficiency of state-owned businesses, privatization has become the most important policy of state government all over the world. From the past experience, the most challenging issue of privatization has been the resist of employees. How to solve employees’ resist against change and enhance their productivity would be the key factor of a privatization project. The purpose of this study is to explore and verify the relationship between employees’ communication satisfaction, role ambiguity and their attitude toward privatization. Companies, which were conducting their privatization project, were chosen as research subject, these companies including: Chung Hwa telecom company (CTC), Keelung harbor Bureau (KLHB) , Su-Ao Harbor Bureau, Taiwan Tobacco and Liquor Corporation. Employees from these companies were invited to join this research. 360 copies of questionnaire were sent to these employees, of which 278 copies were completed and sent back. Hierarchical regression analysis and correlation analysis were used for further analysis. Major findings are summarized as below: 1. Major dimensions of employees’ communication satisfaction such as communication climate, communicate with direct superiors, operation of integral organization, horizontal & diagonal communication and top management communication are all negatively correlated with role ambiguity. 2. Employees’ role ambiguity is also negatively correlated with their attitude toward privatization. That means employees thought privatization would have negative impact on their self-achievement, privilege and benefits. 3. Role ambiguity has no mediating effect on communication satisfaction and privatization. According to the verified research comments, some suggestions are offered for government and future research. Keyword: communication satisfaction, role ambiguity, privatization.

Introdução: Dada a alta prevalência de exames de escolha múltipla com penalização na formação médica, diversos estudos têm procurado identificar outros fatores, além do nível do conhecimento dos alunos, que influenciam seus padrões de resposta. Este estudo visa medir o efeito da atitude face ao risco e à ambiguidade no número de respostas corretas, erradas e em branco dos alunos. Métodos: Em outubro de 2018, 233 alunos matriculados no 3.º ano do Mestrado Integrado em Medicina da Faculdade de Medicina da Universidade do Porto responderam a um questionário que avaliou a sua tolerância para o risco e ambiguidade, e aversão à ambiguidade. Modelos de regressão simples e múltipla e os respetivos coeficientes de regressão foram usados para medir a associação entre as atitudes dos alunos e as suas respostas em dois exames que eles tinham feito em junho de 2018. Resultados: Ter um nível intermedio de Aversão à Ambiguidade em Medicina (em oposição a um nível muito alto ou baixo) foi associado a um aumento significativo no número de respostas corretas e diminuição no número de respostas em branco no primeiro exame. No segundo exame, altos níveis de Aversão à Ambiguidade em Medicina foram associados a uma diminuição no número de respostas erradas. Não houve associações significativas com atitude face ao risco, tolerância para ambiguidade ou com gênero. Conclusão: a aversão à ambiguidade em medicina dos alunos afeta o seu desempenho em exames de múltipla escolha com penalização para as respostas erradas. Portanto, sugere-se o planeamento e implementação de sessões de aconselhamento com estudantes de medicina quanto ao impacto da aversão à ambiguidade no seu desempenho em questões de múltipla escolha com penalização.
Introduction: Given the high prevalence of multiple-choice examinations with formula scoring in medical training, several studies have tried to identify other factors, in addition to the degree of knowledge of students, which influence their response patterns. This study aims to measure the effect of attitude towards risk and ambiguity on the students' number of correct, wrong, and blank answers. Methods: In October 2018, 233 students enrolled on the 3rd year of the Integrated Master of Medicine at the Faculty of Medicine of the University of Porto completed a questionnaire which assessed the student's tolerance for risk and ambiguity, and aversion to ambiguity. Simple and multiple regression models and the respective regression coefficients were used to measure the association between the students' attitudes and their answers in two examinations that they had taken in June 2018. Results: Having an intermediate level of Ambiguity Aversion in Medicine (as opposed to a very high or low level) was associated with a significant increase in the number of correct answers and decrease in the number of blank answers in the first examination. In the second examination, high levels of Ambiguity Aversion in Medicine were associated with a decrease in the number of wrong answers. There were no significant associations with risk attitude, tolerance for ambiguity, or with gender. Conclusion: Students' Ambiguity Aversion in Medicine affect their performance in multiple-choice examinations with negative marking. Therefore, it is suggested the planning and implementation of counseling sessions with medical students regarding the ambiguity aversion impact on their performance in multiple-choice questions with negative marking.

Introdução: Dada a alta prevalência de exames de escolha múltipla com penalização na formação médica, diversos estudos têm procurado identificar outros fatores, além do nível do conhecimento dos alunos, que influenciam seus padrões de resposta. Este estudo visa medir o efeito da atitude face ao risco e à ambiguidade no número de respostas corretas, erradas e em branco dos alunos. Métodos: Em outubro de 2018, 233 alunos matriculados no 3.º ano do Mestrado Integrado em Medicina da Faculdade de Medicina da Universidade do Porto responderam a um questionário que avaliou a sua tolerância para o risco e ambiguidade, e aversão à ambiguidade. Modelos de regressão simples e múltipla e os respetivos coeficientes de regressão foram usados para medir a associação entre as atitudes dos alunos e as suas respostas em dois exames que eles tinham feito em junho de 2018. Resultados: Ter um nível intermedio de Aversão à Ambiguidade em Medicina (em oposição a um nível muito alto ou baixo) foi associado a um aumento significativo no número de respostas corretas e diminuição no número de respostas em branco no primeiro exame. No segundo exame, altos níveis de Aversão à Ambiguidade em Medicina foram associados a uma diminuição no número de respostas erradas. Não houve associações significativas com atitude face ao risco, tolerância para ambiguidade ou com gênero. Conclusão: a aversão à ambiguidade em medicina dos alunos afeta o seu desempenho em exames de múltipla escolha com penalização para as respostas erradas. Portanto, sugere-se o planeamento e implementação de sessões de aconselhamento com estudantes de medicina quanto ao impacto da aversão à ambiguidade no seu desempenho em questões de múltipla escolha com penalização.
Introduction: Given the high prevalence of multiple-choice examinations with formula scoring in medical training, several studies have tried to identify other factors, in addition to the degree of knowledge of students, which influence their response patterns. This study aims to measure the effect of attitude towards risk and ambiguity on the students' number of correct, wrong, and blank answers. Methods: In October 2018, 233 students enrolled on the 3rd year of the Integrated Master of Medicine at the Faculty of Medicine of the University of Porto completed a questionnaire which assessed the student's tolerance for risk and ambiguity, and aversion to ambiguity. Simple and multiple regression models and the respective regression coefficients were used to measure the association between the students' attitudes and their answers in two examinations that they had taken in June 2018. Results: Having an intermediate level of Ambiguity Aversion in Medicine (as opposed to a very high or low level) was associated with a significant increase in the number of correct answers and decrease in the number of blank answers in the first examination. In the second examination, high levels of Ambiguity Aversion in Medicine were associated with a decrease in the number of wrong answers. There were no significant associations with risk attitude, tolerance for ambiguity, or with gender. Conclusion: Students' Ambiguity Aversion in Medicine affect their performance in multiple-choice examinations with negative marking. Therefore, it is suggested the planning and implementation of counseling sessions with medical students regarding the ambiguity aversion impact on their performance in multiple-choice questions with negative marking.

This dissertation consists of three essays studying different topics in macroeconomics under the common aim of assessing the role of nonlinear dynamics in explaining selected facts of interest. In Chapter 1, co-authored with Marzio Bassanin and Ester Faia, we explore the linkages between financial crises and debt markets, where collateral constraints and opacity of asset values are the norm. We, therefore, introduce ambiguity attitudes in beliefs formation in a small open economy model where borrowers investing in risky assets face occasionally binding collateral constraints. We estimate the ambiguity attitudes process and derive that borrowers endogenously act optimistically in booms and pessimistically in recessions. Analytically and numerically we show that our ambiguity attitudes coupled with the collateral constraints crucially help explaining asset price and debt cycle facts. Chapter 2 studies the pass-through of sovereign risk in an environment where latent condence factors, along with fundamentals, might feed debt crises. A Markov-switching VAR with three variables (private spread, sovereign spread, debt-to-GDP) is estimated on fiscally-leveraged economies (Italy, Spain, Portugal). By allowing fiscal and financial sources of amplication, the model historically identies: i ) an high vulnerability regime, where sovereign spreads show excessive sensitiveness to fiscal imbalances. Those periods line up mostly with the global financial turmoil and the sovereign European debt crisis; ii ) an high synchronization regime where the sovereign and financial risk measures are strongly tied in a synchronized comovement. Those period identify more the first phases of the two crises. Finally, Chapter 3, co-authored with Othman Bouabdallah and Pascal Jacquinot, aims to extract an empirical narrative for France on the relationship between fiscal policy and debt sustainability, in the context of fiscal regimes. We build a DSGE model, where Markov-switching dynamics are introduced on the tax revenues response to debt, expenditure and output gap. We then bring the model to the data and show that two distinct fiscal regimes took place over the period 1955-2009: a sustainable regime covered `Les Trente Glorieuses' until 1977 and then re-emerged in 1999 with the euro membership; an unsustainable regime, instead, characterised the 1978-1998 period, where a policy mix of disinflation, external and internal balance led to primary deits and unstable debt-to-GDP accumulation.