No description available.

Interest in evaluating the performance and safety of offshore oil and gas platforms has been expanding due to the growing world energy supply and recent offshore catastrophes. In order to accurately assess the reliability of an offshore platform, all relevant uncertainties must be properly accounted for. This necessitates the development of a probabilistic demand model that accounts for the relevant uncertainties and model errors. In this study, a probabilistic demand model is developed to assess the deformation demand on asymmetric offshore jacket platforms subject to wave and current loadings. The probabilistic model is constructed by adding correction terms and a model error to an existing deterministic deformation demand model. The correction terms are developed to capture the bias inherent in the deterministic model. The model error is developed to capture the accuracy of the model. The correction terms and model errors are estimated through a Bayesian approach using simulation data obtained from detailed dynamic analyses of a set of representative asymmetric offshore platform configurations. The proposed demand model provides accurate and unbiased estimates of the deformation demand on offshore jacket platforms. The developed probabilistic demand model is then used to assess the reliability of a typical offshore platform considering serviceability and ultimate performance levels. In addition, a sensitivity analysis is conducted to assess the effect of key parameters on the results of the analyses. The proposed demand model can be used to assess the reliability of different design options and for the reliability-based optimal design of offshore jacket platforms.

No abstract available. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2006.

Despite the rich literature on theories of stock splits, studies have omitted public utility firms from their analysis and only analyzed split by industrial firms when examining managerial motives for splitting their stock. I examine the liquidity-marketability hypothesis, which states that stock splits enhance the attractiveness of shares to individual investors and increase trading volume by adjusting prices to an optimum trading range. Changes in the regulatory process, resulting from EPACT, have opened a window of opportunity for the study and comparison of the two traditional motives for splitting stock --signaling versus liquidity-marketability motives. Public electric utility firms provide a clean testing ground for these two non-mutually exclusive theories as liquidity/marketability hypothesis should dominate before the enactment of the EPACT since the conventional signaling theory of common stock splits should not apply given the low levels of information asymmetry in regulated utility companies. In the post-EPACT period, however, the signaling effect is expected to play a more dominant role. Based on both univariate and multivariate analyses, my results are consistent with the hypothesis posed. For the pre-EPACT period, liquidity motive seems to predominate in explaining the abnormal announcement return of utility stock splits. On the other hand, the results support the signaling motive as a leading explanation of abnormal returns in the post-EPACT period.

This thesis examined the extent to which there is convergence in inflation rates, interest rates and incomes in the Common Monetary Area (CMA). It also investigated if countries in the area exhibit asymmetric adjustments to aggregate shocks. Based on optimum currency area theory, lack of convergence and the presence of asymmetric adjustments to shocks is likely to pose serious challenges that need to be addressed as the CMA moves towards a fully-fledged monetary union. I formulated and estimated a macroeconomic model to capture the transmission of shocks in the CMA. The model consists of four equations namely; Phillips curve, IS curve, exchange rate and monetary policy rule. The model links the CMA countries via the aggregate demand, inflation and interest rate equations. I simulated the model to assess the economic performance of the smaller countries when subjected to either a single monetary policy rule or country specific monetary policy rules. Such an analysis is used to gauge if a move towards a fully-fledged monetary union will result in higher benefits for the smaller countries. Furthermore, I estimated a structural VAR model based on the theoretical model. The identification restrictions in the VAR are also derived from the model. The analysis confirms monetary convergence, which is supported by the strong evidence of co-movement in interest rates and inflation rates in the CMA. Monetary convergence is an indicator of strong financial sector integration in the area. There is also evidence that inflation in the smaller countries is driven by that of South Africa. This result is mainly attributable to the strong trade links in the area as well as the existing parity between currencies in the area. The results also show that countries in the area are likely to face asymmetric shocks based on their composition of exports as well as the low correlation of growth rates. However, this asymmetry does not mean that countries cannot move towards iii creation of a fully-fledged monetary union, but rather that the existing asymmetries should be considered seriously by ensuring that other adjustment mechanisms are put in place. Extending the analysis to the SADC region shows that this region exhibits weak monetary convergence even though the poor countries show some form of real convergence with South Africa. Simulations from the VAR model show a price puzzle for Swaziland and South Africa but it is not prolonged. Based on the analysis the study concludes that a monetary union is possible in the CMA and is likely to be less costly. However, the evident asymmetries call for gradual step by step phasing in of the monetary union.

This dissertation consists of three essays on the role of asymmetric information in economics. The central theme is on how asymmetric information, which can arise either exogenously or endogenously, have important implications on welfare and market design. Chapter 1 is entitled Within-Household Selection in the Health Insurance Market. This chapter studies the existence of adverse selection in Vietnam's Social Health Insurance program and how household decision making affects individual enrollment into insurance. I find that while there is a strong evidence of adverse selection at the individual level, selection into insurance happens both \emph{across} and \emph{within} households. I then explore different household factors that affect the selection of health insurance within the household such as the household's ability to share risk and within-household bargaining power. These findings have important policy implications for two reasons. First, in the presence of household decision making, price discrimination policy to reduce adverse selection at the individual level such as age-based pricing might not always be welfare improving. Second, any policy that attempts to generate pooling beyond the level sustained by the private market can distort the household's incentive to buy health insurance and worsen adverse selection for the rest of the market. Chapter 2 is entitled Household Bundling to Reduce Adverse Selection: Application to Social Health Insurance. This chapter explores the use of bundling to reduce adverse selection in insurance markets and its application to social health insurance programs. When the choice to buy health insurance is made at the household level, bundling the insurance policies of household members eliminates the effect of adverse selection \emph{within} a household since the household can no longer select only sick members to enroll. However, this can exacerbate adverse selection \emph{across} households, as healthier households might choose to drop out of the insurance market. The net effect of this trade-off depends on the characteristics of the household demand for medical care and risk preferences. I explore this issue using individual survey data on insurance enrollment and medical spending in Vietnam that contain detailed information about the structure of the household. I develop and estimate a model of household insurance bundle choice and medical utilization that accounts for these features. The results suggest that much of the adverse selection is concentrated within the household. Counterfactual analysis reveals that under optimal pricing, household bundling yields significantly higher consumer surplus and insurance enrollment than individual purchase. Furthermore, the insurance market is less susceptible to complete unraveling under household bundling. Chapter 3 is entitled Information Control in the Hold-up Problem, and it is a joint work with Teck Yong Tan. In this chapter, we study the use of information control to mitigate hold-up risks. Our main result identifies a separation between information that creates ex-ante investment incentive and information that causes ex-post inefficiency, which then allows ex-post inefficiency to be eliminated without compromising the ex-ante investment incentive. We characterize the properties of the optimal information structure and the investment levels and welfare achievable with information control in the presence of hold-up risks.

One of the cultural traditions in Saudi Arabia is that the Saudi female patient has to be accompanied by a third-party on her medical visits, thus giving rise to consultations between three parties. By third-party, I mean a chaperone or a family member who can be a patient’s spouse, parent, adult child, sibling, or relative. This person shares responsibility for the patient’s health and the patient relies on them to support them generally with assistance in terms of their health care needs and especially for medical visits. In this research, I focus on the presence of a third party in medical consultations with reference to patient satisfaction, how patients perceive the role of their chaperones during the medical visit and the nature of three-party medical interactions. To investigate these aspects, a convergent parallel mixed method design was used in order to develop a better understanding of doctor-patient-three party interactions, as no mixed method study has been conducted on these issues in medical consultations in Saudi Arabia. Hence, this study addresses this gap in literature by focusing on the interaction between the Saudi female patients, their male physicians and their chaperones. I have concentrated on the Saudi female patients (from different age groups, i.e. 19-75) for religious and cultural reasons. Therefore, the overall aim of this thesis is to understand the phenomenon of three-party consultations in Saudi Arabia through a variety of aspects including patient satisfaction, patients’ perceptions, and what actually happens in three-party medical interactions (e.g., alignment and epistemic asymmetry). The data for this study included quantitative (i.e. questionnaires) and qualitative (i.e. four open-ended questions and observational and audio-recorded) data collected in one phase from 20 clinics in 3 hospitals in Jeddah in Saudi Arabia (two private and one governmental). A total of 117 female patients along with their chaperones were recruited. Statistical analysis of the questionnaire ratings showed that only patient’s education has a positive effect on patient satisfaction with chaperone involvement. Findings from thematic analysis of the open-ended questions data revealed that patients described three supportive roles of the chaperones, namely emotional, informational and logistical support. The patients’ perceptions regarding their chaperones’ supportive roles are re-evaluated in a real-life context by observing the chaperone’s facilitative role in three-party consultations. Therefore, conversation analysis of the audio-recorded data showed three main patterns of alignment: (1) doctor-patient, (2) chaperone-patient (and patient-chaperone), and (3) chaperone-doctor (and chaperone-patient) alignments. All these actions indicate that the participants were collaboratively involved in the positive interaction and this enhanced patient participation. However, in analysing three exceptional cases from the Chemotherapy and Haematology clinics, it was found that the presence of a chaperone dominates as well as complicates doctor-patient interaction and thus can significantly override or ostracise the patient who does not know her illness. For example, by using the Conversation Analysis approach, various epistemic resources used by the interlocutors (i.e. the oncologist and chaperones) are displayed by which the patient’s epistemic primacy is usurped and her epistemic access is controlled in terms of participation and the amount of information given. In comparing the mixed methods used in this study, congruent and discrepant results are found between the quantitative and qualitative data. In terms of congruent results, overall, the findings of this study concurred on the importance of having a supportive chaperone during a female patient’s medical appointment. Chaperones’ supportive roles appear to differently influence female patients’ symptoms, diagnosis or treatment plan. Chaperones in the current study have provided a useful contribution to the doctor-patient interactions. However, in terms of discrepancy, findings yielded by the conversation analysis (in Chapters 6 and 7) showed a discrepancy between what patients reported (see Chapter 5) about their chaperones’ supportive roles and what their chaperones did in the consultation. For example, the thematic analysis of the open-ended questions found that both genders were equally likely to be active in speaking for the patient. However, the conversation analysis of observational data adds and clarifies to what patients reported about their chaperones speaking on their behalf. The conversation analysis has given a good picture of the chaperone’s supportive role during medical visits in orienting towards patients as being the actual owners of their bodies and illness (see Chapter 6). Therefore, patients were given the chance to present their problem. Chaperones, in working collaboratively with patients and physicians, support the patient and facilitate the physician’s understanding. However, in only two exceptional cases (see Chapter 7) of actual medical interactions, the chaperone acts as a surrogate patient and restricts the patient’s own knowledge of their illness. Therefore, the current study contributes to three important areas, namely: (1) the literature of three-party interactions, (2) three-party interactions in Saudi Arabia, and (3) clinical practices in Saudi Arabia.

The motivation of this thesis is the study of markets in which consumers are under-informed concerning the quality of any given product and in which the quality of consumers also matters to producers of products. This study has resulted in a primary application paper, comprising the first chapter which focuses on the market for training lawyers, as well as a second technical chapter exploring theory which can prove useful in analyzing these markets. The first chapter is based on the observation that the number of lawyers being produced at high cost combined with the relative lack of job options has recently created significant concern. In order to partially explain this phenomenon, I propose a game of incomplete information modeling the strategic interaction between law schools as they compete for potential students. The information asymmetries come from the fact that any given law school is better informed about the quality of its education than its potential students. Using a change in market information structure generated by student placement reporting requirements, I use the model to estimate the dynamic effect of increased information on distributions of tuition rates, incoming student ability, class sizes, and the rate at which law schools open and potentially close. Using these estimates, I show that there have not necessarily been too many law schools or students, but rather an equilibrium enforced mismatch between students and their optimal schooling choices. The new information has acted as a forced collusion mechanism to partially overcome this mismatch, which has differentially decreased school welfare, strictly increased student welfare, and resulted in a positive total welfare gain of $685 million. The second chapter provides a thorough exploration of the microeconomic foundations for the multi-variate linear demand function for differentiated products that is widely used in industrial organization. A key finding is that strict concavity of the quadratic utility function is critical for the demand system to be well defined. Otherwise, the true demand function may be quite complex: Multi-valued, non-linear and income-dependent. The solution of the first order conditions for the consumer problem, which we call a local demand function, may have quite pathological properties. We uncover failures of duality relationships between substitute products and complementary products, as well as the incompatibility between high levels of complementarity and concavity. The two-good case emerges as a special case with strong but non-robust properties. A key implication is that all conclusions derived via the use of linear demand that does not satisfy the law of Demand ought to be regarded with some suspicion.

This dissertation consists of three stand-alone but interrelated empirical studies investigating various aspects of the well-documented ??home bias anomaly?? in international investment. The findings help to understand the international investment allocation behaviour of mutual funds as well as their implications for asset pricing and mutual fund evaluation. The first study investigates the roles of various firm attributes that encapsulate the deadweight costs in determining firm level investment bias. The main findings suggest that firm characteristics related to transaction costs, corporate governance and information asymmetry create significant barriers for fund managers. In addition, foreign funds are more constrained than domestic funds by information asymmetry, even in developed and liberalized markets. Moreover, this study stylises the international investment allocation model in Cooper and Kaplanis (1986) with a quadratic cost function, which reveals the marginal influence of market level deadweight costs on the relationship between firm characteristics and investment bias. It is found that when market level cross-border barriers are exacerbated, as in the case of emerging and restricted financial markets, foreign fund managers become more sensitive to market level deadweight costs and ignore firm characteristics. In general, these findings imply that the market level ??home bias anomaly?? is an outcome of the complementary effects of investment barriers at both firm and market levels. The second study examines the role of firm level investment bias in predicting future stock returns. It is found that both firm level foreign and domestic biases contain valuable information with respect to firm prospects. However, domestic bias is more informative than foreign bias in terms of subsequent stock returns, partially because of information asymmetry. The third study explores the determinants of fund level investment bias and its ability to predict fund performance. It is found that fund portfolio attributes determine fund level investment biases after controlling for market and fund investment objective specific effects, and fund level investment bias is positively related to fund performance due to lower deadweight costs. Moreover, good macroeconomic environments foster the development of the mutual fund industry.

In this thesis, we have analyzed one-dimensional fermion-spin interactions in the dilute limit. The two cases we analyze represent different paradigms. For the first part, we look at the existence of spins for all sites as an effective model to describe the rearrangement of core electrons within the dynamic Hubbard model. Within this model, the behavior of electrons and holes will be compared in the presence of fermion-spin coupling and on-site repulsion. It will be shown that in this framework, electrons and holes behave differently and even though electrons experience increased repulsion, holes show attraction for a range of on-site repulsions. The characteristics of the interaction show effective nearest-neighbor attraction though no such term exists within the model. By the analysis of dynamic properties, two regions of interaction are identified. The gradual change from weak to strong coupling of fermions is presented. The effect of introducing on-site repulsion for both ranges of coupling is presented for both the dynamic Hubbard model and electron-hole symmetric version. For the second case involving fermion-spin interaction, we look at the interaction of a fermion with spins existing only for a small portion of the lattice, representing a coupled magnetic layer that an itinerant fermion interacts with through Heisenberg-like spin flip interaction. The interaction represents a spin-flip interaction of a spin current and magnetic layer. This interaction has been extensively studied for its relevance to computer hard drives both experimentally and theoretically. Most theoretical descriptions utilize the semi-classical Landau-Lifshitz-Gilbert (LLG) formalism. However, with recent improvements in experimental methods with very small magnetic layers and very fast real time measurements, quantum effects become more pronounced. We present quantum mechanical results that show considerable modification to spin-flip interaction. We identify a set of conditions that exhibits the existence of an emerging bound state for the spin current both numerically and analytically. The bound state is a quantum mechanical state and cannot be achieved with a classical picture. We present results in a one-dimensional lattice for a spin-1/2 system, and generalize our arguments to higher dimension and spins with S > 1/2.