This thesis examines the statistical properties of the Poisson AR(1) model of Al-Osh and Alzaid (1987) and McKenzie (1988). The analysis includes forecasting, estimation, testing for independence and specification and the addition of regressors to the model. The Poisson AR(1) model is an infinite server queue, and as such is well suited for modeling short-term disability claimants who are waiting to recover from an injury or illness. One of the goals of the thesis is to develop statistical methods for analyzing series of monthly counts of claimants collecting short-term disability benefits from the Workers' Compensation Board (WCB) of British Columbia. We consider four types of forecasts, which are the k-step ahead conditional mean, median, mode and distribution. For low count series the k-step ahead conditional distribution is practical and much more informative than the other forecasts. We consider three estimation methods: conditional least squares (CLS), generalized least squares (GLS) and maximum likelihood (ML). In the case of CLS estimation we find an analytic expression for the information and in the GLS case we find an approximation for the information. We find neat expressions for the score function and the observed Fisher information matrix. The score expressions leads to new definitions of residuals. Special care is taken to test for independence since the test is on the boundary of the parameter space. The score test is asymptotically equivalent to testing whether the CLS estimate of the correlation coefficient is zero. Further we define a Wald and likelihood ratio test. Then we use the general specification test of McCabe and Leybourne (1996) to test whether the model is sufficient to explain the variation found in the data. Next we add regressors to the model and update our earlier forecasting, estimation and testing results. We also show the model is identifiable. We conclude with a detailed application to monthly WCB claims counts. The preliminary analysis includes plots of the series, autocorrelation function and partial autocorrelation function. Model selection is based on the preliminary analysis, t-tests for the parameters, the general specification test and residuals. We also include forecasts for the first six months of 1995. / Business, Sauder School of / Graduate

The theoretical properties of the Maximum Likelihood estimator, for both single input-single output and multivariable systems, are considered. New results relative to convergence properties of some identification methods of single input-single output systems are obtained. A unified approach to the Maximum Likelihood identification method of multivariable systems is proposed. Numerical tests on a computer are performed. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Ph.D. / Harmonic time series are often used to describe the periodic nature of a time series, for example the periodic nature of a variable star’s observed light curve. Statistical methods for determining the number of harmonic components to include in harmonic time series are limited. In this thesis a stepwise bootstrap procedure based on a F-type statistic is suggested. The performance of the stepwise procedure is compared to that of Schwartz’s Bayesian Criterion (SBC) and a procedure based on a statistic described by Siegel (1980). Harmonic series with correlated noise terms and irregularly spaced observations are also considered. Tests to detect changes in harmonic parameters are also derived in this thesis. A cumulative sum statistic to test for constant amplitude is derived. It is shown that testing for constant amplitude is equivalent to testing for constant slope in simple linear regression. We also derive a likelihood ratio statistic to test for constant amplitude. It is shown that the latter likelihood ratio statistic is asymptotically equivalent to the cumulative sum statistic. These statistics are compared to a quadratic form statistic used by Koen (2009). Likelihood ratio tests are also derived for detecting changes in the frequency or phase of harmonic time series. Graphical devices to aid in diagnostic checking are suggested.

Professional skepticism is a critical component of audit practice and current auditing standards direct auditors to remain skeptical throughout the duration of each audit engagement. Despite the importance and prevalence of an emphasis on professional skepticism throughout auditing standards, evidence indicates that auditors often fail to exercise an appropriate degree of professional skepticism. Prior accounting research suggests that auditors’ professionally skeptical behavior is affected by individual personality traits as well as situational (state) influences, whereby both factors contribute to auditor professional skepticism. Yet, prior research has primarily focused on trait skepticism; and little research to date has investigated the concept of state skepticism. The purpose if this research study is to experimentally investigate the impact of time pressure and trait skepticism on state skepticism, and to test a potential debiasing procedure on the impact of time pressure on state skepticism. In addition, this study examines the influence of both skepticism types on skeptical behavior.This research offers several contributions to accounting literature and practice. First, I contribute to the existing debate regarding the influences of professional skepticism by providing evidence that professional skepticism may be categorized as a temporary state, induced by situational aspects, in addition to being classified as an enduring trait. Second, I identify certain situational conditions which create differences in the level of state professional skepticism exhibited within an auditing context. Lastly, my findings may also be important to audit firms as they consider tools within their training arsenal equipped to promote an appropriate level of professional skepticism among employees. If auditor skepticism can be influenced by the frames they are provided, then audit firms may create an environment that promotes consistency in auditors’ application of professional skepticism, simply by engaging in goal framing.

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Acceleration has long fascinated managers. Their captivation is reflected in a century of popular business strategies designed to speed up work, including "scientific management," "lean production," and "lean startup". Scholars have paid significant attention to acceleration, examining the effects of greater speed on numerous work outcomes (e.g., decisions, new product success) as well as work processes (e.g., information processing, consideration of alternatives). Despite this relatively robust literature, there are two areas where our knowledge of acceleration is still limited. First, we lack knowledge about the varied ways in which organizations enact acceleration; prior research has focused on the use of deadlines to speed up task completion, with little consideration of other approaches. Second, because previous studies have yielded conflicting results regarding the implications of acceleration, it remains unclear exactly how an emphasis on increasing speed shapes people’s experiences and work. To advance theorizing in these two areas, I conducted an ethnographic study of a seed accelerator ("InnoTech"), a relatively new form of organization that runs time-limited programs with the explicit intent of speeding up the process of venture creation. Through an inductive, grounded analysis, I found that InnoTech mandated acceleration through a broad set of tactics that included, but was not limited to, the imposition of deadlines. These tactics were rooted in InnoTech's localized conceptualization of acceleration: securing funding faster. I also found that InnoTech created both time-based (i.e., temporal) and event-based (i.e., sequential) triggers for beginning fundraising. Some of the entrepreneurs participating in InnoTech's program perceived these triggers as compatible, and thus felt a sense of synchrony. Other entrepreneurs perceived the triggers as incompatible, and thus experienced a sense of asynchrony. The entrepreneurs' differing perceptions had important implications for their experiences and work. By building theory about localized approaches to acceleration, and how they may shape people's responses in varying ways, I suggest that speed is a situated phenomenon that must be understood as such. My research contributes to the literatures on acceleration, pacing, deadlines, and time as a form of control in organizations.

archives@tulane.edu / Abstract: A search in a research database for “large specific rotation” or anything similar produces few articles. Large specific rotation is not commonly used as an indicator for extraordinary chiroptical response. Alternatively, anisotropy factors obtained from circular dichroism spectra and calculated rotational strengths are more widely used to gauge chiroptical response. To another point, a search for “large chiroptical response” gives few articles that discuss pure organic compounds, and the result list is populated by organometallic clusters, nanostructures, and thin films. A search of the Reaxys database for organic compounds with [α]Ds larger than 1000 revealed that there are about 600, and there are only two that have [α]Ds larger than 10,000.30 We wondered if we could design a compound that would break the record in specific rotation and possess extraordinary chiroptical properties. Guided by time-dependent density functional theory (TD-DFT) calculations, various chiral, polycyclic aromatic compounds (PACs) were chosen as candidates to display extraordinary chiroptical properties, such as high optical rotation, strong circular dichroism, or a high degree of circularly polarized luminescence (CPL). PACs comprise a large class of organic compounds. In addition to synthetic PACs, numerous naturally occurring PACs exist in coal tar and as decomposition products of organic material. Since their pi electrons are delocalized, PACs have interesting and possibly useful electronic properties and a variety of applications. The PACs described in this dissertation, e.g., helical mesobenzanthrones, a cyclophane, are twisted pentacenes are chiral and have interesting optoelectronic properties. TD-DFT was primarily used to predict which compounds had the greatest potential to yield record-breaking specific rotations or other chiroptical properties, and ordinary DFT calculation were used to determine if these compounds had sufficiently high racemization barriers to be resolved at room temperature. With regard to specific rotation, the accuracy of TD-DFT calculations was examined by comparing experimental specific rotations to the calculated values. / 1 / Kelly Jane Dougherty

MPH / Department of Public Health / Post-apartheid South Africa’s healthcare system improved with many community members being able to easily access basic health care services. However, patient waiting time has remained a critical issue. Patients are well-known for arriving at healthcare facilities very early for the reason of avoiding lengthy queues. This, however, does not solve their problem. The purpose of the study was to explore factors influencing patient waiting time in Nthabiseng clinic in the Capricorn district of the Limpopo Province. The study was conducted at Nthabiseng clinic in the Capricorn District. A qualitative approach was adopted, and a sample was chosen from a targeted population through purposive sampling. Data were collected through a one-to-one semi-structured interview and analysed through the Thematic Data Analysis approach. The study found out that the Department of Health does not have a patient waiting time specific policy or legislative framework and/or a guiding document. It also showed that healthcare professionals define and calculate patient waiting time differently. Moreover, what is an acceptable waiting time to one is an unacceptable waiting time to another. The study recommended that a policy and Standard Operation Procedure be drafted to guide healthcare professionals on how to improve waiting time in their specific facilities.

This thesis contains some results on the behavior of a delay differential equation (DDE) with two delays, at a Hopf bifurcation, for the nonzero equilibrium, using the growth rate, r, as bifurcation parameter. This DDE is a model for population growth, incorporating a maturation delay, and a second delay in the harvesting term. Considering a Taylor expansion of the non-dimensionalized model, we find a region of stability for the nonzero equilibrium, after which we find a pair of ODEs which help define the flow on the center manifold. We then find an expression for the first Lypapunov coefficient, which changes sign, so we also find the second Lyapunov coefficient, allowing us to predict multi-stability in the model. Numerical simulations provide examples of the behavior expected. For a similar model with one delay (PMC model), we prove the Hopf bifurcation at the nonzero equilibrium is always supercritical.

Electronic transport properties have been used to classify and characterize materials and describe their functionality. Recent surge in computational power has enabled computational modelling and accelerated theoretical studies to complement and accelerate experimental discovery of novel materials. This work looks at methods for theoretical calculations of electronic transport properties and addresses the limitations of a common approximation in the calculation of these properties, namely, the constant relaxation time approximation (CRTA). This work takes a look at the limitations of this approximation and introduces energy and temperature dependent relaxation times. This study is carried out on models and real systems and compared with experiments.