Measures of data quality are important for the evaluation and improvement of survey design and procedures. A detailed investigation of the sources, magnitude and impact of errors is necessary to identify how survey design and procedures may be improved and how resources allocated more efficiently among various aspects of the survey operation. A major part of this thesis is devoted to the overview of statistical theory and methods for measuring the contribution of response variability to the overall error of a survey. A very common practice in surveys is to select groups (clusters) of elements together instead of independent selection of elements. In practice cluster samples tend to produce higher sampling variance for statistics than element samples of the same size. Their frequent use stems from the desirable cost features that they have. Most data collection and sample designs involve some overlapping between interviewer workload and the sampling units (clusters). For those cases, a proportion of the measurement variance, which is due to interviewers, is reflected to some degree in the sampling variance calculations. The prime purpose in this thesis is to determine a variance formula that decomposes the total variance into sampling and measurement variance components for two commonly used data collection and sample designs. Once such a decomposition is obtained, determining an optimum allocation in existence of measurement errors would be possible.

Aquesta tesi s'emmarca en l'anàlisi de la supervivència. A la primera part es proposa una metodologia per estimar els coeficients d'un model lineal amb censura a la resposta i error de mesura a les covariants. Es proposa un estimador consistent que combina les metodologies per estimar models lineals de resposta censurada i, les utilitzades per als models amb variables explicatives mesurades amb error. Els errors estàndard de l'estimador es calculen numèricament mitjançant bootstrap. Algunes simulacions mostren les propietats de l'estimador.A la segona part s'analitzen històries laborals espanyoles. Hi ha tres tipus d'episodis: de treball autònom, per compte d'altri i sense treballar. Es duen a terme els següents estudis: estimació no paramètrica de la funció de supervivència pels diferents episodis; anàlisi de la durada del primer episodi de la història laboral; models de competing risk per a cada tipus d'episodis; i una anàlisi longitudinal dels cinc primers episodis tractats conjuntament. / This thesis is about survival analysis. The first part is focused on linear regression models with a censored dependent variable and, the explanatory variable contaminated with measurement error. A methodology which produces consistent estimates of the regression coefficients is proposed. It combines the procedures for fitting linear models with censoring and, the estimation methods for linear models with measurement error. Standard errors of the estimator are computed using the bootstrap method. The performance of the estimator is evaluated by Monte Carlo studies.The second part analyzes data about Spanish labor market histories. We study the duration of three types of labor spells (self-employment, wage-earner and non-working). We carry out several analyses: non-parametric approaches of the survival functions for several sets of spells a standard duration analysis for the first spells of the labor history a competing risk analysis for each type of spell; and a longitudinal analysis for the five early spells of the labor histories.

Thesis (M.App.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 92-105). Also available in electronic format on the Internet.

Thesis (M.P.H.)--University of Texas Health Science Center at Houston, School of Public Health, 2008. / Source: Masters Abstracts International, Volume: 46-05, page: 2641. Advisers: Jan Bressler; Raol Caetano. Includes bibliographical references.

Due to technology scaling, the probability of a high energy radiation particle striking multiple transistors has continued to increase. This, in turn has created a need for new circuit designs that can tolerate multiple simultaneous errors. A common type of error in memory elements is the double node upset (DNU) which has continued to become more common. All existing DNU tolerant designs either suffer from high area and performance overhead, may lose the data stored in the element during clock gating due to high impedance states or are vulnerable to an error after a DNU occurs. In this dissertation, a novel latch design is proposed in which all nodes are capable of fully recovering their correct value after a single or double node upset, referred to as DNU robust. The proposed latch offers lower delay, power consumption and area requirements compared to existing DNU robust designs. Multiple simultaneous radiation induced errors are a current problem that must be studied in combinational logic. Typically, simulators are used early in the design phase which use netlists and rudimentary information of the process parameters to determine the error rate of a circuit. Existing simulators are able to accurately determine the effects when the problem space is limited to one error. However, existing methods do not provide accurate information when multiple concurrent errors occur due to inaccurate approximation of the glitch shape when multiple errors meet at a gate. To improve existing error simulation, a novel analytical methodology to determine the pulse shape when multiple simultaneous errors occur is proposed. Through extensive simulations, it is shown that the proposed methodology matches closely with HSPICE while providing a speedup of 15X. The analysis of the soft error rate of a circuit has continued to be a difficult problem due to the calculation of the logical effect on a pulse generated by a radiation particle. Common existing methods to determine logical effects use either exhaustive input pattern simulation or binary decision diagrams. The problem with both approaches is that simulation of the circuit can be intractably time consuming or can encounter memory blowup. To solve this issue, a simulation tool is proposed which employs partitioning to reduce the execution time and memory overhead. In addition, the tool integrates an accurate electrical masking model. Compared to existing simulation tools, the proposed tool can simulate circuits up to 90X faster.

M.A. (Applied Linguistics) / This dissertation explores the phenomenon of errors in the writing of second language learners. The concepts of language error and standard language are discussed briefly. The Contrastive Analysis and Error Analysis hypotheses are presented and the notions of interlanguage and fossilization explored. The limitations and strengths of the Error Analysis hypothesis are pointed out. Research on error correction and remediation is reviewed. Questions such as whether errors should be corrected, when, how and by whom, as well as which errors should be attended to, are considered. An error analysis of the written work of a group of English second language students is undertaken. Errors of a mainly syntactic nature are identified and classified and the possible causes of some are pointed out. The dissertation considers the implications of these errors for language teaching and concludes by making recommendations with 'special reference to the distance teaching situation.

The work of the author was to investigate the static, dynamic and machining behaviour of some new designs of slug damped boring bars with a 10 to 1 overhang ratio. The bars were mounted on a centre lathe. The static behaviour of a boring bar in relation to the geometric form errors that might be produced during boring was studied both analytically and experimentally. Specifically, two types of errors were considered, namely, a) errors that arise on entry of the boring tool into the workpiece) known as the "bell-mouth" errors; and b) reproducibility of eccentricity errors, known as the "copying" errors. The theory for "bell-mouth" errors did not seem to fit the results well; however, the theory did prove that such errors could exist. The theory for “copying” errors agreed remarkably well with the results provided that the initial eccentricity was small compared with the depth of cut. The dynamical behaviour of the slug damped boring bar was modelled by a mathematical analogue. Despite its inability to properly account for the compressibility effect of the gaseous damping fluid, the model revealed the possibility of design improvements. In consequence, the optimally-tuned slug-damped tungsten-bunged bar was conceived, Manufactured and tested along with a solid bar for comparison purposes, a slug-damped recessed bar and a slug-damped steel-bunged bar. The machining behaviour of a boring bar was studied in terms of the maximum depth of cut that it could cope before the occurrence of chatter. At first, a stability model was developed based on the mathematical analogue formulated in the study of the dynamical behaviour. But since this analogue did not fit the results accurately, a second and more precise model was set up using the frequency response obtained from dynamic experiments instead. The concept of negative damping coefficient was used; and a one-to-one correspondence between the asymptotic value of the negative damping coefficient and the limiting depth of cut was found to exist. By virtue of this, it is in principle possible to predict the limiting depth of cut of any machine tool system whose frequency response characteristics are known. Compared with other bars tested, the optimally-tuned tungsten-bunged bar was found to have the best dynamic and machining characteristics as reflected in the limiting depth of cut of 0.10511 (2.67 mm) to 0.110" (2.79 mm) at the feed of 0.0065"/rev (0.165 mm/rev) and the speed of 500 rprn on a 3.5" dia. bore (140 m/min) of EN8 steel. By constrast, the solid bar was hardly able to cut stably even at the light cut of 0.005".

Background: Dispensing medication is a chain of multiple stages, and any error during the dispensing process may cause potential or actual risk for the patient. Few research studies have investigated the nature and contributory factors associated with dispensing errors in hospital pharmacies. Aim: To determine the nature and severity of dispensing errors reported in the hospital pharmacies at King Saud Medical City (KSMC) hospital in Saudi Arabia, and at Luton and Dunstable University Hospital (L&D) NHS Foundation Trust in the UK; and to explore the pharmacy staff perceptions of contributory factors to dispensing errors and strategies to reduce these errors. Materials and Methods: A mixed method approach was used and encompassed two phases. Phase I: A retrospective review of dispensing error reports for an 18-month period at the two hospitals. The potential clinical significance of unprevented dispensing errors was assessed. Data was analysed using descriptive statistics in SPSS and A Fisher's test was used to compare the findings. Phase II: Self-administered qualitative questionnaires (open-ended questions) were distributed to the dispensary teams in KSMC and L&D hospitals. Content analysis was applied to the qualitative data using NVivo qualitative analysis software. Result: Dispensing the wrong medicine or the incorrect strength were the most common dispensing error types in both hospitals. Labelling errors were also common at the L&D pharmacy dispensary. The majority of the unprevented dispensing errors were assessed to have minor or moderate potential harm to patients. Look-alike/sound-alike medicines, high workload, lack of staff experience, fatigue and loss of concentration during work, hurrying through tasks and distraction in the dispensary were the most common contributory factors suggested. Ambiguity of the prescriptions was a specified factor in the L&D pharmacy, while poor pharmacy design and unstructured dispensing process were specified contributory factors in the KSMC pharmacy. Conclusions: Decreasing distractions and enhancing the pharmacy design and the dispensing workflow are necessary to reduce dispensing errors. Furthermore, monitoring and reporting errors and educating the dispensary team about these errors is also needed. Automation and e-prescribing systems may improve dispensing efficiency and safety. The findings of this study reemphasise the fact that dispensing errors are prevalent in hospital pharmacies. Efficient interventions need to be implemented to mitigate these errors.

In Chapter 1 a review of the literature concerning aspects of erythrocyte membrane transport and metabolism, and purine and pyrimidine metabolism is presented. The effects of pH, pO₂ and inorganic phosphate (Pi) on the uptake and metabolism of hypoxanthine by erythrocytes has been studied in Chapter 2. Uptake of hypoxanthine and accumulation of inosine 5'-monophosphate (IMP) were markedly increased at acid pH, high external phosphate concentrations, and low pO₂. Release of accumulated IMP as hypoxanthine occurred at alkaline pH values and low external phosphate concentrations. Conditions favouring IMP accumulation gave rise, in the absence of hypoxanthine, to a corresponding increase in 5'-phosphoribosyl-1-pyrophosphate (PRPP). Intracellular phosphate concentrations were markedly pH dependent and a model is presented whereby hypoxanthine uptake and release are controlled by intracellular concentrations of inorganic phosphate and 2,3- bisphosphoglycerate (2,3-DPG). These allosteric effectors influence, in opposing ways, two enzymes governing IMP accumulation, namely PRPP synthetase and 5'-nucleotidase. These metabolic properties suggest that the erythrocyte could play a role in the removal of hypoxanthine from anoxic tissue. In Chapter 3 the kinetics and mechanism of transport of orotate across the human erythrocyte membrane and the effect of pH and inorganic phosphate on its metabolism (in the erythrocyte) have been studied. It has been shown that orotate enters erythrocytes with non-saturable kinetics and with a capacity of 190 μmoles/1 packed cells/min at a concentration of 4-6 mmolar. The presence of competition for transport by a number of anions and the lack of competition by uridine is indicative of transport by a general anion transporter, with the ability for concentrative uptake in the absence of other external anions being compatible with transport via a ping-pong mechanism. Inhibition of transport by the specific band 3 inhibitors DIDS and CHCA confirm that transport is via the band 3 anion transporter. This explains the lack of significant uptake of orotate by most differentiated tissues which lack the intact band 3 protein. However, the demonstration of band 3 in rat hepatocytes (Cheng and Levy, 1980) provides a mechanism for the orotate transport which has been observed in liver (Handschumacher and Coleridge, 1979). Changes in pH and inorganic phosphate (Pi) concentrations have been shown to have marked effects on the relative quantities of metabolic products produced by the erythrocyte from orotate. There was an increase in orotate metabolised with increasing Pi, an effect augmented by lowering the pH, and most easily explained by the allosteric activation of PRPP synthetase by Pi. The increase in UTP levels with decreasing pH may be the consequence of both increased PRPP availability for the formation of uridine nucleotide from orotate, and decreased conversion of UMP to uridine by pyrimidine 5'-nucleotidase, which is known to be inhibited by phosphate. The accumulation of UDP sugars is optimal at a phosphate concentration of 10 mmolar, which is unexplained but would be compatible with an inhibitory effect of Pi on CTP synthetase. A PRPP wasting cycle at alkaline pH values is proposed to explain the apparent paradox where no PRPP was observed to accumulate in erythrocytes (Chapter 2) at pH values of 7.6 and above in the presence of 10 mmolar phosphate and no added hypoxanthine, yet the metabolism of orotate, which is a PRPP utilising reaction, at alkaline pH values was readily demonstrable here. This (apparent paradox) can be resolved if one assumes that even in the absence of added hypoxanthine and demonstrable intracellular IMP there are sufficient quantities of hypoxanthine and/or IMP to maintain a PRPP wasting cycle at alkaline pH values. The cycle is interrupted at acidic pH values as phosphate levels rise and inhibit 5'-nucleotidase, an effect augmented by the decreasing levels of 2,3-DPG which accompany decreasing pH. This wasting cycle has recently been confirmed by P. Berman (unpublished). The kinetics of orotate uptake by erythrocytes and its eventual release as uridine provides a role for the erythrocyte in the transport and distribution of pyrimidines to peripheral tissues. A model is proposed and involves the de novo production of orotate in the liver. In the next step erythrocytes take up the orotate secreted by the liver into the circulation, convert it into an intermediate buffer store of uridine nucleotides, whose distribution is a function of pH and phosphate concentration, and eventually release it as uridine, which is a readily available form of pyrimidine for utilisation by peripheral nucleated cells. The enhancement of uptake of labelled orotate into nucleic acids of cultured cells is demonstrated here. The degradative half of the cycle proposes that uracil and palanine are the predominant degradative forms of pyrimidines produced by peripheral cells, and their ultimate metabolic fate is complete catabolism in the liver to CO₂ and water. In the final chapter the possible role of the human erythrocyte in the prevention of reperfusion injury has been investigated. The development of a model of renal ischaemia in the rat is described. The ability of human erythrocytes, "primed" by preincubating in acid medium of high Pi concentration and low pO₂, to take up hypoxanthine in a concentrative manner when perfused through ischaemic rat kidney is demonstrated. Attempts to demonstrate improved survival and renal function in rats with "primed" human erythrocytes prior to reperfusion were, however, unsuccessful. It is further demonstrated that "unprimed" human erythrocytes, resident in ischaemic rat kidney for 3 hours, take up hypoxanthine and convert it to IMP. that erythrocytes could play a physiological prevention of reperfusion injury.

Given that the usage and complexity of spreadsheets in the accounting profession are expected to increase, it is more important than ever to ensure that accounting graduates are aware of the dangers of spreadsheet errors and are equipped with design skills to minimize those errors. Although spreadsheet mechanics are prevalent in accounting curricula, less attention has been given to design considerations that can reduce the incidence of spreadsheet errors. The extant literature provides evidence of the most common types of spreadsheet errors and explanations as to why they occur. Using the work of Panko and others, this paper outlines a three-step approach for introducing spreadsheet design practices to novice spreadsheet developers. To facilitate design instruction, this paper provides a summary of foundational readings related to spreadsheet errors as well as specific teaching strategies for addressing the most common spreadsheet errors identified in the literature.