Without a valid assessment of accuracy there is a risk of data users coming to incorrect conclusions or making bad decision based on inaccurate data. This dissertation proposes a theoretical method for developing data-accuracy metrics specific for any given person-centric integrated system and how a data analyst can use these metrics to estimate the overall accuracy of person-centric data. Estimating the accuracy of Personal Identifiable Information (PII) creates a corresponding need to model and formalize PII for both the real-world and electronic data, in a way that supports rigorous reasoning relative to real-world facts, expert opinions, and aggregate knowledge. This research provides such a foundation by introducing a temporal first-order logic language (FOL), called Person Data First-order Logic (PDFOL). With its syntax and semantics formalized, PDFOL provides a mechanism for expressing data- accuracy metrics, computing measurements using these metrics on person-centric databases, and comparing those measurements with expected values from real-world populations. Specifically, it enables data analysts to model person attributes and inter-person relations from real-world population or database representations of such, as well as real-world facts, expert opinions, and aggregate knowledge. PDFOL builds on existing first-order logics with the addition of temporal predicated based on time intervals, aggregate functions, and tuple-set comparison operators. It adapts and extends the traditional aggregate functions in three ways: a) allowing any arbitrary number free variables in function statement, b) adding groupings, and c) defining new aggregate function. These features allow PDFOL to model person-centric databases, enabling formal and efficient reason about their accuracy. This dissertation also explains how data analysts can use PDFOL statements to formalize and develop formal accuracy metrics specific to a person-centric database, especially if it is an integrated person- centric database, which in turn can then be used to assess the accuracy of a database. Data analysts apply these metrics to person-centric data to compute the quality-assessment measurements, YD. After that, they use statistical methods to compare these measurements with the real-world measurements, YR. Compare YD and YR with the hypothesis that they should be very similar, if the person-centric data is an accurate and complete representations of the real-world population. Finally, I show that estimated accuracy using metrics based on PDFOL can be good predictors of database accuracy. Specifically, I evaluated the performance of selected accuracy metrics by applying them to a person-centric database, mutating the database in various ways to degrade its accuracy, and the re-apply the metrics to see if they reflect the expected degradation. This research will help data analyst to develop an accuracy metrics specific to their person-centric data. In addition, PDFOL can provide a foundation for future methods for reasoning about other quality dimensions of PII.

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One of the major applications of wireless sensor networks is to sense accurate and reliable data from the physical environment with or without a priori knowledge of data statistics. To extract accurate data from the physical environment, we investigate spatial data correlation among sensor nodes to develop data accuracy models. We propose three data accuracy models namely Estimated Data Accuracy (EDA) model, Cluster based Data Accuracy (CDA) model and Distributed Cluster based Data Accuracy (DCDA) model with a priori knowledge of data statistics. Due to the deployment of high density of sensor nodes, observed data are highly correlated among sensor nodes which form distributed clusters in space. We describe two clustering algorithms called Deterministic Distributed Clustering (DDC) algorithm and Spatial Data Correlation based Distributed Clustering (SDCDC) algorithm implemented under CDA model and DCDA model respectively. Moreover, due to data correlation in the network, it has redundancy in data collected by sensor nodes. Hence, it is not necessary for all sensor nodes to transmit their highly correlated data to the central node (sink node or cluster head node). Even an optimal set of sensor nodes are capable of measuring accurate data and transmitting the accurate, precise data to the central node. This reduces data redundancy, energy consumption and data transmission cost to increase the lifetime of sensor networks. Finally, we propose a fourth accuracy model called Adaptive Data Accuracy (ADA) model that doesn't require any a priori knowledge of data statistics. ADA model can sense continuous data stream at regular time intervals to estimate accurate data from the environment and select an optimal set of sensor nodes for data transmission to the network. Data transmission can be further reduced for these optimal sensor nodes by transmitting a subset of sensor data using a methodology called Spatio-Temporal Data Prediction (STDP) model under data reduction strategies. Furthermore, we implement data accuracy model when the network is under a threat of malicious attack.

OBJETIVO: Avaliar a relação entre mensurações de gordura (subcutânea e periprostática) realizadas em ressonância magnética, com o prognóstico do paciente portador de câncer de próstata. MATERIAIS E MÉTODOS: A mensuração da gordura periprostática e subcutânea com exame de ressonância magnética com ênfase na próstata foram realizadas em 58 pacientes com o diagnóstico histopatológico de câncer de próstata. Dados demográficos, clínicos e patológicos dos pacientes foram coletados e a correlação com o prognóstico, realizada. RESULTADOS: Na análise univariada, as gorduras periprostática e a subcutânea indicaram serem preditores de evolução desfavorável com significância estatística para o observador 1, no caso da gordura periprostática e para o observador 2 no caso da gordura subcutânea. Na análise multivariada, não houve associação com significância estatística. CONCLUSÃO: A associação entre obesidade e o câncer de próstata é complexa. Os dados obtidos neste estudo indicam que a medida da gordura periprostática, pelas imagens em T2, na RM, podem ser um preditor independente, da evolução desfavorável de pacientes com neoplasia de próstata / PURPOSE: Evaluate the relationship between fat measurements (subcutaneous and periprostatic) performed on MRI, with the prognosis of the patient with prostate cancer. MATERIALS AND METHODS: Measurements of periprostatic and subcutaneous fat with magnetic resonance imaging with emphasis on the prostate were performed in 58 patients with the histopathological diagnosis of prostate cancer. Demographic, clinical and pathological data of the patients were collected and the correlation with the prognosis was performed. RESULTS: In the univariate analysis, the periprostatic and subcutaneous fat were predictors of unfavorable evolution with statistical significance for the observer 1, in the case of the periprostatic fat and for the observer 2 in the case of the subcutaneous fat. In the multivariate analysis, there was no association with statistical significance. CONCLUSION: The association between obesity and prostate cancer is complex. The data obtained in this study indicate that the measurement of periprostatic fat by T2-weighted images in MRI may be an independent predictor of the unfavorable evolution of patients with prostate neoplasia

Le CyberKnifeTM est composé d’un accélérateur linéaire de 6 MV monté sur un bras robotisé, avec 6 axes de rotation et d’un système d’imagerie permettant de guider le faisceau d’irradiation sur la cible à traiter. Le but est d'améliorer la précision du traitement et la réduction de l’irradiation des organes critiques environnants. Le traitement est réalisé par la convergence « isotrope » d’une centaine d’orientation pour créer jusqu’à 1200 mini faisceaux dirigés sur la cible avec une précision sub-millimétrique. Cet ensemble est complété par une table de traitement montée sur un bras robotisé qui offre 6 degrés de liberté supplémentaires, permettant d’améliorer encore la précision du traitement et de lever d’éventuelles limitations. Grâce à son sous système SynchronyTM, le CyberKnifeTM est capable de traiter les tumeurs abdo-thoraciques, qui bougent avec la respiration en déplaçant dynamiquement le LINAC afin de compenser le mouvement respiro-induit. La forte dose utilisée dans ce genre de traitement hypofractionné, rend toute erreur même minimale inacceptable et impose une très grande précision géométrique, tout en assurant une précision dosimétrique maximale.Notre travail est consacrée à évaluer la qualité de traitement en termes des précisions géométrique et dosimétrique, pour les différents modes de suivi disponibles dans le système en statique, et en dynamique avec suivi respiratoire. Dans cette étude, nous avons utilisé différents types de détecteurs, et trois plateformes afin de simuler des simples mouvements respiratoires, des mouvements réels provenant des patients traités et enfin des mouvements complexes avec hystérésis / The CyberKnifeTM consists of 6MV LINAC mounted on a robotic arm, with six degree of freedom and is coupled to an image guiding system, allowing us to guide the irradiation beams toward the target. The aim is to improve the treatment accuracy and to reduce the irradiation of critical surrounding organs. The treatment is realized by the isotropic convergence of hundreds of orientations for creating up to 1200 mini-beams, which are orientated to the target with submillimetric accuracy. This group is completed by a treatment couch, which is also mounted on a robotized arm, that offers 6 additional degrees of freedom, allowing an additional improvement of accuracy, and eliminates the possible limitations. Using its subsystem SynchronyTM, the CyberKnifeTM is capable of treating the abdo -thoracic tumors, which move with respiration, by moving dynamically the LINAC to compensate the respiratory motion of the tumors. The high dose level, which is used in this kind of hypofractionated treatment, makes the smallest error unacceptable, and needs a very high geometric accuracy with keeping a maximal dosimetric accuracy. Our work is dedicated to evaluate the quality of treatment, in the terms of dosimetric and geometric accuracies. For the different modes of tracking, which are available in the system in static mode, and dynamic mode with respiratory motion tracking. By using different kinds of detectors (ionization chambers, radiochromic films) and three different platforms, which allow simulating simple respiratory motion, real respiratory motion coming from real treated patients, and finally complex motion with hysteresis

Please note: This degree was awarded by the University of Kwazulu-Natal. Permission was granted to archive it in this database for teaching purposes.This study reports the development and use of an original methodology to measure inflation credibility, as well as the first results of such measurement in terms of an inflation credibility barometer. The barometer is an instrument measuring the degree of acceptance of the accuracy of historic inflation figures. Despite the lack of knowledge about inflation and the low inflation credibility recorded by this first calculation of an inflation credibility barometer for South Africa, valuable information about inflation is unveiled to the authorities. The research results serve as a benchmark, but cannot be compared to earlier research, as this study represents the first systematic measurement of inflation credibility in South Africa. The barometer yields better results than the limited current international measurement of perceptions of the accuracy of historic inflation figures. The barometer (i) reports the credibility of inflation figures as a figure between zero and 100; (ii) will highlight changes in credibility over time with repeated use; (iii) can be explained easily to the general public; (iv) provides for international comparison between countries; and (v) can be used by all countries. The use of inflation credibility barometers and changes in barometer readings over time can also serve as an early warning system for changes in inflation perceptions that might feed through to inflation expectations. Sampling results used to calculate a South African inflation credibility barometer show little public understanding of the rate of inflation. Owing to an increased focus on inflation figures in countries using an inflation-targeting monetary policy, central banks entrusted with such a policy should adopt a communication strategy highlighting the calculation and measurement of the rate of inflation. This study shows that no generally accepted international benchmarks for successful central-bank communication strategies have been developed, but the use of the methodology developed in this study will assist in the assessment of the effectiveness of communication strategies. This study makes three further contributions of significance to available literature on inflation in South Africa. The first is an analysis of prices increases and inflation over a period of 85 years (1921 to 2006) and a selected comparison of salaries and remuneration over a period of 78 years (1929 to 2006). To this end data sets were developed for comparative purposes, thereby distinguishing between perception and reality about the accuracy of inflation figures over time. As this comparison has not been done before, a methodology was developed that can be used in future research. Based on these comparisons an inflation accuracy indicator (IAI) is developed for the first time. The research showed no systematic over or under-reporting of price increases, therefore confirming the general accuracy of the consumer price index (CPI) over time. As with the inflation credibility barometer, this methodology can be used internationally to confirm the accuracy of countries’ inflation figures over time. This methodology can also be used by developing countries with capacity constraints in economic modelling and forecasting. The second contribution to available literature is the first analysis of South Africa’s experience with inflation over a period of 85 years from the perspective of the central bank. This analysis highlights not only the difficulties encountered by a central bank to contain inflation, but also focuses the attention on the policy errors of the authorities in their quest to contain rising prices. The third contribution is an analysis of international and domestic initiatives aimed at improving the accuracy and measurement of inflation. The implications of these initiatives for developing countries are considered in the interest of a level international playing field between developed and developing countries. eo / Thesis (PhD)--University of Pretoria, 2008. / Economics / PhD / Unrestricted

This diploma thesis deals with the influence of electronic compensation on accuracy of the measurement using the touch probe. The theoretical part concerns touch probes, specifically their classification, principles of working and applications. This part also includes devices used later in the experiment, particularly double ballbar, laser interferometer and LaserTRACER. The Practical part describes an experiment, demonstrating the correlation between the accuracy improvement of the touch probe and the electronic compensation’s level. All measurements were executed in accordance with the norm VDA 5 and were evaluated by the Matlab software. The graphs of reliance tolerance of capability of measurement on the length of the benchmark. At the end of this diploma thesis there are partial conclusions deduced. The deduction is based on generated graphs. The partial conclusions synoptically compare the influence of individual machine´s configurations on the accuracy of the touch probe.

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Background: The coronavirus disease 2019 (COVID-19) presents diagnostic evaluation and patient management challenges, including uncertainty regarding the role of imaging tests. This series of reviews from the suite of Cochrane ‘living systematic reviews’ aims to evaluate the accuracy of chest imaging (computed tomography (CT), X-ray and ultrasound) for diagnosis and management of individuals with suspected COVID-19. Methods: The Bern COVID-19 Living Database, Cochrane COVID-19 Register, and CDC Library were searched through 30 September 2020 (for review version 3) and 17 February 2021 (for review version 4). Diagnostic accuracy studies involving participants with suspected COVID-19 were included. Screening, data extraction, and risk of bias assessments (using the QUADAS-2 tool) were completed independently, in duplicate. Pooled accuracy estimates and 95% confidence intervals (CIs) were determined using a bivariate random effects model. Results: In the third version of the review, chest CT (41 studies, 16133 participants, 8110 (50%) cases) had a pooled sensitivity of 87.9% (95%CI 84.6-90.6) and specificity of 80.0% (74.9-84.3). Chest X-ray (9 studies, 3694 participants, 2111 (57%) cases) had a pooled sensitivity of 80.6% (69.1-88.6) and specificity of 71.5% (59.8-80.8). Ultrasound of the lungs (5 studies, 446 participants, 211 (47%) cases) had a pooled sensitivity of 86.4% (72.7-93.9) and specificity of 54.6% (35.3-72.6). Indirect comparisons showed that chest CT gave higher specificity (P=0.0052) and similar sensitivity (P=0.77) compared to ultrasound. There were no differences (P≥0.05) in accuracy between CT and X‐ray, or X‐ray and ultrasound. In the fourth version of the review, chest CT (69 studies, 28285 participants, 14342 (51%) cases) had a pooled sensitivity of 86.9% (83.6-89.6) and specificity of 78.3% (73.7-82.3). Chest X‐ray (17 studies, 8530 participants, 5303 (62%) cases) had a pooled of sensitivity=73.1% (64.1-80.5) and specificity of 73.3% (61.9-82.2). Ultrasound of the lungs (15 studies, 2410 participants, 1158 (48%) cases) had a pooled sensitivity of 88.9% (84.9-92.0) and specificity of 72.2% (58.8-82.5). Indirect comparisons showed that chest CT and ultrasound had similar sensitivities (P=0.42), and each gave higher sensitivities than X-ray (P=0.0003 and P=0.001, respectively). All modalities had similar specificities (P≥0.05). Conclusion: The most recent evidence indicates that both chest CT and ultrasound of the lungs are sensitive and moderately specific for diagnosing individuals with suspected COVID-19, while chest X-ray is moderately sensitive and moderately specific. Chest CT and ultrasound may be useful for ruling out COVID‐19, but not for distinguishing COVID-19 from other illnesses. Research assessing the prognostic value of imaging for predicting morbidity and mortality in individuals with COVID-19 is underway and will also be published in the suite of Cochrane ‘living' systematic reviews.