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MPhilPH / Female tubal sterilisation, often referred to as "tubal ligation" but more often performed these days using laparoscopically-applied metal clips, remains a popular form of contraception in women who have completed their families. A review of the literature on the incidence of failure of tubal sterilisation found many reports of case-series and small clinic-based studies, but only a few larger studies with good epidemiological designs, most recently the US CREST study conducted during the 1980s and early 1990s. The CREST study reported a conditional (life-table) cumulative incidence of failure of 0.55, 0.84, 1.18 and 1.85 per 100 women at 1, 2, 4 and 10 years of follow-up respectively. The study described here estimated a lower bound for the incidence of tubal sterilisation failure in NSW by probabilistically linking routinely-collected hospital admission records for women undergoing sterilisation surgery to hospital admission records for the same women which were indicative of subsequent conception or which represented censoring events such as hysterectomy or death in hospital. Data for the period July 1992 to June 2000 were used. Kaplan-Meier and proportional-hazards survival analyses were performed on the resulting linked data set. The conditional cumulative incidence per 100 women at 1, 2 4 and 8 years of follow-up was estimated to be 0.74 (95% CI 0.68-0.81), 1.05 (0.97-1.13), 1.33 (1.23-1.42) and 1.51 (1.39-1.62) respectively. Forty percent of failures ended in abortion and 14% presented as ectopic pregnancies. Age, private health insurance status and sterilisation in a smaller hospital were all found to be associated with lower rates of failure. Strong evidence of time-limited excess numbers of failures in women undergoing surgery in particular hospitals was also found. The study demonstrates the feasibility of using linked, routinely-collected health data to evaluate relatively rare, long-term outcomes such as sterilisation failure on a population-wide basis.

MPhilPH / Female tubal sterilisation, often referred to as "tubal ligation" but more often performed these days using laparoscopically-applied metal clips, remains a popular form of contraception in women who have completed their families. A review of the literature on the incidence of failure of tubal sterilisation found many reports of case-series and small clinic-based studies, but only a few larger studies with good epidemiological designs, most recently the US CREST study conducted during the 1980s and early 1990s. The CREST study reported a conditional (life-table) cumulative incidence of failure of 0.55, 0.84, 1.18 and 1.85 per 100 women at 1, 2, 4 and 10 years of follow-up respectively. The study described here estimated a lower bound for the incidence of tubal sterilisation failure in NSW by probabilistically linking routinely-collected hospital admission records for women undergoing sterilisation surgery to hospital admission records for the same women which were indicative of subsequent conception or which represented censoring events such as hysterectomy or death in hospital. Data for the period July 1992 to June 2000 were used. Kaplan-Meier and proportional-hazards survival analyses were performed on the resulting linked data set. The conditional cumulative incidence per 100 women at 1, 2 4 and 8 years of follow-up was estimated to be 0.74 (95% CI 0.68-0.81), 1.05 (0.97-1.13), 1.33 (1.23-1.42) and 1.51 (1.39-1.62) respectively. Forty percent of failures ended in abortion and 14% presented as ectopic pregnancies. Age, private health insurance status and sterilisation in a smaller hospital were all found to be associated with lower rates of failure. Strong evidence of time-limited excess numbers of failures in women undergoing surgery in particular hospitals was also found. The study demonstrates the feasibility of using linked, routinely-collected health data to evaluate relatively rare, long-term outcomes such as sterilisation failure on a population-wide basis.

<p> In the field of communications electronic plug-in units operating together form a system. In the event of failure a plug-in unit can easily be replaced by another. Each unit consists of electronic components soldered onto a board in a particular pattern. A component may be either a single electronic part such as a transistor or a combination of single parts such as an integrated circuit. Electronic components with similar properties have been grouped into families. This reduces the number of parameters to be estimated from the observations available.</p> <p> The method of maximum likelihood is used to estimate the failure rates of component families. The number of unit failures and the number of units in use observed during measured periods of time and the component family makeup of the observed units are used to make the estimates.</p> <p> The probability of an electronic component from a given component from a given family being acceptable after the production process will be referred to as the component yield for that family. Similarly, the probability of a given type of unit being acceptable after the production process will be referred to as the yield for that type of unit. By taking the logarithms of the yields, the estimation problem can be reduced to the linear problem of estimating logarithms of component family yields. Using unit yields, the total number of each type of unit produced, and the component family makeup of those units produced, component family yields are estimated. The method of maximum likelihood is applied directly to the data and the method of weighted least squares is applied to the linearized problem.</p> / Thesis / Master of Science (MSc)

Purpose The purpose of the present study was to assess the clinical outcomes of mandibular overdentures supported by dental implants (ISMO - implant-supported mandibular overdenture) based on a systematic review of the literature.   Materials and methods An electronic search, limited to studies published between 2018-2021, was performed in three databases, supplemented by hand searching of selected journals. Eligibility criteria included clinical human studies, either randomized or not, reporting case series of patients rehabilitated with ISMO. Interval survival rate (ISR) and cumulative survival rate (CSR) of implants and prosthesis were calculated in life-table survival analyses.   Results Sixty studies were included in the review, which reported 2261 ISMOs, supported by 4495 implants. A total of 111 implants and 191 ISMOs failed. The correlation between the survival rate of implants and the number of implants was very weak. Patients with less implants presented higher prosthesis failure rates than patients with more implants per prosthesis. There was no influence of the attachment system on the implant failure rates. The estimated CSR for the implants and the prostheses were 92.2% and 75.6%, respectively (23-year period). Replacement of attachment components was very often needed, as well as relining of the ISMO base. Complete transverse fracture of the ISMO was the most common technical complication.   Conclusion Using only one implant to support a mandibular overdenture is risky and should be avoided. In addition, metal reinforcement of the prosthesis base is recommended to minimize or prevent ISMO fractures, a common technical complication. / Syfte Syftet med denna studie var att undersöka de kliniska effekterna av implantatretinerade täckproteser i underkäken genom en systematisk översikt av befintlig litteratur. Material och metod En elektronisk sökning av studier publicerade mellan år 2018–2021, utfördes på tre olika databaser och kompletterades med en manuell sökning i utvalda tidskrifter. Studier som inkluderades var humana kliniska fall-kontrollstudier på patienter som behandlades med täckprotes. Både randomiserade och icke-randomiserade studier inkluderades. Intervall avöver överlevnadsfrekvensen och den kumulativ överlevnadsfrekvensen för implantat och täckproteser beräknades med hjälp av överlevnadsanalyser. Resultat I denna studie inkluderades 60 kliniska studier med totalt 2261 täckproteser som stöddes av 4495 implantat. Totalt misslyckades det 111 implantat och 191 täckproteser. Korrelationen mellan antal implantat som installerades och deras överlevnadsgrad var inte tydlig, däremot så uppvisade patienter med färre implantat mer omfattande problem med deras täckproteser jämfört med de proteser som stöddes av fler implantat. Val av retentionselement hade ingen påverkan på misslyckade frekvensen av implantaten. Den uppskattade kumulativa överlevnadsfrekvensen för implantaten och proteserna var 92,2 % respektive 75,6 % över en uppföljning på 23 år. Byte av retentionselement var vanligt förekommande och behövde utföras ofta, likaså relining av täckproteserna. Den vanligast förekommande tekniska komplikationen av täckproteser var en komplett tvärgående fraktur. Slutsats Att endast använda ett implantat för att stödja en täckprotes i mandibeln är riskabelt och bör undvikas. Metallförstärkning av protesbasen rekommenderas för att minska eller förhindra frakturer av täckprotesen, vilket var den vanligaste tekniska komplikationen som påträffades.

Standup forklift trucks are extensively used primarily for material handling in high density warehouses. These forklifts over the years have been involved in severe accidents causing injuries and taking lives of the operator and that of people on the floor. The major accidents involving these trucks are tip-over, off the dock accidents, compartment intrusions and under the rack injuries. The objective of the work is to analyze the accident data and to provide a conceptual design to ensure safety of the operator riding the standup forklift trucks. The operator is assumed to be safe when retained within the compartment similar to that of the safe space environment of a sit down forklift truck or tractors. Thus a door on the standup forklift would provide a safer compartment. This design would help in preventing severe injuries to the operator in case of any accidents. The important criterion of this design is to provide a door with latch and slide mechanism to ensure easy egress and ingress of the operator. The compartment is designed ergonomically for 95th percentile industrial male population. The accident data is studied by performing statistical and failure analysis. Weibull plots are fitted for life time distribution data and are found to be of increasing rate. This suggests that present safety precautions are increasingly ineffective.

Modern society is unquestionably heavily reliant on supply of electricity. Hence, the power system is one of the important infrastructures for future growth. However, the power system of today was designed for a stable radial flow of electricity from large power plants to the customers and not for the type of changes it is presently being exposed to, like large scale integration of electric vehicles, wind power plants, residential photovoltaic systems etc. One aspect of power system control particular exposed to these changes is the design of power system control and protection functionality. Problems occur when the flow of electricity changes from a unidirectional radial flow to a bidirectional. Such an implication requires redesign of control and protection functionality as well as introduction of new information and communication technology (ICT). To make matters worse, the closer the interaction between the power system and the ICT systems the more complex the matter becomes from a reliability perspective. This problem is inherently cyber-physical, including everything from system software to power cables and transformers, rather than the traditional reliability concern of only focusing on power system components. The contribution of this thesis is a framework for reliability analysis, utilizing system modeling concepts that supports the industrial engineering issues that follow with the imple-mentation of modern substation automation systems. The framework is based on a Bayesian probabilistic analysis engine represented by Probabilistic Relational Models (PRMs) in com-bination with an Enterprise Architecture (EA) modeling formalism. The gradual development of the framework is demonstrated through a number of application scenarios based on substation automation system configurations. This thesis is a composite thesis consisting of seven papers. Paper 1 presents the framework combining EA, PRMs and Fault Tree Analysis (FTA). Paper 2 adds primary substation equipment as part of the framework. Paper 3 presents a mapping between modeling entities from the EA framework ArchiMate and substation automation system configuration objects from the IEC 61850 standard. Paper 4 introduces object definitions and relations in coherence with EA modeling formalism suitable for the purpose of the analysis framework. Paper 5 describes an extension of the analysis framework by adding logical operators to the probabilistic analysis engine. Paper 6 presents enhanced failure rates for software components by studying failure logs and an application of the framework to a utility substation automation system. Finally, Paper 7 describes the ability to utilize domain standards for coherent modeling of functions and their interrelations and an application of the framework utilizing software-tool support. / <p>QC 20140505</p>

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-07-21T17:31:24Z No. of bitstreams: 1 rosanecordeirorafael.pdf: 1078166 bytes, checksum: e85302b525d2964f46b2bb837a10c169 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-09T13:21:35Z (GMT) No. of bitstreams: 1 rosanecordeirorafael.pdf: 1078166 bytes, checksum: e85302b525d2964f46b2bb837a10c169 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-09T13:22:07Z (GMT) No. of bitstreams: 1 rosanecordeirorafael.pdf: 1078166 bytes, checksum: e85302b525d2964f46b2bb837a10c169 (MD5) / Made available in DSpace on 2017-08-09T13:22:07Z (GMT). No. of bitstreams: 1 rosanecordeirorafael.pdf: 1078166 bytes, checksum: e85302b525d2964f46b2bb837a10c169 (MD5) Previous issue date: 2017-04-05 / O presente estudo investigou as intervenções metodológicas realizadas por universidades públicas e privadas no que se refere a estratégias para reduzir o percentual de não aprovação, isto é, reprovados e evadidos na disciplina Cálculo Diferencial e Integral. Para tanto, consta neste a investigação e exposição dos principais fatores apresentados por professores, alunos e pesquisadores de matemática, mais especificamente, de Cálculo Diferencial e Integral que influenciam no baixo rendimento na disciplina. Constatados esses fatores, o trabalho relacionou as intervenções metodológicas realizadas pelas instituições para reduzir os índices de não aprovação em Cálculo Diferencial e Integral e seus desdobramentos no decorrer do curso. Por meio da pesquisa qualitativa, foram coletados e analisados os dados das secretarias universitárias, além de um questionário aplicado para professores e alunos da disciplina em questão. Em virtude da pesquisa realizada, constatou-se que nas universidades privadas, os percentuais de não aprovação na disciplina em questão, apesar de serem elevados, demonstram ser relativamente menores do que os apresentados pelas instituições públicas. Além disso, o volume de intervenções propostas pelas instituições privadas foi maior que o apresentado pelas instituições públicas, fator que pode ter contribuído para essa diferença. Outro ponto que os resultados mostraram encontra-se no fato de as intervenções realizadas pelas instituições serem consideradas por grande parte dos professores e alunos entrevistados como incapazes de resolver o problema de compreensão do conteúdo. Apesar dos resultados mostrarem a redução no percentual de não aprovação, a pesquisa não conseguiu constatar significativa melhora na aprendizagem, podendo considerar assim, como paliativas as intervenções realizadas. / This present paper aims to investigate the methodological interventions conducted by public and private universities concerning the strategies to reduce students failure rates (reprobation and abandon) on the discipline Differential and Integral Calculus. The investigation for the main factors that influence the low performance in this area are conducted with the help of teachers, students and researchers of mathematics, mainly focusing on this discipline. Having identified these factors, this work analyzed the methodological interventions carried out by institutions and exposed its consequences. Qualitative surveys were realized with teachers and students and historical data were collected from course secretaries. Survey shows that, although students failure rates in private schools are high, they are relatively smaller than those in public schools. We verified that the number of interventions done by private schools are higher than those presented by public schools, a factor that may have contributed to this difference. We also verified that that these interventions are seen, by the majority of the interviewed teachers and students, as being incapable of solving the problems for the subject's content comprehension. Another point that the results show is in fact interventions carried out by institutions they are considered by most of the teachers and students interviewed as unable to solve the problem of understanding of content. Although the results showed a reduction in the percentage of failure rates, the research was not able to verify a significant improvement in learning, and thus, the interventions were considered as palliatives.