D. Ing. / This dissertation deals with the important issue of reliability management for 3kV DC Traction Substations used by the national railway company in South Africa. Maintenance is one of the critical and most costly phases in the lifecycle of any plant. It looks at the total life cycle of the equipment in a typical substation, but the focus in the latter chapters is on the maintenance. Through improved maintenance management, the reliability of the system can be improved. The approach to maintenance is addressed as a predictive strategy, avoiding even more costly nonproductive time due to downtime caused by failure or induced by maintenance. Condition monitoring and assessment is described as one of the effective tools in the maintenance engineer’s armoury to apply a predictive approach. A direct link between predictable maintenance and reliability is explored. In the definition of reliability, concepts such as time and expected performance can be linked to a predictable delivery of the designed function. In other words, if down time is expected and can be prepared for, it is more acceptable than the unexpected. In essence, the system is still reliable as it performs according to expectation. The concept of predictable maintenance can be applied wider than just the 3kV traction substation. The process of identifying critical equipment, to measure the condition and to take decisions based on the rate of change in the condition can be used in any maintenance environment, even outside electrical. The crucial ingredient to this is to understand that condition monitoring is not based on fixed values, but the rate at which these values change. This is called Fuzzy logic. Can we predict the future? If yes, how accurate will the predictions be?

Fire in building structures represents a risk both to life and property that cannot be fully eliminated. It is the aim of fire safety engineering to reduce this risk to an acceptable level through the application of scientific and engineering principles to evaluate the risk posed by fire and to determine the optimal set of protective measures. This is increasingly being achieved through performance-based design methods. Performance-based design sets out performance requirements, typically related to life safety and control of property losses, and the designer is free to choose the most suitable approach to meet these requirements. Accurate performance-based design requires the evaluation of the risks to a structure through the evaluation of the range of hazards that may occur and the resulting structural responses. The purpose of this research is to develop simplified methodologies for the reliability based design of steel framed structures in fire. These methodologies are incorporated into a software package, FireLab, which is intended to act as a tool for practicing engineers to aid in learning and applying performance-based design. FireLab is a Matlab based program that incorporates a number of different models for analysing the response of structural elements exposed to fire. It includes both deterministic and probabilistic analysis procedures. A range of simple fire models are presented for modelling compartment fires. A set of heat transfer processes are discussed for calculating the temperature distribution within common structural elements exposed to fire. A variety of structural models are discussed which may be used to model the effects of fire on a structure. An analytical model for the analysis of composite beams has been implemented in the software program. Interfaces between the software and 2 separate third party programs have also been created to allow for the analysis of composite beams using the finite element method. Analytical methods for the analysis of composite slabs under thermo-mechanical load have been implemented in the software. These methods account for the additional load carrying capacity that slabs have in fire due to the positive effects of tensile membrane action. A numerical analysis method for the vertical stability of structures subjected to multi-floor fires has been implemented using the direct stiffness method. This method uses an elastic 2nd order solution in order to check the stability of a column under the fire induced horizontal loads from sagging floors. These models of potential failure scenarios provide the basis for the probabilistic analysis methods. A variety of methods for reliability analysis are evaluated based on ease of use, accuracy and efficiency. A selection of these methods has been implemented in the software program. A selection of sample cases are examined in order to illustrate the procedures and to evaluate the important input variables. These methods provide the probability of failure of a structure under specific loads. The probability of failure is a useful parameter in comparing the level of safety between various design options. A more comprehensive framework is developed for the evaluation of the probable costs due to fire associated with a given design. This framework is based on an existing framework from earthquake engineering. It involves calculating the statistical spread of both the magnitude and likelihood of occurrence of fire and the resulting structural responses. The damage that occurs from the structural response may be then estimated. Finally, given the likely level of damage that will occur it is possible to estimate the cost of the damage either in terms of monetary cost of repair or downtime due to repair works. This method is applied to a variety of design options for a typical office building in order to illustrate the application of the framework.

Good reliability of the encapsulation system of Photovoltaic (PV) modules is crucial to ensure the long-term performance of PV modules. A carefully controlled lamination process is required to produce a reliable encapsulation system. To date, the influences of different lamination conditions on the reliability of the encapsulation system are poorly understood. To predict the performance of the encapsulation system, the correlation of the reliability of the encapsulation system with various stress levels is required, which is poorly developed. This thesis improves the understanding of these issues by investigating the correlation of different lamination conditions with the reliability of the encapsulation system and the degradation of adhesion strength under variable damp-heat conditions. The influence of the curing temperature and curing time on the long-term reliability of the encapsulation system is investigated from various viewpoints such as curing level of EVA, chemical and optical stability of EVA and adhesion strength within the encapsulation system. The correlation of curing level and lamination quality has been identified. The effects of over-curing are demonstrated. Results show that the chemical stability, optical stability and the adhesion strength between encapsulant and backsheet increases with the increasing curing level. However, the best long-term adhesion performance at the glass-encapsulant interface is obtained at lower gel content. Too high curing can cause problems of bubble generation, discoloration and unstable interfaces. Among those identified degradation phenomena, interfacial adhesion strength demonstrates the fastest and the largest degradation. The reliability of the adhesion strength is further examined under different stress levels. Among different environmental stress factors, moisture is considered to cause the greatest problems of adhesive interfacial stability. Therefore, the adhesion strength is investigated under different damp-heat conditions. A methodology is developed that can be used to model the adhesion degradation induced by moisture at different humidity and temperature conditions. To do so, a stress model is established which enables quantitative description of the moisture related stresses on PV modules. Based on this model, an exponential correlation is established between the adhesion strength and the humidity and temperature levels. This enables the comparison of adhesion strength of PV modules operating at different humid environments.

This bachelor thesis has been done in cooperation with IKEA of Sweden in Älmhult. It is about a mapping and comparison study of how different companies handle their cost of poor quality (COPQ) in their logistics processes. In this study, we have collaborated with Electrolux, Gekås and Rusta. IKEA has a high COPQ, this means when poor quality occurs in their processes. This has attracted much attention in recent years and there is room for improvement. The part of the value chain chosen in this project is the logistics process. The purpose of this bachelor thesis is to map IKEA´s logistics process, then compare IKEA´s way of working with other companies through a benchmarking study and finally come up with areas for improvement. This gave the questions: How does IKEA's operate in their logistics process today and handle their cost of poor quality? How do our other partners operate and handle their logistics processes and cost of poor quality? What are the similarities and differences between the different companies? To find out how IKEA operates in their logistics process today, it was decided to make a corporate visit to one of IKEA's CDC:s. Here, a questionnaire has been used to get the information that was needed. Later this questionnaire formed the basis for the survey that was used to gather information from our other partners. To gather information from our partners, we have used benchmarking. This was done to see how our other partner organizations operate today and how they work accordingly to this study. The first step of the benchmarking, was to send out the survey to our partners. Later we followed up with personal interviews and visits. The collected data from the different companies formed the basis of the status report of them all. In the analysis, IKEA has been compared to each of our different partners and a summary of the analysis has been made. With the analysis finished, it has been clear that IKEA has some problems in their logistic process and that the cost of poor quality can decrease. This gave us some areas that IKEA can make improvements in. After that conclusion, forklift damages and packaging design are two areas that IKEA can make big improvements in. / Detta examensarbete har gjorts tillsammans med IKEA of Sweden i Älmhult. Det handlarom en kartläggning och jämförelse av hur olika företag hanterar sinakvalitetsbristkostnader inom logistikprocessen. Våra samarbetspartners i dettaarbetet är Electrolux, Gekås och Rusta

As an international phenomenon, school bullying negatively impacts children, adolescents, and young adults all over the world. In China, bullying problem has drawn increased research attention in recent years. Research on school bullying depends on valid and reliable measurement of bullying and victimization behaviors. Unfortunately, however, psychometrically sound bullying measures for use with Chinese students are lacking. The Revised Peer Experiences Questionnaire (RPEQ) is a widely used self-report bullying measure that has demonstrated adequate psychometric properties in students from the United States and several European countries. In the current study, the psychometric properties and factor structure of the RPEQ were examined with a sample of Chinese college students.

Magister Artium (Psychology) - MA(Psych) / The diagnosis of adult ADHD is a complex process that requires information from different sources. Instruments are used to screen or diagnose adult ADHD. The aim of the study was to identify instruments measuring adult ADHD from good quality research. This systematic review was executed following the recommended PRISMA steps. A comprehensive search was conducted across identified databases. The SFS scoring system was used to critically appraise for methodological rigour and coherence. Meta-synthesis was used to summarize extracted data from 26 articles included in the final summation. Ethics clearance was issued by the UWC Senate Research Committee. Sixteen instruments measuring adult ADHD were identified. Screening instruments measure core symptoms whereas diagnostic instruments assess all criteria. Fourteen instruments were based on DSM-IV criteria and four were based on DSM-V criteria for adult ADHD including rival explanations for the symptoms. The lack of adoption of DSM-V criteria remains a concern given criticism against DSV-IV criteria for adult ADHD. Overall instruments presented acceptable psychometric properties. However, the performance of the instruments was study dependent. A cautionary note is that these indices must be interpreted carefully. Further research must explore the reasons underlying the lack of adoption of DSM-V criteria in research, and the lack of revision of instruments measuring adult ADHD.

Student Number: 0110826H - MSc research report - School of Occupational Therapy - Faculty of Health Sciences / A comparative study was undertaken to assess the reliability of the MVPT-3 when the instructions were translated into Afrikaans and the scores were then compared to the normative data obtained during the standardization process on a normal population of American children. The study was undertaken by testing 80 randomly selected, normally distributed, Afrikaans first language speaking eight year old children from the eastern suburbs of Pretoria, South Africa. The study confirmed that the MVPT-3 is reliable when the instructions are given in Afrikaans with a Chonbach’s alpha score of 0.79 compared to 0.83 obtained for the American population. The item analysis revealed some anomalies that suggest that the test may have a cultural bias as many items had a negative sign in the item analysis. Afrikaans girls and boys performed differently on the test, suggesting that the test may need to be adjusted for differing skills in the visual perception. There were a high number of non-contributing items that suggest that some items in the test may not be valid for South African Children.

The field of psychometrics in South Africa faces many challenges. Among these are, that practitioners in the field of psychology do not always have access to standardised assessments for the South African context. Imported assessments pose various biases to South Africa’s multilingual and multicultural situations, hence the need for test adaptation. The Suffolk Reading Scale (2) (SRS2) is an English proficiency assessment that measures reading comprehension. English, being the language of learning and teaching in most South African schools, makes the SRS2 a significant gain to practitioners and the field of psychometrics. Consequently, this research aimed to narrow the gaps in this area of knowledge and contribute to it by evaluating the applicability of the SRS2 as a measure of reading comprehension for South African learners. Primary school learners in Kwa-Zulu Natal were administered the SRS2. The purpose of the study was to ascertain the degree of reliability of the SRS2. Of the 338 participants, 51.9 percent (n=140) of the sample were female, and 48.1 percent (n=130) were male. Sixty-six percent (n=164) of the participants spoke English as an Additional Language (EAL), while thirty-four percent (n=83) spoke English as a first language (EFL). Results indicated a significant difference in performance between EFL and EAL learners, whereby EAL learners performed lower than EFL learners. However there was no difference in performance between female learners and their male counterparts on individual items of the SRS2. The SRS2 proved to have a suitable internal consistency; however questions of bias do arise.

O objetivo deste estudo foi de analisar a confiabilidade teste reteste do posicionamento dos eletrodos na aquisição do sinal eletromiográfico dos músculos do antebraço na tarefa de preensão palmar, por meio de dois posicionamentos. O primeiro posicionamento proposto por Cram; Durie e o segundo proposto por Mogk; Keir. Foram recrutados 30 voluntários sendo divididos em 2 grupos com 15 indivíduos cada. O primeiro grupo era formado por indivíduos saudáveis, isto é, que não apresentavam qualquer patologia, trauma ou dor no membro superior. Este grupo era composto por 13 mulheres e 2 homens com idade média de 23,4 anos, sendo 13 destros e 2 canhotos. O segundo grupo era formado por indivíduos que apresentavam algum trauma no antebraço, punho ou mão, recrutados no centro de reabilitação e no ambulatório de cirurgia do membro superior do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo. A amostra era composta por 13 homens e 2 mulheres com idade média de 34,6 anos, sendo 14 destros e 1 canhoto. Todos os participantes assinaram o Termo de Consentimento Livre e Esclarecido. O procedimento foi realizado em dois dias com diferença de 24h entre as avaliações. A avaliação consistia em realizar a tarefa de preensão palmar com o dinamômetro analógico da marca Jamar® , realizando a máxima contração voluntária pelo período de 10 segundos com repouso de 3 minutos entre cada preensão, sendo coletados o sinal eletromiográfico de sete canais dos músculos do antebraço volar e dorsal, segundo cada método. Foi analisada a confiabilidade pelo índice de ICC e o SEM (Standard Error of Measurement). Os resultados obtidos mostram excelente correlação entre os dois posicionamentos em ambos os grupos. Quando verificado o valor de ICC do grupo de saudáveis verificou valores acima de 0.75 em todos os canais, o que demonstrou uma alta correlação entre as medidas em ambos os posicionamentos, com pequeno SEM. No grupo pacientes foi observado que nos músculos FUC, FSD e ERC uma correlação moderada para o posicionamento Mogk; Keir e somente no músculo FRC apresentou correlação moderada no posicionamento Cram; Durie. Os gráficos de Bland e Altman mostraram alta concordância entre as medidas, visto que, em ambos os posicionamentos, os valores ficaram entre o intervalo de confiança de 95% e próximos da linha média. Como conclusão pode-se inferir que ambos os posicionamentos apresentaram alta confiabilidade e alta correlação quando avaliado por meio do teste e re-teste, podendo ser utilizados para medida eletromiográfica dos músculos do antebraço / The objective of this study was to analyze test retest reliability of the electrodes placement in the acquisition of electromyography forearm muscles during a isometric hand grip task, through two different methods. The first method was proposed by Cram; Durie and the second by Mogk; Keir. We recruited 30 volunteers divided into 2 groups with 15 subjects each. The first group consisted of healthy subjects, who did not show any pathology, trauma or pain in the upper extremity. This group consisted of 13 women and 2 men with a mean age of 23.4 years, and 13 right-handed and 2 left-handed. The second group consisted of individuals who had previous trauma on the forearm, wrist or hand. They were recruited from the rehabilitation center and upper limb surgery clinic of the Medical School of Ribeirão Preto Clinical Hospital. The sample consisted of 13 men and 2 women with a mean age of 34.6 years, 14 right-handed and left-handed one. All participants signed the consent form. The procedure was performed in two days with 24 hours difference between assessments. The evaluation was to carry by a isometric handgrip task with a analog dynamometer Jamar®, with maximum voluntary contraction for 10 seconds with 3 minutes of rest and analised by CCI and SEM (Standard Error of Measurement) . The results obtained have a high correlation between the two methods in both groups. Analyzing the ICC value of the healthy group value noted above 0.75 in all channels, demonstrating a excelent correlation between the measurements in both positions and low SEM. Checking in group patients realize that the FUC, FSD and ERC muscles has a moderate correlation for Mogk; Keir positioning and only on FRC showed moderate correlation in Cram; Durie electrode placement method. Analyzing Bland and Altman method a high concordance was found between the measures, since in both positions, the values were between the confidence interval of 95% and close to the midline. Through this we can infer that both positions have high reliability and high correlation when measured by the test and retest

A abertura do mercado brasileiro e o fenômeno da globalização observado nos últimos anos, influenciaram em que as quatro tradicionais empresas do setor automobilístico (VW, Ford, FIAT e GM) passassem a dividir a participação de mercado brasileiro com os concorrentes estrangeiros. Devido a este fato, a demanda por qualidade e confiabilidade nos produtos oferecidos cresceu continuamente. Nenhuma empresa gosta de gastar com garantia, isto significa que algo saiu errado, um cliente está insatisfeito e isto custará à montadora. Deste modo as empresas automotivas necessitam desenvolver veículos com qualidade superior e com menores custos e para isso utilizam diversas ferramentas de engenharia. Atingir a satisfação dos clientes, melhorar a qualidade de seus produtos, reduzir custo de garantia tem sido a missão de todas as empresas no mercado brasileiro e em especial nas empresas do setor automobilístico, já que os principais fatores na decisão de compra de um veículo tem sido preço e confiabilidade, torna-se necessário oferecer cada vez mais opções de escolha para os clientes e acredita-se que a extensão da garantia oferecida pela empresa automotiva pode ser um fator decisivo de compra. Portanto o objetivo deste estudo é desenvolver um modelo para descrever o comportamento de um produto e predizer sua confiabilidade no campo. O modelo considera a utilização dos dados de reclamações de garantia, incluindo a consideração da existência de veículos que não apresentaram falhas ao final deste período. De posse da estimativa da confiabilidade do veículo ou subsistema e considerando os recursos gastos com falhas no período de garantia, propõe-se um modelo de análise baseado nos conceitos da Teoria da Decisão, que permite avaliar o efeito da extensão da garantia sobre o valor monetário economizado do total reservado para os gastos com garantia. Esta análise subsidia unicamente a tomada de decisão estratégica a respeito da viabilidade da extensão da garantia de um veículo. O modelo ora proposto é aplicado no intuito da extensão da garantia do conjunto motor e transmissão de um veículo popular. / As the Brazilian market opened to foreigner automakers and the phenomenon of globalization started some years ago, the four traditional automakers began to share its market with many others competitors. As a result, demand for quality and reliability on products offered to the customers grew continuously and it is more perceptive on the automobile business. Nobody likes warranty expenses; it is a universally recognized evil. It means that something went wrong, a customer is not satisfied and it probably will cost to the manufacturer. As it happens, automakers need to develop vehicles with superior quality, less manufacturing costs and better processes, shorten development process and to accomplish this goal it is necessary to use engineering tools available as much as possible. Many companies are setting as their goal: customer satisfaction, quality improvement, warranty cost reduction and it happens more often on the automobile market that is because reliability and warranty became one of the key points when making decisions of purchasing a vehicle. Today it is necessary to offer more options to the customers so they can decide which one is the best deal for them. It is believed that warranty extension already offered by some companies in this market can be a significant differential on the moment of a purchase decision in buying a vehicle. Therefore, the main objective of this study is to develop a model to describe the behavior of a product and predict its reliability in the field. The model considers the use of warranty claims and also the use of a number of vehicles which did not have any warranty claim in the subsystem under analysis. As one have the subsystem predicted reliability and the expenses on warranty failures occurred during their warranty period, it is possible to draw a model based on the concept of Decision Theory which allows the analysis of warranty extention effects over the warranty accrual. This analysis only helps on the decision making strategy regarding the warranty extention feseability. The model proposed on this study is applied for warranty extention of the subsystems engine and transmission.