Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: In recent years, the management of physical assets has become increasingly important, even more so, in asset intensive organisations. This research work presents an overall approach to quantify reliability of rolling stock assets in the rail environment. The current maintenance management system in the case studied is over-reliant on cancellations and delays as reliability measure. The objectives of this study were, therefore, to develop a scientific approach to quantify the reliability of the rolling stock fleet and to develop a maintenance planning model based on system reliability. The research methodology followed made use of failure statistics, failure distributions and the interdependence of different systems to determine the impact of component failures on the overall system reliability. This could then be used to determine the reliability of individual train sets in order to better understand their performance. The reliability measure could be used for predicting component and train set failures as well as to better understand the contribution of maintenance towards reliability, hence the term Reliability Based Maintenance. The model, validated with real data, illustrates how the reliability measure can be used to determine maintenance intervals of different train sets. Based on the results, recommendations are made in relation to future planning of the maintenance strategy. / AFRIKAANSE OPSOMMING: Die bestuur van fisiese bates het in die afgelope tyd meer belangrik geword, veral in organisasies wat afhanklik is van hulle fisiese bates. Hierdie navorsing stel ‘n metode voor wat die betroubaarheid van rollende materiaal bates in die spoor bedryf kwantifiseer deur gebruik te maak van falingstatistiek. In die huidige instandhouding bestuurstelsel van die gevallestudie word daar te veel gesteun op kansellasies en vertragings van treine as ‘n betroubaarheids meting. Daarom was die doelwitte van die navorsing om ‘n wetenskaplike benadering te ontwikkel om betroubaarheid van rollende materiaal the kwantifiseer, en om ‘n instandhouding beplannings model voor te stel, gebaseer op sisteem betroubaarheid. Die navorsingsmetodologie is gebaseer op falingstatistieke, falingverspreidings, en die interafhanklikheid van stelsels word gebruik om die invloed van komponent falings op die betroubaarheid van die totale stelsel te bepaal. Hierdie benadering word dan gebruik om die betroubaarheid van individuele treinstelle en die werksverrigting van individuele trainstelle te bepaal. Hierdie instandhouding meting kan gebruik word om falings van komponente en treinstelle te voorspel, asook om die bydrae van instandhouding tot betroubaarheid beter te verstaan, daarom genoem Betroubaarheids Gebaseerde Instandhouding. Dit is ook geïllustreer hoe die betroubaarheid meting gebruik kan word om instandhouding intervalle te bepaal. Die betroubaarheid model is met werklike data gevalideer en aanbevelings word gemaak hoe om betroubaarheid te gebruik om die toekomstige beplanning van instandhouding te doen.

Program slicing has been used as a way to improve the efficiency of debugging and program analysis. Nowadays, automated test generation is being used to create tests automatically by analysing the program structure and suggesting necessary tests. This kind of techniques are prone to efficiency problems when applied to large programs containing many lines of code. This is especially true for software in industrial practice, such as the ones running on Programmable logic controllers (PLC) that are used in a wide variety of tasks from toys to avionics and rail transport. Function Block Diagram (FBD) is a language used for programming PLCs that has gained lots of attention in industrial practice due to its graphical nature. These FBD programs are often used in real time and safety critical systems, and these systems require extensive testing in order to prove that they pass safety requirements of their respective domains. In order to improve the efficiency of applying automated test generation on FBD programs we propose two FBD program slicing algorithms based on the structure of these diagrams and how they are programmed. These FBD program slicing algorithms are applied on several industrial programs for PLCs in order to evaluate their feasibility and what effect slicing has on test generation. Six FBD programs were selected out of 189 provided by Bombardier Transportation Sweden AB. The six programs were sliced according to these FBD slicing algorithms and then evaluated in terms of efficiency and applicability. Our results suggest that slicing can be used to reduce the needed generation time and memory usage required for automated test generation. However, our observations show that slicing can also increase the number of test cases generated and how this test cases are merged into one test suite for the entire program.

<div>Nowadays, electrical motors are widely used in the automotive industry because of their high efficiency and lossless characteristics. One downside is that the system is complicated to control and it requires more complex control strategies. Moreover, compared to other motors, electrical motors produce less torque, which limits its capability.</div><div><br></div><div>Therefore, in this thesis, an air-gapless electric motor is presented. Instead of having a static air gaps between the rotor and the stator, the gap changes dynamically creating contact which generates higher torques. A SIMULINK simulation method is used for this motor in order to show the systems dynamic behaviors.</div><div><br></div><div>Five blocks are used in the system: the block to nd phase currents, the block to find phase torque, the block to find self-inductance, the block to obtain mechanical speed of the motor and the block to simulate the saturation effect. These blocks are developed based on the analytical relationships between components, which are shown in Chapter two.</div><div><br></div><div>Moreover, saturation effect in the iron cores is taken into consideration in this thesis due to the fact that it always effects the shape of the magnetic eld curves. And four different materials are discussed and compared in Chapter three. The findings in this chapter is that carbon steel and silicon steel serve as better materials of the rotor in the air-gapless motor than soft ferrite and nickel steel because they tend to have higher torques under same levels of the currents and they have larger torque stability regions.</div><div><br></div><div><div>As for Chapter four, a current control strategy is proposed with an inverter, this could simulate the current controller in a real application. Trial and error PID controller tuning method is discussed in Chapter four.</div></div>

A method able to analyze and optimize subsystems could be useful to reduce project cost, increase subsystem reliability, improve overall aircraft safety and reduce subsystem weight. The earlier the optimization of development of an aircraft in the design phase can be performed, the better the yield of the optimization becomes. This master thesis was formed in order to construct an automatic analysis method, implementing a Matlab script, evaluating devices forming aircraft subsystems using a Genetic Algorithm. In addition to aircraft subsystems, the method constructed in the work is compatible with systems of various industries with minor modifications of the script.

Marine renewable energy promises to provide a significant contribution to the future electricity supply. It is estimated that 17% of today's UK electricity demand could be generated from wave and tidal sources. The ambition to harvest this resource is in the public interest, as it eases the pressures on energy security, holds the potential to reduce carbon emissions and has the prospect to create a new UK industry sector worth £15 billion. From an engineering perspective, marine energy is one of the least developed renewable energy technologies and has to be regarded as unproven. The reliability of components and devices in the harsh marine environment is one of the main engineering challenges. Reliability assessments and the assurance of acceptable reliability levels are dependant on the adequacy of failure information, which is scantily available for marine energy. This thesis shows that large failure rate uncertainties impede the reliability assessment for wave energy converters and how a suite of experimental, numerical and statistical methods can be applied to improve scarcely available reliability information. The analysis of component load conditions identifies fatigue as failure mode of concern and the fatigue life of mooring lines and marine power cables is quantified in a floating wave energy application. A Bayesian statistical approach and dedicated service-simulation component testing is proposed, and implemented to improve the quality of reliability estimates and to provide relevant data and assurance. The methods presented, along with the results, will assist reliability assessment and design during early development stages, and will inform the prediction of maintenance requirements during operation. Reliable marine energy systems will be the technical enabler for the successful transition of prototype devices to a commercially viable marine energy industry.

Tato diplomová práce pojednává o možnostech simulace a modelování elektrických pohonů na základě Bondových grafů. Je zde uvedena základní teorie k problematice. V práci jsou představeny modely stejnosměrného a synchronního stroje sestavené touto technikou. Dále je zde seznámení s Freeware knihovnou Bondových grafů BG V2.1 k programu MATLABSimulink. Za pomocí této knihovny byly sestaveny oba modely strojů. V poslední kapitole je uvedeno srovnání modelování na základě teorie Bondových grafů s modelováním v blokových diagramech.

This thesis is focused on a receiver for digital television broadcasting set-top box, mainly on its features, parameters and measurement. The important point of this work is the possibility to analyze and visualize the parallel transport stream in the same time and the solution of this problem. The principle of tuner and its measuring is deeply discussed. The text is supported with oscilloscope screenshots in particular parts of decoding stream. The set-top box is modified for laboratory measurement purpose and the transport stream output is added. An example laboratory exercise was created as a part of this work.

This Masterâs thesis concerns about the safety of machinery, in the literary research part you can find information about the law system and requirements of European Union and Czech Republic. There is a description of the legal enactments, which the manufacturers of machinery needs to follow. Second part of this thesis is about the safety of a milling center. The milling center is analyzed here, you can find here the description of its components. The milling center was then described with the help of block diagrams. For each component from the block diagram you can find here a list of dangerous situations which can occur and also a list of safety precautions for each situation. Based on these information the list of requirements for the milling center was made.

The Master´s thesis concerns about the safety of tool grinder, and in the research part deals with the legislative requirements of the European Union and the Czech Republic. The basic legal provisions governing machinery manufacturers are described and analyzed here. The second part deals with the safety of tool grinder, risk analysis and proposal of preventive measures for risk reduction. The tool grinder is analyzed here and the results are summarized in the block diagram is drawn. Moreover, there are identified potential hazards for individual parts and the appropriate safety requirements are construed.

The main objective of this study is to learn about the audiovisual stimulator and to create hardware resolution of stimulation LED glasses and in environment of the program LabView application, which operate this stimulation LED glasses and in the same time create sound of stimulation. Use environment of the program LabView. Application, which is create in environment of the program LabView, enable operate stimulation LED glasses and arrange sound from three source with two different method, which use modern AVS. Application contains a lot of security, informative and agreement components.