Within the nuclear industry there is an extensive need for evaluation of the safety of the plant. In such evaluations there is one phenomenon requiring some particular treatment, namely common cause failure (CCF). This involves the occurrences of components failing dependently, meaning failures that can overcome the applied redundancy or diversity. The impact of CCF is relatively large, but unfortunately the process of CCF analysis is complicated by the complex nature of CCF events and a very sparse availability of CCF data. Today, there are a number of methods for CCF analysis available with different characteristics, especially concerning their qualitative and quantitative features. The most common working procedure for CCF treatment is to divide the analysis in a qualitative and a quantitative part, but unfortunately the development of tools for the qualitative part has to a certain extent got behindhand. This subject is further explored in a comparative study focused on two totally different approaches for CCF analysis, the impact vector method and the unified partial method. Based on insights from this study an integrated impact vector and ‘Relations of Defences, Root causes and Coupling factors’ (RDRC) methodology is suggested to be further explored for progress towards a methodology incorporating both qualitative and quantitative aspects.

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Thesis (M.S.)--California State University, Dominguez Hills, 1998. / Typescript (photocopy). "Spring 1998." Includes bibliographical references (leaf 39) and abstract.

Thesis (MTech (Business Information Systems))--Cape Peninsula University of Technology, 2016. / The aim of this research project was to determine what the degree of usability is of a sample of online reservation systems of Cape Town hotels. The literature has indicated that the main aim of website usability is to make the engagement process with a website a more efficient and enjoyable experience. Researchers noted that well designed, high-quality websites, with grammatically accurate content, create a trustworthy online presence. User-friendly sites also attract far more traffic. Previous research has also shown that a loss of potential sales is possible due to users being unable to find what they want, if poor website design has been implemented. Loss of potential income through repeat visits is also a possibility, due to a negative user experience. The research instrument that was employed in this research is usability testing. It is a technique used to evaluate product development that incorporates user feedback in an attempt to create instruments and products that meet user needs, and to decrease costs. The research focused on Internet-based hotel reservation systems. Only the usability was measured. Both standard approaches were used in this research project, in a combined quantitative and qualitative research design. In conclusion, the purpose of this research was to determine the degree of usability of specified Cape Town hotel online reservation systems. The outcomes of this study indicated interesting patterns in that reservation systems met user requirements more often than expected. However, the figures of acceptability obtained were still below the generally accepted norms for usability. The amount of time spent to complete a booking also decreased, as users worked on more than one reservation system.

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The vehicle routing problem (VRP) determines preferred vehicle routes to visit multiple customer locations from a depot location based on a defined objective function. The VRP is an NP-hard network optimization problem that is challenging to solve to optimality. Over the past 60 years, multitudes of heuristics and metaheuristics have been developed in order to minimize the computational burden of solving the VRP. In order to compare the performance of VRP heuristics, researchers have developed bench-marking datasets. These datasets, however, lack properties found in industry datasets. In this dissertation, we explore how properties of industry datasets influence VRP heuristics and objective functions. In Chapter 2, we quantify and compare features of bench-marking and industry datasets. In order to determine if these features influence heuristic performance, we conduct extensive computational runs on three heuristics, Tabu Search, Genetic Algorithm, and Clarke-Wright Savings Procedure, on standard and industry datasets. In Chapter 3, we derive worst-case analysis on how VRP objective functions and metrics relate to one another. These bounds depend on properties of customer locations. These bounds illustrate how customer locations can influence how different routes behave for different routing metrics. Finally, in Chapter 4, we improve two VRP heuristics, Clarke-Wright Saving Procedure and Hybrid Genetic Search Algorithm, by developing new enhancements to the algorithms. These enhancements rely on certain properties of the datasets in order to perform well. Thus, these heuristics perform better on specific VRP dataset types. / Doctor of Philosophy / The vehicle routing problem (VRP) creates vehicle routes that have the shortest travel distance. The routes determine how vehicles should visit multipl customer locations, to deliver or pickup goods, and return to a depot location. While explaining what the VRP entails is simple, the VRP is actually very difficult for even the most sophisticated algorithms on the best computers to solve. Over the past 60 years, many algorithms have been developed in order to more easily and quickly solve the VRP. In order to compare the performance of VRP algorithms, researchers have developed bench-marking datasets. However, these datasets lack properties of datasets found in industry. In this dissertation, we look to connect the disconnect between industry and bench-marking datasets by 1) comparing feature differences between these two types of datasets, 2) determining if differences in datasets imply differences in algorithm performance, 3) proving how problem differences influence VRP routes, and 4) enhancing existing VRP algorithms to perform better on specific VRP dataset types.

Thesis (MBA (Business Management))--University of Stellenbosch, 1996. / ENGLISH ABSTRACT: The ferroalloy industry is, in contrast to the operationally complicated chemical industry, very reliant on the wealth of experience that has been built up by the operating personnel over a long period of time. The industry has not been at the forefront of technical development and has, in many respects, lagged behind in technological development. Information technology is one such area that has not received its fair share of attention. This study resulted from the requirement that the control systems of the submerged arc furnaces at the Samancor Meyerton Works be integrated in such a way that the plant subsystem controllers could operate off a single database. This would ensure that the reliance of the operation on the experience of personnel could be reduced by the judicious application of data from the process. The integration was expanded to include the control of the electricity generation plant that will utilize the waste gasses from the submerged arc furnaces to generate the electricity. The boundaries of the study were subsequently expanded to include a proposal for the integration of the control systems into a management information system for the Meyerton Works. The study gives consideration to the theory underlying management information systems after the strategic issues of the Manganese Division of Samancor are discussed. The theoretical aspects of management information systems together with the strategic issues of the Manganese Division are brought together to form the practical proposal of the integrated control and management information system. The case studies considered are based on two incidents that occurred on one of the submerged arc furnaces where the resulting financial losses were substantial. An integrated control system would have reduced the financial losses significantly. Finally, the recommendations of the study are firstly, that the management information system as proposed be expanded to include the furnaces that were not originally envisaged to have their control systems integrated, secondly that the maintenance management function be integrated with the control systems and management information system, and finally that the production planning system be included in the management information system so as to give substance to the control and optimization of the flow of manganese units from the mines to the customer. This will entrench the position of Samancor as a world class supplier of manganese units. / AFRIKAANSE OPSOMMING: Die ferroallooi industrie is, in teenstelling met die chemiese nywerheid wat 'n ingewikkelde bedryf het, afhanklik van die ondervinding van personeel wat oor 'n lang tyd opgebou is. Die industrie was nie 'n baanbreker ten opsigte van tegniese ontwikkeling nie en het ook grotendeels agtergebly op die gebied. Inligting tegnologie is een van die gebiede wat nie die gewensde hoeveelheid aandag gekry het nie. Hierdie studie het sy oorsprong gehad in die behoefte om die beheer sisteme van die dompelboog oonde van die Meyerton Werke van Samancor te integreer sodat die beheerders van die subsisteme van aanleg vanaf 'n enkele databasis kon funksioneer. Dit sou die resultaat gehad het om die afhanklikheid van die bedryf op die ondervinding van die personeel te verminder. Die integrasie gedagte was uitgebrei om die beheer van die elektrisiteits opwekkings aanleg, wat die afgase van die oonde gebruik, in te sluit. Die afbakening van die studie was later verbreed om te dien as 'n voorstel vir die integrering van die beheersisteme in 'n bestuursinligting stelsel vir die Meyerton Werke. Nadat die strategiese aangeleenthede van die Mangaan Afdeling aandag geniet, word die teorie aangaande bestuursinligting stelsels bespreek. Die teorie van die bestuursinligting stelsels en die strategiese aangeleenthede van die Mangaan Afdeling word bymekaar gebring om die voorstel van die geintegreerde beheer sisteem en bestuursinligting stelsel te vorm. Die gevallestudies wat bespreek is, is gebaseer op twee insidente wat op een van die oonde gebeur het waar daar geweldige finansiele verliese was. Geintegreerde beheer stelsels sou die verliese beperk het. Die aanbevelings wat gemaak is, is eerstens dat die bestuursinligting stelsel soos voorgestel is uitgebrei word om die oonde waar die beheerstelsels nie oorspronlik geintegreer sou wees in te sluit, tweedens dat die instandhouding bestuursstelsel geintegreer word met die bestuursinligting stelsel, en derdens dat die produksiebeplanning stelsel in die bestuursinligting stelsel gesluit word. Hierdeur sal die beweging van mangaan eenhede vanaf die myne na die kliente geoptimiseer word om Samancor se posisie as 'n wereld klas verskaffer van mangaan eenhede te verstewig.