Since the development of the Internet, the amount of individuals and organisations making use of the World Wide Web (or Web) has grown significantly, and it is likely to continue increasing as the world continues to become intertwined. With the Internet, users are able to conduct various activities online, one being online shopping which has changed the retailing sector. Online shoppers are able to purchase goods and services over the Web in the comfort of their own homes without having to set foot into a physical store. Due to the fact that greater numbers of South African consumers are becoming accustomed to online shopping and the number of online retailers is growing, there is a need to determine which quality factors of websites influence these consumers when shopping online, which is the primary purpose of this study. A broad and in-depth literature review was provided on online shopping as well as the website quality factors influencing online shopping. An empirical study was conducted, where the data were collected from South Africans who met the requirements by means of an Internet-based self-administered questionnaire. The study followed a quantitative approach in order to satisfy the research objectives of the study. Based on the research results, it was found that all system, information and service quality factors influence respondents when shopping online and therefore need to be taken into consideration by online retailers when developing shopping sites. / Business Management / M. Com. (Business Management)

abstract: Microwave properties of low-loss commercial dielectric materials are optimized by adding transition-metal dopants or alloying agents (i.e. Ni, Co, Mn) to tune the temperature coefficient of resonant frequency (τf) to zero. This occurs as a result of the temperature dependence of dielectric constant offsetting the thermal expansion. At cryogenic temperatures, the microwave loss in these dielectric materials is dominated by electron paramagnetic resonance (EPR) loss, which results from the spin-excitations of d-shell electron spins in exchange-coupled clusters. We show that the origin of the observed magnetically-induced shifts in the dielectric resonator frequency originates from the same mechanism, as described by the Kramers-Kronig relations. The temperature coefficient of resonator frequency, τf, is related to three material parameters according to the equation, τf = - (½ τε + ½ τµ + αL), where τε, τµ, and αL are the temperature coefficient of dielectric constant, magnetic permeability, and lattice constant, respectively. Each of these parameters for dielectric materials of interest are measured experimentally. These results, in combination with density functional simulations, developed a much improved understanding of the fundamental mechanisms responsible for τf. The same experimental methods have been used to characterize in-situ the physical nature and concentration of performance-degrading point defects in the dielectrics of superconducting planar microwave resonators. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2016

In recent years, the number of digital services and tools available has increased rapidly. When companies want to digitalize their business, they have the opportunity to browse a large number of existing platforms and applications available on the market to find a good match for their specific needs. However, when a company wishes to digitalize a work task that already has a well-established workflow, problems may arise. Due to this, a tailored digital solution may in some cases be the better suited option, rather than the ones available on the market.  The intention of this work was to investigate the challenges that companies face in relation to digitalization of the workplace in general, and the challenges of a company’s expense management process in particular. As an example of how a workplace digitalization can take place, a collaboration with a forest industry company was conducted. An evaluation of their analog and internal expense management process was done, where the found challenges were assessed with respect to chosen quality factors. The evaluation and the found challenges regarding digitalization constituted the basis for a process mapping and a digital solution aiming to improve the company’s expense management process. The resulting work emphasizes how a digital solution can be tailored with simple means within a limited time frame, taking specific needs and existing challenges into account in order to digitalize the workplace. In addition, the work presents what challenges that exists within the concept of digitalizing the workplace and regarding expense management, and how quality factors can be used in combination with a process improvement in order to relieve and eliminate them.

Tracking and tracing are a key technology for production process optimization and subsequent cost reduction. However, several industrial environments (e.g. high temperatures in metal processing) are challenging for most part-marking and identification approaches. A method for printing individual part markings on metal components (e.g. data matrix codes (DMCs) or similar identifiers) with high temperatures and chemical resistance has been developed based on drop-on-demand (DOD) print technology and special ink dispersions with submicrometer-sized ceramic and glass particles. Both ink and printer are required to work highly reliably without nozzle clogging or other failures to prevent interruptions of the production process in which the printing technology is used. This is especially challenging for the pigmented inks applied here. To perform long-term tests with different ink formulations and to assess print quality over time, we set up a test bench for inkjet printing systems. We present a novel approach for monitoring the printhead’s state as well as the print-quality degradation. This method does not require measuring and monitoring, e.g. electrical components or drop flight, as it is done in the state of the art and instead uses only the printed result. By digitally quantifying selected quality factors within the printed result and evaluating their progression over time, several non-stationary measurands were identified. Some of these measurands show a monotonic trend and, hence, can be used to measure print-quality degradation. These results are a promising basis for automated printing system maintenance.

The focus of the dissertation is on software quality assurance for object-oriented information systems development. A Quality Assurance Reference Model is proposed with aspects dealing with technical and managerial issues. A revised Spiral life cycle model is adopted as well as the Object Modelling Technique. The Quality Assurance Reference Model associates quality factors at various levels, quality criteria and metrics into a matrix framework that may be used to achieve quality assurance for all cycles of the Spiral Model. / Computing / M. Sc. (Information Systems)

The focus of the dissertation is on software quality assurance for object-oriented information systems development. A Quality Assurance Reference Model is proposed with aspects dealing with technical and managerial issues. A revised Spiral life cycle model is adopted as well as the Object Modelling Technique. The Quality Assurance Reference Model associates quality factors at various levels, quality criteria and metrics into a matrix framework that may be used to achieve quality assurance for all cycles of the Spiral Model. / Computing / M. Sc. (Information Systems)

Les résonateurs à modes de galerie sont des cavités diélectriques qui supportent des modes à très haut facteur de qualité et à faible volume qui demeurent confinés à l'interface air-diélectrique pour des durées pouvant atteindre voire dépasser la microseconde. L'intérêt de ce fort confinement des modes pour de longues durées est l'accentuation de l'interaction lumière-matière. Par conséquent, de nombreuses interactions non-linéaires telles que l'effet Kerr ou encore l'effet Brillouin à des puissances seuil inversement proportionnelles au carré voire au cube du facteur de qualité du résonateur ont lieu en son sein. Ces propriétés donnent accès à de nombreuses applications dans des domaines divers et variés tels que la spectroscopie, les télécommunications ou encore les micro-ondes. Les travaux de cette thèse ont pour but d'exploiter les non-linéarités Kerr et Brillouin dans les résonateurs à mode galerie à la longueur d'onde de 1550 nm afin de générer des micro-ondes ultra-stables à des fréquences comprises entre 5 et 30 GHz. Le premier chapitre introduit la théorie, la fabrication, le couplage et la caractérisation de résonateurs à des modes de galerie. Le second chapitre concerne la génération de micro-ondes. Nous y présentons nos résultats expérimentaux, la modélisation numérique de peignes de Kerr, ainsi que l'analyse d'instabilités oscillatoires d'origine thermique observées lors de nos travaux expérimentaux, puis nous concluons. Le dernier chapitre traite de l'interaction photons-phonons via le processus de diffusion Brillouin stimulée dans ces mêmes expérimentaux ainsi que le modèle temporel que nous avons développé pour suivre la dynamique de l'onde transmise et de celle rétrodiffusée. Le dernier chapitre conclue nos travaux. Les travaux présentés dans ce manuscrit ont été financé par l'European Research Council dans le cadre du projet NextPhase. / Whispering galery mode resonators are dielectric cavities that support modes with ultra-high quality factor and small volume that remain confined in their inner periphery for time duratioons that can be as long as few microseconds. The strong confinement of these modes for such long durations strongly enhances nonlinear effect suchs as Kerr effect or Brillouin effect. These resonators can therefore be used for several applications such as spectroscopy, telecommunications or microwave generation. The objective of this thesis is to use Kerr and Brillouin nonlinearities in these resonators at the laser wavelength of 1550 nm, in order to generate high spectral purity microwave signals with frequencies rangong fros 5 to 30 GHz. The first chapter oh the thesis intriduces the theory, fabrication, coupling and characterisation of whispering gallery mode resonators. The second chapter is about the generation of Kerr optical frequency combs in these resonators and their application to the generation of microwave signals. We present our experimental resuktsdn the numerical modelling of Kerr combs, the analysis of oscillatory instabilities (due to thermal effect) observed during our experiments, and conclue. The third chapter concerns photon-phonon interactions via stimulated Brillouin scattering in these resonators and their application to the generation of microwave signals. We present our experimental results and the temporal model that we developed to track the dynamics of the forward and backscattered fields. The last chapter conclude the thesis. The research presented in this thesis has benne funded by the European Research Council through the project Nextphase.