The objective of this dissertation is to investigate the factors that influence the design of wide-area wavelength division multiplexing (WDM) optical networks. Wide-area networks are presented as communication networks capable of transporting voice and data communication over large geographical areas. These networks typically span a whole country, region or even continent.The rapid development and maturation of WDM technology over the last decade have been well-received commercially and warrants the development of skills in the field of optical network design.The fundamental purpose of all communication networks and technologies is to satisfy the demand of end-users through the provisioning of capacity over shared and limited physical infrastructure. Consideration of the business aspects related to communications traffic and the grooming thereof are crucial to developing an understanding of customer requirements in terms of the selection and quality of services and applications. Extensive communication networks require complex management techniques that aim to ensure high levels of reliability and revenue generation.An integrated methodology is presented for the design of wide-area WDM optical networks. The methodology harnesses physical, logical, and virtual topologies together with routing and channel assignment (RCA) and clustering processes to enhance objectivity of the design process. A novel approach, based on statistical clustering using the Ward linkage as similarity metric, is introduced for solving the problem of determining the number and positions of the backbone nodes of a wide-area network, otherwise defined as the top level hub nodes of the multi-level network model. The influence of the geographic distribution of network traffic, and the intra/inter-cluster traffic ratios are taken into consideration through utilisation of modified gravity models and novel network node weighting. / Dissertation (MEng)--University of Pretoria, 2005. / Electrical, Electronic and Computer Engineering / unrestricted

The thesis "Extending the methodology MMSP in test analysis and design" characterizes the discipline of test analysis and design carried out by its inclusion in the Methodology for small software projects (MMSP). The theoretical part defines the concept of discipline Test analysis and design and characterizes its role in the context of software testing and use in developing software products. It also analyzes attitude of commonly known models and methodologies of software development, certification, standards and norms in testing methodology including MMSP to the analytical activities in the field of testing. The practical part describes the methodology MMSP extension by discipline Test analysis and design, which allows the use of this discipline even on small projects developing uncritical IS/ICT solutions, which previously was not possible. Discipline Test analysis and design expands MMSP at considerable amount of analytical activities in the area of testing. Extending the methodology MMSP includes the introduction of new role Test analyst, modification of existing roles, the introduction of new products and descriptions of the recommended testing techniques and test design.

The overall objective of this study was to develop an optimised Ultra-High-Performance Concrete (UHPC) matrix based on the modified Andreasen and Andersen optimum particle packing model by using available South African materials. The focus of this study was to determine the optimum combined fibre and superplasticiser content for UHPC by using a response surface design. The UHPC was appropriately designed, produced and tested. Various changes in mechanical properties resulting from different combinations of steel fibre and superplasticiser contents was investigated. The flowability, density and mechanical properties of the designed UHPC were measured and analysed. Both the fibre and superplasticiser content play a significant role in the flowability of the fresh concrete. The addition of fibres significantly improved the strength of the concrete. The results show that the superplasticiser content can be increased if a more workable mix is required without decreasing the strength significantly. The statistical analysis of the response surface methodology confirms that the designed models can be used to navigate the design space defined by the Central Composite Design. The optimum combined fibre and superplasticiser content depend on the required mechanical properties and cost. Using the modified Andreasen and Andersen particle packing model and surface response design methodology, it is possible to efficiently produce a dense Ultra-High-Performance Fibre Reinforced Concrete (UHPFRC) with a relatively low binder amount, low fibre content and good workability. The effect of heat curing on the mechanical properties was investigated. It was concluded that heat curing is not recommended when considering the long-term strength development. The estimated strength development of concrete obtained by using the fib Model Code 2010 (2013) does not incorporate the detrimental effect of high curing temperatures on long-term strength and therefore overestimate the long-term strengths. The strength estimates for both early and long-term ages can be improved by considering this effect in the strength development functions obtained from fib Model Code 2010 (2013). The effect of specimen size on the compressive and flexural tensile strength of UHPFRC members were established. It was found that the specimen size has a significant effect on the measured cube compressive strength. Smaller beam specimens showed higher ductility compared to those of the larger beam specimens. The crack width decreased as the beam’s depth decreased. A lower variability was experienced in the beams with limited depth (< 45 mm). Further testing is required to determine whether a span-to-depth ratio of 10 would yield optimum results. The utilisation of by-products, such as undensified silica fume and fly ash, as cement replacement materials makes UHPFRC sustainable, leading to a reduced life-cycle cost. The calculated Embodied Energy per unit strength (EE/unit strength) and Embodied Carbon per unit strength (EC/unit strength) values for the UHPFRC mixture yield lower values compared to that of the 30 MPa concrete mixture, indicating that UHPFRC can be used to reduce the environmental footprint of the concrete industry. The inverse analysis method used was successful in providing an improved simplified stress-strain response for the UHPFRC. The analysis provided valuable information into the stress-strain, load-deflection and moment-curvature responses of the UHPFRC. Standard material test results were used to theoretically calculate moment-curvature responses and were then compared to the experimental results obtained. The study demonstrated that it is possible to efficiently produce a dense and workable UHPFRC with relatively low binder amount and low fibre content. This can result in more cost-effective UHPFRC, thus improving the practical application thereof. / Dissertation (MEng)--University of Pretoria, 2020. / Civil Engineering / MEng (Structural engineering) / Unrestricted

At one point or another we have all felt overwhelmed or stressed. It is part of human nature and can at times be beneficial as it can boost our performance and make us more alert. However when it becomes a part of daily life to worry about everything, it turns into a hindrance. This is where Iyashikei, the japanese word referring to the feeling of calm and relaxed, comes into play. We explore what makes a medium “Iyashikei” and define a design methodology based on those findings. The design methodology consists of three parts in which feelings and Iyashikei have been the main focus when deciding what to include. This design methodology is then evaluated by using it to design a game. The game is a small proof of concept design and can be expanded upon further to increase its calming effect. However we believe that it is sufficient as proof of concept.

Three-dimensional literature is a virtually non-existent or in any case very rare and emergent digital art form, defined by the author as a unit of text, which is not confined to the two-dimensional layout of print literature, but instead mediated across all three axes of a virtual space. In collaboration with two artists the author explores through a bodystorming workshop how writers and readers could create and experience three-dimensional literature in mixed reality, by using mobile devices that are equipped with motion sensors, which enable users to perform embodied interactions as an integral part of the literary experience.For documenting the workshop, the author used body-mounted action cameras in order to record the point-of-view of the participants. This choice turned out to generate promising knowledge on using point-of-view footage as an integral part of the methodological approach. The author has found that by engaging creatively with such footage, the designer gains a profound understanding and vivid memory of complex design activities.As the outcome the various design activities, the author developed a concept for an app called TEXTILE. It enables users to build three-dimensional texts by positioning words in a virtual bubble of space around the user and to share them, either on an online platform or at site-specific places. A key finding of this thesis is that the creation of three-dimensional literature on a platform such as TEXTILE is not just an act of writing – it is an act of sculpture and an act of social performance.

This dissertation aims to understand the female Saudi mathematics teachers' formative assessment practices after coming back to in-person instruction and the impact of such practices on female student attitudes toward learning mathematics. The study was conducted in two middle schools located in the North and South districts of a large city in Saudi Arabia, using a sequential mixed study design methodology . The study's sample included 4 female mathematics teachers and 104 8th grade mathematics female students. For the qualitative research design, I conducted four interviews and used the NVivo program to thematically analyze my results. Additionally, I used AssessToday observational protocol to conduct 12 observations (three per teacher) and triangulated to analyze the data, including my filled notes, lessons audio recordings, and photos. For my quantitative design, I administered the Attitudes Towards Mathematics Inventory (ATMI) Scale to 104 8th-grade mathematics female students in a pre- and post-survey and I performed a confirmatory factor analysis (CFA) to assess the internal structure of my data. Overall, the study revealed that despite teachers' claims of practicing formative activities, their actual practices may not reflect it. The study confirmed the literature that using AssessToday is applicable regardless of the location, culture, language, and education system. The study contributes to short-cycle formative assessment literature by showing a positive and linear relationship (although not statistically significant) between teacher's use of formative assessment and students' attitudes toward learning mathematics.

The research is conducted in the area of Software Engineering, with emphasis on the design phase of the Software Development Life Cycle (SDLC). The object-oriented paradigm is the point of departure. The investigation deals with the problem of creating support for the design phase of object-oriented system development. This support must be able to guide the system designer through the design process, according to a sound design method, highlight opportunities for prototyping and point out where to re-iterate a design step, for example. A solution is proposed in the form of a knowledge-based support system. In the prototype this support guides a designer partially through the first step of the System Design task for object-oriented design. The intention is that the knowledge-based system should capture the know-how of an expert system designer and assist an inexperienced system designer to create good designs. / Computing / M. Sc. (Information Systems)

Die Konferenz Entwerfen – Entwickeln – Erleben bietet ein besonderes Podium zum Austausch von Wissenschaftlern und Praxisvertretern aus den zentralen Bereichen der Produktentwicklung. Der vorliegende Band enthält Beiträge der EEE2016 unter anderem zu Industrie 4.0, Cyber-Physical Systems und Virtual Reality in vielfältigen Anwendungsbereichen des Maschinenbaus, zu Innovationsmanagement, Konstruktionsmethodik und Product Lifecycle Management sowie zu Reverse Engineering und generativen Verfahren. Die Technische Universität Dresden und technischesdesign.org ermöglichten in Kooperation mit der Gruppe Virtuelle Produktentwicklung der Wissenschaftlichen Gesellschaft für Produktentwicklung (WiGeP) und dem Rat für Formgebung die fachübergreifende Diskussion des Schwerpunkt- Themas inmitten der interdisziplinären Dresdner Wissenschaftslandschaft. In diesem Band sind die Beiträge zur Konstruktionstechnik und zur Virtuellen Produktentwicklung enthalten, ein weiterer Band (ISBN 978-3-95908-061-3, herausgegeben von Jens Krzywinski et al.) fasst die Beiträge zum Industrial Design zusammen.

Designers often look for inspiration in their environment when exploring possible solutions to a given problem. However, many studies have reported that external stimuli may constrain designers’ imagination and limit their exploration to similar solutions, a phenomenon described as design fixation. Inspiration and fixation effects are traditionally studied with a similar experimental paradigm, which has produced a complex web of findings and explanations. Yet, when analysing the experiments and their findings closely, it becomes clear that there is considerable variation in how studies are conducted and the results they produce. Such variation makes it difficult to formulate a general view of how external stimuli affect the design process, and to translate the research findings into education and practice. Moreover, it raises questions about the reliability and effectiveness of the traditional experimental method. This thesis reports on a collection of studies that examine how design inspiration and fixation research is done and how it can be improved. It explores the research area by reviewing the literature and analysing data from a workshop; describes the research method by scrutinising experiments and their procedures; and explains the variation in research findings by testing experimental procedures empirically and suggesting new interpretations. My main findings are that: abstract stimuli can inspire or fixate designers to different degrees depending on how explicitly the stimuli are represented; external stimuli can inhibit the exploration of ideas that would otherwise be explored; the effect of experimental instructions varies depending on how encouraging the instructions are; and the way participants represent and elaborate ideas can moderate fixation results. Whilst this thesis offers insights into design practice and education, its main contribution is to design research, where it represents a fundamental material for those who are new to inspiration and fixation research, and for those who are already expert.

Le transport et la distribution de l'énergie électrique sont traditionnellement réalisés en alternatif (50 Hz ou 60 Hz), un des éléments-clés de ces infrastructures est le transformateur de puissance. Ce dernier est utilisé depuis plus d'un siècle et donc sa conception est maîtrisée (avec des rendements très élevés, supérieurs à 99 %). Depuis quelques années, la part des énergies renouvelables est en constante augmentation. Bien souvent, la production des énergies renouvelables est éloignée des centres de consommation. Or, le transport en courant continu sous haute tension (HVDC) sur de grandes distances est plus rentable. Dans ce cas, nous avons besoin de convertisseurs de puissance fonctionnant pour certains avec des Transformateurs Moyennes Fréquences (TMF) entre 1 kHz et quelques dizaines de kilohertz. Dans ces applications, la recherche du rendement maximal est primordiale. L'augmentation de la fréquence de fonctionnement a pour effet bénéfique de diminuer l'encombrement d'un transformateur. Cependant un certain nombre de problèmes vont apparaître avec cette augmentation. Nous pouvons citer : les pertes dans les conducteurs et dans le circuit magnétique sont liées à la fréquence ; le type de bobinages (fil de Litz et feuillard) et les matériaux magnétiques (ferrites et nanocristallins) en moyennes fréquences sont différents de ceux utilisés en 50 Hz ; le refroidissement est plus complexe car la densité de puissance volumique est plus élevée... Ainsi dans cette thèse, nous avons mis en place une méthodologie de conception afin de maîtriser au mieux le dimensionnement d'un TMF avec un compromis précision et coût de calculs. Nous avons identifié les modèles (analytiques et numériques) susceptibles d'être utilisés pour estimer les performances d'un TMF. Deux TMF d'une puissance de 180 kVA et de 1 kVA ont été dimensionnés, fabriqués et testés afin de mettre en évidence le domaine de validité et d'ajuster les différents modèles. Ce travail nous a permis de mettre en place une méthodologie de conception allant des spécifications du convertisseur jusqu'à la simulation de celui-ci avec le modèle du transformateur dimensionné. Nous avons mis en évidence : l'influence de paramètres technologiques sur l'élévation de la résistance pour des bobinages de type feuillard et l'influence de paramètres technologiques sur les propriétés magnétiques des matériaux nanocristallins. Ce travail de thèse a été réalisé avec le groupe « Matériaux du Génie Electrique » du laboratoire Ampère et financé par l'institut pour la transition énergétique SuperGrid Institute / The transmission and distribution of electric power is normally made by ac networks (50 Hz or 60 Hz), where one of the key elements of this infrastructure is the power transformer; used for more than a century, its design is very well understood, with a level of operating efficiency normally greater than 99%. In recent years, the share of renewable energy has been increasing. Often times the energy generated from renewable sources is produced far from consumption centers, and so transportation in the form of high voltage direct current (HVDC) over long distances is more profitable, due to the lower losses seen than with HVAC after a certain length of transmission line. In this case, we need power converters operating with Medium Frequency Transformers (MFT) from 1 kHz to tens of kilohertz. For these applications, the research of their maximum efficiency in operation is paramount. Increasing the transformer operating frequency has the beneficial effect of reducing its size. However, a number of problems will appear with this frequency increase, such as: the increase in the losses in the conductors and the magnetic circuit that are related to the frequency; the less well understood winding type (Litz wire and foil) and magnetic materials (ferrites and nanocrystalline) in the MF that are different from those used at 50 Hz; the cooling is more complex because the power density is higher, etc. In this thesis, a design methodology was developed in order to optimise the design of MFTs with respect to the compromise between accuracy and the length of calculations. In addition, analytical and numerical models were identified that can be used to accurately estimate the performance of an MFT. Furthermore, two MFTs (apparent power: 180 kVA and 1 kVA, respectively) were sized, manufactured and tested in order to demonstrate the domain of validity of the models, and also for optimisation of the different models. This work has enabled the development of a design methodology using the converter specifications and build a simulation with complete model of the transformer, which can then be used to validate an MFT design. We have highlighted: the influence of the technological parameters on the rise of resistance in the foil coils and the influence of the technological parameters on the magnetic properties of nanocrystalline materials. This work was performed with the group "Materials for Electrical Engineering" Ampère laboratory and funded by the Institute for Energy Transition SuperGrid Institute.