Cross-cultural differences in the perception of pictorial material has long been established and documented. In the Republic of South Africa, which is increasingly globalized, and where it is appealing from financial, economic and training perspectives, the temptation is to use Western-based AAC symbol systems and strategies in intervention with clients from other language and cultural orientations. The aim of this study was to determine the translucency ratings of specific Blissymbols as rated by six-to seven-year-old Setswana-speaking children. A secondary aim was to determine whether the ratings changed after second and third exposures in order to determine the learnability of these symbols. A brief comparison was made between the results of the current study and the results reported in the Quist et al., study (1998). Thirty-five Setswana learners were exposed to 93 selected Blissymbols, based on a study by Quist et al., (1998). A three-point semantic differential scale, consisting of three faces accompanied each Blissymbol. Participants marked the face that best described his/her perception of the specific symbol’s iconicity. This procedure was repeated over a period of three days. The results indicated that the translucency ratings of the majority of the Blissymbols ranged from moderate to high. The research further demonstrated significant differences in translucency ratings between the first and second exposures, suggesting learning of the symbols. A smaller difference was noted between Days 2 and 3. A correlation in findings was noted between the current study and the Dutch and US studies (Quist et al., 1998). / Dissertation (M (Augmentative and Alternative Communication))--University of Pretoria, 2007. / Centre for Augmentative and Alternative Communication (CAAC) / MA / unrestricted

The largest software companies in the world are racing to develop their Intelligent Personal Assistants. Each with more and more capabilities and ways for users to access them. The different assistants have different capabilities and one of the ways the companies are differentiating is in the interaction techniques their assistants that are controlled with, most uses voice, and some uses text. This thesis walks through these interaction techniques, give a brief overview of intelligent personal assistants today and explores how learnability differentiate when using these interaction techniques. The thesis also investigates when users have access to multiple interaction techniques to use in combination when interacting with such an assistant. To evaluate the field, a literature study was conducted covering Intelligent Personal Assistants, interaction techniques, conversational user interfaces, modalities, multimodal interaction, voice and chat interfaces. Interviews with early adopters of Intelligent Personal Assistants was performed to better understand the current state of the technology and how users were using it. To evaluate the learnability differences in different interaction techniques, a series of user tests in a wizard-of-oz setup was conducted. In the user tests the different groups was using different interaction techniques to interact with their assistants. The main findings of the user tests was that there are indications to that the type of language used differs depending on the interaction techniques. Users who interact through voice is more prone to use a more natural language, while users using a chat interface quickly started to treat the interactions with the Intelligent Personal Assistant as commands. The result observed was that users who interacted with the assistant using chat and then switched to interacting through voice used a shorter, more command-like language when they interacted through voice as well.

No / This paper introduces a comparative multi-group study carried out to investigate the use of multimodal interaction metaphors (visual, oral, and aural) for improving learnability (or usability from first time use) of interface-design environments. An initial survey was used for taking views about the effectiveness and satisfaction of employing speech and speech-recognition for solving some of the common usability problems. Then, the investigation was done empirically by testing the usability parameters: efficiency, effectiveness, and satisfaction of three design-toolkits (TVOID, OFVOID, and MMID) built especially for the study. TVOID and OFVOID interacted with the user visually only using typical and time-saving interaction metaphors. The third environment MMID added another modality through vocal and aural interaction. The results showed that the use of vocal commands and the mouse concurrently for completing tasks from first time use was more efficient and more effective than the use of visual-only interaction metaphors.

Availability of internet to a wide audiences has revolutionized how business is performed. Businesses now use e-commerce to trade products and services. The growth of e-commerce has been dramatically rapid among developed countries. Therefore, the adoption of e-commerce platforms is studied in these countries. Meanwhile less attentions has been given to developing countries. Developing countries can take advantage of lessons learned in the developed countries. One of the major success factors of e-commerce platforms in developed countries is improving the usability of e-commerce platform by considering user’s preferences. User preferences can be defined as feelings and attitudes of users for the interface and functional design of the ecommerce platform. This influences user’s decision and behavior. Considering the users preferences within an e-commerce platform enhances user’s satisfaction and increases user’s loyalty to the platform. To evaluate the user preferences a selection of usability factors are usually studied. Avicenna Research Institute (ARI) is currently considering the development of an e-commerce platform. For this ARI is investigating ways to consider users preferences in the design. This study aims to satisfy this goal. In this study previous research are analyzed, user’s preferences are identified, common used e-commerce platforms are investigated, and ARI’s perspective is included in the analysis. Using these information a set of recommendations on how to improve the usability of an e-commerce platform is given. For this task based approaches are used in form of participatory heuristic evaluation and observations. Interview is used to obtain ARI’s perspective on usability. The study has identified ten usability factors affecting the usability of the e-commerce platform based on user’s preferences. These include consistency, learnability, navigability, simplicity, readability, content relevance, supportability, interactivity, credibility, and telepresence. In addition a set of eighty evaluation criteria are presented to evaluate these factors. Using a qualitative approach, the study has analyzed all these factors in a multiple-case study. The analysis includes input from the users in form of observations, comments and questionnaire. This is combined with input from ARI in form of interviews. Finally the study concludes by providing a path for future research.

This thesis presents three papers within the field of dynamic macroeconomics. The first paper, entitled “Medium-frequency cycles and the remarkable near trend-stationarity of output”, presents a dynamic stochastic general equilibrium model with endogenous growth, capable of reconciling the observed large medium-frequency fluctuations in output, with its long run (near) trend-stationarity. This requires a model in which standard business cycle shocks lead to highly persistent movements around trend, without significantly altering the trend itself. The robustness of the trend also requires that scale effects are eliminated both in the long and short runs. In an estimated version of the model, a financial-type shock to the stock of ideas emerges as the key driver of the medium frequency cycle. The second paper, entitled “Learning from learners”, is an intervention into two long running debates: the first, on whether learnability may be used to rule out explosive paths for inflation in New Keynesian models, and the second, into whether Taylor rule parameters may be identified from observing the data. We find that in an economy populated with traditional macroeconomic learners, Taylor rule parameters can always be identified by sophisticated econometric techniques. Furthermore, when all agents in the economy use such sophisticated techniques, stationary sunspot solutions are readily learnable, and there is no guarantee of convergence to a stationary solution even in the “determinate” case. This implies that learnability cannot be used for equilibrium selection. Finally, in the third paper, “Efficient simulation of DSGE models with inequality constraints” (joint with Michael Paetz), we present a new algorithm for the simulation of models subject to inequality constraints, such as the zero lower bound on nominal interest rates. Our algorithm is shown to deliver higher accuracy than all other non-global algorithms, and leading speed. We go on to provide a number of applications of our algorithm.

Les travaux présentés sont dédiés à la possibilité de faire de l'inférence statistique à partir de données séquentielles. Le problème est le suivant. Étant donnée une suite d'observations x_1,...,x_n,..., on cherche à faire de l'inférence sur le processus aléatoire ayant produit la suite. Plusieurs problèmes, qui d'ailleurs ont des applications multiples dans différents domaines des mathématiques et de l'informatique, peuvent être formulés ainsi. Par exemple, on peut vouloir prédire la probabilité d'apparition de l'observation suivante, x_{n+1} (le problème de prédiction séquentielle); ou répondre à la question de savoir si le processus aléatoire qui produit la suite appartient à un certain ensemble H_0 versus appartient à un ensemble différent H_1 (test d'hypothèse) ; ou encore, effectuer une action avec le but de maximiser une certain fonction d'utilité. Dans chacun de ces problèmes, pour rendre l'inférence possible il faut d'abord faire certaines hypothèses sur le processus aléatoire qui produit les données. La question centrale adressée dans les travaux présentés est la suivante : sous quelles hypothèses l'inférence est-elle possible ? Cette question est posée et analysée pour des problèmes d'inférence différents, parmi lesquels se trouvent la prédiction séquentielle, les tests d'hypothèse, la classification et l'apprentissage par renforcement.

Abstract in English and Afrikaans / The learnability principle relates to improving usability of software, performance and productivity. It was formulated mainly for the adult user group. Children represent an important user group, but fewer guidelines exist for their educational and entertainment applications. This study compares these groups, addressing the question: “Does learnability of software interfaces have a different meaning for children and adults?”. A literature survey conducted on learnability and learning processes considered the meaning of learnability across generations. Users learning software systems were observed in a usability laboratory where eye tracking data could also be recorded. Insights emerged, from data analysis, showing different tactics when children and adults approached unfamiliar software and revealing aspects of interfaces they approached differently. The findings will help designers distinguish varying needs of users and improve learnability. An additional subprinciple of learnability, „engageability‟, is proposed. Factors that make products engaging for children are different from those engaging adults. / Die leerbaarheidsbeginsel hou verband met die verbetering van die bruikbaarheid van sagteware, werkverrigting en produktiwiteit. Dit was hoofsaaklik vir die volwasse gebruikersgroep geformuleer. Kinders verteenwoordig in belangrike gebruikersgroep, maar minder riglyne is vir hulle opvoedkundige en vermaaktoepassings beskikbaar. Hierdie studie vergelyk hierdie groepe en speek die volgende vraag aan: “Het leerbaarheid van sagtewarekoppelvlakke verskillende betekenisse vir kinders en volwassenes?” „n Literatuuroorsig oor leerbaarheid en leerprosesse is uitgevoer met in ag neming van die betekenis van leerbaarheid vir verskillende generasies. Gebruikers is waargeneem in „n bruikbaarheidslaboratorium terwyl hulle geleer het om sagetware te gebruik. Data in verband met oogbewegings op die skerm is ook opgeneem. Insigte wat uit die data-analise te voorskyn gekom het toon verskillende taktieke wanneer kinders en volwassenes met onbekende sagteware gekonfronteer word. Hulle benadering tot sekere aspekte van „n koppelvlak verskil. Die bevindinge sal ontwerpers help om te onderskei tussen wisselende gebruikersbehoeftes. „n Addisionele sub-beginsel van leerbaarheid, naamlik „engageability‟ word voorgestel. Faktore wat „n produk aantreklik maak vir kinders is verskillend van dit wat volwassenes aantrek. / Information Systems / M. Sc. (Information Systems)

The need to learn programming increases as more jobs require basic programming skills and computer knowledge. Compulsory school is adding programming to the curriculum, which leads to challenges due to both teachers and students are new to this subject. Even at the university level some students get in touch with programming for the first time in their lives.  This thesis aim to develop a web application that can be used by teachers as a reliable and informative tool when evaluating the learning process of its students, by combining data collected through user interactions while solving programming related puzzles in Python, with answers from periodic self-evaluation surveys.  The study shows that the web application can be seen as a valid tool when evaluating the students' learning process.

In the aviation industry, digitally produced and presented flight, navigation, and aircraft information is commonly referred to as glass flight decks. Glass flight decks are driven by computer-based subsystems and have long been a part of military and commercial aviation sectors. Over the past 15 years, the General Aviation (GA) sector of the aviation industry has become a recent beneficiary of the rapid advancement of computer-based glass flight deck (GFD) systems. While providing the GA pilot considerable enhancements in the quality of information about the status and operations of the aircraft, training pilots on the use of glass flight decks is often delivered with traditional methods (e.g. textbooks, PowerPoint presentations, user manuals, and limited computer-based training modules). These training methods have been reported as less than desirable in learning to use the glass flight deck interface. Difficulties in achieving a complete understanding of functional and operational characteristics of the GFD systems, acquiring a full understanding of the interrelationships of the varied subsystems, and handling the wealth of flight information provided have been reported. Documented pilot concerns of poor user experience and satisfaction, and problems with the learning the complex and sophisticated interface of the GFD are additional issues with current pilot training approaches. A case study was executed to explore ways to improve training using GFD systems at a Midwestern aviation university. The researcher investigated if variations in instructional systems design and training methods for learning glass flight deck technology would affect the perceptions and attitudes of pilots of the learnability (an attribute of usability) of the glass flight deck interface. Specifically, this study investigated the effectiveness of scenario-based training (SBT) methods to potentially improve pilot knowledge and understanding of a GFD system, and overall pilot user experience and satisfaction. Participants overwhelmingly reported positive learning experiences from scenario-based GFD systems flight training, noting that learning and knowledge construction were improved over other training received in the past. In contrast, participants rated the usability and learnability of the GFD training systems low, reporting various problems with the systems’ interface, and the learnability (first-time use) of the complex GFD system. However, issues with usability of the GFD training systems did not reduce or change participant attitudes towards learning and mastering GFD systems; to the contrary, all participants requested additional coursework opportunities to train on GFD systems with the scenario-based flight training format.

Teachers have demanding jobs in often stressful, high-paced work environments with heavy workloads. This has been shown to have negative consequences on health and job retention. This study aimed to ease the burden teachers experience in at least one area of their jobs – formative assessments. This was done by developing a timesaving design framework based on the insights gained from language teachers’ formative assessment practices which center on translanguaging, or strategic principles for using multilingualism in teaching. The framework, grounded in researched UX and UI design principles that reduce cognitive load, was used to create a rubric-based digital formative assessment (DFA) translanguaging tool prototype that was then tested for its impact on teacher workload. The results indicated that the developed DFA tool had the potential to reduce teacher workload with relatively high user satisfaction. One of the most significant findings from the study was that the learnability design principle had the greatest impact on the timesaving design framework. Further findings show that the DFA tool may be most effective if used in conjunction with other more traditional formative assessment processes. This study benefits teachers who use or want to use DFA tools, but mostly developers and designers who want to create more efficient systems using timesaving design principles. This study’s contribution is a timesaving design framework, which can be used to design and build DFA tools for translanguaging learning development.