A common way of organizing Windows, Icons, Menus, and Pointers (WIMP) interfaces is to group tools into tool containers, providing one visual representation. Common tool containers include toolbars and menus, as well as more complex tool containers, like Microsoft Offices Ribbon, Toolglasses, and marking menus. The location of tool containers has been studied extensively in the past using Fittss Law, which governs selection time; however, selection time is only one aspect of user performance. In this thesis, I show that tool container location affects other aspects of user performance, specifically attention and awareness. The problem investigated in this thesis is that designers lack an understanding of the effects of tool container location on two important user performance factors: attention and group awareness. My solution is to provide an initial understanding of the effects of tool container location on these factors. In solving this problem, I developed a taxonomy of tool container location, and carried out two research studies. The two research studies investigated tool container location in two contexts: single-user performance with desktop interfaces, and group performance in tabletop interfaces. Through the two studies, I was able to show that tool container location does affect attention and group awareness, and to provide new recommendations for interface designers.

A common way of organizing Windows, Icons, Menus, and Pointers (WIMP) interfaces is to group tools into tool containers, providing one visual representation. Common tool containers include toolbars and menus, as well as more complex tool containers, like Microsoft Offices Ribbon, Toolglasses, and marking menus. The location of tool containers has been studied extensively in the past using Fittss Law, which governs selection time; however, selection time is only one aspect of user performance. In this thesis, I show that tool container location affects other aspects of user performance, specifically attention and awareness. The problem investigated in this thesis is that designers lack an understanding of the effects of tool container location on two important user performance factors: attention and group awareness. My solution is to provide an initial understanding of the effects of tool container location on these factors. In solving this problem, I developed a taxonomy of tool container location, and carried out two research studies. The two research studies investigated tool container location in two contexts: single-user performance with desktop interfaces, and group performance in tabletop interfaces. Through the two studies, I was able to show that tool container location does affect attention and group awareness, and to provide new recommendations for interface designers.

Ideas are formed in a process of idea generation that includes creation, development, and communication of new ideas. Drawing has been used as a support for ideation for centuries. Today, computerized tools are commonly used for drawing. Such tools form a user interface between the human and the resulting drawing presented on the screen. The interface may come between the user and the drawing in a disruptive way also affecting the ideation process. Using controlled laboratory studies, this thesis investigates the consequences of drawing with different user interfaces in two types of tasks: creative drawing tasks (based on a standardized test of creativity) and non-creative drawing tasks (i.e. shape-tracing tasks where no new idea is created). The goal was to identify and evaluate the consequences of the several issues originating from the use of different input devices, the functionality of the graphical user interfaces, the formulation of the drawing task, and the user’s previous experience. The results showed that drawing tasks are oriented toward quality of outcomes and that higher input accuracy led to higher quality of outcomes of both creative and non-creative drawing tasks. This came with a trade-off between the quantity and quality. In ideation, less accurate input devices facilitated significantly more ideas but these were of lower quality. In non-creative tracing, higher speeds caused lower quality of outcomes. The users subjectively preferred higher accuracy, also when an inaccurate user interface offered an eraser function. However, using the eraser allowed avoiding reinterpretations of ideas and led to ideation strategies characterized by laborious drawing that negatively affected the quality and quantity of the ideas produced. For non-creative drawing, the more difficult the shapes were, the lower the tracing accuracy. In the thesis a new framework for interaction analysis is introduced that improves the theoretical and practical understanding of computerized drawing tasks and the phenomena resulting from different aspects of the user interface design of computerized drawing tools. This thesis demonstrates that the inaccuracy of computerized tools cannot only make our drawings less aesthetically pleasing but also negatively affect ideas that are created in the process.

Information systems provide users with valuable information that is relevant to users’ tasks, as well as irrelevant information that is not helpful to the user. Irrelevant information become a distraction and distract the users from their current task, there by impairing performance. Guided by distraction-conflict theory, processing efficiency theory, attentional control theory, cognitive load theory and memory for goals theory, this study investigated the distraction effect by exploring the research question, “How do task-irrelevant distractions interrupt the users of information systems and influence their performance?”. To investigate how distractions from technology influence users’ performance, this experimental research examined the relationship between the variables of distraction, cognitive load, anxiety and task performance. Data were gathered through lab experiment using imotion eye tracking system. The major findings revealed that task-irrelevant distraction negatively influenced the users by increase anxiety and cognitive load as well as increase the time devoted to primary task. We also found that the cognitive load partially mediates the relationship between distraction and time spending on task.

In order to operate UAVs under human supervisory control in more complex arenas such as urban environments, an obstacle detection system is a requirement to achieve safe navigation. The development of a system capable of meeting these requirements is presented. The first stage of development was sensor selection and initial testing. After this, the sensor was combined with a servomotor to allow it to rotate and provide obstacle detection coverage in front, below, and to both sides of the UAV. Utilizing a PC-104 single board computer running LabView Real-time for on-board control of the sensor and servomotor, a stand alone obstacle detection system was developed meeting the requirements of light weight, low power, and small size. The detection performance of the system for several parameters has been fully characterized. A human subjects study was conducted to assess the any advantages resulting from the addition of the obstacle detection system compared to that of a normal nadir camera. The study demonstrated that users with access to the three-dimensional display were able to navigate an obstacle course with greater success than those with only a camera. Additional development into more advanced visualization of the environment has potential to increase effectiveness of this obstacle detection system. / Master of Science

The purpose of this study is to investigate the relationships between selected end-user training programs corporations provide to their employees and subsequent employee performance based on these opportunities.

In recent years, 3D graphics has become more available for web development with low-level access to graphics hardware and increased power of web browsers. With core browsing tasks for users being to quickly scan a website and find what they are looking for, can 3D graphics – or depth cues – be used to facilitate these tasks? Therefore, the main focus of this work was to examine user performance on websites in terms of visual attention. Previous research on the use of 3D graphics in web design and other graphical interfaces has yielded mixed results, but some suggest depth cues might be used to segment a visual scene and improve visual attention. In this work, the main question asked was:  How do depth cues affect visual search in a web-based environment? To examine the question, a user study was conducted where participants performed a visual search task on four different web-based prototypes with varying depth cues. The findings suggest depth cues might have a negative effect by increasing reaction time, but certain cues can improve task completion (hit rate) in text-rich web environments. It is further elaborated that it might be useful to look at the problem from a more holistic perspective, also emphasizing other factors such as visual complexity and prototypicality of websites.

A system is described for identifying obstacle-free landing sites for a vertical-takeoff-and-landing (VTOL) semi-autonomous unmanned aerial vehicle (UAV) from point cloud data obtained from a stereo vision system. The relatively inexpensive, commercially available Bumblebee stereo vision camera was selected for this study. A "point cloud viewer" computer program was written to analyze point cloud data obtained from 2D images transmitted from the UAV to a remote ground station. The program divides the point cloud data into segments, identifies the best-fit plane through the data for each segment, and performs an independent analysis on each segment to assess the feasibility of landing in that area. The program also rapidly presents the stereo vision information and analysis to the remote mission supervisor who can make quick, reliable decisions about where to safely land the UAV. The features of the program and the methods used to identify suitable landing sites are presented in this thesis. Also presented are the results of a user study that compares the abilities of humans and computer-supported point cloud analysis in certain aspects of landing site assessment. The study demonstrates that the computer-supported evaluation of potential landing sites provides an immense benefit to the UAV supervisor. / Master of Science

L'utilisation croissante des sites en web 2.0 sur internet a favorisé l'utilisation des outils du Web 2.0 par de nombreuses organisations à travers le monde. L’un des outils les plus largement utilisés aujourd’hui dans les organisations est la technologie Wiki, et ce tout particulièrement dans la gestion de projet. Parce qu’un nombre croissant d’organisations déploie des systèmes Wiki et que le Web 2.0 fait encore l’objet d’un véritable battage médiatique, il est important de travailler sur ces technologies collaboratives et de mesurer leur succès en termes d’utilisation dans l’environnement de l’organisation. Cette étude traite de l’utilisation de la technologie Wiki dans les entreprises et du besoin de développer cette technologie. Il s’agit également de déterminer comment mesurer le succès des systèmes wiki internes du point de vue des « end-users ». La littérature sur les systèmes Wiki publics et d’entreprise est également présentée. Cette étude propose un modèle théorique de recherche sur le succès des wikis internes des entreprises, fondé sur la précédente théorie sur le succès des systèmes d’information. Enfin, le modèle proposé est testée empiriquement et les déterminants importants du succès des wikis interne des entreprises sont présentés / With the ever increasing use of Web 2.0 sites on the internet, the use of Web 2.0 based tools has been employed by the organizations across the globe. One of the most widely used Web 2.0 tool in organizations is the wiki technology particularly in project management. Since growing number of organisations are deploying wiki systems as Web 2.0 still remains a hype, it is important to investigate into these collaborative technologies and measure the success in corporate environment usage. In this study, we discuss the use of Wiki technology in the enterprise setting, the need for wiki deployment and how can we measure the success of corporate wiki systems from end-user’s perspective. The literature on corporate and public wiki systems is also presented. The paper presents a theoretical research model of enterprise wiki systems’ success based on the previous IS success theory. Finally, the research model of corporate Wiki success is empirically tested and the important determinants of corporate Wiki systems are presented

The federal communications commission (FCC) has predicted that, under the current regulatory environment, a spectrum shortage may be faced in the near future. This impending spectrum shortage is in part due to a rapidly increasing demand for wireless services and in part due to inefficient usage of currently licensed bands. A new paradigm pertaining to wireless spectrum allocation, known as cognitive radio (CR), has been proposed as a potential solution to this problem. This dissertation seeks to contribute to research in the field of CR through an investigation into the effect that a primary user (PU) channel occupancy model will have on the performance of a secondary user (SU) in a CR network. The model assumes that PU channel occupancy can be described as a binary process and a two state Hidden Markov Model (HMM) was thus chosen for this investigation. Traditional algorithms for training the model were compared with certain evolutionary-based training algorithms in terms of their resulting prediction accuracy and computational complexity. The performance of this model is important since it provides SUs with a basis for channel switching and future channel allocations. A CR simulation platform was developed and the results gained illustrated the effect that the model had on channel switching and the subsequently achievable performance of a SU operating within a CR network. Performance with regard to achievable SU data throughput, PU disruption rate and SU power consumption, were examined for both theoretical test data as well as data obtained from real world spectrum measurements (taken in Pretoria, South Africa). The results show that a trade-off exists between the achievable SU throughput and the average PU disruption rate. Significant SU performance improvements were observed when prediction modelling was employed and it was found that the performance and complexity of the model were influenced by the algorithm employed to train it. SU performance was also affected by the length of the quick sensing interval employed. Results obtained from measured occupancy data were comparable with those obtained from theoretical occupancy data with an average percentage similarity score of 96% for prediction accuracy (using the Viterbi training algorithm), 90% for SU throughput, 83% for SU power consumption and 71% for PU disruption rate. / Dissertation (MEng)--University of Pretoria, 2012. / Electrical, Electronic and Computer Engineering / unrestricted