The development of effective multidimensional map-based interfaces is an important area of research in need of design techniques and guidelines. To date, guidelines for multidimensional interfaces have been generalized from text-based interfaces and few experimental studies have been conducted to asses their effectiveness. Guidelines for design were studied with the goal of extending the current body of knowledge about the usability of these interfaces. Based on design guidelines, multidimensional map-based interfaces with various levels of depth and breath, with and without scent-based components were used to perform simple and compound tasks. The goal of this study was to investigate the effectiveness of design guidelines on response time, preferences, and navigation and task accuracy. Results showed relationships exist among navigation and task accuracy, response time, and preferences within simple or compound tasks. However, few relationships exist between simple and compound tasks. Contrary to results from previous research, interface depth and breadth was found to have no significant effect on navigation and task accuracy or response time. For compound tasks, interfaces with scent-based components were found to be more effective regarding task accuracy at greater depth levels. The absence of scent in the interface was shown to be more efficient regarding response time and navigation accuracy during compound tasks.

Leading human-computer interaction (HCI) researchers recognize a fundamental difference exists between men and women. Some HCI research has been done regarding gender differences in hand-eye coordination for interactions with computer touch display interfaces, navigation through virtual environments (VE) and language in computer-mediated communication. In these previous studies, gender differences were found in the use of words and language in computer-mediated communication and in navigation strategies for VE but no gender-related differences were found for the hand-eye coordination needed to effectively use a touch display. The current study used a cross-modal (auditory-visual), dual-task, computer interface to examine gender differences in crisis control simulations. For the primary task of alarm monitoring, no gender differences were found for average or maximum response and completion times. Likewise, no gender differences were found in terms of error rates for the primary task or the number correct on the secondary task. However, in terms of minimum response and completion times for alarm monitoring, gender differences were found.

E-sports is currently estimated to be a billion dollar industry which is only growing in size from year to year. However the cinematography of spectated games leaves much to be desired. In most cases, the spectator either gets to control their own freely-moving camera or they get to see the view that a specific player sees. This thesis presents a system for the generation of cinematically-pleasing views for spectating real-time graphics applications. A custom real-time engine has been built to demonstrate the effect of this system on several different game modes with varying visual cinematic constraints, such as the rule of thirds. To create the cinematic views, we encode cinematic rules as cost functions that are fed into a non-linear least squares solver. These cost functions rely on the geometry of the scene, minimizing residuals based on the 3D positions and 2D reprojections of the geometry. The final cinematic view is found by altering camera position and angle until a local minimum is met. The system was evaluated by comparing video output from a traditional rigidly constrained camera and the results of our algorithm’s optimally solved views. User surveys are then used to qualitatively evaluate the system. The results of these surveys do not statistically find a preference between the cinematic views and the rigidly constrained views. In addition, we present performance and timing considerations for the system, reporting that the system can operate within modern expectations of latency when enough constraints are placed on the non-linear least squares solver.

This thesis describes the design, development, and evaluation of an interactive Microsoft HoloLens application that projects landscape models in Augmented Reality. The application was developed using the Unity framework and 3D models created in Sketchup. Using the application, students can not only visualize the models in real space but can also interact with the models using gestures. The students can interact with the models using gaze and air-tap gestures. Application testing was conducted with 21 students from the Landscape Architecture and Environmental Planning department at Utah State University. To evaluate the application, students completed a usability survey after using the application. Students also participated in a focus group. Results indicate that students were excited to use the application and found it helpful for learning landscape construction concepts. Some of the students found the application and the HoloLens device cumbersome to use, and they offered suggestions for how to improve the application. The thesis concludes with recommendations for future work.

Advances and new insights into algorithms for piecewise smooth image reconstruction are presented. Such algorithms fit a piecewise smooth function to image data without prior knowledge of the number of regions or the location of region boundaries in the best fitting function. This is a difficult model selection problem since the number of parameters of possible solutions varies widely. The approach followed in this work was proposed by Yvan Leclerc. It uses the Minimum Description Length principle to make the reconstruction problem well-posed: the best fitting function yields the shortest encoding of the image data. In order to derive a code length formula, the class of functions is restricted to piecewise polynomial. The resulting optimization problem may have many local minima, and a good initial approximation is required in order to find acceptable solutions. Good initial approximations may be generated at the cost of solving a sequence of related optimization problems, as prescribed by a continuation method. Several problems with this approach are identified and addressed. First, success or failure of the continuation method is found to be sensitive to the choice of objective function parameters. Second, the optimization method used in prior work may fail to converge, and, third, it converges too slowly to be useful in many vision applications. I address the first problem in three different ways. First, a revised continuation method is less sensitive to parameter choice. Second, I show how to move control over success or failure from the objective function parameters to the continuation method. Third, a new objective function is derived which includes one parameter instead of the two parameters used in prior work. Experimental results show that all measures improve robustness with respect to parameter choice. In order to address the optimization-related problems I use a quasi-Newton line-search method. This method is guaranteed to converge and may converge at a faster rate than the relaxation method used in prior work. To realize a faster convergence rate, I introduce a new parameter whose role is to improve variable scaling and problem conditioning. Further runtime improvements result from using extrapolation in the continuation method. Experimental results show overall runtime improvements of an order of magnitude and more. My reconstruction algorithm performs superior to the well-known Canny edge detector on the Berkeley boundary detection task. This is a novel result that demonstrates the merits of image reconstruction as a means for extracting information from an image.

This paper explores how vision affects spatial audio perception in virtual reality. We created four virtual environments with different reverb and room sizes, and recorded binaural clicks in each one. We conducted two experiments: one where participants judged the audio-visual match, and another where they pointed to the click direction. We found that vision influences spatial audio perception and that congruent audio-visual cues improve accuracy. We suggest some implications for virtual reality design and evaluation.

Usability guidelines for user interface (UI) design formulated by Nielsen and other authorities were used to redesign the web interface for a web based distance education course. The website's original UI, as judged by a group of web design professionals, violated standard guidelines for usability, readability, learnability, consistency, efficiency of use and flexibility. The original and redesigned UIs were tested using thinking aloud testing, a user satisfaction survey, and usability inspection. The results of user testing and heuristic evaluation suggest that the use of these guidelines in website redesign had a positive impact on user performance. A more conclusive result would have required a larger sample size and a redesigned testing protocol that varied the order in which participants worked with the old and redesigned interfaces.

Individuals who suffer from severe motor disabilities face the possibility of the loss of speech. A Brain-Computer Interface (BCI) can provide a means for communication through non-muscular control. Current BCI systems use characters that flash from gray to white (GW), making adjacent character difficult to distinguish from the target. The current study implements two types of color stimulus (grey to color [GC] and color intensification [CI]) and I hypotheses that color stimuli will; (1) reduce distraction of nontargets (2) enhance target response (3) reduce eye strain. Online results (n=21) show that GC has increased information transfer rate over CI. Mean amplitude revealed that GC had earlier positive latency than GW and greater negative amplitude than CI, suggesting a faster perceptual process for GC. Offline performance of individual optimal channels revealed significant improvement over online standardized channels. Results suggest the importance of a color stimulus for enhanced response and ease of use.

Several studies have applied recommender technologies to support requirements engineering activities. As in other application areas of recommender systems (RS), many studies have focused on the algorithms’ prediction accuracy, while there have been limited discussions around users’ interactions with the systems. Since recommender systems are designed to aid users in information retrieval, they should be assessed not just as recommendation algorithms but also from the users’ perspective. In contrast to accuracy measures, user-related issues can only be effectively investigated via empirical studies involving real users. Furthermore, researchers are becoming increasingly aware that the effectiveness of the systems goes beyond recommendation accuracy, as many factors can be relevant to their adoption besides accuracy. To better understand recommender systems in RE, it has become necessary to explore them from users’ perspectives. Consequently, this research evaluates a feature recommender system from users’ perspectives adopting the “Recommender systems’ Quality of user experience” (ResQue) model - a user-centered evaluation model from the RS field. This was done by designing a content-based feature recommender system and then assessing it from the users’ view point. A between-subjects user study was conducted involving two groups of participants, an experimental and a control group. The experimental group interacted with the feature recommender system while developing a list of software requirements for a software product (an antivirus software). In contrast, the control group performed the same task without receiving support from the recommender. After completing the task, both groups completed a post-task evaluation questionnaire, including questions about their experiences and opinions about the task they completed. In addition, participants in the experimental group rated their perceptions of various aspects of the recommender; question items were adapted from the ResQue questionnaire. Users’ subjective evaluation of the recommender was investigated using the ResQue constructs - perceived system qualities, user beliefs, user attitudes, and behavioral intentions. Additionally, the impact of recommendations on the requirements elicitation process was assessed in terms of the process and outcome level measures. Possible qualitative differences were also examined. Users' preferences were identified, and possible HCI issues requiring attention in recommender systems used in RE are discussed.

In computer graphics applications, the choice and implementation of a rendering technique is crucial when targeting real-time performance. Traditionally, rasterization-based approaches have dominated the real-time sector. Other algorithms were simply too slow to compete on consumer graphics hardware. With the addition of hardware support for ray-intersection calculations on modern GPUs, hybrid ray tracing/rasterization and purely ray tracing approaches have become possible in real-time as well. Industry real-time graphics applications, namely games, have been exploring these different rendering techniques with great levels of success. The addition of ray tracing into the graphics developer’s toolkit has without a doubt increased what level of graphical fidelity is achievable in real-time. In this thesis, three rendering techniques are implemented in a custom rendering engine built on the Vulkan® Explicit API. Each technique represents a different family of modern real-time rendering algorithms. A largely rasterization-based method, a hybrid ray tracing/rasterization method, and a method solely using ray tracing. Both the hybrid and ray tracing exclusive approach rely on the ReSTIR algorithm for lighting calculations. Analysis of the performance and render quality of these approaches reveals the trade-offs incurred by each approach, alongside the performance viability of each in a real-time setting.