Publications
Introduction: Informational graphics and data representations (e.g., charts and figures) are critical for accessing educational content. Novel technologies, such as the multimodal touchscreen which displays audio, haptic, and visual information, are promising for being platforms of diverse means to access digital content. This work evaluated educational graphics rendered on a touchscreen compared to the current standard for accessing graphical content. Method: Three bar charts and geometry figures were evaluated on student (N = 20) ability to orient to and extract information from the touchscreen and print. Participants explored the graphics and then were administered a set of questions (11-12 depending on graphic group). In addition, participants' attitudes using the mediums were assessed. Results: Participants performed statistically significantly better on questions assessing information orientation using the touchscreen than print for both bar chart and geometry figures. No statistically significant difference in information extraction ability was found between mediums on either graphic type. Participants responded significantly more favorably to the touchscreen than the print graphics, indicating them as more helpful, interesting, fun, and less confusing. Discussion: Accessing and orienting to information was highly successful by participants using the touchscreen, and was the preferred means of accessing graphical information when compared to the print image for both geometry figures and bar charts. This study highlights challenges in presenting graphics both on touchscreens and in print. Implications for Practitioners: This study offers preliminary support for the use of multimodal, touchscreen tablets as educational tools. Student ability using touchscreen-based graphics seems to be comparable to traditional types of graphics (large print and embossed, tactile graphics), although further investigation may be necessary for tactile graphic users. In summary, educators of students with blindness and visual impairments should consider ways to utilize new technologies, such as touchscreens, to provide more diverse access to graphical information.
While many advanced haptic devices are under development, touchscreens are one of the most readily available platforms. In this paper, we leverage a leap forward in vibration-based haptics, Apple's new CoreHaptics API, and investigate its potential for a multi-finger vibration experience. We present a perceptual user study (N=15) that investigates multi-finger vibration identification and exploration strategies and we conduct a laser doppler vibrometry study, uncovering the challenges of developing consistent, high-quality vibration feedback across hardware platforms that vary in actuation principle, screen size, and external attachments. Repeated-measures ANOVA tests showed no statistically significant results in time, error, or weighted error for vibration identification across all participants based on number of fingers. However, one-way ANOVAs did show significant results within individuals, illustrating benefits of multiple-finger exploration. The most effective strategies for locating vibrations involved multiple fingers grouped together using sweeping motions across the screen. Our LDV study demonstrated that CoreHaptics and the Taptic Engine in the iPhone were capable of more accurately recreating specific frequencies than coin motors in Android devices. This research supports a move to a multi-finger, vibrotactile touchscreen experience, while highlighting the challenges of creating a consistent vibration experience across hardware platforms.
This paper explores the viability of new touchscreen-based haptic/vibrotactile interactions as a primary modality for perceiving visual graphical elements in eyes-free situations. For touchscreen-based haptic information extraction to be both accurate and meaningful, the onscreen graphical elements should be schematized and downsampled to: (1) maximize the perceptual specificity of touch-based sensing and (2) account for the technical characteristics of touchscreen interfaces. To this end, six human behavioral studies were conducted with 64 blind and 105 blindfolded-sighted participants. Experiments 1-3 evaluated three key rendering parameters that are necessary for supporting touchscreen-based vibrotactile perception of graphical information, with results providing empirical guidance on both minimally detectable and functionally discriminable line widths, inter-line spacing, and angular separation that should be maintained. Experiments 4-6 evaluated perceptually-motivated design guidelines governing visual-to-vibrotactile schematization required for tasks involving information extraction, learning, and cognition of multi-line paths (e.g., transit-maps and corridor-intersections), with results providing clear guidance as to the stimulus parameters maximizing accuracy and temporal performance. The six empirically-validated guidelines presented here, based on results from 169 participants, provide designers and content providers with much-needed guidance on effectively incorporating perceptually-salient touchscreen-based haptic feedback as a primary interaction style for interfaces supporting nonvisual and eyes-free information access.
Polyglot programming, the use of multiple programming languages during the development process, is common practice in modern software development. This study investigates this practice through a randomized controlled trial conducted under the context of database programming. Participants in the study were given coding tasks written in Java and one of three SQL-like embedded languages. One was plain SQL in strings, one was in Java only, and the third was a hybrid embedded language that was closer to the host language. We recorded 109 valid data points. Results showed significant differences in how developers of different experience levels code using polyglot techniques. Notably, less experienced programmers wrote correct programs faster in the hybrid condition (frequent, but less severe, switches), while more experienced developers that already knew both languages performed better in traditional SQL (less frequent but more complete switches). The results indicate that the productivity impact of polyglot programming is complex and experience level dependent. © 2020 ACM.
Vibration plays a significant role in the way users interact with touchscreens. For many users, vibration affords tactile alerts and other enhancements. For eyes-free users and users with visual impairments, vibration can also serve a more primary role in the user interface, such as indicating streets on maps, conveying information about graphs, or even specifying basic graphics. However, vibration is rarely used in current user interfaces beyond basic cuing. Furthermore, designers and developers who do actually use vibration more extensively are often unable to determine the exact properties of the vibration signals they are implementing, due to out-of-the-box software and hardware limitations. We make two contributions in this work. First, we investigate the contextual properties of touchscreen vibrations and how vibrations can be used to effectively convey traditional, embossed elements, such as dashes and dots. To do so, we developed an open source, Android-based library to generate vibrations that are perceptually salient and intuitive, improving upon existing vibration libraries. Second, we conducted a user study with 26 blind or visually impaired users to evaluate and categorize the effects with respect to traditional tactile line profiles. We have established a range of vibration effects that can be reliably generated by our haptic library and are perceptible and distinguishable by users.
With content rapidly moving to the electronic space, access to graphics for individuals with visual impairments is a growing concern. Recent research has demonstrated the potential for representing basic graphical content on touchscreens using vibrations and sounds, yet few guidelines or processes exist to guide the design of multimodal, touchscreen-based graphics. In this work, we seek to address this gap by synergizing our collective research efforts over the past eight years and implementing our findings into a compilation of recommendations, which we validate through an iterative design process and user study. We start by reviewing previous work and then collate findings into a set of design guidelines for generating basic elements of touchscreen-based multimodal graphics. We then use these guidelines to generate exemplary graphics in mathematics, specifically bar charts and geometry concepts. We discuss the iterative design process of moving from guidelines to actual graphics and highlight challenges. We then present a formal user study with 22 participants with visual impairments, comparing learning performance on using touchscreen-rendered graphics to embossed graphics. We conclude with qualitative feedback from participants on the touchscreenbased approach and offer areas of future investigation as these recommendation are expanded to include more complex graphical concepts.
Touchscreen-based smart devices, such as smartphones and tablets, offer great promise for providing blind and visually-impaired (BVI) users with a means for accessing graphics non-visually. However, they also offer novel challenges as they were primarily developed for use as a visual interface. This paper studies key usability parameters governing accurate rendering of haptically-perceivable graphical materials. Three psychophysically-motivated usability studies, incorporating 46 BVI participants, were conducted that identified three key parameters for accurate rendering of vibrotactile lines. Results suggested that the best performance and greatest perceptual salience is obtained with vibrotactile feedback based on: (1) a minimum width of 1 mm for detecting lines, (2) a minimum gap of 4 mm for discriminating lines rendered parallel to each other, and (3) a minimum angular separation (i.e., cord length) of 4 mm for discriminating oriented lines. Findings provide foundational guidelines for converting/rendering visual graphical materials on touchscreen-based interfaces for supporting haptic/vibrotactile information access.
Scientific computing has become an area of growing importance. Across fields such as biology, education, physics, or others, people are increasingly using scientific computing to model and understand the world around them. Despite the clear need, almost no systematic analysis has been conducted on how students in fields outside of computer science learn to program in the context of scientific computing. Given that many fields do not explicitly teach much programming to their students, they may have to learn this important skill on their own. To help, using rigorous quantitative and qualitative methods, we looked at the process 154 students followed in the context of a randomized controlled trial on alternative styles of programming that can be used in R. Our results suggest that the barriers students face in scientific computing are non-trivial and this work has two core implications: 1) students learning scientific computing on their own struggle significantly in many different ways, even if they have had prior programming training, and 2) the design of the current generation of scientific computing feels like the wild-wild west and the designs can be improved in ways we will enumerate.


