Calvin Swart

Biometric authentication on a mobile device: a study of user effort, error and task disruption

We examine three biometric authentication modalities -- voice, face and gesture -- as well as password entry, on a mobile device, to explore the relative demands on user time, effort, error and task disruption. Our laboratory study provided observations of user actions, strategies, and reactions to the authentication methods. Face and voice biometrics conditions were faster than password entry. Speaking a PIN was the fastest for biometric sample entry, but short-term memory recall was better in the face verification condition. None of the authentication conditions were considered very usable. In conditions that combined two biometric entry methods, the time to acquire the biometric samples was shorter than if acquired separately but they were very unpopular and had high memory task error rates. These quantitative results demonstrate cognitive and motor differences between biometric authentication modalities, and inform policy decisions in selecting authentication methods.

Improving web accessibility through an enhanced open-source browser

The accessibilityWorks project provides software enhancements to the MozillaTM, Web browser and allows users to control their browsing environment. Although Web accessibility standards specify markup that must be incorporated for Web pages to be accessible, these standards do not ensure a good experience for all Web users. This paper discusses user controls that facilitate a number of adaptations that can greatly increase the usability of Web pages for a diverse population of users. In addition to transformations that change page presentation, innovations are discussed that enable mouse and keyboard input correction as well as vision-based control for users unable to use their hands for computer input.

Exploring pinch and spread gestures on mobile devices

Pinching and spreading gestures are prevalent in mobile applications today, but these gestures have not yet been studied extensively. We conducted an exploratory study of pinch and spread gestures with seated participants on a phone and a tablet device. We found device orientation did not have a significant effect on gesture performance, most pinch and spread tasks were completed in a single action, and they were executed in 0.9-1.2 seconds. We also report how participants chose to sit with the mobile device, variations in gesture execution method, and the effect of varying target width and gesture size. Our task execution times for different gesture distances and precision levels display a surprisingly good fit to a simple Fittss Law model. We conclude with recommendations for future studies.

Understanding the role of age and fluid intelligence in information search

In this study, we explore the role of age and fluid intelligence on the behavior of people looking for information in a real-world search space. Analyses of mouse moves, clicks, and eye movements provide a window into possible differences in both task strategy and performance, and allow us to begin to separate the influence of age from the correlated but isolable influence of cognitive ability. We found little evidence of differences in strategy between younger and older participants matched on fluid intelligence. Both performance and strategy differences were found between older participants having higher versus lower fluid intelligence, however, suggesting that cognitive factors, rather than age per se, exert the dominant influence. This underscores the importance of measuring and controlling for cognitive abilities in studies involving older adults.

Towards a tool for keystroke level modeling of skilled screen reading

Designers often have no access to individuals who use screen reading software, and may have little understanding of how their design choices impact these users. We explore here whether cog-nitive models of auditory interaction could provide insight into screen reader usability. By comparing human data with a tool-generated model of a practiced task performed using a screen reader, we identify several requirements for such models and tools. Most important is the need to represent parallel execution of hearing with thinking and acting. Rules for placement of cogni-tive operators that were developed for visual user interfaces may not be applicable in the auditory domain. Other mismatches be-tween the data and the model were attributed to the extremely fast listening rate and differences between the typing patterns of screen reader usage and the models assumptions. This work in-forms the development of more accurate models of auditory inter-action. Tools incorporating such models could help designers create user interfaces that are well tuned for screen reader users, without the need for modeling expertise.

Toward modeling auditory information seeking strategies on the web

Human performance models based on information foraging theory have proved capable of predicting navigation behavior on the Web. They can therefore provide a useful tool for Web site design. They may also be effective for modeling auditory navigation within a single Web page. Designers often struggle to accommodate this sort of access, different as it is from their own experience. As a step toward realistic simulations based on models of auditory Web access, we describe information seeking strategies observed in people with visual impairment using screen reading software for Web navigation tasks. We outline one example strategy for approaching a new Web page that, guided by information foraging theory, may expose access barriers that current design tools miss.

Perceptions of Risk in Mobile Transaction

Mobile users are unlikely to guard against information security risks that do not come to mind in typical situations. As more people conduct sensitive transactions through mobile devices, what risks do they perceive? To inform the design of mobile applications we present a user study of perceived risk for information technology workers accessing company data, consumers using mobile personal banking, and doctors accessing medical records. Shoulder surfing and network snooping were the most commonly cited classes of risk, and perceived risk was influenced by the surrounding environment and source of information. However, overall risk awareness was low. The possible risks of device theft and loss, hacking, malware and data stored on devices were not prominent concerns. The study also revealed differences in the way the groups think about network-related threats. Based on these results, we suggest research directions for effective protection of sensitive data in mobile environments.

A decade of progress in parallel programming productivity

Looking at the design and benefits of X10.

Productivity in Parallel Programming: A Decade of Progress

In 2002 DARPA (Defense Advanced Research Projects Agency) launched a major initiative in HPCS (high-productivity computing systems). The program was motivated by the belief that the utilization of the coming generation of parallel machines was gated by the difficulty of writing, debugging, tuning, and maintaining software at peta scale.

Business insight toolkit: Flexible pre-requirements modeling

Pre-requirements analysis requires modeling tools with unprecedented flexibility. The Business Insight Toolkit (BITKit) is a prototype of a new kind of modeling tool, aimed at offering the flexibility of office tools along with many of the advantages of modeling tools.