Mary F. Theofanos

Bridging the gap: between accessibility and usability

Guidelines for Accessible---and Usable---Web Sites: Observing Users Who Work With Screenreaders

Guest Editors' Introduction: Shouldn't All Security Be Usable?

Usability is defined as the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use. It is more than a well-designed user interface.

A field study of user behavior and perceptions in smartcard authentication

A field study of 24 participants over 10 weeks explored user behavior and perceptions in a smartcard authentication system. Ethnographic methods used to collect data included diaries, surveys, interviews, and field observations. We observed a number of issues users experienced while they integrated smartcards into their work processes, including forgetting smartcards in readers, forgetting to use smartcards to authenticate, and difficulty understanding digital signatures and encryption. The greatest perceived benefit was the use of an easy-to-remember PIN in replacement of complicated passwords. The greatest perceived drawback was the lack of smartcard-supported applications. Overall, most participants had a positive experience using smartcards for authentication. Perceptions were influenced by personal benefits experienced by participants rather than an increase in security.

Does habituation affect fingerprint quality

Interest in the environmental factors that affect biometric image quality is increasing as biometric technologies are currently being implemented in various business applications. This study aims to determine, through repeated trials, the effects of various external factors on the image quality and usability of prints collected by an electronic reader. These factors include age and gender but also the absence or presence of immediate feedback. A key factor in biometric systems that will be used daily or routinely is habituation. The users behavior could potentially change as a result of acclimatization; ones input might increase in quality as one learns how to use the system better, or decrease in quality since comfort with the system could translate into carelessness.

Real-time feedback for usable fingerprint systems

Compared with traditional password and other identification methods, biometrics such as face, iris, and fingerprints for automatic personal identification and verification have many advantages, and are increasingly gaining popularity in all kinds of applications. As the technologies mature, the community has begun to realize that usability has great impact on the final accuracy and efficiency of a biometric system. Although research has shown that effective user feedback can improve the quality of the fingerprint images captured and user satisfaction, currently user feedback information of fingerprint devices used in real world applications is very limited. We design a rich, quality-driven interactive real-time user feedback mechanism for unattended fingerprint kiosk. The system aims to improve the quality of biometric samples during the acquisition process by feeding rich information back to the user instantaneously by measuring objective parameters of the image. The paper proposes an innovative, cost-efficient, real-time algorithm for fingertip detection, slap/thumb rotation detection, and finger region intensity estimation. The paper provides detailed information on the technical solution and its implementation. Preliminary results show that the methodology can potentially increase efficiency, effectiveness, and user satisfaction of a fingerprint biometric system.

Biometric Systematic Uncertainty and the User

Often biometric technology and system evaluators are concerned with capturing accurate performance estimates that predict performance for target populations of interest. Occasionally, predictions, and perhaps adjustments, for subpopulations based on convenient characteristics such as sex or age are examined. Few experiments have been performed to explicitly study the interaction of the user and the biometric system -how a users behavior, cognition, perception, and anthropometric qualities affect performance metrics and error estimates. This paper summarizes three studies performed in this emerging field of biometric usability. Each study focused on fingerprint recognition and the systematic uncertainty in system performance induced by different human factors. First, the effect of feedback and habituation on image quality is examined. Second, results from a study on the influence of the height of the surface upon which the fingerprint sensor is placed are presented. A summary of an experiment on the effect of instructional materials on the timing and error rates for a 10-print capture process closes the paper.

Effects of Scanner Height on Fingerprint Capture

Although the deployment of biometric technologies such as fingerprints is becoming more widespread, little attention is being paid to the human-computer interaction that such technologies involve. Most biometric systems employ both hardware and software measures to maximize the capture quality of the biometric data. The physical presentation of the biometric data by the participant to the system involves many anthropometric and ergonomic factors that have been largely ignored. This study examined the effect of the height of the sensor on the quality and the time required to collect fingerprints. User performance, both fingerprint quality and timing, was impacted by scanner height.

Development of a test bed for evaluating human-robot performance for explosive ordnance disposal robots

This paper discusses the development of a test bed to evaluate the combined performance of the human operator and an explosive ordnance disposal robot. We have other means of evaluating the capabilities of the robots but for the robots to be truly useful it is necessary to understand how effectively and efficiently operators will be able to use these robots in critical situations. In this paper we discuss the tasks developed for the test bed and how we are going about development of the metrics for assessing the human-robot performance and, more specifically, the human-robot user interface.

A practical guide to the CIF: usability measurements

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Usability Testing of Face Image Capture for US Ports of Entry

46 MILLION COMPUTER SYSTEM installed at the US General Services Administration (GSA) regional offices in Denver and Philadelphia in 2004 slowed business operations to a trickle [1]. The new system, designed to improve financial management, did not work out as planned. The Federal Times quoted one Federal Technology Service (FTS) procurement worker as saying, “People are so upset that they can’t figure out how to do their jobs on the new system that someone bursts into tears almost hourly.” FTS commissioner Sandra Bates was aware of the frustration: “I know it is very, very difficult to learn the new system... It is one of our lessons learned. We gave everyone extensive training before the system went live but didn’t realize employees would need the trainers there while they started using the new system.” The system is unnecessarily complicated to use. Instead of being able to save a file with a few clicks, employees now must learn 15 steps. Bates was also quoted in the Times as saying, “The system is not simple, and how to do things is not always intuitive. The problems people are having are not trivial, but we have to work through them by getting [people] more training.” The UK Passport Office experienced similar problems in 1999 when installing a new system for issuing passports. After installation, a backlog of passports started building up, eventually leading to delays of up to three months to obtain a passport. Reasons for the loss in productivity included the need to correct errors in scanned data and the large number of keystrokes and onscreen operations required. The test program had not extended to thorough testing of the system’s impact on productivity.