Barbara Leporini

Increasing usability when interacting through screen readers

The application of appropriate Web site design and evaluation methods helps to ensure more usable and accessible Web sites. While in the literature guidelines and evaluation methods for accessibility and usability are given and discussed separately, we aim at identifying the relationships between these two concepts, in particular considering usability criteria for accessible Web sites. In this work, we propose a set of such criteria targeted to improving the navigability for a specific group of disabled users, i.e., vision-impaired people. The identification of the eighteen criteria suggested herein was performed through empirical feedback, by which potential issues were identified. Subsequently, a systematic method was developed on the basis of the analysis of potential solutions, resulting in a classification of the criteria according to usability aspects. Some example applications of the proposed criteria to three existing public administration Web sites are discussed.

Applying Web Usability Criteria for Vision-Impaired Users: Does It Really Improve Task Performance?

Available accessibility guidelines do not necessarily guarantee usable Web sites, particularly when specific groups of users with special needs are considered. We have identified 15 Web design criteria aiming to provide integrated support of accessibility and usability for vision-impaired users. In this article, we present the results of a study investigating whether the application of such guidelines for vision-impaired users can actually improve their task performance when accessing Web applications. We report on two user tests, both involving vision-impaired users, that aim to provide empirical validation of the design criteria. During each test, users had to access and navigate two versions of a Web site, one version supporting the selected design criteria and one obtained with traditional techniques. Our results indicate that the 15 design criteria improved Web site usability both quantitatively and qualitatively by reducing the navigation time needed to perform the assigned tasks and by making the Web sites easier to navigate for blind and low-vision users.

Flexible tool support for accessibility evaluation

The increasing need to check Web site accessibility has stimulated interest in tools to aid the various activities involved. While some tools for this purpose already exist, we believe that there is a demand for making their support more flexible. In particular, there is often a need for validation of multiple sets of guidelines, repairing Web pages and providing better reports for the evaluators. In this paper, we discuss such issues and how we have addressed them in the design of MAGENTA, our new tool for supporting inspection-based evaluation of accessibility and usability guidelines.

Vibrotactile feedback to aid blind users of mobile guides

In this work, we report on a solution for providing support to the blind using mobile museum guides by exploiting the haptic channel as a complement to the audio/vocal one. The overall goal is to improve the autonomy and social integration of blind visitors. We followed an iterative approach in which the proposed system went through various user evaluations and further refinements. The final solution includes vibrotactile feedback enhancement for orientation and obstacle avoidance obtained through the use of unobtrusive actuators applied to two of the users fingers combined with an electronic compass and obstacle detector sensors connected wirelessly to the mobile guide. Our study indicates that vibrotactile feedback is particularly useful to provide frequent unobtrusive indications of useful dynamic information, such as the level of proximity of an obstacle or the distance from the right orientation.

Vibrotactile feedback as an orientation aid for blind users of mobile guides

In this paper, we present a solution for supporting vibrotactile feedback in mobile museum guides for blind users. To this end, we have designed and implemented a hardware/software module, which can be easily plugged into current PDAs to assist blind users in orientation. The solution, which comprises a two-channels haptic module as well as vocal support, has been exploited for moving through tagged objects. We also report on a user evaluation carried out with a number of blind users.

Improving search engine interfaces for blind users: a case study

This article describes a research project aimed at improving search engine usability for sightless persons who use assistive technology to navigate the web. At the beginning of this research, a preliminary study was performed concerning accessibility and usability of search tools, and eight guidelines were formulated for designing search engine user interfaces. Then, the derived guidelines were applied in modifying the source code of Google’s interface, while maintaining the same look and feel, in order to demonstrate that with very little effort it is possible to make interaction easier, more efficient, and less frustrating for sightless individuals. After providing a general overview of the project, the paper focuses on interface design and implementation.

Criteria for usability of accessible web sites

The application of appropriate web site design and evaluation methods help to ensure more usable and accessible web sites. While in the literature guidelines and evaluation methods for accessibility and usability are given and discussed separately, we aim to identify the relationships between these two concepts, in particular considering usability criteria for accessible web sites. In this work, we propose a set of usability criteria for accessible web sites in order to improve the navigability for special users, i.e. the vision impaired. The identification of the 16 criteria suggested herein was performed through empirical feedback, in which simple hypotheses were formulated, then tested. Subsequently, a systematic method was developed on the basis of the tests, resulting in a classification of the criteria according to usability aspects. The proposed criteria have been applied to an existing public administration web site.

Making visual maps accessible to the blind

Visual maps deliver content in a simple and effective way. They can be useful for various purposes in areas such as street guidance, surrounding information, and education. However, sightless persons are unable to explore visual maps and risk being cut off from several multimedia Web applications. In this paper, starting from accessibility issues of map-based applications, we discuss possible interaction modalities and devices to use for truly achieving usage perspectives desired by blind people. New ways to interact with a mobile device (such as gestures or touch commands) and possible solutions for making a map truly effective are investigated. In order to better explain the issues and needs of blind users accessing visual maps, an example of an interaction is presented.

Supporting orientation for blind people using museum guides

Novel environments exploiting recent technology can enhance several tasks in applications such as mobile guides. However, in the many museum mobile guides that have been proposed, accessibility is often not explicitly addressed and the benefits of such technology are rarely made available to blind users. In this paper, we propose a solution for flexible orientation support in a multimodal and location-aware museum guide, which has been developed specifically for blind users.

Designing search engine user interfaces for the visually impaired

Search engines are a fundamental tool for retrieving specific and appropriate information on the Internet; for this reason it is essential for any user to be able to interact with simple, clear and accessible interfaces. In this paper we describe the main design issues affecting the user interface of a search engine when a sightless user interacts by means of a screen reader or voice synthesizer. In particular, the most important differences between a visual layout and aural perception are discussed, in order to propose appropriate and specific guidelines for improving the design of search engine interfaces.