Amaia Aizpurua

Automatically generating tailored accessible user interfaces for ubiquitous services

Ambient Assisted Living environments provide support to people with disabilities and elderly people, usually at home. This concept can be extended to public spaces, where ubiquitous accessible services allow people with disabilities to access intelligent machines such as information kiosks. One of the key issues in achieving full accessibility is the instantaneous generation of an adapted accessible interface suited to the specific user that requests the service. In this paper we present the method used by the EGOKI interface generator to select the most suitable interaction resources and modalities for each user in the automatic creation of the interface. The validation of the interfaces generated for four different types of users is presented and discussed.

Evaluating web accessibility for specific mobile devices

This paper presents a tool for evaluating web accessibility for mobile devices regardless their software, hardware or user agent characteristics. Taking the mobileOK Basic tests by the W3C as a basis, these tests are extended so that device characteristics can be considered in the evaluation process. A sound tool that takes into account these extended tests has been developed. Device features of a given device are retrieved from heterogeneous device description repositories and CC/PP based profiles are automatically generated. Based on these profiles, evaluation queries are dynamically created obtaining device-tailored evaluation reports. Finally, in order to demonstrate the feasibility of the tool, a case study has been conducted concluding that the tool reduces the number of false positives and false negatives.

Transition of accessibility evaluation tools to new standards

While automatic tools are not intended to replace human judgement they are crucial in order to develop accessible web sites. The release of WCAG 2.0 entails that the existing plethora of accessibility review tools will have to be updated. This paper presents an evaluation framework for making the transition from WCAG 1.0 to WCAG 2.0 in a less painful way. A framework is thus proposed that allows developers to create new guidelines, and update or reuse the existing ones. A case study to test its feasibility has been carried out by incorporating WCAG 2.0 guidelines into the framework. The results are satisfactory, since 55% of the automatic and 16% of the semi-automatic ones could be expressed using the framework. Therefore, it is demonstrated that even if the framework does not fully support the transition process, at least it makes it less burdensome. Moreover, by analyzing WCAG 2.0 we have learnt how to extend the existing tools in order to provide greater coverage and thus increase their effectiveness.

Uncovering the role of expectations on perceived web accessibility

Compliance to accessibility standards does not guarantee a satisfying user experience on the Web. Both unmet content and functionality expectations have been identified as central factors on the lack of coverage shown by guidelines. We expand on this by examining the role played by subjective dimensions, and particularly expectations, on the perception that users have on web accessibility. We conducted a study with 11 blind users to explore how these expectations shape the perception of web accessibility. Our preliminary findings corroborate that expectations can affect the perception of web accessibility. Additionally, we find that expectations on the Web are built up on previous experiences and prejudices. What is more, we reveal that these expectations are not only shaped by previous Web usage, but also by real life experiences. Our outcomes suggest that user expectations should be considered in user tests.

Validating the effectiveness of EvalAccess when deploying WCAG 2.0 tests

While automatic tools are not intended to replace human judgment, they are crucial in order to develop accessible websites. The release of WCAG 2.0 has caused great expectation, as it is supposed to be precisely testable with automated review tools. Therefore, more effective tools could be developed. However, so far few tools applying WCAG 2.0 have been developed. This paper presents an evaluation framework which has been updated in order to evaluate the new tests. In addition, it describes a validation process carried out in order to verify the effectiveness of the new version of the evaluation tool. The effectiveness is validated by conducting a quantitative and qualitative analysis of the results obtained by applying both versions of the tool (the one implementing WCAG 1.0 and the one implementing WCAG 2.0) to a set of selected web pages, as well as by manual evaluation of an expert for detecting the possible false positives and false negatives produced by each tool.

Automatic device-tailored evaluation of mobile web guidelines

Mobile web guidelines aim at providing developers with guidance to develop web content suitable for mobile devices. Automatic guideline review tools help evaluating conformance with respect to these guidelines in a systematic way. Yet, a number of mobile web guidelines refer to specific device features such as screen size, support for particular picture formats or support for pointing device. Since mobile devices are very diverse, in order to address the greater number of devices, guidelines adopt a device profile that may be considered as the common denominator device which is able to provide a satisfactory experience. While this approach is useful to define guidelines and make them more understandable, it introduces critical inaccuracies that make tool effectiveness decrease. This paper presents an application that considers specific device features in the evaluation process to produce device-tailored reports. As a result, higher rates of evaluation tool completeness, correctness and specificity are obtained.

Are users the gold standard for accessibility evaluation

User testing is considered a key part of web accessibility evaluation. However, little is known about how effective is for identifying accessibility problems. Our experience, informed by a series of studies with blind users, corroborates that a website with a significant number of guideline violations can be perceived as accessible, and on the contrary, some participants may not perceive a highly accessible website as accessible. Accessibility guidelines are often criticised by their partial coverage and questionable validity. However, we should be very careful about making categorical statements in this regard as there are a number of variables that may introduce biases in user tests. We identify sources of bias related to user expertise, the experimental setting, employed language and reporting that, if not adequately controlled, may influence on the validity and reliability of the evaluation results. We discuss the limitations and practical implications of user testing with blind users for web accessibility evaluation.

Extending In-Home User and Context Models to Provide Ubiquitous Adaptive Support Outside the Home

Ubiquitous Computing has proved to be an excellent way of providing technological support for the daily life of people within its range. Ambient Assisted Living (AAL), which is largely based on Ubiquitous Computing, aims at tutoring and supervising elderly people and users with physical, sensory or cognitive disabilities in the performance of routine household activities. AAL’s main aim is to increase the autonomy of dependent people in their daily life by providing them with supportive instructions for everyday routines and warnings about home safety issues. This concept can be extended to public spaces, where ubiquitous accessible services allow people with disabilities to access location-dependent web services (providing maps, addresses, transport schedules, etc.) and local intelligent machines (such as information kiosks or ATMs). This approach allows existing knowledge about the users, their common activities, and their environment to be used to extend the in-home AAL concept to the support of common routines performed outside the home. This chapter surveys the modelling techniques used inside the home and discusses the methodologies required for their extension for out-of-home use, including interoperation and sharing of models.

Exploring Automatic CSS Accessibility Evaluation

Automatic evaluation tools are crucial for helping designers to develop accessible web content. However, most of the existing automatic tools are focused on evaluating the accessibility of (X)HTML code and do not consider style sheets. CSS provides mechanisms for separating content from display which is a requirement for accessible web documents. Although the use of CSS has become essential, sometimes its powerful mechanisms and functionalities may lead to a misuse. This paper presents an accessibility evaluation framework for verifying the correct application of CSS techniques. For this purpose, a flexible accessibility evaluation framework was selected and adapted to incorporate CSS test cases defined in WCAG 2.0. As a result of a detailed analysis, 6 different types of test cases were identified and a total number of 92 test cases were accommodated into the framework. This process has lead to obtain a flexible framework which performs more comprehensive automatic evaluations.

Some issues regarding the design of adaptive interface generation systems

This paper describes the main issues related to the design of user adaptive interaction systems, in order to discuss their applicability to a specific domain: the automatic generation of accessible user interfaces for people with disabilities who make use of ubiquitous services. Advances in the domain of the accessible Web are especially interesting for this purpose. Nevertheless, even if several procedures are similar, there are specific features that require new approaches, such as the formal specification of the functionality of the interface that will be generated.