1,721,030 research outputs found
Is accessibility conformance an elusive property? A study of validity and reliability of WCAG 2.0
No full textThe Web Content Accessibility Guidelines (WCAG) 2.0 separate testing into both “Machine” and “Human”
audits; and further classify “Human Testability” into “Reliably Human Testable” and “Not Reliably Testable”;
it is human testability that is the focus of this paper. We wanted to investigate the likelihood that “at least 80%
of knowledgeable human evaluators would agree on the conclusion” of an accessibility audit, and therefore
understand the percentage of success criteria that could be described as reliably human testable, and those
that could not. In this case, we recruited twenty-five experienced evaluators to audit four pages for WCAG
2.0 conformance. These pages were chosen to differ in layout, complexity, and accessibility support, thereby
creating a small but variable sample.
We found that an 80% agreement between experienced evaluators almost never occurred and that the
average agreement was at the 70–75% mark, while the error rate was around 29%. Further, trained—but
novice—evaluators performing the same audits exhibited the same agreement to that of our more experienced
ones, but a reduction on validity of 6–13%; the validity that an untrained user would attain can only be a
conjecture. Expertise appears to improve (by 19%) the ability to avoid false positives. Finally, pooling the
results of two independent experienced evaluators would be the best option, capturing at most 76% of the
true problems and producing only 24% of false positives. Any other independent combination of audits would
achieve worse results.
This means that an 80% target for agreement, when audits are conducted without communication between
evaluators, is not attainable, even with experienced evaluators, when working on pages similar to the ones
used in this experiment; that the error rate even for experienced evaluators is relatively high and further,
that untrained accessibility auditors be they developers or quality testers from other domains, would do
much worse than this
How Much Does Expertise Matter? A Barrier Walkthrough Study with Experts and Non-Experts
No full textManual accessibility evaluation plays an important role in validating the accessibility of Web pages. This role has become increasingly critical with the advent of the Web Content Accessibility Guidelines (WCAG) 2.0 and their reliance on user evaluation to validate certain conformance measures. However, the role of expertise, in such evaluations, is unknown and has not previously been studied. This paper sets out to investigate the interplay between expert and non-expert evaluation by conducting a Barrier Walkthrough (BW) study with 19 expert and 51 non-expert judges. The BW method provides an evaluation framework that can be used to manually assess the accessibility of Web pages for different user groups including motor impaired, hearing impaired, low vision, cognitive impaired, etc. We conclude that the level of expertise is an important factor in the quality of accessibility evaluation of Web pages. Expert judges spent significantly less time than non-experts; rated themselves as more productive and confident than non-experts; and ranked and rated pages differently against each type of disability. Finally, both effectiveness and reliability of the expert judges are significantly higher than non-expert judges
Understanding web accessibility and its drivers
No full textAccess is what the web is 'about', it is the motivation behind its creation, and it is the rationale behind HTML. The desire to provide all users at CERN with the ability to access all documents was Tim Berners-Lee's primary goal, and this goal must also be carried through to equal access for all users. But this equality of access -- accessibility -- is difficult to quantify, define, or agree upon. In a constantly evolving field, understanding each other can be tricky; indeed, there are many different definitions in the literature, all with a different perspective. This makes it difficult for our community to interact, reach agreement, or share understanding. What is more, it makes it very difficult for those outside the web accessibility community to understand, plan, budget, enact policy, or conform to accessibility requirements and legislation when the community itself has so many, in some cases, conflicting definitions. We asked over 300 people, with an interest in accessibility, to discuss their views and definitions in an attempt to harmonise our understanding and support the expectations of users outside the community. We find that misunderstanding accessibility definitions, language, and terms might cause tension between different groups. That social, and not economic, aspects drive our perspectives of accessibility, and that definitions used by standards and regulatory bodies are most accepted - not those of individual experts. Forcing accessibility adoption does not encourage the acceptance of an accessibility ethos, but providing empirical evidence that accessibility benefits all, does. Finally, realistic and concise language was preferred when attempting to communicate, or define accessibility
Testability and Validity of WCAG 2.0: The Expertise Effect
No full textWeb Content Accessibility Guidelines 2.0 (WCAG 2.0) require that success criteria be tested by human inspection. Further, testability of WCAG 2.0 criteria is achieved if 80% of knowledgeable inspectors agree that the criteria has been met or not. In this paper we investigate the very core WCAG 2.0, being their ability to determine web content accessibility conformance. We conducted an empirical study to ascertain the testability of WCAG 2.0 success criteria when experts and non-experts evaluated four relatively complex web pages; and the differences between the two. Further, we discuss the validity of the evaluations generated by these inspectors and look at the differences in validity due to expertise.
In summary, our study, comprising 22 experts and 27 non-experts, shows that approximately 50% of success criteria fail to meet the 80% agreement threshold; experts produce 20% false positives and miss 32% of the true problems. We also compared the performance of experts against that of non-experts and found that agreement for the non-experts dropped by 6%, false positives reach 42% and false negatives 49%. This suggests that in many cases WCAG 2.0 conformance cannot be tested by human inspection to a level where it is believed that at least 80% of knowledgeable human evaluators would agree on the conclusion. Why experts fail to meet the 80% threshold and what can be done to help achieve this level are the subjects of further investigation
Exploring perceptions of web accessibility: a survey approach
No full textThe equality of access – accessibility – is difficult to quantify, define, or agree upon. Our previous work analysed the responses of web accessibility specialists in regard to a number of pre-defined definitions of accessibility. While uncovering much, this analysis did not allow us to quantify the communities’ understanding of the relationship accessibility has with other domains and assess how the community scopes accessibility. In this case, we asked over 300 people, with an interest in accessibility, to answer 33 questions surrounding the relationship between accessibility, user experience (UX), and usability; inclusion and exclusion; and evaluation, in an attempt to harmonise our understanding of web accessibility. We found that respondents think that accessibility and usability are highly related and also think that accessibility is applicable to everyone and not just people with disabilities. Respondents strongly agree that accessibility must be grounded on user-centred practices and that accessibility evaluation is more than just inspecting source code; however, they are divided as to whether training in ‘Web Content Accessibility Guidelines’ is necessary or not to assess accessibility. These perceptions are important for usability and UX professionals, developers of automated evaluation tools, and those practitioners running website evaluations
eMINE Scanpath Analysis Algorithm.
Get PDFhe existing re-engineering, namely transcoding, techniques improved disabled and mobile Web users experience by making Web pages more accessible in constrained environments such as on small screen devices and in audio presentation. However, none of these techniques use eye tracking data to transcode Web pages based on understanding and predicting users’ experience. The overarching goal of eMINE project is to improve the user experience in such constrained environments by using a novel application of eye tracking technology. The project proposes an algorithm to identify common scanpaths, which are eye movement sequences, and relating those scanpaths to visual elements of Web pages. It can then be used to transcode Web pages, for instance, unnecessary information can be removed and/or the visual elements can be re-ordered. We assert that both visually disabled and mobile users would benefit from such development
This is the second issue of NRHM in 2004, the first volume to appear with two issues. The main theme for the issue is Accessible Hypermedia and Multimedia (Guest Editors, Simon Harper, Yeliz Yesilada, Carole Goble). We would like to thank all the authors who submitted papers and the reviewers who contributed substantially both t
“Read That Article”: Exploring synergies between gaze and speech interaction
Get PDFGaze information has the potential to benefit Human-Computer Interaction (HCI) tasks, particularly when combined with speech. Gaze can improve our understanding of the user intention, as a secondary input modality, or it can be used as the main input modality by users with some level of permanent or temporary impairments. In this paper we describe a multimodal HCI system prototype which supports speech, gaze and the combination of both. The system has been developed for Active Assisted Living scenarios.info:eu-repo/semantics/acceptedVersio
“Read That Article”: Exploring synergies between gaze and speech interaction
No full textGaze information has the potential to benefit Human-Computer Interaction (HCI) tasks, particularly when combined with speech. Gaze can improve our understanding of the user intention, as a secondary input modality, or it can be used as the main input modality by users with some level of permanent or temporary impairments. In this paper we describe a multimodal HCI system prototype which supports speech, gaze and the combination of both. The system has been developed for Active Assisted Living scenarios.info:eu-repo/semantics/acceptedVersio
Özdevimli öğrenimi ile web sayfalarındaki tablo başlıklarını otomatik olarak algılama
No full textAlthough table recognition is an old research area, due to the diversity of table formats and styles on the web, the results are far from satisfactory. Automatically recognising tables, is especially important for visually disabled people who cannot see tables, because tables are among the most common way of presenting and structuring data with a high information density. This thesis aims to automatically detect table headings using Artificial Intelligence (AI) techniques, especially machine learning algorithms. In this thesis, we first try to understand various table structures and accessibility challenges for visually disabled people to achieve the best results. We then analyse the existing studies on table recognition on web pages and PDF documents. Based on the existing work, we propose first identifying relational tables, and then their headings using the rendered web page features with machine learning algorithms. We also investigate the existing data sets and conclude that we cannot use them for the proposed approach, and therefore we create our dataset based on HTML and the related information such as CSS. After that, we create a tool that extracts tables from a given page and then use the created dataset with machine learning algorithms to detect the table headings automatically. To do this, we also investigate existing machine learning algorithms to identify the best that can be used for this purpose. This thesis has two main contributions: (1) understanding table structures on the web and a large dataset of tables on the web; (2) investigating machine learning algorithms for automatically identifying the headings of tables. Based on our results achieved by using machine learning with rendered pages to detect relational tables and their headings, we concluded that by using features extracted from rendered pages perform better than using HTML structural features alone.Tablo tanıma eski bir araştırma alanı olmasına rağmen, web'deki tablo formatlarının ve stillerinin çeşitliliği nedeniyle sonuçlar tatmin edici olmaktan uzaktır. Tabloları otomatik olarak tanıma, özellikle tabloları göremeyen görme engelliler için önemlidir, çünkü tablolar, yüksek bilgi yoğunluğuna sahip verileri sunmanın ve yapılandırmanın en yaygın yollarından biridir. Bu tez, Yapay Zeka (AI) tekniklerini, özellikle de makine öğrenimi algoritmalarını kullanarak tablo başlıklarını otomatik olarak tespit etmeyi amaçlamaktadır. Bu tezde, öncelikle görme engelliler için en iyi sonuçları elde etmek için çeşitli masa yapılarını ve erişilebilirlik zorluklarını anlamaya çalışıyoruz. Ardından, web sayfalarında ve PDF belgelerinde tablo tanıma üzerine yapılan ilgili çalışmaları inceliyor ve analiz ediyoruz. Mevcut çalışmadan yola çıkarak, önce ilişkisel tabloların tanımlanmasını, ardından işlenmiş web sayfası özelliklerini kullanarak makine öğrenimi algoritmalarıyla başlıklarının tanımlanmasını öneriyoruz. Ayrıca mevcut veri setlerini araştırıyor ve bunları önerilen yaklaşım için kullanamayacağımız sonucuna varıyoruz ve bu nedenle veri setimizi HTML ve CSS gibi ilgili bilgilere dayalı olarak oluşturuyoruz. Bundan sonra, belirli bir sayfadan tabloları çıkaran bir araç oluşturuyoruz ve ardından oluşturulan veri setini, tablo başlıklarını otomatik olarak algılamak için makine öğrenme algoritmaları ile kullanıyoruz. Bunu yapmak için, bu amaç için kullanılabilecek en iyiyi belirlemek için mevcut makine öğrenimi algoritmalarını da araştırıyoruz. Bu tezin iki ana katkısı vardır: (1) Web'deki tablo yapılarını ve web'deki büyük bir tablo veri setini anlamak; (2) tabloların başlıklarını otomatik olarak tanımlamak için makine öğrenimi algoritmalarını araştırmak.M.S. - Master of Scienc
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