- From: Ian B. Jacobs <ij@w3.org>
- Date: Tue, 18 Dec 2001 14:17:45 -0500
- To: w3c-semweb-ad@w3.org, w3c-wai-ua@w3.org
Dear Semantic Web Advance Developers and User Agent Accessibility Guidelines Working Group, NOTE: I have sent this email to two mailing lists, w3c-semweb-ad is Member-confidential and w3c-wai-ua is public. If possible, I would like for this discussion to go on on the public UAWG mailing list. On 14 December, Eric Miller and I started thinking about how to represent in RDF relationships between the accessibility requirements of W3C's UAAG 1.0 [1] and those of section 508 [2]. The User Agent Accessibility Guidelines Working Group (UAWG) would like to have a resource to show developers how the documents relate. Some of the UAWG participants began to write up relationships in HTML [3], but this seems like a great RDF application from which we could (1) generate multiple views (2) do some automation, for example in the area of test suites and evaluations. I am primarily interested today in different views of the relationships. While RDF seems to be the obvious choice for representing these relationships, what I have found by comparing the two documents is that the relationships are very fuzzy. Rare are the requirements one could really call equivalent. And it is even rare that one neatly subsumes another. The most comment relationship seems to be "overlaps", and it would be good to be able to add information to explain where two requirements do and don't overlap. This is my first foray into Semantic Web work, so I hope that the Semantic Web Advance Development (SWAD) folks will take this opportunity to educate not just me but all those on the UAWG mailing list. In particular, I look forward to your comments on a) How to represent these relationships in RDF. b) How to represent what seem to be fuzzy relationships. You probably have experience with vocabularies that may do some of what we are trying to do. Furthermore, Charles has pointed out that we should be thinking of EARL [4] at the same time. For instance, if we write down in EARL that a user agent U satisfies 10 requirements in UAAG 1.0 and in turn we have written down in RDF that satisfying those 10 requirements implies satisfaction of 12 section 508 requirements, machines will be able to deduce that U also satisfies section 508 requirements. Refer to the implementation reports of UAWG [5], not yet in EARL but we hope to migrate to EARL soon. Below are some suggested attributes and relationships. Your comments are very welcome! - Ian ---------- ATTRIBUTES ---------- - Priority. UAAG 1.0 checkpoints are prioritized (1,2,3) and section 508 checkpoints are not, so by default, all 508 checkpoints should be considered priority 1. When comparing two requirements, they may be the same technically, but have different priorities and thus need to be distinguished. - Content v. User Interface. Both documents distinguish content and user interface. For example, from 508, Subpart B, 1194.21: (k) Software shall not use flashing or blinking text, objects, or other elements having a flash or blink frequency greater than 2 Hz and lower than 55 Hz. In UAAG 1.0, checkpoint 3.3: 1.Allow configuration to render animated or blinking text as motionless, unblinking text. Comment: In UAAG 1.0, the control is only required for content. In 508, presumably the requirement is for both content and UI (though not entirely clear). In conjunction with an "Overlaps" relationship, one could learn that the two requirements differ along the content/UI axis. - Output modality. UAAG 1.0 identifies three output modalities: visual, audio, braille. UAAG 1.0 doesn't include any braille requirements. Section 508 includes primarily visual requirements. Two requirements might be the same except that the UAAG 1.0 also applies to audio output (e.g., focus highlight). Thus, the requirements need to be distinguished along this axis. - Topic. I would like to be able to suggest some categories for grouping relationships. These categories would be based on the table of contents of either UAAG 1.0 or section 508, for example. Should this be an attribute or more RDF that you layer on top of the requirement relationships? ------------- RELATIONSHIPS ------------- - 'overlaps'. In most cases, the requirements of the two documents are very similar, and overlap in some way. It would be useful to be able to indicate where two requirements overlap and where they don't. For example, from 508, Subpart B, 1194.21: (a) When software is designed to run on a system that has a keyboard, product functions shall be executable from a keyboard where the function itself or the result of performing a function can be discerned textually. UAAG 1.0, checkpoint 1.1: 1.Ensure that the user can operate through keyboard input alone any user agent functionality available through the user interface. Comment: Both requirements involve the keyboard. Both requirements carve out exceptions (508 exceptions: it doesn't apply when software not designed for keyboard or when function cannot be discerned textually. UAAG 1.0 exceptions: doesn't apply if not available through the UI). The exception cases are different, so the requirements are not equivalent, and one does not strictly subsume the other. - equivalence relationships. There are few cases of real equivalence between UAAG 1.0 and section 508. [There are equivalent requirements in WCAG 1.0 and the Web content part of section 508 since there was greater coordination.] There are shades of equivalence, but I'm not sure how to represent those shade, nor do I have concrete criteria for picking one shade over another. For instance, we might have 'nearlyEquivalentTo'. From 508, Subpart B, 1194.21: (b) Applications also shall not disrupt or disable activated features of any operating system that are identified as accessibility features where the application programming interface for those accessibility features has been documented by the manufacturer of the operating system and is available to the product developer. UAAG 1.0, checkpoint 7.2 1. Ensure that default input configurations do not interfere with operating environment accessibility conventions. Comment: There is an exception carved out for 508 (when API not documented, don't need to do this), but these requirements are nearly equivalent. Another example: 508 d.1 and UAAG 1.0, 6.4.1 Another example: 508 c.1 and UAAG 1.0, 10.6. However, UAAG 1.0 is more than visual highlighting. See "output modality" attribute. - 'partOf'. N requirements together from document A may comprise a single requirement of document B. Note: since we are interested in sentence level comparisons (refer to note on references below), "partOf" means that the requirement made by a given sentence is part of a requirement made in the other document. Example: 508 c.2 is met by UAAG 1.0, 9.1.1 + 9.2.1 + 6.5.1 - 'seeAlso'. For cross references to related requirements. Example. From 508: (e) When bitmap images are used to identify controls, status indicators, or other programmatic elements, the meaning assigned to those images shall be consistent throughout an application's performance. Comment: There is no corresponding requirement in UAAG 1.0, but the WG expects that related requirements will cover this one. For instance: UAAG checkpoint 7.3 1. Follow operating environment conventions that benefit accessibility. In particular, follow conventions that benefit accessibility for user interface design, keyboard configuration, product installation, and documentation. ------------------------ Citing requirements ------------------------ * For Section 508: Subpart, para, provision (e.g., Subpart B, 1194.21, provision a). * For UAAG 1.0: Checkpoint, provision (e.g., checkpoint 2.3, provision 3). In both cases, we would like to have sentence-level comparisons. ------------------------------------------------- [1] http://www.w3.org/TR/UAAG10/ [2] http://www.access-board.gov/sec508/508standards.htm [3] http://www.w3.org/WAI/GL/508/508-UAAG.html [4] http://www.w3.org/WAI/ER/#earl [5] http://www.w3.org/WAI/UA/implementation/report-cr2-checkpoint-summary -- Ian Jacobs (ij@w3.org) http://www.w3.org/People/Jacobs Tel: +1 718 260-9447
Received on Tuesday, 18 December 2001 14:17:45 UTC