Semantically Enhanced Browsing for Blind People in the WWW Michail Salampasis

Christos Kouroupetroglou

Athanasios Manitsaris

Department of Informatics, T.E.I. of Thessaloniki Thessaloniki, 57 400, Greece +30 +30 2310 791284

Department of Informatics, T.E.I. of Thessaloniki Thessaloniki, 57 400, Greece +30 +30 2310 791604

Dept. of Applied Informatics, University of Macedonia Thessaloniki, Greece +30 2310 891898

[email protected]

[email protected]

[email protected]

characterized by the existence and potential parallel use of multiple information seeking strategies. Since it is based on a hypermedia paradigm, it supports opportunistic browsing strategies (e.g. across document browsing). In addition to browsing, with the backing of web search engines, the WWW supports also analytical (i.e. query-based) strategies, because these are usually more effective in large electronic environments and could provide starting points for browsing. In this paper we specifically discuss problems of VI when browsing in the WWW and we present a solution based on metadata.

ABSTRACT The WWW is today the biggest source of information and an essential tool for many activities of daily life. Unfortunately, information seeking in this complex hypermedia environment is generally not an easy task. The potentially complex task of information seeking in the WWW is further complicated when the end-user is blind or visually impaired (VI). Usually, web pages are created without taken accessibility into account and without using HTML markup correctly to express the functional structure of documents. Both facts pose a lot of problems to VI during information seeking in the web. In this paper we discuss problems related to this issue and how the information seeking process in the WWW could become more effective and efficient for the VI. We also present an ongoing research effort, inspired from the idea of Semantic Web, aiming to enhance browsing efficiency as a result of rationalizing the way VI browse the WWW.

2. PROBLEMS OF BLIND USERS IN BROWSING THE WEB According to Marchionini [4] browsing can be categorized in two main categories: •

Across document browsing where users move from document to document and decide which are relevant to their information need.

•

Within document browsing where the user is reading or scanning a single (candidate) relevant document so that the appropriate information is located and extracted.

Categories and Subject Descriptors H.3.3 [Information storage and retrieval]: Information Search and Retrieval-search process, selection process.

General Terms Human Factors, Measurement.

2.1 Problems in across document browsing

Keywords

To support across document browsing usually designers and developers of web applications provide users with various navigational aids such as navigational bars, guided tours or landmark documents that could assist them in the information seeking process. The perceived expectation is that navigation will be more efficient, and in fact this expectation is confirmed by many works reported in the hypertext literature. Goble et al. [2] argues that VI need these aids even more, because this is how they navigate in physical environments. However, the detection, recognition and approach of these aids is mostly based on their visual appearance (e.g. color, position on the page). This design prevents VI to use these navigational aids because they cannot identify them easy.

Voice web browser, Semantic Web, information seeking

1. INTRODUCTION One of the main goals in the development of the WWW is accessibility for everyone. Unfortunately this goal is not yet fully accomplished and visually impaired (VI) are an example of people having problems in accessing the web. This problem becomes increasingly worse when the WWW is used for information seeking purposes. The problems of high cognitive overhead, user disorientation and low efficiency of information seeking in such large electronic environments, have long been considered as serious issues in the hypertext community [4]. It is obvious that information seeking in the WWW is less effective and efficient for VI than for sighted ones. Therefore, research efforts should be undertaken to improve the effectiveness and the efficiency in a comparable level with this of sighted users.

Also, because VI are keen on memorizing landmarks and directions, mechanisms such as bookmarks and history in browsers could make their navigation easier. However, most browsers use as identifiers of a page the URL and the title. This is a problem because URL’s are difficult to memorize and titles are not unique amongst pages.

The WWW as an information seeking environment is

Finally another problem of across document browsing is the decision making process during which a user recognizes relevant from irrelevant pages. Sighted users require few seconds to accomplish this task, since they use more efficiently functions such as content scanning that depends heavily on sight. On the contrary, VI cannot use a similar function and this makes the

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decision making process much more time consuming. Therefore we argue that a mechanism which would improve the scanning process, exploiting semantic annotation found on a web page, could be very useful during the decision making process.

machine understandable too. This is accomplished by adding metadata of some form in web pages. The idea of Semantic Web has raised many different expectations ranging from the more pragmatic of taming the Web, to the more enthusiastic that views the Semantic Web as the field in which knowledge (agent) assistants complete tasks on behalf of humans[3]. In our work, the idea of Semantic Web is used in a more pragmatic way. Metadata are used to enrich web pages in a way that could augment the browsing process of VI. Metadata can be utilized in various ways and the ultimate goal is to augment the various sub-processes of the information seeking process. One example is to supply VI with browsing shortcuts to visual cues and navigational aids. This gives VI a variety of landmarks within a page improving the (within page) browsing process.

2.2 Problems in within document browsing The second aspect of the problem involves the browsing within a web page. Sighted users reach a point of a document using a combination of functions such as scanning, observation etc. These functions depend heavily on a variety of visual cues such as colors, headlines, tables etc., which are not accessible to VI. However, if structural elements and visual cues are annotated properly, a VI person using specialized voice browsers could comprehend easier and arrive faster at a specific point of a web page.

Another way to make browsing more efficient could be achieved by adapting the structure of a web page, or by restructuring a document according to user needs. Those needs might be explicitly expressed by the blind user (e.g. “I need to hear the menu on this page before anything else.”), or can be deducted proactively according to a learning process based on previous experience (e.g. the user always moved to main context of the page on previous visits, so s/he needs to hear it first.).

Besides visual cues, VI cannot reach the core content of a web page for three main reasons: •

firstly, because of the construction of web pages. It is well known that in modern web design, pages are constructed with sighted users in mind, usually with lots of peripheral material next to the main content of a web page. Basic navigational aids such as a web page (document) contents index that will help VI to move to specific points of a document are not available.

•

Secondly, inspection and analysis of existing web pages, even those produced using “sophisticated” web authoring tools, shows that HTML is rarely used as functional markup to capture the structure of a document. For example heading tags such as

,

are not used to express the structure of a web page. If tags would be used better, the functional meaning expressed could help VI to navigate easier.

The second use of metadata is to semantically annotate the actual content of web pages. This type of annotation can be utilized in various ways too. The first one is similar to browsing shortcuts for visual cues and navigational aids (e.g. move directly to sports news headlines on a portal page). Similarly, web pages could also be rearranged from the browser based on either previous user behavior or user request. In addition this information will mainly help in the across document browsing since it will enable a scanning simulation process which will give a brief overview of the page content (e.g. this page has 3 sports headlines about football and 5 about basketball).

•

Finally, because of the serialized-monolithic way that web pages are spoken out from voice browsers and screen readers (usually from top left to bottom right corner). A potential solution to the problems described above could be to annotate a web page. For example annotation in a news portal may inform a VI that there is a sports news section, a political news section and so on. Based on this information the VI could move faster to the interesting points of a web page.

From a technical perspective, the application framework which is briefly discussed above requires three components which in our implementation are: •

Finally, as already discussed blind users need landmarks and routes during their browsing. However, current generic and specialized voice web browsers do not have such a mechanism. Semantic annotation could also the basis for providing functions similar to bookmarking and history, but in this case to facilitate within page browsing.

A semantic vocabulary based on ontological approach.

•

An annotation tool, which uses the vocabulary to create annotated web pages.

•

A specialized voice web browser, called SeEBrowser, which exploits the annotations to semantically enhance the browsing.

3.1 The vocabulary. The vocabulary used is developed in OWL and serves two objectives:

3. THE SEMANTICS SOLUTION The issues raised and the problems discussed in Section 2 are not solved by guidelines such as the W3C Accessibility Guidelines (WCAG). WCAG deal more with primary accessibility issues of user interface elements, and do not take into strong consideration the problems encountered during an information seeking process that have been discussed in Section 2. The problems of VI searching for information in the WWW, are related more to inefficiency of the information seeking process. Inefficiency comes both as a result of inability of VI to use navigational aids and also to rationalize both across and within document browsing.

•

Describe visual cues and navigational aids used by sighted users such as menus, headers, footers etc. in order to help in the navigation within a web page.

•

Describe specific subject domains such as the news, educational sites etc.

3.2 The annotation tool. The annotation tool is used by annotators who apply the concepts described in the vocabulary to annotate a web page or a set of web pages based on annotation templates. It can produce either annotated web pages that include special attributes and values within the annotated tag elements, or external annotation files in RDF format, stored in external annotation servers.

This is the focus of our research work, i.e. to utilize the idea of Semantic Web for making the browsing process of VI more efficient. The “Semantic Web” [1] is the next era of the WWW which aims to produce web sites that are not only human but

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3.3 The SeEBrowser agent

4.2 Results

The SeEBrowser browser (Semantically Enhanced Browser) is a specialized voice web browser based on the Demosthenes text-tospeech system [5]. It presents web pages aurally and if the web page is properly annotated, provides shortcuts to the annotated elements. The browser decomposes a web page in two levels. The first one is determined by the browsing mode selected, where browsing mode can be either full document mode or links mode. The browsing mode determines in which group of elements will the user navigate through. The second level is the speaking mode and can be set either to paragraph by paragraph, sentence by sentence or word by word speaking.

The evaluation was based on the following 3 sources:

The distinctive feature of SeEBrowser is the ability to use metadata within a web page. The function implemented in the experimental prototype discussed in Section 4, was the move directly to annotated parts of the document. For example, if there is a section in the page appropriately annotated as a navigation bar or a contents list, then the user can be informed about its existence and can move directly to this point. When the navigation through the specific element is achieved, the navigation continues to the rest of the page according to the browsing and speaking modes selected.

•

Log files keeping the keystrokes of each user and timestamps for each of them. Log files were further coded and analyzed so we could have measurements of how many keystrokes and how long did it took for each user to answer each answer.

•

A questionnaire examining their opinion about the browser generally. The questionnaire was investigating their background and relevance to the information problem, their opinion on various features of the browser and their how easy and friendly they found the interface.

•

A short interview about their general impression of the browser, possible improvements and defects found during use.

Although some marginal differences were measured, statistical analysis of the log files showed no significant differences in terms of time and keystrokes needed for answering a question. The questionnaire provided useful feedback indicating that the browser was quite user friendly and the shortcuts feature was very helpful. More specific all users rated as highly useful the shortcuts feature and the usability increased radically when the feature was used. Finally, in the interviews after the experiment most of the users pointed out the usefulness of the shortcuts and asked for further development of this feature.

5. DISCUSSION Summing up, usability and information seeking problems in the WWW are not yet dealt by guidelines or rules such as WCAG. An approach for solving this kind of issues may be based on annotation of web pages. Of course a crucial point in using metadata is the creation of them which depend heavily on human factor (annotators). One way to solve this problem is to enhance the metadata creation process to make it semi-automatic or fully automatic by using heuristics for discovering visual cues, navigational aids and semantics within pages.

Figure 1: Screenshot of SeEBrowser with available special elements shown in rectangles

In conclusion, initial evaluation of our work demonstrates that blind users could benefit from semantically enhanced browsing to improve the efficiency of information seeking in the WWW.

4. EVALUATION The browser described previously was tested and evaluated from a group of blind users. The purpose of the evaluation was twofold. The first one was to get some feedback on its user-friendliness and acceptance by the blind users. The second reason was to identify whether an annotated web page was more usable than a non-annotated one.

6. ACKNOWLEDGMENTS This research project is funded by the Greek Ministry of Education under the research program “Archimedes”.

7. REFERENCES [1] Berners-Lee, T. Semantic Web roadmap. Available at

4.1 Environment

http://www.w3c.org/DesignIssues/Semantic

The investigation involved 6 blind users separated in 2 groups. Each user conducted 3 search sessions based on a given question. The first group was given one set of questions to answer and users were not informed for the existence of shortcuts. In the second group users were informed of the shortcuts existence and their use.

[2] Goble, C., Harper, S. and Stevens, R. The travails of visually impaired web travelers, In: Proceedings of the eleventh ACM on Hypertext and hypermedia, ACM Press, 2000, 1-10. [3] Marshall C. and Shipman F. Which Semantic Web? In proceedings of the ΗΤ03 conf., Nottingham, UK, 2003, 57-66. [4] Marchionini, G., Information Seeking in Electronic Environments, Cambridge University Press, Cambridge, UK, 1995. [5] Xydas G. and Kouroupetroglou G. The DEMOSTHeNES Speech Composer, Proceedings of the 4th ISCA Tutorial and Workshop on Speech Synthesis (SSW4), Perthshire, Scotland, September 2001, pp. 167-172.

The experimental site had 20 web pages containing information about Greece. The web pages (only in second group) were annotated to inform SeEBrowser for the existence of a navigational bar, a table of contents and a content element , which means that users could be informed of their existence and move directly to them if needed (Figure 1).

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