Making hypertext based
study material accessible and user friendly to blind
students
- Abstract
- Table of contents
- Content
- Author information
- Bibliography
Abstract
This paper explains the services provided and the current
projects at the Dresden University of Technology. The primary goal of
the projects is to make study
material accessible over the World Wide Web to blind and
partially sighted students by using structured
hypertext based document formats, like SGML. The paper describes the
material preparation processes
and the strategies used to improve access by blind students. We also
describe a Web service that
transforms validated HTML documents into American, French, and
German Braille.
The final part
of the presentation describes a project to design and implement a
hypertext Script Reader for SGML
based documents, running on the graphical user interface Windows. This
program will allow a blind
user to read documents that follow a particular guideline to design
accessible study material, on
the WWW.
Development and improvement of designing methods for
accessible and user friendly
information systems is the main challenge of this work.
Table of
contents
- Introduction
- Improving access to study material
- Preparation of accessible study material
- Transformation of ASCII documents into HTML
- Transformation of HTML documents into Braille
- Hypertext reader for SGML based study material
- Script Reader
- Table Browser
- General principles
- Provided functions
- Conclusion
This paper explains the services provided and the current projects at the Dresden University of Technology. The primary goal of our projects is to make study material accessible to blind and partially sighted students by using structured hypertext based document formats,
like SGML [1]. The advantage of using SGML based document formats to
improve the quality of electronically available reading material for print disabled persons is described in
reports about the EU projects HARMONY [2] and MATHS [3] and
in our report "A Journal Header Reader for the blind", [4] presented at the SGML
Europe conference in May 1995.
The most common SGML DTD is HTML, used in the WWW.
This document format provides structured markup which allows us to represent text based study material in an accessible format to blind users.
Usually accessible study material at the Dresden University of Technology is provided in flat ASCII format. Information about the structure of the document, tables, mathematical expressions, graphics and pictures are represented in a textual format, according to particular guideline developed at the German Universities Dresden and Karlsruhe. The guideline (Tutorenanleitung -
zur Umsetzung sehgeschädigtengerechter Studienmaterialien) [5] describes the following rules: - the general structure of an accessible
document
- how to set up tables in textual form
- how to capture and describe graphic information and pictures
Mathematical expressions are specified in a particular notation called AMS (ASCII
Mathematik Schrift) [6], which uses a programming language like syntax of ASCII characters to linearize
equations. - Example AMS01 (A fraction):
- y = (x**2 + 3x4)/(x-1)
- Example
AMS02 (An integral):
- y = Int[0;z] e**x dx
Blind and partially sighted students in Dresden
do have access to the documents by using PC's with adaptive technology (Braille display, screen magnifier and speech synthesizer) in a local area network. The file service which stores these documents is called ELVIS (Elektronisches Literaturverzeichnis und Informationssystem für Sehgeschädigte) [7]. The provided study material in ASCII Format is
less structured, which makes searching and linking for particular data
difficult for the user. Our
group decided to look for opportunities to improve access to the
documents by using a platform
independent structured hypertext system, like the WWW.
To make study material accessible
over the Web, we
developed a transformation service for ASCII text documents into the
HTML format. The
transformation is implemented as a batch process on a UNIX platform.
The process is designed into
two steps. The first step converts the ASCII files into a format
according to the ICADD22 DTD
[8]. This DTD provides a basic set of SGML elements
necessary to markup a
document structure which is accessible to print disabled persons. This
particular set of markup,
designed by the ICADD (International Committee for Accessible Document
Design), provides easy
access to the general document structure in translating the data into
different formats e.g. Braille, large
print and computer voice.
The second step converts the ICADD files into
the HTML V. 2.0
format.
In the current version of the service, tables are represented
as plain text without using the
particular HTML markup.
Mathematical expressions, which are given
in the AMS notation, are
not changed during the conversion process. This kind of data remains in
the format and can be read by
using text oriented WWW browsers.
To extend the service with the
capability of translating tables
and mathematical expressions into the appropriate HTML markup, it is
necessary to improve our
designing guideline for the ASCII documents. A new approach of this
guideline is available in German
at:
- URL: http://elvis.inf.tu-dresden.de/~kahlisch/rl_v01/
Note, there is an English
document available "Guidelines
for the preparation of text
materials on computer disk for people with print disabilities" [9], it describes a
similar approach to provide structure information into ASCII
documents. The new guideline uses a
number of tags, similar to the HTML markup, to represent more
structure in the documents. This will
allow us to rewrite and to improve the transformation
process.
To provide
better access to the WWW,
for persons who can read Braille, we developed a form based
transformation service for HTML
documents into American, French and German Braille. This service is
designed by using the
ICADD guidelines for the transformation of SGML documents into
accessible formats for print
disabled persons, published in Appendix 8 of the standard ISO 12083 [10]. The
TU Dresden "International HTML to Braille Service" extends Jeff
Suttors [11] idea
of translating HTML files into American Braille, from one - into three
languages. The transformation
of the documents into the different Braille notations is designed by the
use of the German HBS
software [12]. The service is available at:
- URL:
href=http://elvis.inf.tu-dresden.de/html2braille/> http://elvis.inf.tu-
dresden.de/html2braille/
The following Braille formats are
available: - German
contracted Braille
- German uncontracted Braille
- French
uncontracted Braille
- American
uncontracted Braille
After filling out and submitting the form, the
specified document will
be translated automatically into the chosen Braille format and
displayed by the browser. The user can
read the result with a Braille display, store the information on disk or
print it with a Braille
printer. A paper, presented at the international conference ICCHP [13],
explains in more detail the implementation of the service and how it
can be used.
Our
current project
"Präsentation von elektronischen Dokumenten für blinde
Menschen" [14]
is due to establish access to hypertext based study material for blind
students. By developing a SGML
based Script Reader, we would like to make our prepared study material
more accessible by using the
WWW. The Script Reader will
run on MS-
Windows 3.X and will be implemented by use of a particular SGML
browser engine ViewPort
href=#b15>[15]. This software, developed by the Swedish company
SYNEX, is used in the
SGML browser PANORAMA [16] from Softquad Inc. The
Script Reader will
provide the following features:
- Access to structured documents
over the network
- Hypertext
navigation
- Presentation of mathematical expressions in the AMS
notation
- Rendering of
HTML tables into textual format
The use of the SGML browser
engine will only allow us to
make study material accessible, which is validated SGML, according to
the HTML DTD. Currently
we work with the HTML V. 2.0 and the table DTD. These DTD's
provide, except for the math markup,
all needed capabilities to describe the study material. The SGML
functionality in the Script Reader will
allow us to change this in further versions. By using bridge software
(Windows screen reader) to
make the graphic user interface accessible to the blind user, the Script
Reader will offer the following
functions in separate windows:
- Document viewing
- Table of
contents
- Tables
rendering
- History
- Bookmarks
The window, which is activated,
will use the full screen
to display the information. By highlighting hypertext links, the user can
trace and navigate through the
given structure of a document. The system will not provide functions
to edit or manipulate the
documents but the user can extract and save information in private note
- or bookmark files. The
history function can be used to trace particular information and
to memorize document
ancestries.
HTML Tables will be treated from the Script Reader
in a separate window
by using a particular table browser. The concept for the navigation
and presentation of table
information was developed by a student of computer science as part of his
master's degree
href=#b17>[17]. To test and evaluate the developed concepts, the
first version of the
table browser is implemented as a separate Windows 3.X application. It
renders less and more complex
structured HTML tables in different ways and displays the information
in a way, which is accessible to
blind users. A less structured and small table is displayed in a two
dimensional way. Tables which are
more complex are displayed using one line of the computer screen for
each cell.
To support
cooperative work of the blind user together with sighted people, the
table browser additionally displays
a small image of the general structure of the current table. This image
can be found in a corner of the
computer screen and does not disturb the blind user.
The current version of the separate table browser
provides general functions over
a pull-down-menu. The following table shows the items of the main
menu and their general functionality:
Table TAB01: (Items of the table browser main menu)
item general functionality
------------------------------------------------------------
FILE open, close or store a table
SEARCH search for content in a cell, repeat search
NAVIGATION table - and cell navigation functions
STATISTIC shows the complexity and the number of
rows, columns and cells in a table
WINDOWS grouping and appearance of windows
HELP information on how to use the program
After a blind user has chosen a table he would like to read, by using the FILE menu, the
SEARCH and the NAVIGATION menus become accessible in the main menu item list. The
Cursor is located on the title of the table.
To get an overview of the displayed table, the user can activate the STATISTIC menu. The STATISTIC window contains information about the complexity of the table and the number of rows, columns and cells in the current table. The complexity is a value between 0 (no complexity) and 1 (highest complexity). It tells the user, whether there are multiple lines in table cells or not.
Note, complexity is calculated as a quotient of vc (virtual cells) divided by vc plus rc (real cell). The vc is the sum of all COLSPAN and ROWSPAN attribute values in one table. The rc is the number of all cell elements in the current table.
To search for particular content in a table, the user can open the SEARCH menu.
By chosing items from the NAVIGATION menu, the cursor is located to the requested position in the table. Most items in this menu are also available as hotkeys. The following navigation functions are available:
Table TAB02: (Functions available to navigate into a table)
Menu item Description Hotkey
-------------------------------------------------------------------------------------------------
HORIZONTAL
HEADER CELL, cursor to the left header cell in a row , CTRL+H
VERTICAL
HEADER CELL, cursor to the top header cell in a column, CTRL+V
RIGHT CELL , cursor to the right cell, CTRL+CURSOR-RIGHT
LEFT CELL, cursor to the left cell, CTRL+CURSOR-LEFT
ABOVE CELL, cursor to the cell above , CTRL+CURSOR-UP
BELOW CELL, cursor to a cell below, CTRL+CURSOR-DOWN
GO TO A CELL, cursor to a requested position (row, column), CTRL+G
CURRENT CELL , cursor to the beginning of the current cell, CTRL+A
UNDO, reverse the last navigation, CTRL+Z
The listed control-key-functions allow the user to navigate from cell to cell in the
structure of a table. The regular cursor keys can be used to move the cursor only in a cell.
These two levels of navigation (outside - and inside a cell navigation) help the blind user explore the structure and the content of a table.
At the end of our project, a new version of the table browser will be integrated in the first version of the Script Reader. It will have the capabilities of downloading files from the network and presenting
tables which are included in HTML documents. In further projects it will be possible to extend the program
with facilities to render HTML Math markup and tables in tables.
Any Feedback regarding this matter would be sincerely appreciated.
Author
information - Author:
- Thomas Kahlisch
- Address:
- Dresden University of Technology
Department of Computer
Science
Institute of
Information Systems
01062 Dresden
Germany
Phone: +49 351
463 8410
Fax:
+49 351 463 8491
Email: kahlisch@inf.tu-dresden.de
WWW: http://elvis.inf.tu-dresden.de/~kahlisch
Bibliography - [1]
- ISO, ISO 8879:1986 Information Processing - Text and Office Systems -
Standard Generalized Markup Language (SGML), Geneva, 15 October 1986.
- [2]
- B. Bauwens, J. Engelen, F. Evenepoel, C. Tobin, T. Wesley:
Structuring Documents: the Key to Increasing Access to Information for the Print Disabled in: 4th International Conference ICCHP '94, Proceedings, Vienna 1994.
- [3]
- European maths project,
URL: http://www.grif.fr
/grifwork/tide.html
- [4]
- Th. Kahlisch, Gunthild Vogel:
A Journal Header
Reader for the blind,
SGML Europe'95 Conference, Gmunden 1995,
URL: http://elvis.inf.tu
dresden.de/~kahlisch/europe.html
- [5]
- TU Dresden, AG Studium für Blinde und
Sehbehinderte, Universität Karlsruhe, Studienzentrum für
Sehgeschädigte:
Tutorenanleitung - zur Übertragung
sehgeschädigtengerechter
Studienmaterialien, 1995.
- [6]
- TU Dresden, AG
Studium für Blinde und Sehbehinderte, Universität Karlsruhe, Studienzentrum
für Sehgeschädigte:
ASCII-Mathematikschrift für Blinde,
1993.
- [7]
- TU Dresden, AG Studium für Blinde und
Sehbehinderte:
ELVIS
(Elektronisches Literaturverzeichnis und Informationssystem für
Sehgeschädigte),
URL:
http://elvis.inf.tu
dresden.de/
- [8]
- ICADD,
(International Committee for Accessible
Document
Design),
Chair America: George Kerscher
<kerscher@montana.com>
Chair Europe:
Tom Wesley <T.A.B.Wesley@bradford.ac.uk>
- [9]
- Round Table on
Reading Materials for People with Print Disabilities Inc.:
Guidelines for
the preparation of text
materials on computer disk for people with print disabilities, V. 1.0,
Sydney, July, 1995.
- [10]
- ISO,
ANSI / NISO / ISO 12083 Electronic
Manuscript Preparation and
Markup, Annex 8: Facilities for Braille, large print and computer voice,
1994.
- [11]
- Jeff Suttor:
HTML to ICADD Transformation
Service, University of
California - Los Angeles,
URL: http://www.ucla.edu/ICADD/html2icadd-form.html
- [12]
- HBS (Hagener Brailleschrift
System),
Fernuniversität Hagen -
Gesamthochschule, Zentrum für Fernstudienentwicklung, Red.
Fernstudium für
Sehgeschädigte.
- [13]
- Th.
Kahlisch:
Improving access to
hypertext-based study material for the blind. In: Interdiscipliniary
Aspects on Computers Helping
People with Special Needs, Proceedings, Linz 1996,
URL: http://elvis.inf.tu
dresden.de/~kahlisch/icchp.html -
[14]
- TU Dresden, Lehrbereich Mensch-Maschine
Kommunikation
ifS, Drittmittelprojekt: Präsentation von elektronischen
Dokumenten für blinde
Menschen,
URL: http://elvis.inf.tu-
dresden.de/projekte/proj2.html
- [15]
- SYNEX
Inc.:
ViewPort
(SGML browser engine),
URL: http://www.synex.se/
- [16]
- SOFTQUAD Inc.:
PANORAMA (SGML
browser),
URL: http://www.sq.com/
- [17]
- A. Al-Kouni:
Tabellen-Browser für Blinde, TU Dróeesden, Institut für Informationssysteme,
Diplomarbeit Dezember 1996.
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