Title in audio
ASTER Demonstration
is dedicated to my Guide-Dog. AsTeR --Audio System
For Technical Readings-- is a computing system for rendering
technical documents in audio. AsTeR was developed by me for my PhD. (141
pages) An audio formatted version of the thesis,
(approximately 6 hours) produced by AsTeR, is being made available
by
RFB (Recordings For the Blind as the first computer generated
talking book. Here is the abstract in print, and here is an audio formatted
version.
This hypertext document demonstrates the audio renderings
generated by AsTeR. Here is an
enhanced demo using inline images. Each example is made up of three
components:
- The original LaTeX input.
- The audio formatted output produced by AsTeR. The speech is
produced by a Dectalk, and has been digitized at 8-bit
mulawAsTeR uses stereo to render tables, an effect that
is not conveyed by the 8-bit mono encoding.
- The visually formatted version produced by LaTeX and
DVIPS.
How to use this demo:
The examples in this demonstration get progressively difficult. I
suggest you go through the initial sections sequentially; For short
demos, I typically show people the first three sections, and round
it off with the continuous fraction in section 4 and a quick
overview of Faa De Bruno's formula.
Here is the Postscript file
containing all the examples, in case you want to look over them
first. I am not placing a single file containing all of the audio
examples since this would be about 9MB.
Section 1 simple
fractions and expressions.
This set of examples demonstrates the use of voice inflection and
pauses to convey grouping of sub-expressions succinctly.
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
Audio state varied along a dimension in audio space before
rendering sub-expressions.
Section 2
superscripts and subscripts.
To convey subscripts, superscripts, and other visual attributes,
vary audio state along a dimension that is orthogonal to
(independent of ) the dimension used to convey sub-expressions.
This will allow the nesting of these mutually independent concepts.
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
Section 3 Knuth's
examples of fractions and exponents.
These examples are taken verbatim from the TeX Book, by Donald
Knuth. They are used in the TeX Book to demonstrate the power of
the TeX layout operators. Notice that all of these examples
comprise of the same 6 symbols, but are very different! AsTeR can
render these as unambiguously as TeX can.
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
Section 4 A
continued fraction.
Moving along a dimension in audio space defines a perceptibly
monotonic change. This notion of perceptible monotonicity is vital
in conveying nesting.
audio LaTeX Postscript
Section 5 Simple
School algebra.
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
Notice the choice of unambiguous renderings for the following
expressions:
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
Section 7
Trigonometric identities.
Written mathematical notation can be ambiguous and hard to
recognize. Notice the complete absence of parenthesis in some of
the examples below. AsTeR uses several heuristics to construct the
correct tree structure for these expressions.
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
Notice the context-specific rendering when speaking the base of the
logarithm. The renderings are chosen to reduce cognitive load;
log base a of x
as opposed to
log of x to the base a
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
Context-specific rendering rules allow AsTeR to interpret the
superscripts as exponents. Such interpretation is not hard-wired
into the renderings; it is fully customizable by the user.
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
The first of these examples, probably the most innocuous, is also
the most difficult to recognize; it is impossible to determine the
variable of integration.
Notice that AsTeR interprets triple integrals as the nested
application of the integral operator. A user can browse the triple
integral and listen to its sub-pieces.
The integrals shown in examples 3 and 4 can trick the most
experienced of human readers into an error.
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
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- audio LaTeX Postscript
- audio LaTeX Postscript
Notice that the same expression can be written in more than one
way.
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
Section 13 Cross
referenced equations.
The following section is meant to illustrate AsTeR's rendering of
cross-references, and is most effective when AsTeR is used
interactively.
AsTeR enables the listener to give meaningful names to
cross-referenceable objects, and uses these names when referring to
such objects in later cross-references.
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
Notice that AsTeR produces good intonational structure when
speaking text that is intermixed with mathematics. audio LaTeX Postscript
Section 15
Quantified expression.
The quantifiers present an interesting challenge to AsTeR's
recognizer. audio LaTeX Postscript
Once again, perceptible monotonicity allows AsTeR to convey the
following deeply nested expressions succinctly.
These examples were produced with the Emacs Calculator, a
full-fledged symbolic algebra system. AsTeR interfaces directly
with this calculator, and renders the output just as well as it can
render any document.
- audio LaTeX Postscript
- audio LaTeX Postscript
- audio LaTeX Postscript
AsTeR uses stereo effects to convey the two-dimensional structure
of the matrix. Rendering commences on the left, and moves
progressively right as each element of any row is spoken.
audio LaTeX Postscript
Section 18 Faa de
Bruno's formula.
This section presents Faa De Bruno's formula, taken from Knuth's
Art Of Computer Programming, Vol. 1. I first heard it spoken by a
RFB reader on a talking book; it took 120 seconds to speak.
Since the renderings produced by AsTeR utilize features of the
audio space not available to a human reader (I still have not met a
reader who can change the size and shape of her head as she
talks:-) the rendering takes under 80 seconds.
As you will hear soon, even this is too long; you forget the
beginning by the time you hear the end.
Later, we present rendering using variable substitution, a
powerful technique for conveying top-level structure of complex
expressions.
- Notice the proper intonational structure produced for text
intermixed with mathematics.
audio LaTeX Postscript
- audio LaTeX Postscript
- Here is Faa De Bruno's formula in all its glory:-
Audio (66 seconds) LaTeX Postscript
AsTeR can process complex expressions like the above, and upon
request, replace complex sub-expressions with meaningful
identifiers. Such renderings convey top-level structure; the
listener can then listen to the sub-expressions separately.
Since this substitution process is performed by AsTeR, there is
no LaTeX or Postscript equivalent for the audio output in this
case.
T.V. Raman raman@crl.dec.com
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Last modified: Fri Aug 5 10:06:00 1994 hhmts end