It is now widely recognized that the creation, management, and
analysis of content other than text is extremely important if the
digital humanities are to deliver access to, and provide an analytical
purchase on, the full range of human culture. However it is not clear
to us whether the cataloguing and classification systems for digital
content are up to the task. Difficulties in this area threaten to
impede both the development of tools and techniques — and the
production of sound theoretical results. In our paper we discuss some
of these problems, focusing on relationships amongst the
various cultural modes of expression. With the intention of convening a
larger discussion of how these confusions might be remedied, we then
propose directions for some clarification and improvement. However, the
larger issues here are not merely terminological and resist any easy
resolution.
Within the humanities computing community it has been a commonplace
that while the emphasis on representing and analyzing textual content
may be understandable, it is important to support the other kinds of
content as well. We agree. The 'digital humanities' must support the
full range of human cultural products: text, music, images, dance,
cinema, architecture, design, and so on. At present there are many
different research communities looking into the organization of, and
enhanced access to, these various modes of cultural expression. There
is a text retrieval community (see Baez-Yates & Ribeiro-Neto), a growing music information
retrieval community (see Futrelle & Downie), an image retrieval community (see Hsin-liang & Rasmussen),
and so on. Notwithstanding the real progress being made by each of these,
very astonishingly little work has yet been done to comprehensively
address the issue that each of these individual modes of expression
interact with each other in the ordinary course of production,
management and use, as well as how formats at varying level of
abstraction interact within a single modality.
First, to illustrate how the modes of expression interact with each
other, let us consider the Othello
corpus. An incomplete inventory of the Othello corpus includes the novella
by Giraldi Cinthio (1565)
"upon which Shakespeare based his play"
(Hunt), Shakespeare's play (1604), the operas by Rossini (1816) and Verdi (1887), Dvorak's concert overture, Op.
93 (1892), and the ballet
by Lubovitch (2002). If we
are going to create a digital humanities repository worthy of use by
humanities scholars and their students, it is incumbent on us to build
a system that can 'collocate', or gather up, all extant digital
representations of Othello:
all recordings, all scores, all movies, all choreographies, all
libretti, all scripts, all set and costume designs, all critiques, and
so on. To aid in this collocation, we need to clearly express the
relationships between each of these things at both the specific and
generic levels. On the specific level, we need to indicate that, for
example, Othello
choreographic labanotation
W
is directly
based on Othello score
X
, which was
specifically used in Othello
movie
Y
,
and also released in Othello
soundtrack recording
Z
. On the
generic level, we need to indicate that all Othello scores have some generic
relationship to all Othello
recordings, to all Othello
movies, etc. in such a way that explicates that the works are all
members of the Othello
corpus.
Second, to illustrate interactions between formats within a single
mode, consider only the music mode of the Othello corpus. For each musical
realization there usually exists a symbolic score and its individual
parts. These symbolic representations can, in turn, be
represented in a variety of digital formats: MusicXML, TIFF, Finale,
etc. The aural aspect of the music is represented in another variety
of digital formats: WAV, MP3, Ogg Vorbis, etc. Again, complex
relationships exist between the 'symbolic' and 'aural'
representations at both the specific (e.g., recording X used score Y) and generic levels (e.g.,
a 'fakebook' score used to generate different recordings of
improvised renditions). Other potentially complex relationships exist
because many of these formats can be used to generate the others. For
example, a TIFF scan of the 'original' score can be fed through an
Optical Music Recognition (OMR) system to create a MusicXML score file
which can generate a MIDI file which then can generate any of the audio
file formats. Further complicating matters, research is also underway
to 'backwards' create scores from audio recordings which would capture,
symbolically, the nuances of a given performance (e.g., Plumbley et al.).
There is, of course, a body of work — standards and related research
— within the cataloguing and classification communities that holds some
promise for supporting the relationships described above. The Dublin
Core (DC) is perhaps the most widely used within the digital
humanities. IFLA's Functional Requirements for Bibliographic Records
(FRBR) is becoming
increasingly important. Work by organizations devoted to specific
modalities such as the Federation Internationale des Archives du Film
(FIAF)
, and the
International Association of Sound and Audiovisual Archives (IASA)
, as well as work by such
researchers as Martha M. Yee (moving pictures — see Yee), and Richard Smiraglia (music — see Smiraglia), etc., are also
contributing insights and theory to this research domain.
We have reviewed results from projects and analyses that suggest
there is still much work to do before the functionality envisaged above
is a reality. Here we describe one such project that attempts to use
FRBR and the DC to support inter- and intra-modal
relationships. The DC does in fact hold the most promise for
representing these relationships in a way that enables computer
supported exploitation for retrieval, navigation, analysis, and so on.
Ayres describes a project at MusicAustralia to use FRBR and
DC to create a digital repository that explicates the
complex relationships between the works, expressions, manifestations
and items of a collection of music and lyrics found that:
The DC.Relation element can be used to display and support
navigation between items with flat, horizontal relationships [i.e.,
inter-modal relationships like those between some music and its text].
However, the kinds of relationships MusicAustralia wants to expose are
a combination of vertical [i.e., intra-modal relationships like those
between a score and its recording] and horizontal relationships, and
rely heavily on abstract but well understood and demonstrable concepts
of the Work and the Expression or version. At this stage, DC does not
offer support exposure of navigational pathways that explicitly
acknowledge both vertical and horizontal relationships. [Bracketed
injections are ours.]
Indeed, a close look at Dublin Core format and type elements suggests
that the level of precision, and subtlety required is probably not yet
available there. For instance the DC type vocabulary includes such
disparate things as 'sound', 'text' and 'physical object', and examples
for 'sound' include 'music playback file format' and 'an audio compact
disc' (DCMI Usage Board).
Because the work of Ayres and her colleagues represents the most
thorough examination of the combination of FRBR modelling and Dublin
Core encoding to build a comprehensive multimodal repository, we are
taking it as the starting point for our present work. The Ayres study
uncovers a series of unresolved open questions associated with FRBR and
the modelling of real-world multimodal information. In the Ayres case,
the two modes are music (i.e., scores, recordings, etc.) and text
(i.e., lyrics, poems, etc.). These two modes come together to create
what we commonly consider to be 'songs'. To paraphrase Ayre's first
open question:
- Should we model as the primary work:
- the music;
- the text; or,
- the combination of text and music?
Ayres clearly illustrates that each modelling approach above
clarifies a specific set of relationships between the music
compositions and the texts while at the same time obscuring other
relationships. The examination of this question has implications beyond
the simpler music-text modelling case. For example, what are the
implications when we attempt to model more complex cases (e.g., the
Othello corpus, a Hollywood musical, etc.) with their exponentially
growing relationships between text (novellas, plays, libretti,
etc), music (i.e., notations, recordings, etc.), choreography (i.e.,
notations, video), and so on? Our paper examines this very question. We
also explore the broader ramifications of Ayre's three related
subsidiary open questions:
- Should all notated and performed expressions of music [or dance,
or text, etc.] be modelled as a single expression category?
- Should expressions themselves be further modelled to include
sub-categories for notated and performed expressions?
- Should performed expressions based on particular notated
expressions be modelled as expressions of expressions?
By examining these fundamental questions, we intend to
encourage a long-overdue conversation within the humanities computing
community. Unless our representation schemes do justice to the
multidimensional complexity of cultural content in all its modes of
expression, we will not realize the full potential of digital
humanities repositories.