will be informative and very useful for us to avail instead of the structure that is provided by a film or television program script.

There are literally thousands of film scripts, including for television programs, for all genres, available and openly accessible on the web (e.g. IMSDb, Internet Movie Script Database). A film script is composed of a succession of scenes, each of which has a header (often in upper case, and indented) indicating internal or external, day or night, location and other metadata, together with transition ("cut to:", "sound cue") and beginning and end details. The variable length scene itself contains dialog between characters, and/or action description.

Supporting movie script analysis, both individually and comparatively, is of major importance in the distributed and collaborative writing process. Indeed machine learning algorithms have been directly applied to scripts themselves to predict later commercial success (Gladwell 2006).

Filmscripts are comprised of semi-structured data, incorporating free text and additional structure. They provide a very good "model" or exemplar for other application fields. Analysis, retrieval and use of scripts could provide a model for medical report handling, and scenario analysis in organization and management. The scripts may provide a more malleable basis for reshaping and restructuring content in order to support interactive training and learning environments, as well as the full gamut of interactive media in entertainment.

An in-depth analysis of content of the film Casablanca can be found in Murtagh et al. (2009, and see discussion in Merali, 2008). Television presents new and interesting challenges for a whole range of reasons. Television series may need to be repeated, they must have characterizing "texture" in each program's content, and support is needed for the distributed writing and production teams. For all these reasons the television program scripts represent (technically) ideal and (application-wise) important exemplars for us. As we will see below, we make full use of whatever structure is available to us in such data.

## 1.4 Euclidean Embedding And Mapping Of Context

In our use of free text, a mapping into a Euclidean space gives us the capability to determine distance in a visual and easily interpretable way. In Correspondence Analysis (Murtagh 2005), the texts we are using - e.g. the scenes - provide the rows, and the set of terms used comprise the column set. In the output, Euclidean, factor coordinate space, each text is located as a weighted average of the set of terms; and each term is located as a weighted average of the set of texts. (This simultaneous display is sometimes termed a biplot.) So texts and terms are both mapped into the same, output coordinate space. This can be of use in understanding a text through its closest terms, or vice versa. Hence it provides semantic context for both the set of texts and the set of terms.

A summary of properties of Correspondence Analysis is provided in the Appendix.

A commonly used starting point for studying a set of texts, e.g. filmscript scenes, is to characterize each text with numbers of terms appearing in the text,