While segmentation algorithms, such as TEXTTILING (Hearst, 1994) and its recent successors using the inter-paragraph similarity matrix (Choi, 2000), all themselves use nonstructural cosine similarity as a measure of semantic proximity between paragraphs.
the distance function so far has been largely defined and used ad hoc, usually by a tf.idf weighting scheme (Salton and Yang, 1973) and a simple cosine similarity, equivalently, an Euclidean dot product.