Starting with a vast number of unstructured or semistructured documents, text mining tools analyze and sift through them to present to users more valuable information specific to their information needs. The technologies in text mining include information extraction, topic tracking, summarization, categorization/ classification, clustering, concept linkage, information visualization, and question answering [Fan, Wallace, Rich, & Zhang, 2006]. In this chapter, we share our hands-on experience with one specific text mining task — text classification [Sebastiani, 2002]. Information occurs in various formats, and some formats have a specific structure or specific information that they contain: we refer to these as `genres’. Examples of information genres include news items, reports, academic articles, etc. In this paper, we deal with a specific genre type, course syllabus. A course syllabus is such a genre, with the following commonly-occurring fields: title, description, instructor’s name, textbook details, class schedule, etc. In essence, a course syllabus is the skeleton of a course. Free and fast access to a collection of syllabi in a structured format could have a significant impact on education, especially for educators and life-long learners. Educators can borrow ideas from others’ syllabi to organize their own classes. It also will be easy for life-long learners to find popular textbooks and even important chapters when they would like to learn a course on their own. Unfortunately, searching for a syllabus on the Web using Information Retrieval [Baeza-Yates & Ribeiro-Neto, 1999] techniques employed by a generic search engine often yields too many non-relevant search result pages (i.e., noise) — some of these only provide guidelines on syllabus creation; some only provide a schedule for a course event; some have outgoing links to syllabi (e.g. a course list page of an academic department). Therefore, a well-designed classifier for the search results is needed, that would help not only to filter noise out, but also to identify more relevant and useful syllabi.
Extraction of Tag Tree Patterns with Contractible Variables from Irregular Semistructured Data
