Successful Data Mining Methods for NLP

Historically Natural Language Processing (NLP) focuses on unstructured data (speech and text) understanding while Data Mining (DM) mainly focuses on massive, structured or semi-structured datasets. The general research directions of these two fields also have followed different philosophies and principles. For example, NLP aims at deep understanding of individual words, phrases and sentences (“micro-level”), whereas DM aims to conduct a high-level understanding, discovery and synthesis of the most salient information from a large set of documents when working on text data (“macro-level”). But they share the same goal of distilling knowledge from data. In the past five years, these two areas have had intensive interactions and thus mutually enhanced each other through many successful text mining tasks. This positive progress mainly benefits from some innovative intermediate representations such as “heterogeneous information networks” [Han et al., 2010, Sun et al., 2012b]. However, successful collaborations between any two fields require substantial mutual understanding, patience and passion among researchers. Similar to the applications of machine learning techniques in NLP, there is usually a gap of at least several years between the creation of a new DM approach and its first successful application in NLP. More importantly, many DM approaches such as gSpan [Yan and Han, 2002] and RankClus [Sun et al., 2009a] have demonstrated their power on structured data. But they remain relatively unknown in the NLP community, even though there are many obvious potential applications. On the other hand, compared to DM, the NLP community has paid more attention to developing large-scale data annotations, resources, shared tasks which cover a wide range of multiple genres and multiple domains. NLP can also provide the basic building blocks for many DM tasks such as text cube construction [Tao et al., 2014]. Therefore in many scenarios, for the same approach the NLP experiment setting is often much closer to real-world applications than its DM counterpart. We would like to share the experiences and lessons from our extensive inter-disciplinary collaborations in the past five years. The primary goal of this tutorial is to bridge the knowledge gap between these two fields and speed up the transition process. We will introduce two types of DM methods: (1). those state-of-the-art DM methods that have already been proven effective for NLP; and (2). some newly developed DM methods that we believe will fit into some specific NLP problems. In addition, we aim to suggest some new research directions in order to better marry these two areas and lead to more fruitful outcomes. The tutorial will thus be useful for researchers from both communities. We will try to provide a concise roadmap of recent perspectives and results, as well as point to the related DM software and resources, and NLP data sets that are available to both research communities.