ABSTRACT : Automated knowledge
discovery is central to augmenting knowledge acquisition and elicitation by humans from
vast amounts of content. Precise and concise representations, both structured and
semi-structured, of knowledge contained in textual content have the potential to boost
human productivity. Further, they can reduce, if not eliminate, human error and bias in
knowledge retrieval and curation by humans from vast collections of content to use for
their subsequent knowledge-based tasks.Conventionally, knowledge discovery in text (KDT)
approaches and paradigms have been designed to build domain knowledge by processing
large collections of text documents and applying them to process individual text
documents using this acquired domain knowledge for guidance. Consequently, these
approaches are blind to the finer topical features of the individual document because
these features are abstracted by topic models that infer topicality in the context of
the whole corpus.We need an unsupervised method to extract topical or thematic phrases
from a single text document without the need to access entire collections of texts or
background domain or language dictionaries and thesauri. Further, the method should not
abstract fine-grained thematic phrases contained in the document, thus, enabling its
application for hierarchical knowledge representation and downstream document level text
analytics tasks.This work describes ThemaPhrase (ThP), a novel framework for
unsupervised extraction of thematic phrases from single text artifacts. The framework
operates without the need for corpus wide statistics and external domain knowledge which
makes it domain agnostic. ThP configurations are more robust than competing methods to
topic-to-partitions ratio and varying average token occurrence frequencies in a
document. Different configurations of ThemaPhrase are identified that outperform
competing methods in extracting thematic phrases that represent the topicality of a
document at varied granularities.Further, this work shows that sentence pre-filtering
based on thematic phrases and thematic words helps improve extractive summarization for
texts, such as patents, that have relatively higher occurrence frequencies of tokens
where the baseline TextRank summarizer underperforms. ThemaPhrase configurations that
outperform competing thematic phrase extraction methods in extractive summarization
using sentence pre-filtering are discussed.