Flat and Nested Named Entity Recognition: A Review

Abstract

The developments in Information Technology have significantly improved our lives. Information is at our fingertips; we can reach a wider audience and explore new things with ease. With all these made possible, there comes an issue that needs to be addressed: Information Overload. There is an extensive amount of information out there that has caused the extraction of relevant information arduous. Here is where the role of Named Entity Recognition (NER) comes into play. Identifying proper nouns from text and labeling them with their semantic type that belongs to a predefined list of classes is called NER. Moreover, NER is the initial step for various other applications in Natural Language Processing (NLP). With the continual endeavors in this promising research area breaking new grounds, we discuss some notable works in this field. Further, we present a comprehensive study on nested NER. This study shall help the readers with a quick rundown of some of the major works proposed for flat and nested NER.