Natural Language Processing · TEE · read
Entity spans, categories and context
Named Entity Recognition
Unit 4, pages 117–128
Named Entity Recognition (NER) identifies text spans referring to entities and assigns their types, such as PERSON, ORGANIZATION and LOCATION. Many practical schemas also include DATE, TIME, MONEY or domain-specific types. The exact allowed labels depend on the application's annotation scheme.
NER has two parts: boundary detection finds where the entity starts and ends; classification assigns the appropriate type. A multiword name should normally be one entity span: “New York” is a location span, not two unrelated location decisions.
Not every noun is a named entity. In “a developer works at Google”, developer is an ordinary job description while Google is a named organization. A specialized HR system may define a JOB_TITLE category, but it must state that schema explicitly. NER identifies mentions; entity linking is the separate task of connecting a mention to a unique database identity.
| Task | Question it answers | Example |
|---|---|---|
| POS | What grammatical role does this token have? | Google/NNP |
| Chunking | Which adjacent words form a phrase? | [NP a skilled developer] |
| NER | Which span names an entity, and of what type? | [Google] ORGANIZATION |
| Entity linking | Which real entity does this mention denote? | Connect Paris to the intended city or person record |
Applications. NER structures search results and documents, extracts organizations/people from news, routes support tickets by product or organization, supports recommendation, and extracts specialized entities from healthcare or legal text. Context is essential: “Apple released a laptop” names an organization, while “she ate an apple” describes fruit.
Yaad rakho: NER mein do kaam: naam kahan se kahan tak, aur kis category ka.
M2 14 — Named entities, boundaries and recognition approaches
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These are recorded generation statuses, not a live service check. Private YouTube and signed-in NotebookLM links require the owner's account. This export publishes existing catalog metadata, not private video files or an invented transcript.