| 词条 | Inside–outside–beginning (tagging) |
| 释义 |
The IOB format (short for inside, outside, beginning) is a common tagging format for tagging tokens in a chunking task in computational linguistics (ex. named-entity recognition).[1] It was presented by Ramshaw and Marcus in their paper "Text Chunking using Transformation-Based Learning", 1995[2] The B- prefix before a tag indicates that the tag is the beginning of a chunk, and an I- prefix before a tag indicates that the tag is inside a chunk. The B- tag is used only when a tag is followed by a tag of the same type without O tokens between them. An O tag indicates that a token belongs to no chunk. Another similar format which is widely used is IOB2 format, which is the same as the IOB format except that the B- tag is used in the beginning of every chunk (i.e. all chunks start with the B- tag). A readable introduction to entity tagging is given in Bob Carpenter's blog post, "Coding Chunkers as Taggers".[3] 'BIO' is plausibly a synonym for 'IOB'. An example with IOB format: Alex I-PERis Ogoing Oto OLos B-LOCAngeles I-LOCAn example with IOB2 format: Alex B-PERis Ogoing Oto OLos B-LOCAngeles I-LOCRelated tagging schemes sometimes include "START/END: This consists of the tags B, E, I, S or O where S is used to represent a chunk containing a single token. Chunks of length greater than or equal to two always start with the B tag and end with the E tag."[4] References1. ^{{cite web|title=Entity Recognition|url=http://www.evalita.it/2009/tasks/entity}} {{DEFAULTSORT:Inside-outside-beginning (tagging)}}{{comp-ling-stub}}2. ^{{cite arxiv|title=Text Chunking using Transformation-Based Learning|author=Ramshaw and Marcus|year=1995|arxiv=cmp-lg/9505040}} 3. ^{{cite web|title=Coding Chunkers as Taggers: IO, BIO, BMEWO, and BMEWO+|url=https://lingpipe-blog.com/2009/10/14/coding-chunkers-as-taggers-io-bio-bmewo-and-bmewo/|author=Bob Carpenter|year=2009}} 4. ^http://cs229.stanford.edu/proj2005/KrishnanGanapathy-NamedEntityRecognition.pdf 1 : Computational linguistics |
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