# US 12,008,305 B2 · Learning device, extraction device, and learning method for tagging description portions in a document

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- Number: US 12,008,305 B2
- Document ID: US12008305B2
- Status: Granted
- Kind: B2
- Application number: 17/272,700
- Filed: 2019-09-04
- Published: 2021-11-04
- Granted: 2024-06-11
- Earliest claimed: 2018-09-19
- Assignees: Nippon Telegraph and Telephone Corporation
- Applicants: Nippon Telegraph and Telephone Corporation
- Inventors: Takeshi Yamada
- Web page: https://patentgrep.com/patent/US12008305B2

## CPC

- G06F 40/117: Tagging; Marking up (details of markup languages G06F40/143); Designating a block; Setting of attributes (style sheets, e.g. eXtensible Stylesheet Language Transformation [XSLT], G06F40/154)
- G06F 40/216: using statistical methods
- G06F 40/279: Recognition of textual entities
- G06N 7/01: Probabilistic graphical models, e.g. probabilistic networks
- G06N 20/00: Machine learning
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS

## Abstract

An extraction apparatus includes: a pre-processing unit configured to perform, on training data that is data described in natural language and in which a tag has been provided to an important description portion in advance, pre-processing for calculating an information gain that indicates a degree of relevance to the tag for each word and deleting a description portion with low relevance to the tag from the training data based on the information gain of each word; and a learning unit configured to learn the pre-processed training data and generate a list of conditional probabilities relating to the tagged description portion.

## Claims

### Claim 1

A learning apparatus comprising one or more processors configured to perform operations comprising:
obtaining training data that includes a plurality of description portions of a natural language document and a plurality of tags, wherein each description portion includes a set of words and each description portion is associated with a tag that was provided to the description portion in advance;
calculating an information gain for each word included in the training data that indicates a degree of relevance of the word to the plurality of tags for the word;
deleting, from the training data, words whose degrees of relevance do not satisfy a threshold to obtain pre-processed training data;
learning the pre-processed training data and the information gain for each word that indicates the degree of relevance of the word to the plurality of tags;
generating a list of conditional probabilities indicating a trend for attaching the plurality of description portions with the plurality of tags;
receiving test data;
tagging, based on the list of conditional probability, description content of the test data by attaching a tag, included in the plurality of tags, to a corresponding portion of the description content;
extracting a test item from the test data based on the tagged description content; and
outputting the test item into a testing apparatus for testing.

### Claim 2 (depends on 1)

The learning apparatus according to claim 1, wherein the operations comprise:
deleting a sentence that does not include a noun for which the information gain is higher than a predetermined threshold value from the training data.

### Claim 3 (depends on 1)

The learning apparatus according to claim 1, wherein the operations comprise:
deleting a sentence that does not include a verb but that includes a noun for which the information gain is higher than a predetermined threshold value from the training data.

### Claim 4

An extraction apparatus comprising one or more processors configured to perform operations comprising:
obtaining training data that includes a plurality of description portions of a natural language document and a plurality of tags, wherein each description portion includes a set of words and each description portion is associated with a tag that was provided to the description portion in advance;
calculating an information gain for each word included in the training data that indicates a degree of relevance of the word to the plurality of tags for the word;
deleting, from the training data, words whose degrees of relevance do not satisfy a threshold to obtain pre-processed training data;
learning the pre-processed training data and the information gain for each word that indicates the degree of relevance of the word to the plurality of tags;
generating a list of conditional probabilities indicating a trend for attaching the plurality of description portions with the plurality of tags;
receiving test data;
tagging, based on the list of conditional probability, description content of the test data by attaching a tag, included in the plurality of tags, to a corresponding portion of the description content;
extracting a test item from the test data based on the attached tags of the description content; and
outputting the test item into a testing apparatus for testing.

### Claim 5

A learning method to be executed by a learning apparatus, the learning method comprising:
obtaining training data that includes a plurality of description portions of a natural language document and a plurality of tags, wherein each description portion includes a set of words and each description portion is associated with a tag that was provided to the description portion in advance;
calculating an information gain for each word included in the training data that indicates a degree of relevance of the word to the plurality of tags for the word;
deleting, from the training data, words whose degrees of relevance do not satisfy a threshold to obtain pre-processed training data;
learning the pre-processed training data and the information gain for each word that indicates the degree of relevance of the word to the plurality of tags;
generating a list of conditional probabilities indicating a trend for attaching the plurality of description portions with the plurality of tags;
receiving test data;
tagging, based on the list of conditional probability, description content of the test data by attaching a tag, included in the plurality of tags, to a corresponding portion of the description content;
extracting a test item from the test data based on the tagged description content; and
outputting the test item into a testing apparatus for testing.
