Natural Language Processing Apparatus for Unknown Word Detection

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Solution Overview

Problem

Existing natural language processing methods fail to efficiently identify unknown words by simply categorizing all unmatched dictionary words as unknown, leading to inefficient word extraction.

Innovation Solution

A natural language processing apparatus and method that utilize multiple morphological analyzers to detect common segmentation points and extract part-of-speech differing patterns, storing these patterns with their frequency, and specifying character strings with low frequency appearances as candidates for unknown words, thereby limiting the search range for unknown words.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If all words that do not match any words in a dictionary are determined as unknown words, then unknown words can be identified, but the identification process becomes inefficient and produces many false positives

Engineering Contradiction:
Improveunknown word detection accuracyVSAvoidword extraction efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the text processing task by dividing it into multiple stages: initial morphological analysis by multiple analyzers, extraction of differing patterns, frequency counting, and threshold-based filtering. This segmentation allows the system to efficiently narrow down candidate unknown words without examining every single unmatched word, thus improving both accuracy and efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of performing complete morphological analysis on all words using multiple analyzers and then filtering, the patent applies partial action by first using multiple analyzers to identify differing patterns, then using frequency counting and thresholding to process only the most likely candidates. This reduces the overall computational burden while maintaining detection accuracy.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If multiple morphological analyzers are used to analyze sentences, then the accuracy of unknown word detection improves, but the computational complexity and processing time increase

Engineering Contradiction:
Improveunknown word detection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential information needed for unknown word detection by comparing the output of multiple morphological analyzers. Specifically, it extracts differing patterns between analyzers and counts their frequencies, discarding redundant analysis results. This extraction approach maintains high detection accuracy while reducing computational complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter of analysis by using multiple morphological analyzers with different dictionaries or analysis rules, then compares their outputs to identify differing patterns. By transforming the problem from complete analysis of all words to comparison of analyzer differences, the system achieves higher accuracy without proportional increases in complexity.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the search range for unknown words is not limited, then all potential unknown words can be detected, but the processing time and computational resources increase significantly

Engineering Contradiction:
Improvecompleteness of unknown word detectionVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary action by using multiple morphological analyzers to pre-process the text and identify differing patterns before the actual unknown word detection. By counting the frequencies of these differing patterns and applying a threshold, the system pre-filters candidate words, significantly reducing the search range and processing time while maintaining detection completeness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent substitutes the mechanical approach of examining every single word against a dictionary with a more efficient system based on pattern recognition and frequency analysis. By replacing brute-force comparison with statistical pattern matching, the system achieves comprehensive detection with reduced time loss.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8880391B2Natural language processing apparatus, natural language processing method, natural language processing program, and computer-readable recording medium storing natural language processing program
Publication Date: 2014.11.04 RAKUTEN GROUP INC
  • US8880391B2 patent drawing
  • US8880391B2 patent drawing
  • US8880391B2 patent drawing

AI summary

A natural language processing apparatus includes a result acquisition unit that acquires a plurality of analysis results indicating parts of speech of morphemes contained in one or more common sentences from a plurality of types of morphological analyzers, a pattern acquisition unit that detects a common segmentation point in the plurality of analysis results, extracts one or more parts of speech corresponding to a character string segmented at the common segmentation point from each of the analysis results, and acquires a set of the parts of speech as a part-of-speech differing pattern, and a candidate specifying unit that extracts the part-of-speech differing pattern with the number of appearances being equal to or less than a predetermined threshold and specifies the character string corresponding to the extracted part-of-speech differing pattern as a character string containing a candidate for an unknown word.