Text Classifier Construction Using Adaptive Phrase Weighting

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing text classification methods are inefficient in accurately classifying documents into specific topics, particularly when relying on linear classifiers that require large amounts of human-labeled data and struggle with document length variations.

Innovation Solution

The method involves generating and filtering candidate phrases using n+k-grams, assigning weights based on initial classifier scores, and iteratively refining the classifier using supervised and unsupervised techniques to improve accuracy with minimal human-labeled data, accounting for document length and using search engine queries to validate phrase relevance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional linear classifiers are used for document classification, then classification can be performed with simple methodology, but large amounts of human-labeled data are required and accuracy is insufficient

Engineering Contradiction:
Improveclassification accuracyVSAvoidamount of human-labeled data
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies preliminary action by pre-processing documents to extract n-gram phrases and automatically generating initial classifier weights using unsupervised techniques before human labeling. This preliminary phase creates a foundation that reduces the amount of human-labeled data needed for achieving high classification accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements self-service through automated phrase extraction from document corpora and self-training mechanisms where the classifier iteratively improves using unlabeled data. The system serves itself by automatically generating training features and refining weights without continuous human intervention, thereby reducing dependency on large amounts of manually labeled data.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If conventional linear classifiers are used, then implementation is straightforward, but the classifiers struggle with document length variations

Engineering Contradiction:
Improvehandling of document length variationsVSAvoidclassifier complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by normalizing phrase scores based on document length, giving different weights to phrases depending on the local context of document length. This allows the classifier to adapt to varying document lengths while maintaining the overall linear classifier structure, balancing adaptability with implementation simplicity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system implements dynamics by making the classifier adaptive to document length variations through iterative re-training and weight adjustment. The classifier dynamically adjusts its parameters based on the characteristics of the input documents, allowing it to handle varying lengths effectively while maintaining a relatively simple linear structure.

Inventive Principle:
Principle #15Dynamics

3Quantity of substance

If automated phrase extraction is used to reduce human-labeled data, then data requirements are reduced, but erroneously included candidate phrases are introduced

Engineering Contradiction:
Improvehuman-labeled data requirementsVSAvoidphrase candidate accuracy
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies feedback through iterative evaluation cycles where extracted phrase candidates are scored using the classifier, and poor-performing phrases are identified and removed. This feedback loop continuously refines the phrase candidate set, maintaining high reliability while reducing dependency on human-labeled data for phrase selection.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system replaces the mechanical process of manual phrase verification with automated evaluation using the classifier itself. Instead of relying on human experts to filter candidate phrases, the system uses computational scoring and iterative refinement to automatically identify and remove erroneous phrases, thereby reducing human-labeled data requirements while maintaining phrase accuracy.

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

4Measurement precision

If iterative classifier refinement is performed to improve accuracy, then classification precision is enhanced, but computational time and complexity increase

Engineering Contradiction:
Improveclassification accuracyVSAvoidcomputational time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by performing iterative refinement only to the extent necessary to achieve satisfactory accuracy thresholds. The system stops iteration when performance plateaus or when diminishing returns are detected, avoiding excessive computational time while still achieving improved classification accuracy through targeted iterative improvements.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS9317564B1Construction of text classifiers
Publication Date: 2016.04.19 GOOGLE LLC
  • US9317564B1 patent drawing
  • US9317564B1 patent drawing
  • US9317564B1 patent drawing

AI summary

Methods, systems, and apparatus, including computer program products, for constructing text classifiers. The method includes receiving a collection of candidate phrases for a given topic; filtering the received candidate phrases to remove erroneously included candidate phrases; assigning weights to the candidate phrases including scoring each candidate phrase using an initial classifier and assigning weights to the candidate phrases based on the scores; and generating a linear classifier using the filtered and weighted candidate phrases, where the linear classifier varies the weights for each phrase candidate depending on the length of the document being classified.