Document Summarization Using Submodular Greedy Selection

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Solution Overview

Problem

Existing sentence compression summarization methods are limited by restricted object functions and incur high calculation costs, making it difficult to efficiently summarize large-scale document data.

Innovation Solution

A document summarizing device and method that utilize submodular maximization with a greedy algorithm to select non-redundant subsets from a dependency structure tree, maximizing information retention while adhering to a length constraint, using a submodular function to evaluate the importance of document subsets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If sentence compression summarization is used to handle long sentences with redundant portions, then a summary with a large amount of information can be created within length constraints, but the types of applicable object functions are limited and the approach of obtaining a better summary by appropriately designing object functions cannot be employed

Engineering Contradiction:
Improveinformation retention in summaryVSAvoidflexibility in object function design
Core Design Contradiction:
Loss of informationVSAdaptability or versatility

Solution Approach 1:

The patent changes the parameter of object function design by introducing a configurable objective function that can be adjusted through parameters such as importance weights for different sentences, redundancy thresholds, and information density metrics. This allows the summarization system to adapt to different information retention requirements while maintaining computational efficiency.

Inventive Principle:
Principle #35Parameter changes

2Loss of information

If sentence compression summarization is used to create summaries with large amounts of information, then length constraints are satisfied, but processing that incurs large calculation costs (integer programming, dynamic programming) is required making application to summary creation of large-scale document data difficult

Engineering Contradiction:
Improveinformation density in summaryVSAvoidprocessing speed for large-scale documents
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The patent extracts only the essential computational elements from complex optimization methods, using a simplified greedy algorithm that selects sentences based on pre-calculated importance scores and redundancy metrics. This extraction of core functionality eliminates the need for computationally expensive integer programming or dynamic programming while maintaining effective information retention.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs lightweight, computationally inexpensive scoring functions that can be rapidly calculated and discarded for each sentence evaluation. These simple objective functions serve as disposable computational tools that provide sufficient guidance for sentence selection without the overhead of complex optimization algorithms, enabling fast processing of large-scale documents.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Length of stationary object

If only a few redundant and long sentences are selected using sentence extraction summarization, then the upper limit of length constraint is reached, but a summary with a large amount of information has not been able to be obtained

Engineering Contradiction:
Improvesummary lengthVSAvoidinformation content in summary
Core Design Contradiction:
Length of stationary objectVSLoss of information

Solution Approach 1:

The patent segments long sentences with redundant portions into multiple shorter, information-dense sentence units. By dividing the document into finer-grained segments and evaluating each independently using the objective function, the system can select more sentences within the length constraint, thereby increasing the total information content while maintaining the summary within the specified length limit.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11216613B2Document summarization device, method, and program
Publication Date: 2022.01.04 NIPPON TELEGRAPH & TELEPHONE CORP
  • US11216613B2 patent drawing
  • US11216613B2 patent drawing
  • US11216613B2 patent drawing

AI summary

The present invention relates to summarization of a document. The method includes receiving texts of the document and a submodular function for defining an amount of information of a subset of the document as a summary of the document, generating a dependency structure tree representing a dependency structure of sentences in a document, identifying a set of paths including the root of the dependency structure tree, recursively selecting a paths using a greedy algorithm for maximizing the submodular function, and outputs a subset with the maximum amount of information as a the summary of the document.