Graph-Based Document Retrieval for Conceptual Similarity

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Solution Overview

Problem

Conventional document retrieval methods struggle to accurately capture the conceptual similarities between documents, particularly in fields like patents and contracts, where similar words are heavily used, leading to a need for a retrieval technology that considers document concepts beyond just word usage.

Innovation Solution

A document retrieval system that creates graph structures from documents, incorporating morphological and modification analyses, part-of-speech tagging, and vectorization using Weisfeiler-Lehman Kernels to evaluate conceptual similarities between documents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If word-based retrieval methods (PageRank, thesaurus, Jaccard coefficient, cosine similarity) are used, then retrieval can be performed using basic word matching, but precision deteriorates because conceptual similarities are not captured

Engineering Contradiction:
Improveretrieval precisionVSAvoidretrieval system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the document into sentences, then segments each sentence into clauses, and finally segments clauses into graph nodes representing concepts. This multi-level segmentation allows the system to capture conceptual relationships while maintaining manageable processing complexity through hierarchical decomposition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a graph structure as an intermediary representation between raw text and retrieval queries. The graph nodes and edges serve as mediators that encode conceptual relationships, allowing the system to bridge the gap between word-based processing and concept-based retrieval without requiring direct complex analysis of entire documents.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If graph structure creation with morphological and modification analysis is performed, then conceptual similarity capture is improved, but processing time increases

Engineering Contradiction:
Improveconceptual similarity measurementVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs morphological analysis and modification analysis as preliminary actions during the graph structure creation phase. By completing these analyses upfront when building the graph representation, the system avoids repeated processing during retrieval operations, thereby reducing query time while maintaining high conceptual similarity measurement accuracy.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If vectorization using Weisfeiler-Lehman Kernels is applied, then conceptual similarity evaluation is enhanced, but computational complexity increases

Engineering Contradiction:
Improvesimilarity evaluation accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by using Weisfeiler-Lehman Kernels to transform graph structures into vector representations. This parameter transformation enables efficient similarity evaluation through vector operations while capturing complex conceptual relationships, balancing computational complexity with improved similarity evaluation accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20250231976A1Document retrieval system
Publication Date: 2025.07.17 SEMICON ENERGY LAB CO LTD
  • US20250231976A1 patent drawing
  • US20250231976A1 patent drawing
  • US20250231976A1 patent drawing

AI summary

A document retrieval system that retrieves documents, with concepts of the documents taken into account, is provided. The document retrieval system (100) includes an input unit (101), a first processing unit (102), a storage unit (105), a second processing unit (103), and an output unit (104). The input unit (101) has a function of inputting a first document (20), the first processing unit (102) has a function of creating a first graph structure (21) from the first document (20), the storage unit (105) has a function of storing a second graph structure (11), the second processing unit (103) has a function of calculating a similarity between the first graph structure (21) and the second graph structure (11), the output unit (104) has a function of supplying information, the first processing unit (102) has a function of dividing the first document (20) into a plurality of tokens, a node and an edge of the first graph structure (21) have a label, and the label includes the plurality of tokens.