Knowledge Graph Keyword Search Using Structural Compact Subgraphs

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for keyword search in knowledge graphs are computationally demanding and often return empty results when input entities are distantly distributed, as they rely on group Steiner trees which are NP-hard and have high run times, especially for large graphs, and structurally compact subgraphs are not guaranteed, limiting their applicability.

Innovation Solution

A method that computes a salient subset of a knowledge graph to find structural compact subgraphs connecting input entities within a predefined diameter bound, using algorithms that prioritize entity salience and distance computation to avoid expensive searches and ensure structural compactness, merging paths with common end vertices to form compact subgraphs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If group Steiner tree approach is used to find relationship subgraphs, then the subgraphs connect input entities with minimum weight, but the computation time becomes prohibitively high for large knowledge graphs

Engineering Contradiction:
Improvesubgraph optimalityVSAvoidcomputation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent changes the optimization parameter from minimum weight (Steiner tree) to structural compactness constraints (diameter bound, order bound). This transforms the NP-hard problem into a tractable problem by imposing predefined structural constraints that limit the search space while still ensuring connectivity and compactness of the relationship subgraphs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the knowledge graph search space by imposing structural constraints (diameter bound, order bound) that divide the potentially infinite search space into manageable bounded regions. This segmentation allows efficient exploration of only those subgraphs that satisfy the compactness constraints, avoiding exhaustive search of the entire graph.

Inventive Principle:
Principle #1Segmentation

2Productivity

If structurally compact subgraphs with predefined constraints are used, then computation efficiency and user perception are improved, but empty results are returned when input entities are distantly distributed

Engineering Contradiction:
Improvecomputation efficiencyVSAvoidresult completeness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces dynamic adaptability by allowing the system to switch between different search strategies based on the distribution of input entities. When entities are closely distributed, structurally compact subgraphs are used; when distantly distributed, the system can relax constraints or use alternative approaches, making the method adaptive to different scenarios rather than rigidly applying fixed constraints.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces intermediate structures (such as virtual entities or relay nodes) that can serve as mediators to connect distantly distributed input entities while maintaining structural compactness. These intermediary elements allow the construction of compact relationship subgraphs even when direct connections between input entities would violate diameter or order bounds.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If minimum weight Steiner trees are computed, then optimal connection is achieved, but the subgraphs may be too large for user perception

Engineering Contradiction:
Improveconnection optimalityVSAvoidsubgraph compactness
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The patent changes the optimization focus from weight minimization to structural compactness by imposing diameter bounds and order bounds. This parameter change ensures that the relationship subgraphs remain visually manageable and comprehensible to users, with limited depth and breadth, while still providing meaningful connections between input entities.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary structural constraints (diameter bound, order bound) before performing the actual subgraph computation. This preliminary action pre-defines the maximum acceptable size and shape of the result, ensuring that the computed subgraphs will be compact and suitable for user perception from the outset, rather than requiring post-processing to reduce size.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11423021B2Computer-implemented method for keyword search in a knowledge graph
Publication Date: 2022.08.23 ROBERT BOSCH GMBH
  • US11423021B2 patent drawing
  • US11423021B2 patent drawing

AI summary

A computer-implemented method for keyword search in a data set. Data of the data set is represented by a knowledge graph. The knowledge graph comprises vertices representing entities of the data set and edges representing relations between said entities. The method comprises the following steps: receiving a search query comprising at least two entities; computing for the at least two entities of the search query a salient subset of the data set, wherein the salient subset is computed such that a structural compact subgraph exists in the knowledge graph, the structural compact subgraph connecting the at least two entities of the search query, and computing for the salient subset a structural compact subgraph of the knowledge graph which connects the at least two entities of the search query.