Demonstrating Online Schema Alignment in Decentralized Knowledge Graphs Querying

2026-04-21

AI Summary

This work addresses the incompleteness of query results in decentralized knowledge graph querying caused by lexical heterogeneity. It proposes a method that dynamically discovers and applies local schema alignment rules during link-traversal query processing (LTQP), without requiring prior centralized alignment or altering the original traversal behavior. This approach enables, for the first time, runtime online schema alignment through scoped, on-demand semantic mappings, significantly improving query completeness. Implemented within the Comunica framework, the system integrates a web interface, command-line tools, and a reusable library. Its effectiveness is demonstrated in a decentralized social media scenario, where it recovers complete results with low overhead, establishing a practical foundation for Web-scale distributed LTQP.

Technology Category

• Data Mining & Knowledge Management: Intelligent Query Processing
• Search and Optimization: Distributed Search
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Graph Algorithms and Modeling for the Web: Querying, indexing, and retrieval in Web-related graphs
• Semantics and Knowledge: Scalable techniques for the creation, curation, publication, maintenance, and consumption of large, Web-based, structured, reusable, knowledge graphs and ontologies
• Search and Retrieval-Augmented AI: Multilingual and cross-lingual Web search

Abstract

Decentralized Knowledge Graphs querying enables integrating distributed data without centralization, but is highly sensitive to vocabulary heterogeneity. Query issuers cannot realistically anticipate all vocabulary mismatches, especially when alignment rules are local, scoped, or discovered at runtime. We present an online schema alignment approach for Link Traversal Query Processing (LTQP) that discovers, scopes, and applies alignment rules dynamically during query execution while preserving traversal behavior. This demo paper demonstrates the approach on a decentralized social-media scenario through a web interface built on a Comunica-based LTQP engine. Source code, a CLI, and a reusable library are publicly available. The demonstration shows that online schema alignment recovers complete query results with low overhead, providing a practical foundation for web-scale reasoning in LTQP systems.

Problem

• Decentralized Knowledge Graphs
• Schema Alignment
• Vocabulary Heterogeneity
• Link Traversal Query Processing
• Online Alignment

Innovation

• online schema alignment
• decentralized knowledge graphs
• Link Traversal Query Processing
• vocabulary heterogeneity
• dynamic alignment