Research

My research focuses on semantic technologies, graph data models, data interoperability, data integration, and knowledge representation for publishing, querying, and exchanging knowledge.

Core interests

  • Semantic Web
  • Linked Data
  • Graph Databases
  • Knowledge Representation
  • RDF
  • Property Graphs
  • Data Interoperability
  • Data Integration
  • Data Modeling

Research directions

  • Knowledge representation on the Web
  • Linked Data and RDF-based integration
  • Property Graphs and graph database models

Project portfolio

The current project list covers software, formats, grammars, converters, validation tooling, and language-specification work across RDF, Linked Data, Property Graphs, and graph query languages.

Projects

RDF / Semantic Web / Linked Data

  • dm-rdf12: A Python implementation of an RDF 1.2-aware rdf2pg prototype that parses RDF 1.1/1.2, supports GDM/SDM/CDM mappings, and emits YARS-PG or JSON debug output.
  • rdf12conv: A self-contained Python converter and validator for RDF 1.2 N-Triples, N-Quads, Turtle, and TriG, with deterministic serialization and readable Turtle/TriG output.
  • rdf-interop: A pure-Python RDF 1.2 interoperability toolkit for format conversion, synthetic benchmark generation, and overhead/statistics analysis for large graphs with quoted triples.
  • rdf12-ntriples-parser: A CLI parser for RDF 1.2 N-Triples that exports SPARQL 1.2 Query Results in CSV or TSV form.
  • rdfstats_stream: A lightweight streaming tool for bounded-memory analysis of very large RDF graphs that produces predicate distributions, cardinalities, co-occurrence summaries, rules, and plots.
  • rdfcompare: A Python utility for comparing RDF files across serializations such as Turtle, JSON-LD, and RDF/XML.
  • yars: A small converter from RDF serializations such as Turtle and N-Triples into YARS serialization.
  • graphConv: A PG-to-RDF converter that transforms property-graph inputs such as GraphML into RDF serializations including Turtle, JSON-LD, and RDF/XML.
  • RDF_database_hashing: A project focused on developing hashing methods for RDF graphs, with support for multiple RDF input serializations and hash algorithms.
  • chemskos: A Semantic Web project based on Skosmos for SKOS-oriented linked-data work in the chemistry domain.
  • cgdl-conv: A Common Graph Definition Language converter that targets formats such as JSON, CBOR, XML, TOML, YAML, SHACL, and ShEx.
  • n3builtins: A documentation/specification repository for N3 builtin functions, generated into a website and tied to the W3C N3 ecosystem.
  • N3 (fork): A fork of the W3C Notation 3 Community Group repository covering N3 grammar, specification, examples, tests, and builtins-related material.
  • rdfsurfaces (fork): A repository for RDF Surfaces, a sublanguage of Notation3 intended to express classical first-order logic with negation in RDF.
  • n3-editor-js (fork): A JavaScript-based editor for Notation3, directly relevant to Semantic Web tooling around N3.
  • sparql-dev (fork): A fork of the SPARQL Dev Community Group repository that collects issues, proposals, and discussion material for SPARQL evolution.
  • shex-ucr: A repository centered on ShEx use cases and requirements in the RDF validation and Semantic Web space.

Property Graphs / Graph Databases / GQL

  • pgs-gen: A PG-Schema data generator that produces random property-graph data and exports it to GraphML and GraphSON variants while supporting list-valued properties and PG-Schema semantics.
  • rules-poc: A lightweight proof-of-concept runner for GQL Rules that executes wrapper-level Cypher rule programs iteratively over Neo4j until fixpoint.
  • gqlrules: A ready-to-run Neo4j 5 + APOC proof of concept that translates GQL Rules use cases into executable Cypher scripts, views, and verification queries.
  • brc: A repository dedicated to binary relation constraints in PG-Schema.
  • pg-schema-pc: An extension of PG-Schema for expressing structural constraints in property graph data models.
  • pgschema: A repository for PG-Schema grammar, including EBNF, ANTLR grammars, railroad diagrams, and examples.
  • PGDL-conv: A Property Graph Definition Language converter that maps PGDL to and from formats such as JSON, CBOR, XML, TOML, YAML, and PG-SHACL.
  • BPG: A repository for efficient and scalable property graph serialization.
  • metadata_gen: A Java tool for generating property-graph metadata, developed in the context of the MMLKG project.
  • pgkeysyntax: A repository for an open-source grammar and parser for PG-Keys.
  • GQL-parser (fork): An ANTLR v4-based parser for GQL created in a graph-query-language research context.
  • gqlrrd: A repository for GQL railroad diagrams, useful for documenting and visualizing graph query language syntax.

Knowledge Representation / Ontologies / Graph Query Conceptualization

  • graphquerylangs: An OWL 2 ontology serialized in Turtle that models a machine-queryable conceptualization of a graph query language domain.