Interoperability & Linked Data

Most systems do not fail because the data is missing — they fail because two systems describe the same thing in incompatible ways. Semantic interoperability solves this by giving data an explicit, machine-readable meaning, so that a system can consume information from a source it was never specifically built for. I design ontologies, RDF pipelines and linked data architectures that let your data outlive the application that produced it.

This work is grounded in a decade of peer-reviewed research on the interoperability and discoverability of positioning systems, published at venues such as ISWC, ESWC, IPIN and ACM IoT.

Why interoperability matters

Conceptual diagram of the POSO ontology relating a positioning system, its deployment, tracked entities and the algorithms and technologies used — Core concepts of the POSO ontology — a positioning system, its deployment, the entities it tracks and the technologies it relies on. From POSO: A Generic Positioning System Ontology (ISWC 2022).

Proprietary data formats create silos. Every new integration becomes a bespoke interface, every vendor change becomes a migration project, and the knowledge about what the data means stays locked in the heads of the people who built the system. Linked data inverts this: meaning travels with the data.

This is also the direction European policy is moving in. The EU's ambition for a Digital Single Market and initiatives such as Gaia-X and the International Data Spaces all depend on shared vocabularies and machine-readable semantics. Building on open standards today means you are not retrofitting compliance later.

Interoperability also has a direct commercial benefit: a system that can describe itself is a system that third parties can build on. That is the difference between a closed deployment and a platform.

What I do

Ontology & vocabulary design

Domain-specific ontologies in OWL and RDFS that capture how your organisation actually models its domain — reusing established vocabularies wherever they exist, rather than inventing another silo.

Alignment with existing standards (SSN/SOSA, GeoSPARQL, schema.org, DCAT)
W3C best practices for publishing and versioning vocabularies
SHACL shapes for validation and contract-style data quality checks
Human-readable documentation generated from the ontology itself

Linked data integration

Turning existing relational, CSV, JSON or sensor data into a queryable knowledge graph without forcing a big-bang migration of your source systems.

RML/R2RML mappings and transformation pipelines
SPARQL endpoints, federated queries and query optimisation
JSON-LD APIs so existing web clients need no changes
Triple store selection, deployment and performance tuning

Decentralised & sovereign data

Architectures where the user — not the application — holds the data, based on the W3C Solid specification and data space principles.

Solid pods as interoperable personal data vaults
Access control, consent and audit trails
GDPR-aligned data minimisation by design
Data space and Gaia-X compatible sharing patterns

Discoverability & service discovery

Making systems findable and self-describing, so that clients can discover what a service offers without prior coordination or a proprietary registry.

Self-describing endpoints and semantic service descriptions
Beacon- and network-based discovery of nearby services
Capability negotiation between independent systems
FAIR (Findable, Accessible, Interoperable, Reusable) data practices

Research behind the practice

The vocabularies below were designed and published as part of doctoral research at the WISE lab of the Vrije Universiteit Brussel. They are open, freely reusable, and actively maintained — and they are the reference implementations behind the consultancy work above.

The Positioning System Ontology extends SSN/SOSA with the concepts needed to describe a positioning system, the environment it is deployed in, and the algorithms and techniques used to produce a position — not just the resulting coordinates.

Ontology Paper

A semantic Bluetooth Low Energy beacon specification, backwards compatible with iBeacon, Eddystone and AltBeacon. A SemBeacon broadcasts a link to linked data describing itself, its environment and the positioning systems available nearby — no proprietary beacon database required.

Specification Paper

A fiducial marker ontology that classifies visual markers, their spatial pose, and the detection and pose-estimation procedures applied to them — enabling augmented reality applications from different vendors to interpret the same markers in a shared space.

Ontology Paper

The open-source hybrid positioning system that puts these vocabularies to work: a modular TypeScript framework where positioning techniques are nodes in a processing graph, with built-in RDF serialisation and Solid persistence.

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