Interoperability, Semantic Interoperability and Standardisation – A Comprehensive Overview of the HIOT Session

Introduction

The HIOT (Hybrid Internet of Things) session opened with a warm welcome and a brief agenda overview. Participants from the EU‑wide data‑space community, industry partners and research projects gathered to discuss the current state of semantic interoperability, standardisation and the role of the Data Act.

European Standardisation Landscape – Sebastian Steinbus (IDSA)

• Regulation vs. standards – Regulations are mandatory; standards are voluntary but essential for compliance and market uptake.
• Harmonised European Norms – Issued after a formal standardisation request (e.g., the Data Act’s Article 33). When a standard is listed in the Official Journal of the EU, compliance can be demonstrated.
• JTC 25 (SENS) – Four working groups focus on:
• Advisory tasks & stakeholder liaison
• Data‑space concepts & governance
• Data‑space technical specifications
• Cloud & edge standards (future‑mandated work)
• Trusted Data Transaction (TDT) suite – Seven parts, of which Parts 1‑3 are harmonised:
• Part 1 – Terminology, concepts, mechanisms (no requirements)
• Part 2 – Trustworthiness requirements
• Part 3 – Interoperability requirements
• Parts 4‑5 – Data‑catalog & semantic‑asset specifications (CTC‑Data)
• Parts 6‑7 – Equality framework for internal data governance & maturity model for European data spaces
• Timeline – Part 1 in final drafting, Part 2 in inquiry stage, Part 3 to close drafting by Dec 2024; other parts follow similar review cycles.

The Hourglass Model – Antonio Kong (Trilog)

• Proposed a two‑layer hourglass architecture: a thin core of common capabilities (e.g., IP, Ethernet, HTTP) supporting a wide range of applications (IoT, cloud, edge).
• Mapped standard hierarchies for data‑space, cloud‑edge‑IoT and trust‑framework ecosystems.
• Highlighted key standards:
• ISO 21501 – Conceptual definition of data spaces (expected 2024/2025).
• ISO 21518 – Digital‑twin reference architecture.
• ISO 19944 – Cloud portability & interoperability.
• ISO 21823‑5 – Behavioural & policy interoperability for IoT.
• Emphasised the need to align European and international standards to avoid fragmentation.

HIT Project’s Standardisation Contributions – Leo Kornik (POG)

• Work Package 7 drives the exploitation of existing standards and the creation of new ones across three domains:
• Connected intelligent secure data ecosystem (data‑space, IoT, digital twins, AI).
• Semantic interoperability (SRF and extensions).
• Energy & smart‑energy.
• Activities include internal workshops, participation in bodies such as SENS‑JTC25, ISO, ETSI, BDVA, Eclipse, and the identification of standardisation gaps.
• Concrete contributions:
• ISO 21823‑1/‑5 (behavioural & policy interoperability).
• EN 304199 (data‑catalog guidelines).
• EN 303760 (semantic‑interoperability guidelines).
• Participation in the GC Code of Conduct for Smart Appliances and IC 61850 data‑model work.
• Future work: align with the 2025 EU‑ICD standardisation roadmap and continue gap‑analysis.

How HIOT Can Influence Existing Standards – Sylvia Castelb (IDSA)

• Four engagement routes:
• Direct participation in technical committees (e.g., SENS‑JTC25, CTC‑Data).
• Liaison activities – sharing project results, feeding use‑case evidence into standard drafts.
• Inviting standards‑body representatives to project workshops and advisory boards.
• Coordinated gap‑identification workshops that produce concrete proposals for new standards or extensions.
• Emphasised the importance of prioritising standards that match project capabilities and allocating dedicated experts for sustained contribution.

Semantic Interoperability in HIT – Cornelius (TNO)

• Tool stack: PowerSim (grid data exchange), Semantic Treehouse (vocabulary hub), Semantic Interoperability Framework (Linux Foundation for Energy).
• Semantic models: SARF (Smart Appliance Reference Framework) core and vertical extensions (energy, building, etc.).
• Maturity levels – Updated EU‑defined levels (1‑7) to reflect technical, semantic and behavioural interoperability; pilots choose the appropriate level.
• Reference architecture – Integrates data‑space connectors, semantic assets, governance, and edge‑cloud components, exposing gaps for future development.
• Learning resources – Centralised repository of webinars, tutorials and documentation for partners and external stakeholders.

Open Distributed & Trustworthy Data Solutions – Diego Lopez (Telefonica, TC‑Data)

• TC‑Data (Etsy) aims at open, distributed, trustworthy data solutions for autonomous “agent applications”.
• Core pillars:
• Openness – Leverage existing standards, avoid reinventing the wheel.
• Distribution – Data‑productisation, data‑mesh/fabric concepts, semantic metadata.
• Trustworthiness – Provenance, evidence collection, identity for non‑human workloads, policy enforcement.
• Aligns with the Data Act (standardisation request 614) and collaborates with SENS‑JTC25.
• Works on semantic metadata exchange, privacy‑preserving governance, and evidence‑based billing for data usage.

Round‑Table Insights – Main Gaps & Future Priorities

Conclusion

The session highlighted a rapidly evolving ecosystem where standardisation, semantic interoperability and trustworthy data exchange are tightly interwoven. European harmonised norms provide a compliance backbone, while open‑source implementations and cross‑domain governance are essential to turn standards into market‑ready solutions. Continued collaboration between research projects (like HIT), industry consortia (TC‑Data, Trilog) and standardisation bodies will be decisive for achieving a seamless, AI‑enabled data‑space future.

A coordinated effort between EU‑mandated standards, open‑source implementations and active R&D projects is the only viable path to achieve scalable, trustworthy and AI‑ready semantic interoperability across data spaces.