## A Brief History of SAREF

NOTE: The text in this page is taken from ETSI TS 103 264, and therefore falls under the ETSI IPR Policy

The SAREF initiative started in 2014/2015 with a study requested by the European Commission on "Available Semantics Assets for the Interoperability of Smart Appliances: Mapping into a Common Ontology as a M2M Application Layer Semantics" [i.1]. Such study acknowledged that the energy utilization of Smart Appliances can be reduced if they are managed and controlled on a system level. The system needs standardized interfaces to ensure interoperability. Many of the required standards already exist, but a common architecture does not, resulting in a market which is too fragmented and powerless. Therefore, a reference ontology of consensus was designed to cover the needs of all appliances relevant for energy efficiency. The study consisted of three tasks:

- Task 1: Take stock of existing semantic assets and use case assets.
- Task 2: Perform a translation exercise of each model (or use case) to a common ontology language and a mapping or matching exercise between all the models.
- Task 3: Propose a reference ontology and document the ontology into the ETSI M2M architecture.

NOTE:The ETSI M2M architecture has evolved into the oneM2M architecture, therefore the latter one was considered.

About 50 different semantic assets (i.e. standards, protocols, data models, ontologies) had been identified that describe various properties of Smart Appliances in residential environments. After translating half of these semantic assets into Web Ontology Language (OWL) (https://sites.google.com/site/smartappliancesproject/ontologies), 20 recurring concepts were used as initial building blocks for creating the Smart Applications REFerence ontology. The concepts were mapped from the semantic assets to SAREF to allow for translations between different semantic assets [i.4].

In November 2015, SAREF was transformed into a Technical Specification and published by ETSI SmartM2M as ETSI TS 103 264 [i.5].

In 2016, ETSI SmartM2M requested a Specialist Task Force (STF) to identify and create possible extensions of SAREF, and provide input to update SAREF according to the requirements collected from the stakeholders that have used SAREF since its first release in April 2015. This led to a new release SAREF V2.1.1 [i.6], which incorporated the feedback both from the STF that created the first SAREF extensions, and from the stakeholders that provided their input for improving SAREF. This feedback can be found in ETSI TR 103 411 [i.3] and was used to create SAREF V2.1.1.

The scope of the first release of SAREF was limited to an indoor managed domain, such as a building managed by a building manager or an apartment managed by a user. This scope also included the outdoor premises that belong to the considered indoor managed domain, in other words, a pergola that is part of the building is also within the scope, as well as a sensor located under that pergola. Note that the smart city domain was not originally considered, i.e. if the same sensor that is under the pergola is also in a street, then the sensor in the street was out of the scope of SAREF. After extending SAREF to different domains, it was clear the need for broadening the scope of SAREF from home appliances and buildings to any device that can be found in smart applications; this motivated the change of name of the ontology from "Smart Appliances REFerence ontology" to "Smart Applications REFerence ontology".

In June 2018, another STF started in SmartM2M with the goal (among others) of consolidating SAREF with new reference ontology patterns, based on the experience from the EUREKA ITEA SEAS project. As a result of this STF, 37 different issues were identified and discussed in ETSI TR 103 549 [i.21], proposing and agreeing on resolutions for most of them. Furthermore, it was identified the need for moving some transversal terms used in several extensions of SAREF to the core SAREF ontology, because of the broad applicability of such terms. This led to the release of SAREF ETSI TS 103 264 V3.1.1 [i.7].

SAREF and its different extensions were developed quite independently by different teams of experts, sometimes in parallel. Sometimes different modelling decisions were made, with the result that SAREF extensions had important discrepancies. SmartM2M started to identify ontology patterns that may be used to homogenise the structure of SAREF extensions. In 2022, two new STFs started in SmartM2M with the goal to homogenise and facilitate the use of SAREF and existing 11 SAREF domain mapping by using common ontology patterns. A total of 91 different issues were identified and discussed in ETSI TR 103 781 [i.22], and a set of SAREF Core reference ontology patterns was specified in ETSI TS 103 548 [5]. Many terms were deprecated in V3.2.1 [i.8], and have been deleted in V4.1.1 (the technical specification ETSI TS 103 264). One notable addition to V4.1.1 is that SAREF explicitly targets two main types of usage:

SAREF in online taxonomies, vocabularies, and catalogues, can be used identify and describe generic or prototypical entities than can then be reused in many verticals and applications, thus facilitating semantic interoperability.

SAREF in smart application, can be used to identify and describe specific entities of the real world for a specific application.

In October 2024, the first ETSI EN about SAREF has been published. ETSI EN 303 760 [1] gives guidance and provisions for making IoT smart applications and products interoperable at the semantic level in compliance to the SAREF framework. It contains provisions about how to use SAREF, and specifies a methodology to follow for showing SAREF compliance. Further on, it describes how to contribute optionally to a new SAREF extension.

Annex A of the technical specification ETSI TS 103 264 contains a summary of the most relevant changes made in SAREF V2.1.1 [i.6], V3.1.1 [i.7], V3.2.1 [i.8], and V4.1.1 (the technical specification ETSI TS 103 264). Annex B contains a migration guide from SAREF V3.1.1 to V4.1.1.

## References

### Normative references

- [0] ETSI TS 103 264 (V4.1.1): "SmartM2M; Smart Applications; Reference Ontology and oneM2M Mapping".
- [1] ETSI EN 303 760: "SmartM2M; SAREF Guidelines for IoT Semantic Interoperability; Develop, apply and evolve Smart Applications ontologies".
- [2] ETSI TS 118 112: "oneM2M; Base Ontology (oneM2M TS-0012)".
- [3] ETSI TS 103 267: "SmartM2M; Smart Applications; Communication Framework".
- [4] ETSI TS 103 673: "SmartM2M; SAREF Development Framework and Workflow, Streamlining the Development of SAREF and its Extensions".
- [5] ETSI TS 103 548: "SmartM2M; SAREF reference ontology patterns".
- [6] W3C® Recommendation 18 August 2009: "SKOS Simple Knowledge Organization System Reference".
- [7] W3C® Recommendation 19 October 2017:"Semantic Sensor Network Ontology", OGC® and W3C® Spatial Data on the Web working Group.
- [8] W3C® Candidate Recommendation Draft 15 November 2022: "Time Ontology in OWL", OGC® and W3C® Spatial Data on the Web working Group.
- [9] OGC® IS 22-047r1 (V1.1): "GeoSPARQL - A Geographic Query Language for RDF Data".

### Informative references

- [i.1] European Commission and TNO: "Study on Semantic Assets for Smart Appliances Interoperability", final report, April 2015.
- [i.2] ETSI SAREF: "The Smart Applications REFerence ontology (SAREF)".
- [i.3] ETSI TR 103 411: "SmartM2M Smart Appliances SAREF Extension Investigation".
- [i.4] European Commission and TNO D-S4 - SMART 2013-0077: "Smart Appliances - Mapping SAREF to short list assets.xlsx", February 2015.
- [i.5] ETSI TS 103 264 (V1.1.1): "SmartM2M; Smart Appliances; Reference Ontology and oneM2M Mapping".
- [i.6] ETSI TS 103 264 (V2.1.1): "SmartM2M; Smart Appliances; Reference Ontology and oneM2M Mapping".
- [i.7] ETSI TS 103 264 (V3.1.1): "SmartM2M; Smart Applications; Reference Ontology and oneM2M Mapping".
- [i.8] ETSI TS 103 264 (V3.2.1): "SmartM2M; Smart Applications; Reference Ontology and oneM2M Mapping".
- [i.9] ETSI TS 103 410-1: "SmartM2M; Extension to SAREF; Part 1: Energy Domain".
- [i.10] ETSI TS 103 410-2: "SmartM2M; Extension to SAREF; Part 2: Environment Domain".
- [i.11] ETSI TS 103 410-3: "SmartM2M; Extension to SAREF; Part 3: Building Domain".
- [i.12] ETSI TS 103 410-4: "SmartM2M; Extension to SAREF; Part 4: Smart Cities Domain".
- [i.13] ETSI TS 103 410-5: "SmartM2M; Extension to SAREF; Part 5: Industry and Manufacturing Domains".
- [i.14] ETSI TS 103 410-6: "SmartM2M; Extension to SAREF; Part 6: Smart Agriculture and Food Chain Domain".
- [i.15] ETSI TS 103 410-7: "SmartM2M; Extension to SAREF; Part 7: Automotive Domain ".
- [i.16] ETSI TS 103 410-8: "SmartM2M; Extension to SAREF; Part 8: eHealth/Ageing-well Domain".
- [i.17] ETSI TS 103 410-9: "SmartM2M; Extension to SAREF; Part 9: Wearables Domain".
- [i.18] ETSI TS 103 410-10: "SmartM2M; Extension to SAREF; Part 10: Water Domain".
- [i.19] ETSI TS 103 410-11: "SmartM2M; Extension to SAREF; Part 11: Lift Domain".
- [i.20] ETSI TS 103 410-12: "SmartM2M; Extension to SAREF; Part 12: Smart Grid Domain".
- [i.21] ETSI TR 103 549: "SmartM2M; Guidelines for consolidating SAREF with new reference ontology patterns, based on the experience from the ITEA SEAS project".
- [i.22] ETSI TR 103 781: "SmartM2M; Study for SAREF ontology patterns and usage guidelines".
- [i.23] ISDA: "ISDA Taxonomy 2.0".
- [i.24] European Environment Agency: "Vocabulary: Standard International Energy Product Classification (SIEC)".
- [i.25] International Renewable Energy Agency: "Energy taxonomy: Classifications for the energy transition". ISBN: 978-92-9260-583-4.
- [i.26] Wikidata.
- [i.27] QUDT.org Quantity Kind: "QUDT Quantity Kind Vocabulary Version 2.1".
- [i.28] QUDT.org Unit: "QUDT Unit Vocabulary Version 2.1".
- [i.29] OM 2.0: "Ontology of units of Measure (OM)".
- [i.30] British Oceanographic Data Centre: "BODC Parameter Usage Vocabulary - P01".