The establishment of National Access Points (NAPs) to transportation data represents a first step towards the realization of semantic interoperable travel information services. This paper presents the Semantic Assets Manager, i.e., an organized collection of asset types (i.e., datasets, APIs, ontologies, and schemas) enhanced by tools for their publication, governance and discovery that represents a semantic-enhanced solution for the establishment of a NAP to multimodal transportation data.
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This paper presents the Semantic Assets Manager, i.e., an organized collection of different asset types (i.e., datasets, APIs, ontologies, and schemas) enhanced by tools for their publication, governance, and discovery. The Semantic Assets Manager represents a semantic-enhanced solution for the establishment of NAPs. Moreover, it promotes the sharing of semantic converters, i.e., software components supporting transport authorities, operators and infrastructure managers in transforming their data into the correct formats/standards.
The paper is organized as follows. Section 2 describes the requirements for a Semantic-enhanced National Access Point. Section 3 proposes our solution. Section 4 outlines future and ongoing work. 2
According to [
Additional requirements come from the following categories of stakeholders involved in the management/usage of the NAP: NAP Manager: is in charge of realizing the NAP governance by managing the technical and procedural aspects. The NAP Manager needs to provide a trusted environment with clearly defined authentication and authorization procedures. Moreover, the NAP Manager needs support in quality assurance and lifecycle management of the published assets. Transport authorities, transport operators and transport infrastructure managers: need support in publishing their data in the NAP and making them discoverable. Moreover, they potentially need support in turning their data in the required formats/standards. Intelligent Transport System (ITS) providers: need support in discovering and using datasets and API from the NAP for ITS app development. Travelers: need support in discovering and using NAP information for their journey planning.
In summary, a solution for the establishment of a NAP should address the following requirements:
R1. Authorization and authentication mechanisms; R2. Tools for the publication of the datasets, their metadata descriptions and storage; R3. A dataset lifecycle management that includes an “IN REVIEW” status where a specific NAP management committee verifies the quality of the dataset and its compliance with the EU regulation; R4. Trustworthiness in the datasets management; R5. Tools for the discovery of the datasets;
R6. Semantic converters of datasets between different format/standards.
The Semantic Assets Manager is our semantic-enhanced solution for the establishment of a NAP to multimodal transportation data. To be market-ready and to reuse basic existing features, we decided to start from the popular and open source WSO2 Governance Manager3 that, out of the box, satisfies requirements R1-R4. We configured the Semantic Assets Manager by extending WSO2 in order to manage the following asset types: (i) ontologies, shared reference domain ontologies; (ii) other schemas, e.g., XSD definitions of the standards, such as NeTEx and GTFS4; (iii) datasets, travel and traffic data of different transport modes; (iv) service descriptions, made available by transport stakeholders to dynamically access data; (v) exploration APIs, supporting the discovery of available assets; (vi) converter services, transforming data between different standards. Each asset type is published according to a specific semantically-enhanced metadata profile and associated with a specific lifecycle management. The Semantic Assets Manager5 is composed of two Web application, namely the publisher6 and the store7, supporting the publishing and the discovery of the assets, respectively.
To further strengthen the satisfaction of R4, we have included blockchain technology
[
To cover also R5, the WSO2 Governance Manager is extended with modules
supporting the transformation, storage, and discovery of the published assets descriptions
in RDF, thus enabling more expressive queries on such data. Following the approach
in [
Finally, to cover also R6, the semantic converters proposed in [
4 http://gtfs.org 5 A detailed description of the Semantic Assets Manager is available at: https://bit.ly/2JG8zL8 6 https://ns3056488.ip-213-32-26.eu:9443/publisher (usr:guest, psw: $ISWC2018_guest#) 7 https://ns3056488.ip-213-32-26.eu:9443/store (usr:guest, psw: $ISWC2018_guest#) 8 https://www.openapis.org/
The Semantic Assets Manager satisfies the FAIR principles9 since the assets,
accessible through public APIs, are associated with metadata profiles and are defined
according to specific standards that make them interoperable and reusable. Moreover, our
solution overcomes most of the limitations of data management platforms mentioned in
[
Together with a network of transport stakeholders, we are defining a governance framework for the Semantic Assets Manager, to enable its adoption and sustainability as a semantic-enhanced NAP for multimodal transportation data. Moreover, we are currently exploring the use of SHACL Advance Features10 to improve the automation of ontology-based annotations and mappings and to enhance further the approach used for the realization of semantic converters.
Acknowledgments This work has been supported by IT2Rail (H2020-636078), ST4RT (H2020-730842) and GoF4R (H2020-730844).
10 https://www.w3.org/TR/shacl-af/