=Paper=
{{Paper
|id=Vol-2180/paper-09
|storemode=property
|title=Semantic-Enhanced National Access Points to Multimodal Transportation Data
|pdfUrl=https://ceur-ws.org/Vol-2180/paper-09.pdf
|volume=Vol-2180
|authors=Alessio Carenini,Marco Comerio,Irene Celino
|dblpUrl=https://dblp.org/rec/conf/semweb/CareniniCC18
}}
==Semantic-Enhanced National Access Points to Multimodal Transportation Data==
https://ceur-ws.org/Vol-2180/paper-09.pdf
Semantic-enhanced National Access Points to
Multimodal Transportation Data
Alessio Carenini, Marco Comerio, and Irene Celino
Cefriel – Politecnico di Milano
viale Sarca, 226 – Milano, Italy
E-mail: {alessio.carenini,marco.comerio,irene.celino}@cefriel.com
Abstract. 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.
1 Introduction
Semantic interoperability in the transportation sector is one of the European
Commission challenges: establishing an interoperability framework enables European
travel and transport industry players to make their business applications ‘interoperate’
and provides the travelers with a new seamless travel experience, accessing a complete
multimodal travel offer which connects the first and last mile to long distance journeys.
The EU-report [5] on the provision of EU-wide multimodal travel information ser-
vices highlighted several barriers for the realization of comprehensive travel infor-
mation services in the EU, such as insufficient accessibility of travel and traffic data
and the lack of travel and traffic data interoperability. Key enablers to address these
barriers are (i) ensuring that users have access to the right scope of data and information
with the appropriate data sharing mechanism, and (ii) making travel and traffic data
interoperable with a common set of data exchange standards.
A first step towards the realization of multimodal travel information services is the
establishment of National Access Points (NAPs) to multimodal transportation data as
defined in the recent Commission Delegated Regulation (EU) 2017/19261 [6], which
establishes the specifications necessary to ensure the accessibility, exchange and update
of static and dynamic transportation data. According to the regulation, each Member
State shall set up a NAP; transport authorities, transport operators and transport infra-
structure managers of each Member State shall provide travel and traffic data to the
NAP defined according to specific standards (e.g., NeTEx1) and described using na-
tional application profiles (e.g., DCAT-AP2). As emerged from the Annual NAP Report
1 http://netex-cen.eu/
2 https://joinup.ec.europa.eu/release/dcat-ap-v11
2017 [6], only a few countries have planned their NAPs, and very few operators are
ready to be compliant with the requested standards.
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 repre-
sents a semantic-enhanced solution for the establishment of NAPs. Moreover, it pro-
motes 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 Se-
mantic-enhanced National Access Point. Section 3 proposes our solution. Section 4
outlines future and ongoing work.
2 Requirements for a National Access Point
According to [6], EU Member States shall set up the first version of their NAPs
within December 2019. For this reason, the first requirement to be considered is that
the proposed solution must be market-ready.
Additional requirements come from the following categories of stakeholders in-
volved 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 man-
agement of the published assets.
Transport authorities, transport operators and transport infrastructure man-
agers: need support in publishing their data in the NAP and making them discov-
erable. 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 jour-
ney 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.
3 The Semantic Assets Manager
The Semantic Assets Manager is our semantic-enhanced solution for the establish-
ment 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 man-
agement. 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
[9]: a transaction is added to a distributed ledger each time an asset changes its lifecycle
state. Such transaction contains all accounting information, enabling all the ecosystem
participants to check the complete history of an asset on a trusted platform.
To cover also R5, the WSO2 Governance Manager is extended with modules sup-
porting the transformation, storage, and discovery of the published assets descriptions
in RDF, thus enabling more expressive queries on such data. Following the approach
in [3,8] of SPARQL query templates, we introduce a new asset type, the exploration
API, for an intelligent asset discovery (e.g., finding all transport datasets/services prov-
ing information about bike sharing in a specific Italian region). When a new exploration
API method is created, the Semantic Asset Manager automatically generates its Open-
API/Swagger documentation8. The benefits introduced by this asset type are: (i) a better
control on RDF data access; (ii) improved usability for users involved in dataset dis-
covery; (iii) easy integration with external systems.
Finally, to cover also R6, the semantic converters proposed in [2] and based on the
approach in [4], are also added as assets. The semantic converters are software compo-
nents supporting the conversion between transportation standards. As an example, a
specific semantic converter enables the translation of transportation schedule, geo-
graphic and fare information expressed in GTFS to a NeTEx specification preserving
the original meaning.
3 http://wso2.org
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, acces-
sible through public APIs, are associated with metadata profiles and are defined accord-
ing to specific standards that make them interoperable and reusable. Moreover, our so-
lution overcomes most of the limitations of data management platforms mentioned in
[1] since we provide (i) access to the source code to permit customization and exten-
sions, (ii) APIs to support easy integration, and (iii) unique identifiers for the assets to
improve findability.
4 Ongoing and Future Work
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 cur-
rently 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).
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