David Chaves-Fraga

PhD Student at OEG

dachafra [at] gmail.com

PhD starts

1 SEP 2016

My PhD starts at the Ontology Engineering Group (OEG), in the area of data integration and with @ocorcho as my PhD advisor

OEG web page

OASIS and GoF4R start

28-30 NOV 2016

OASIS and GoF4R European Project Kick-off meetings in Belgium. Both are focused on semantic interoperability in Transport


Output 1.1 and 2.1 OASIS

27 JAN 2017

White paper about our vision on transport and public services data sharing in the smart cities of Madrid and Ghent

Transport - White Paper Public Services - White Paper

Internship at CIWS

1 APRIL 2017

Research visitor at Universidad de Chile and Center of Semantic Web Research (CIWS). I work with @claudiogutierrez during three months learning and experimenting with federated SPARQL queries and their performance


Output 2.1 OASIS

MAY 2017

TransportDCAT-AP: A common metadata model for representing public transport at the European level

TransportDCAT-AP documentation

Open Summer of Code 2017

17-28 JULY 2017

I attend to the Open Summer of Code 2017 as one of the coaches of OASIS team. During one month we develop Tripscore, a route planning linked data client based on user preferences and historical data.

Open Summer of Code Tripscore

Civic Hack Night in Brussels

18 JULY 2017

Invited by @DVRansbeeck to present TransportDCAT-AP and the relevance of the metadata in the transport domain

Slides Civic Hack Night

Visiting Ghent University

25 JULY 2017

One day visiting the IDLab of Ghent University invited by @pietercolpaert . The current state of my thesis is presented to the group and we discuss about SPARQL and semantic data integration.

Accepted papers at ISWC17

AUG 2017

Position paper "On the Role of the GRAPH Clause in the Performance of Federated SPARQL Queries" accepted at PROFILES2017 workshop, collocated with ISWC17

Demo paper "The tripscore Linked Data client: calculating specific summaries over large time series" accepted at DeSemWeb workshop, collocated with ISWC17

Demo paper "Providing Reliable Access to Real-Time and Historic Public Transport Data Using Linked Connections" accepted at Demo&Poster session ISWC17

GRAPH paper Tripscore demo paper LC demo paper

9th IT Combined Meeting

19 SEPT 2017

We celebrate the 1st GoF4R workshop, collocated with the 9th IT Combined Meeting in Cologne. I present the relevance of Semantic Interoperability in Transport Domain and we discussed in groups about different topics with relevant stakeholders from the domain.

Slides D4.1 Deliverable

Triscore at DataMad

20 OCT 2017

Tripscore is selected as one of the projects for a 1 month dataton of the Madrid's council

ISWC17 Workshops

22 OCT 2017

I present in two workshops: the Tripscore demo paper at @DeSemWeb and the Graph position paper at @Profiles2017

Slides Tripscore Slides Graph

ISWC17 Main Conference

22 OCT 2017

@pietercolpaert @julianrojas and I present our demo paper about linked connections and historical data during the Poster&Demo session

Trispcore won 2nd prize

16 DEC 2017

Tripscore wins the 2nd prize in the DataMad. We included public transport data from the city of Madrid to recommend routes

Spanish Tripscore

Next Steps for 2018

20 DEC 2017

After one year identifying the limitations of the problem I would like to resolve in my thesis and doing some proofs of concepts, I finished 2017 discussing with @ocorcho about the next steps for 2018. At that moment I knew which would be the contributions of my thesis and the problem I would like to solve: Online query processing over joins in CSV files

Post Proceeding Paper at ICTERI 2017

FEB 2018

Our paper "Cross-Evaluation of Term Extraction Tools by Measuring Terminological Saturation" was accepted at PP of ICTERI17.


Open Summer of Code 2018

MARCH 2018

From a collaboration between Open Knowledge Belgium and Ontology Engineering Group, Open Summer of Code 2018 will turns into an International program and it will take place in Spain for the first time.

oSoc18 Spain Web Page oSoc18 Twitter


MARCH 2018

Our paper "Refining Terminological Saturation using String Similarity Measures" was accepted to present during the conference.


RMLC starts

JUNE 2018

I start to develop RMLC, a RDF Mapping Language for heterogeneous CSV files.

RMLC Github

Best paper award at SemStats Workshop

JULY 2018

In a collaboration with some colleagues of OEG, we write a paper for the SemStats Workshop (co-located with ISWC18) and we receive the best paper award. The paper is the first contribution about RMLC, the RMLC-Iterator for statistics data.

RMLC-Iterator paper


JULY 2018

I attend to the International Semantic Web Research School 2018 being part of the Jedis team, coordinated by @Maria-Esther Vidal. The Jedis team research about Linked Data Validity in the context of Federated SPARQL queries. We receive the best paper award and the second best presentation.

Paper Presentation

Coordinating #oSoc18 Spain

JULY 2018

During two weeks in July, I coordinate the Open Summer of Code Spain 1Ed. 8 students were working on 3 real and innovation projects. During the Demo Day, more than 30 people came to see the projects and met the students.

Aftermovie oSoc18

Assitant Lecturer

SEPT 2018

I start as assitant lecturer at UPM. First experience teaching in one bachelor course and two master courses, all focused on Linked Data and Semantic Web

Visit Ghent

OCT 2018

My colleague Freddy and I visit IDLAB to meet the RML team for trying to find ways to collaborate. We present our last contributions on Virtual Knowledge Graph Generation

VKG Generation Morph-GraphQL

Events at ESWC2019

DIC 2018

Our proposals (i) Knowledge Graph Building Workshop (KGBW_2019) and (ii) Tutorial on Generating and Querying Virutal Knowledge Graphs from Heterogenous Data sources are accepted in ESWC2109. The KGBW2019 is a collaboration between RML team, OEG Data Integration Team and Juan Sequeda from Capsenta

VKG2019 KGBW2019

Datos 4.0 Meeting

JAN 2019

Presentation of my contributions in Knowledge Graph Generation in the plenary meeting of the Spanish National Project Datos 4.0

Slides (Spanish)


FEB 2019

Our paper "Similar Terms Grouping Yields Faster Terminological Saturation" is accepted at ICTERI 2018 PP


RML Test-cases

March 2019

In collaboration with RML Team we transform and extend the R2RML test-cases to RML. The scientific contribution is presented in the 1st Iberoamerican Knowledge Graphs and Semantic Web Conference

Paper Test-Cases Implementation-Report


FEB 2019

I start a 4-months internship in the "Scientific Data Managment Group" leaded by Maria-Esther Vidal in TIB (Hannover). The first days I attend to the retreat of the group and present my work and plan for the internship


Morph-GraphQL at SEKE

APRIL 2019

Our paper "morph-GraphQL: GraphQL Server Generation from R2RML Mappings" is accepted at Software Engineering and Knowledge Engineering Conference 2019 (SEKE2019). We win the best demo award, with a contribution on morph-GraphQL.

Scientific Paper Demo Paper


APRIL 2019

In the context of the KGBW2019 we write the "SAD Generator: eating our own dog food to generate KGs and websites for academic events" demo paper accepted at ESWC2019.

Demo Paper Soruce code

RMLC to Morph-CSV

MAY 2019

We transform RMLC to Morph-CSV, a engine to enhance query translation over open tabular data exploiting implicit information on mappings and annotations

Source Code

Sem4Tra Workshop

MAY 2019

In collaboration with the semantics-transport community (IDLAB, POLIMI and CEFRIEL) we organise a workshop in SEMANTiCS Conference 2019:International Workshop On Semantics For Transport



JUN 2019

We present our suite of open tools for Virtual Knowledge Graph Generation during the tutoral: morph-CSV, morph-GraphQL, TADA and HELIO. The KBGW2019 is a success with more than 70 attendees and a keynote from Mariano Rodriguez-Muro from Google

VKG2019 Material


JULY 2019

Second edition of Open Summer of Code Spain: 20 students and 7 coaches work on 6 innovative and digital projects during 4 weeks in July in La Nave (Madrid)

Website Aftermovie


AUG 2019

In collaboration with the SDM group, we develop a RML engine for an efficient transformation of multiple heterogenous datasources to a RDF-base knowledge graph

Source Code

Vision Paper at SWJ

AUG 2019

Our paper "Towards a New Generation of Ontology Based Data Access" is accepted in the Special Issue of 10-years of the Semantic Web Journal (Q1)

Paper at ODBASE2019

AUG 2019

Our paper "What are the Parameters that Affect the Construction of a Knowledge Graph?" is accepted at ODBASE2019. This is the first output of my internship at the SDM group (TIB).

ONETT at Sem4Tra

AUG 2019

Our demo paper "ONETT: Systematic Knowledge Graph Generation for National Access Points" is accepted at Sem4Tra. This is a output of the work made during Open Summer of Code in the context of the SNAP project.

Demo Paper