Ontop

07/01/2022

[ANN] Ontop 4.2.0
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Easier data manipulation with Ontop views, time operators, improved support for Apache Spark and better queries to the data schema.

Ontop 4.2 focuses on some major and many minor improvements. Mapping to the data source becomes much easier and more flexible with the new Ontop views.

Ontop is the leading Open Source Virtual Knowledge Graph engine. Virtual Knowledge Graphs are an innovative approach to data access and integration, allowing to integrate heterogeneous data coming from relational databases and data lakes progressively, one aspect at a time, making data integration projects more agile and easier to manage.

This open-source software, which is released under the conditions of the Apache License, Version 2.0, is actively maintained and new releases are made regularly. This new version introduces:
- Ontop views for increased flexibility and manageability of mapping entries
- Support for Apache Spark
- Time functions
- Support for Java 17
- Additional information about the data model in the queryable graph, such as subclass relationships
- A large number of changes to improve compliance with standards and robustness.

More detailed release notes can be found at https://ontop-vkg.org/guide/releases.

The harmonized knowledge graph is queryable in SPARQL, the querying language used for the Semantic Web and used in major knowledge projects, like Wikidata, Google’s Data Common, and DBpedia. The support for industry leading federation software and W3C standards guarantees excellent interoperability with a large number of databases and analytic software.
The high code quality, welcoming community, documentation targeted at end-users, conformance to standards, and a solid theoretic foundations developed in more than 100 scientific publications, helped growing a community of industrial and academic users relying on Ontop, as is demonstrated by an increasing number of downloads (in 2021 there were 16374 downloads on Sourceforge, version 4.1 was downloaded 943 times from GitHub and the docker images were pulled 2800 times from DockerHub). Ontop is the foundation for the commercial offerings by Ontopic and is handling data virtualization for products as GraphDb by Ontotext and AllegroGraph by Franz Inc.

Major contributions to this new version came from Ontopic (https://ontopic.ai), the Free University of Bozen-Bolzano (https://unibz.it), Birkbeck, University of London (https://dcs.bbk.ac.uk) and Politecnico di Milano (http://www.chimera.polimi.it). These contributors have authored more than 400 commits to the code base leading from version 4.1 to version 4.2.

Project page: https://ontop-vkg.org/
GitHub: https://github.com/ontop/ontop
Twitter: https://twitter.com/ontop4obda
Mailing list: https://groups.google.com/d/forum/ontop4obda

For more information:
Benjamin Cogrel
Guohui Xiao or
Roman Kontchakov

A Virtual Knowledge Graph System

03/03/2021

[ANN] Release of Ontop 4.1.0
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Dear Ontop users,

We are happy to announce the stable release of Ontop 4.1.0!
This new version focuses on improved manageability, increased performance, and improved compatibility with third-party software and GeoSPARQL:

- Support for GeoSPARQL allows for the integration of data from PostGIS databases.
- An extensive logging system allows for better monitoring of running endpoints.
- It provides the ability to create Web APIs above the Virtual Knowledge Graph.
- It supports the data lake engine Dremio.
- A large number of changes improve performance and decrease memory consumption compared to version 4.0.

More detailed release notes can be found at https://ontop-vkg.org/guide/releases.html

Best regards,

Guohui Xiao, on behalf of the Ontop development team

Note that this is the first release from version 3 series with many internal refactoring and improvements, and bug fixes. However, these changes also cause incompatibility with Ontop v1. See the migration guide.

04/08/2020

We are very happy that two papers about Ontop have been accepted in ISWC 2020.

The first paper "The Virtual Knowledge Graph System Ontop", accepted at the resource track, is about the latest version of Ontop. It will serve the canonical reference of Ontop in the future.

The second paper "Semantic Integration of Bosch Manufacturing Data Using Virtual Knowledge Graphs", accepted at the in-use track, is about a use-case in collaboration with Bosch.

04/08/2020

[ANN] Release of Ontop 4.0.0
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Dear Ontop users,

After a beta and an RC, we are happy to announce the stable release of Ontop 4.0.0! Thanks for all the feedback.

This release fixed a few issues and made the following improvements:

- Dependencies updated (e.g. RDF4J 3.3.0)
- SERIAL datatypes of PostgreSQL better handled
- Anonymous blank nodes are now supported in CONSTRUCT blocks
- JSON-LD now supported for graph queries
- Denodo support improved.

For a more detailed release note, please see https://ontop-vkg.org/guide/releases.html

Best regards,

Guohui Xiao, on behalf of the Ontop development team

Note that this is the first release from version 3 series with many internal refactoring and improvements, and bug fixes. However, these changes also cause incompatibility with Ontop v1. See the migration guide.

09/07/2020

[ANN] Release of Ontop 4.0.0-rc-1
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Dear Ontop users,

We are proud to announce the Release Candidate of Ontop v4. Ontop v4 undergoes significant internal refracting and brings many new features.

The highlights of this new release are:
- Support of GROUP_CONCAT added. All the standard SPARQL aggregation functions are now supported.
- Support of Named Graphs added.
- Support of Denodo added.
- Support of XML catalog file. It enables resolving owl:imports assertions from the ontology by loading local files instead of fetching remote URLs.
- Support of the CASE and CAST operators in the mapping.
- Streaming mode enabled by default for query answering. It fetches data by batches of 500 results.
- The RDF4J Workbench based SPARQL endpoint is now deprecated in favor of the `ontop endpoint` CLI and its Docker image.

For a more detailed release note, please see https://ontop-vkg.org/guide/releases.html

Please give a try to this release candidate. The final official stable release of Ontop v4 is planned by the end of July.

Best regards,

Guohui Xiao, on behalf of the Ontop development team

Note that this is the first release from version 3 series with many internal refactoring and improvements, and bug fixes. However, these changes also cause incompatibility with Ontop v1. See the migration guide.

27/12/2019

Diego Calvanese è stato nominato ''fellow'' dall'Association for Computing Machinery per il suo contributo a numerosi settori dell'informatica. Nell'intervista spiega che è il momento di preoccuparsi di cosa vogliamo dall'intelligenza artificiale

24/12/2019

[ANN] Ontop v4.0.0-beta-1 release
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Dear Ontop users,

We are very happy to announce the first beta release of the Ontop 4.0, as promised in 2019.

Ontop v4 undergoes significant internal refracting and brings many new features. In particular:
- SPARQL Aggregation functions SUM, COUNT, AVG, MIN, MAX are now supported. SAMPLE is currently implemented as MIN.
-Some functions (such as IRI templates) can now be post-processed (that is, they are not always included in the SQL query anymore). Generated SQL queries are generally much less verbose than before.

For a more detailed release note, please see https://github.com/ontop/ontop/wiki/OntopReleases

Best regards,

Guohui Xiao, on behalf of the Ontop development team

Ontop is a platform to query relational databases as Virtual RDF Knowledge Graphs using SPARQL. It's fast and is packed with features. - ontop/ontop

30/10/2019

Virtual Knowledge Graphs for Data Integration

29/08/2019

[ANN] Release Plan for version 4.0

Dear Ontop users,

The last beta versions of 3.0 have been proved to be quite stable and to be already in use in several projects so we decided to make a stable release out of them, labeled 3.0. As the next important version will introduce important internal changes compared to 3.0., we decide to treat it as major release and name it 4.0.

We are working hard on version 4, which is already in an advanced state. We are planning to release the first beta of version 4.0 within October. It will, among others, features the main SPARQL aggregation functions (COUNT, SUM, AVG, MIN, MAX).

For those interested, you can have a look at the version4 branch, which is actually now the default branch on GitHub.

Best regards,

The Ontop development team

29/08/2019

[ANN] Release of Ontop 3.0.0

We have recently updated our release plan and we are pleased to announce that the first stable release of Ontop 3.0 is out!

Some important refactoring and new features (SPARQL aggregation) initially planned for 3.0 have been rescheduled to 4.0. More info on this is in a separate post.

Highlights of this release include:

New command-line interface for SPARQL endpoint
Docker container for SPARQL endpoint (https://hub.docker.com/r/ontop/ontop-endpoint)
Preliminary support of Dremio
Preliminary support of Denodo
Support of BNode in R2RML
A new repository for the tutorial (https://github.com/ontop/ontop-tutorial)
A detailed release note available at:
https://github.com/ontop/ontop/wiki/OntopReleases

Cheers,

The Ontop development team

Download: https://sourceforge.net/projects/ontop4obda/files
Website: https://ontop.inf.unibz.it
Documentation: https://github.com/ontop/ontop/wiki
Github: https://github.com/orgs/ontop/
Follow us on Facebook: https://www.facebook.com/obdaontop
Twitter: https://twitter.com/ontop4obda

19/07/2019

We are HIRING! 5 POSITIONS!

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5 Research positions on Virtual Knowledge Graphs at KRDB, Univ. Bolzano, Italy
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The KRDB group at the Faculty of Computer Science of the Free University of Bozen-Bolzano/Italy is offering 5 positions at various levels on foundational and applied aspects of the management of virtual knowledge graphs (VKGs), a research area also known as ontology-based data access and integration. The positions address the study, design, and implementation of techniques for query answering, for accessing and integrating linked open data, and for using virtual knowledge graphs to support process mining.

The positions are funded by different research projects (from basic research to academia-industry collaborations) that are currently starting within the In2Data research group coordinated by Prof. Diego Calvanese [1]:

- EU Project INODE on data management infrastructures (3 years)
- Italian basic research project HOPE on open data publishing (3 years)
- CHIST-ERA EU Project PACMEL on VKG for process mining (2 years)
- ESF Project IDEE on data integration in the energy sector (3 years)
- unibz funded project GeoVKG on geo-spatial VKG (2 years)

We seek highly motivated and ambitious candidates with an MSc or Ph.D. in computer science or closely related fields. Good programming skills and a background on semantic technologies and standards (e.g., RDF, SPARQL, OWL, R2RML) are highly appreciated. The willigness to collaborate across institutional boundaries with partners from both academia and industry is a plus. Successful candidates will also be encouraged to join the development team of the popular open source framework Ontop [2]. The Ontop team has recently spinned off the startup Ontopic [3], which provides services and develops technologies for data integration based on VKGs, and has strong ties to the Ontop research team. Ontopic is located in the novel NOI Techpark of Bolzano [4], which provides strong links to the local tech-scene.

The positions should be filled as early as possible and have an initial contract duration of 1 year. However, we are looking for candidates willing to stay for several years, as the positions are renewable and funding is secured.

The positions come with a vibrant international working environment in a great location. The university is located right in the center of Bolzano, a charming city in the Dolomites (Alps) [5,6]. The region, South Tyrol, is among the top destinations for hikers, cyclists, mountaineers, rock climbers, skiers, etc. And last, as one would expect from any Italian location, food in Bolzano is great.

For an informal discussion about the positions, interested applicants are invited to get in contact immediately with Dr. Guohui Xiao ([email protected]). The formal calls for the positions are about to be issued.

[1] https://www.inf.unibz.it/krdb/in2data/
[2] https://ontop.inf.unibz.it
[3] https://ontopic.biz/
[4] https://noi.bz.it/it/
[5] https://en.wikipedia.org/wiki/Bolzano
[6] https://www.google.com/search?q=bolzano+italy&prmd=imvns&tbm=isch

In2Data: Intelligent Integration and Access to DataMission At In2Data, we investigate foundational, methodological, experimental, and application oriented aspects of access to structured and semi-structured data and information by leveraging its semantics. We combine techniques developed in the area...