# Transactions on Graph Data and Knowledge

The Transactions on Graph Data and Knowledge (TGDK) is a peer-reviewed scientific journal published by Dagstuhl Publishing. It covers research on graph-based abstractions for data and knowledge and related methods and techniques, in particular graph algorithms, graph databases, graph representation learning, knowledge graphs, knowledge representation, linked data and the Semantic Web. The journal implements a diamond open access model, charging no fees for authors or readers, and allowing authors to retain copyrights.

## History

The journal was initiated by the former Editors-in-Chief of the Elsevier publication Journal of Web Semantics – Ian Horrocks, Lalana Kagal [Wikidata], and Andreas Hotho [Wikidata] – who jointly resigned from their role at Elsevier in late 2022 to initiate a new journal that they hoped might better serve the community. A task force of senior researchers was formed to develop the concept of a new journal, including publishing model, scope, and the actual title. In addition to the three original Editors-in-Chief, this group also included Abraham Bernstein [de], Tim Finin, Chiara Ghidini [Wikidata], Aidan Hogan [Wikidata], Markus Krötzsch [de], and Axel Polleres [Wikidata].
The task force decided that the scope of the new journal should go beyond Semantic Web and generally include knowledge graphs and graph databases, thereby strengthening connections in particular to research in artificial intelligence and data management. Hogan, Horrocks, Hotho, and Kagal were selected as the initial Editors-in-Chief of the new journal, and further Associate Editors were invited to join the editorial board. The initial board includes many researchers who also served on the editorial board of the Journal of Web Semantics, as well as new members to strengthen the focus beyond the Semantic Web.
In the course of 2023, Dagstuhl approved the new journal for inclusion into its publishing portfolio, making it one of the first such publication to be hosted by this organisation (the only other research journal at the time being Leibniz Transactions on Embedded Systems [Wikidata]). The first issue with twelve original peer-reviewed articles appeared in December 2023.
In 2024, Uli Sattler became an Editor-in-Chief after Ian Horrocks had completed his initial term.

## Indexing and archiving

As of 2024, the journal is listed in the Directory of Open Access Journals and indexed by DBLP. Long-term archives of the journal are maintained by the German National Library.

## Contribution to open access publishing

An important motive for creating the journal was the desire to foster free knowledge and scholarly open access. The Editor-in-Chief Aidan Hogan emphasized the importance of these values in the journal's creation, which he connected to the legacy of activist Aaron Swartz. The journal now provides peer-reviewed publication and professional support at no cost to authors or readers (diamond open access, sometimes also known as platinum open access).
As of 2023, there was no standard approach for setting up new diamond OA journals, and TGDK is notable for establishing new ways of addressing the associated challenges. These challenges include legal issues (especially clarifying the role of the official publisher), technical needs (especially submission and review system), archiving (especially long-term preservation), and infrastructural requirements (running web services). Commercial publishers cover these needs but rarely support diamond OA, with MIT Press being the only major such publisher in 2023 Another existing model at the time were overlay journals, in computer science most notably Episciences [fr]. Some further diamond OA journals in computer science relied on the support of large professional societies, examples being Journal of Machine Learning Research and the Journal of Artificial Intelligence Research. A summary of the options and challenges for diamond OA publishing in computer science as of 2022 was given by Aidan Hogan.
The strategy of TGDK was to approach Dagstuhl as a potential publishing organisation. Dagstuhl had previously published conference proceedings in its LIPIcs series, but its only journal was Leibniz Transactions on Embedded Systems, established in 2014. The proposal for hosting TGDK as a new entry had to be evaluated positively by Dagstuhl's Publishing Advisory Board. The choice of Dagstuhl as a publisher addressed most of the legal, organisational, infrastructural, and archival challenges.
Even with the support of Dagstuhl, some costs need to be covered for processing articles, even if they do not amount to the level of typical article processing fees of commercial publishers. These remaining costs are covered by sponsoring organizations, so that no fees need to be charged to authors. The Semantic Web Science Association [Wikidata] is the current main sponsor of TGDK.
For organising the submission and peer-review process, TGDK uses the free and open source publishing platform Janeway, which is based on the Django framework. The submission system is hosted by Dagstuhl.