All posts in Tech Updates

In the Spring of 2022, the BHL Cataloging and Metadata Committee investigated the possibility of harvesting persistent identifiers (PIDs) from Wikidata as part of the group’s longstanding project to disambiguate and deduplicate author records in the BHL database. The motivation behind this one-time experimental data harvest was to see if BHL could:

1. Enhance BHL author records with additional PID data points;
2. Improve the committee’s ability to disambiguate author names in the BHL database; and
3. Respond to an outstanding user request from two of Wikimedia’s super star editors, Siobhan Leachman and Andy Mabbett, to expose BHL’s author data on BHL and include hyperlinks to other authoritative knowledge bases on the web.

In particular, Wikimedians wanted to see the Wikidata Q identifier exposed, providing a link to the corresponding creator item record in Wikidata.

There are multiple motivations for undertaking this work. By adding the BHL Creator ID to the corresponding Wikidata item, Wikidata editors help link BHL to the richer biographical data about that person held in Wikidata. The Wikidata item for a person may contain links to their Wikipedia page or to images of the person held in the image repository Wikimedia Commons. Wikidata items also act as identifier hubs and contain links to other databases and identifiers.

By adding the BHL Creator ID to this list of identifiers, the Wikidata editor is linking the content held in BHL to the content held in multiple other datasets and repositories.

These extra author data points provide Wikimedians and BHL catalogers with crucial clues that aid in name disambiguation. In particular, hyperlinks to other knowledge bases are incredibly valuable because they lead to new knowledge pathways that help confirm a person’s identity in a complex game of “Who’s Who?”

Recently, BHL performed a comprehensive review of all live data feeds and outputs to ensure that we are providing robust metadata to our downstream consumers. Live BHL data can be found at BHL’s Developer and Data Tools. BHL’s live data outputs include:

• API v3
• OAI-PMH

OAI-PMH is an acronym for the Open Archives Initiative Protocol for Metadata Harvesting. It allows other discovery services and aggregators to harvest BHL’s metadata in standard formats such as Metadata Object Description Schema (MODS) and Dublin Core (DC).

To provide more robust data in BHL’s OAI-PMH Dublin Core feed, three changes have been made to the feed:

1. Creative Commons (CC) license information was added as a second <rights> element;
2. A <relation> element was added to titles that are part of a monographic series, allowing BHL to model more complex bibliographic relationships that exist in the BHL database; and
3. A non-standard “type” attribute was removed from the <relation> element for parts.

Important: If you are a developer, using the non-standard “type” attribute in your code at the part-level, this is a breaking change. Please take note and update your code accordingly.

For BHL, 2022 was a year to focus on critical upgrades for the BHL platform to ensure the sustainability of our services for our global users. Although BHL’s basic technical infrastructure remains the same, consisting of years of refinement, knowledge, and reliability, a few updates were definitely in order. Most of these upgrades were “behind-the-scenes” work and would not be noticeable to a majority of our users. However, keeping up with these important enhancements is a crucial component of any technology project.

Optical character recognition (OCR) plays a critical part in BHL’s contributions to the scientific community. OCR in and of itself is a remarkable achievement, converting images of typewritten text to computer-readable text with “pretty good” accuracy. OCR on handwritten text is an even greater challenge to address and is beyond the scope of the improvements discussed here. The scientific work that BHL supports demands the best accuracy that we can provide using available tools, and let’s be honest, available budgets.

Recently, our colleagues at the Internet Archive made the transition away from the ABBYY FineReader OCR software to the Tesseract Open Source OCR engine. Over the past year or more, the OCR team at the Internet Archive has adapted and fine-tuned Tesseract to their workflows. Our first impression is that Tesseract OCR is more than “pretty good” in its ability to identify text from the page images provided to it.

The downside to this is that the Internet Archive has rightfully chosen to not re-process all existing text content through the Tesseract OCR engine. This is a prohibitively expensive and time-consuming prospect given that they have 35 million text-based items and reprocessing them would take several years and use up resources that could otherwise be used for gathering new content.

However, in the interests of supporting the efforts of the BHL community, the BHL Tech Team is working with our Internet Archive partner to reprocess some of BHL’s oldest content with the newest available version of Tesseract OCR. We are currently in a testing phase, and this blog post details some of our early results.

The BHL Tech Team is pleased to announce a new form of content available in BHL: Article PDFs. While this may not sound like anything new, after all, we have had a tool to download PDF content for some time, this update changes both how the PDFs are created and maintained, and how BHL is viewed by content aggregators on the internet, most notably Unpaywall.

In October 2020, BHL launched a new working group with a momentous goal: to make the content on BHL persistently discoverable, citable and trackable using DOIs (Digital Object Identifiers).

A DOI is like an electronic fingerprint in the form of a unique and permanent alphanumeric string that provides a persistent link to a piece of content online. Modern publications receive a DOI at the point of publication. A DOI is a key part of a publication’s bibliographic metadata and should be included in any mention or citation of that publication. Reference lists in modern publications are filled with DOIs, which allows readers to click from publication to publication in (in theory) a never-ending chain of knowledge.

We have updated the bibliography pages in BHL to streamline the presentation of information about and metadata export options for content in the Library.