I can hardly believe it's been eight months since I last wrote about the NISO I2 project. A lot has changed since then[1]. I continue to work on I2 however; they won't get rid of me that easily.

In the last post, I wrote:

The next step is to build upon the report to draw yet more conclusions from the data — there's an awful lot there — and flesh out some repository use cases for institutional identifiers. The I2 core group is moving quickly towards finalizing identifier metadata elements so that a standard may be drafted, and I think having some use cases documented will help drive the standard in a direction the community can get behind.

Since that time, the three scenario groups — Electronic Resources; Institutional Repositories and Learning Management Systems; and Library Resource Management — have concluded their work. The work of the scenario groups included surveys of over 300 people working in these fields. The survey results have been analyzed and reports were posted on the NISO website. These reports have been used to flesh out use cases for an institutional identifier. Upon completion of this work, the scenario groups were disbanded and work continued in a broader I2 working group.

The I2 working group has concentrated its work on analysis of similar standards and, as I alluded to earlier, significant effort has gone into defining core metadata to identify institutions, such as institution name, institution type, location information, variant identifiers, domain name(s), URL(s), and (optionally-typed) relationships to other institutions. During these discussions it was difficult for me to hear the issues and needs around I2's metadata and identifiers without linked data springing to mind.

While we are designing a standard and not a system or a service per se, it seems useful to include in the standard an informative section about implementation and architecture[2]; I find that reading standards is much easier on the brain when you get not only the standard itself but some examples of implementation, and that will be true as well, one hopes, of I2 standard implementers. To that end, the group will be producing an XML schema of the I2 metadata elements and also an RDF schema.

I have been working on the RDF for I2 on and off for the past month or two. Below are my impressions, as someone who is new to modeling in RDF, and the procedures I used to produce the draft RDF schema.

Despite their names, RDF schema and XML schema are quite different[3]. The XML schema is a tool for validating an XML-based document or record, and it's a common tool for modeling metadata in libraryland. Not so with RDF schema, where the notion of document or record is replaced by the notion of a set of triples. The focus in RDF is on the triple not on the document, and so validation of documents or records is not the point of RDF schema. This took some effort to wrap my mind around.

Before I modeled I2 in RDF, I sketched out a domain model of I2 by copying relevant bits of information from I2 documents and pasting them into a text editor. Then I put them into classes. In I2's case, the domain model contained three classes of things: metadata elements about an institution, relationships between institutions, and types of institution.

I gathered some examples of relatively simple RDF schemas and transformed them into the Turtle serialization format[4] for ease of reading, using them as a template for the I2 schema.

In the RDF schema (RDFS) specification, there are two classes of things in the domain model: classes and properties. If you are familiar with object-oriented programming, chances are you already grok this way of modeling, but otherwise, generally: a class is like a type and a property is an attribute. If I were to model myself in RDF schema, then, I might say I am in the class of human beings, and one of my many properties is having a particular birth date, and another is having been born in a particular city. The next step was to take the I2 domain model (metadata elements about an institution, relationships between institutions, and types of institution) and decide whether each thing was a class or a property. I decided that the former two were sets of properties and that type of institution could be modeled as a set of classes.

Having a conceptual model of I2 and how it fit into the RDF schema way of thinking about things, I wrote a simple ontology defining one RDFS class per type of institution, and one RDFS property per metadata element and one per relationship type. This would have sufficed as an ontology.

Exposing RDF-based resources on the web as linked data, however, represents an opportunity for metadata element-level interoperability at global scale. In order to interoperate with the existing corpus of linked data available on the web, I went through the new I2 ontology and looked for areas where I could re-use, or subclass or otherwise link to, classes and properties already defined in more widely-used ontologies. I realized at this point just how different coming up with a new XML document format was from writing an RDF ontology; whereas I might have wanted the former to be comprehensive and inclusive of every single aspect within the I2 domain model, my goal with the latter became to eliminate it (by trimming it down to only those bits which are not defined elsewhere).

Since the RDF ontology for I2 is not inclusive of the entire domain model, it seemed necessary to produce another reference document: a set of instances of I2 resources showing the mingling of new I2-specific classes and properties with well-defined classes and properties from other ontologies.

I shared rough first drafts of these documents and received very helpful feedback from some folks who are better-versed in this than myself. I've now incorporated their feedback into the latest I2 ontology and instance document. I hope to include both of these into a draft of the I2 specification which will go out for comment in the coming months. Here's the latest ontology and the latest set of instances.

Notes

1. I've moved and changed jobs, in fact
2. This practice seems more or less common in my (admittedly limited) experience, cf. the unAPI specification.
3. This reflection should come as little surprise since RDF and XML are different kinds of things: RDF is a data model and XML is a serialization format.
4. Using rapper, a nifty little tool.

I wrote in June that the I2 subgroup surveyed "repository managers to determine the current practices and needs of the repository community regarding institutional identifiers. Results from the survey will inform a set of use cases that will be shared with the community, and that are expected to drive the development of a new standard for institutional identifiers."

The survey closed in July, and the subgroup spent August writing a report on the survey results. That report is now final and it's available to the public. Feedback may be sent to our (woefully underutilized) public i2info mailing list, left as a comment on this post, or e-mailed to me privately which I can forward to our internal list.

The next step is to build upon the report to draw yet more conclusions from the data — there's an awful lot there — and flesh out some repository use cases for institutional identifiers. The I2 core group is moving quickly towards finalizing identifier metadata elements so that a standard may be drafted, and I think having some use cases documented will help drive the standard in a direction the community can get behind.

Onward and upward.

[Series]

Near the end of my strawman post, I wrote:

The I2 repositories subgroup will be sending out its survey on identifier use cases in the coming week. It will be interesting to see if the requirements we have thus far identified still obtain in light of the data we collect from the survey.

We completed the survey late last week and began distributing it. Here's what we sent out:

The NISO I2 Working Group is surveying repository managers to determine the current practices and needs of the repository community regarding institutional identifiers. We value your time and your input in the process to create a standard for a new institutional identifier. We hope that you will complete the survey which should take less than 15 minutes. The survey will remain open through Monday, July 6th.

Here is a link to the survey:
http://www.surveymonkey.com/s.aspx?sm=RGQgZ3090DVrb3kFzr3P3Q_3d_3d

Please feel free to share this message with other interested parties.

First we used Survey Monkey to send the survey link to approximately one-hundred repository managers that the subgroup identified. Our process for identifying repository managers involved pulling together a list of prominent repositories from subgroup members, and then gathering more from OpenDOAR, "an authoritative directory of academic open access repositories." Then subgroup members were encouraged to share the survey link with colleagues, and post it far and wide via blogs, listservs, and tweets. The listservs we targeted were: JISC-REPOSITORIES, metadataLibrarians, digital-curation, SPARC-IR, ir-net, REPOMAN-L, PALINET-IR-L, dspace-general, fedora-commons-users, DC-IDENTIFIERS, and code4lib.

I've already received a few responses and have gotten useful feedback. Two of the hardest questions to answer so far have been: "What is an institutional identifier?" and "What is a repository?"

Institutional identifier

An institutional identifier is defined as a symbol or code that uniquely identifies an institution. Domain-specific examples of existing identifiers include SAN, IPEDS, GLN, MARC Org Code, and ISIL. Another example might be a Handle prefix or ARK name authority assigning number.

Repository

Institutional repositories and subject repositories like arxiv.org are clearly 'repositories', but beyond that it is a somewhat ill-defined term. One might look to the Kahn-Wilensky architecture, or the OAIS reference model (PDF), or even Wikipedia for definitions, but it's not clear that even the authorities agree on what constitutes a repository.

It's a system. It's network-accessible and typically has a web interface of some sort. Files and groups of files sometimes known as objects tend to be deposited in them, perhaps for some combination of management, access, or preservation. Many run Fedora, DSpace, and ePrints, and factor heavily in scholarly communication. Some are document-centric. Some will accept anything. To some, a learning management system may be a repo. To others, a content management system may fit.

My background is in academia so my own definition is somewhat based in that context, but I wouldn't say the term is necessarily limited to that context. There are other NISO I2 scenarios for library workflows and electronic resources, so it's safe to assume that repository does not mean ILS or OPAC or ERP system. My hope is that folks have their own working definitions of the term and can decide for themselves what it means.

We've given folks a little over two weeks to respond to the survey, so the constant I2 drum-beating will quiet down for a while around here. I am very interested in what sorts of responses we get from the survey. Fun times!

Oh, and perhaps it goes without saying, but if you're a repository owner, manager, expert, developer, or stakeholder with an interest in identifiers, please feel free to take the survey!

[Series]

In the prior I2 post, I wrote about the requirements the repositories subgroup has come up with for an institutional identifier standard (with the hope that our findings re: repositories could be generalized to other scenarios).

My strawman proposal of sorts is to explore how well linked data patterns fit this problem space. Linked data, briefly, is a way to expose and link data on the web in a more semantically meaningful way, and is often summarized using the four principles put forward by Tim Berners-Lee:

1. Use URIs as names for things
2. Use HTTP URIs so that people can look up those names.
3. When someone looks up a URI, provide useful information.
4. Include links to other URIs. so that they can discover more things.

That's the crux of it.  Linked data takes well-known patterns on the web (linking, dereferencing, etc.) and applies them to data, which in this case could be metadata for identifying institutions.

Let's examine each of the requirements and the applicability of linked data thereto.

1. Should be agnostic to type of institution, e.g., libraries, museums, personal collections, historical societies: The web is already agnostic to type of institution.  HTTP URIs do not favor one type of institution over another.
   
2. Should handle varying institutional granularity, e.g., institution-level, campus-level, division-level, unit-level: HTTP URIs are flexible in this regard.  Hierarchy, should one wish it to be surfaced in the identifier, may be encoded in either a DNS hostname or the path appended to the DNS name.  One can imagine a URI like "http://department.division.institution.tld/unit/subunit" or "http://institution.tld/campus/office/individual".
   
   Hierarchy needn't be surfaced in the identifier if one favors opacity, in which case "http://registry.tld/xnjsdasd" would suffice as an identifier, and may instead be entirely reflected in the (RDF) representation returned by dereferencing the URI.
   
3. Should handle linking among institutions and subordinate units: Linked data handles linking via well-known HTTP mechanisms, referenced in the fourth principle of linked data.  Unlike the HTTP link, which has limited semantics, linked data links are semantically rich and extensible.
   
4. Should express different sorts of relationships among these institutions and units: The "useful information" in the third principle of linked data is typically provided by an RDF representation, which is itself a list of assertions.  These assertions, or triples, consist of subjects, predicates, and objects.  The ability to express the relationships in this requirement is limited only by the availability of vocabularies that contain sets of predicates and classes for subjects and objects.  Think of the predicates as elements defined within a metadata standard, e.g., Dublin Core "creator", MODS "relatedItem", and so forth.  Vocabularies that contain these predicates and classes are growing and evolving daily, and should there not be a vocabulary that contains the relationship one wishes to express, it is fairly easy to create a custom vocabulary.
   
   The ability to mix and match vocabularies provides an expressiveness that is often not found in document-based metadata formats and the flexibility to express radically different relationships on a per-industry or per-institution basis.  This latter point is important as the I2 group has identified both core metadata elements for identifying institutions of different types and additional elements for specific types of institutions.  Why re-invent a new metadata format or schema when all one needs to express may already be contained in others?
   
5. Should relate to existing relevant identifiers and registries: Same as requirement#4.  Linked data is all about expressing relationships between things, e.g., institutions, identifiers, registries, etc.
   
6. Should be globally unique: HTTP URIs are guaranteed to be globally unique by virtue of the distributed DNS system and hierarchical naming within each HTTP service.
   
7. Should be actionable: HTTP URIs provide dereferenceability/actionability via the well-known HTTP protocol.
   
8. Should enable retrieval of metadata sufficient to identify the institution, which may vary widely by institution: HTTP URIs are actionable per requirement #7 and the metadata returned is flexible per requirement #4.
   
9. Should accommodate changes as institutions come and go and re-organize and be able to relate defunct institutions to new ones: Linked data patterns provide for redirecting from defunct representations (institutional identifiers) to new ones via HTTP redirects.  One may also add assertions to institutional metadata such as owl:sameAs, for instance, which says that the institution identified by the given URI is the same as another institution identified by another URI.
   

This seems like a compelling path to follow for the I2 standard.

The I2 repositories subgroup will be sending out its survey on identifier use cases in the coming week.  It will be interesting to see if the requirements we have thus far identified still obtain in light of the data we collect from the survey.  If so, I would like to explore the idea of linked data for institutional identifiers a bit more.

[Series]

The I2 IR scenario subgroup approached the issue of institutional identifiers in repositories by first brainstorming about the various issues, problems, and sticking points that make identifiers in this space (and elsewhere) such a complex topic. Folks on the subgroup are repository managers or are otherwise involved with or knowledgeable about the repository space, so the brainstorming exercise yielded a good number of concerns.

The purpose of the exercise was to enumerate concerns and issues that could inform a draft survey to be administered to repository managers and experts around the globe in different organizational contexts: libraries, subject disciplines, archives, historical societies, etc. The purpose of the survey is to get an idea of the use cases and constraints around institutional identifiers in these different repository contexts, the assumption being that we ought to have requirements grounded in real world usage before we go off building a standard.

I will note here that the subgroup has worked up a draft survey that has just recently been reviewed by a small group of folks who know about survey design, and we hope to administer the survey to the aforementioned Reporati this week[1]. Which is to say that I don't yet have a strong grasp of the use cases out there in the wild, and this series should be construed as my own premature cognitive fumblings. But let's assume for now that what we learn from the survey results matches our initial brainstorming exercise.

Here is a slightly modified and boiled down version of the concerns and issues the subgroup came up with for a potential institutional identifier standard, which resembles a set of minimum requirements:

1. Should be agnostic to type of institution, e.g., libraries, museums, personal collections, historical societies
2. Should handle varying institutional granularity, e.g., institution-level, campus-level, division-level, unit-level
3. Should handle linking among institutions and subordinate units
4. Should express different sorts of relationships among these institutions and units
5. Should relate to existing relevant identifiers and registries
6. Should be globally unique
7. Should be actionable
8. Should enable retrieval of metadata sufficient to identify the institution, which may vary widely by institution
9. Should accommodate changes as institutions come and go and re-organize and be able to relate defunct institutions to new ones

I doubt the list is exhaustive; I am almost certain we will uncover all sorts of tangly and esoteric use cases that add requirements. I expect it. Why else would we be gathering to discuss the need for an institutional identifier if it were a solved problem or a simple one? [2]

Nevertheless, looking at the above list, the task we've taken on starts to feel less onerous. And thinking about identifier systems constrained by the list of concerns, the mind starts to cook up all sorts of possible solutions. I'll share one in the next post in this series, a strawman proposal of sorts, and how it addresses each of these requirements.

Notes

1. We will also x-post to repo-related mailing lists as well, and some of us may blog or tweet about it. My inclination is to cast as wide a net as possible so as not to miss important use cases. We can always scope things out later on, but it's useful to be inclusive at this point lest our own assumptions carry the group forward.
2. The cynical among you might have interesting answers to this question.

[Series]

This is the first in a series of posts about institutional identifiers[1].

In my last post, I alluded to some documentation that I've written. That was somewhat misleading, which will soon be apparent, but I liked the parallel construction I had going, and I am but a slave to orderliness.

For about the past six months, I have been working with a NISO group looking into how institutions are identified within information systems:

The I2 (Institutional Identifiers — pronounced "I 2") working group will build on work from the Journal Supply Chain Efficiency Improvement Pilot (http://www.journalsupplychain.com/), which demonstrated the improved efficiencies of using an institutional identifier in the journal supply chain. The NISO working group will develop a standard for an institutional identifier that can be implemented in all library and publishing environments. The standard will include definition of the metadata required to be collected with the identifier and what uses can be made of that metadata. …

The I2 group is split into a few subgroups which have been charged with looking into how institutional identifiers are used in particular scenarios. These scenarios are e-resources, repositories and e-learning systems, and library resource workflows. The scenario names pain me a bit, but so be it; this is our industry, and there are bigger windmills to tilt at.

I am currently co-chairing the subgroup looking at repositories and e-learning, and apparently I am its "tech lead." I don't want to get caught up on names and roles and titles, though; this series isn't about those at all. I'm just setting the scene and explaining why my head's in this space and laying bare my stake in the issue.

The remainder of this series will provide a bit more detail on the issues around institutional identifiers, share how the repository subgroup is grappling with identifier issues and engaging the repository community to assess needs, propose an approach for an identifier system that may meet said needs, and explore what seems to be the thorniest issue[2].

Notes

1. I offer that very tentatively, knowing what a spectacular failure my last attempt at a series was.
2. Hint: management. I know, "duh," right?

I finally pushed out some embarrassingly outdated WordPress plugin updates a few moments ago.

• Updated unAPI plugin with a patch contributed by Jay Luker that removes the hard-coded "wp_" table prefix. The updated version of the plugin has been tagged as 1.4.1.
• Updated LinkPURL plugin with a patch contributed by Mark Matienzo that enables partial redirects. I made some additional tweaks to the plugin to make this feature configurable via the WordPress management UI. This has been tagged as 1.1.
• Created a new unAPI plugin branch for Mark Matienzo's Scriblio-oriented tweaks. The branch is called 1.4.1-anarchivist-scriblio and it contains the scriblio.diff file. I have yet to integrate the diffs, as the file that was patched has changed since the patch was issued. If anyone is interested in working on unAPI/Scriblio integration, please get in touch with me.

And here is my to-do list which I hope will keep me honest.

• Update OAI-ORE plugin to support version 1.0 of the ORE specification.
• Add per-post (and per-page?) resource maps that wrap all embedded images and links.
• Enable "cool URIs" for all resource maps.

It is my hope that I'll get to those sometime before the summer begins. :)

Reading Adam Smith's D-Lib article has got me thinking about identifiers again. I don't agree with some of the assertions in the section titled "A Persistent Identifier Primer" — URIs are in fact persistent; we just break them through poor management — and so I'm led to a fundamental question: what are the good use cases for Handle (or ARK, or PURL) identifiers?

I get the need for persistent and globally unique identifiers; I'm just wondering why one needs special software with a separate URI namespace to gain persistence.

One potential use case might be resources that are outside of the organization's control — i.e., licensed content from vendors — but surely folks are using Handles for many resources that are created and managed within the organization. And I'm curious why they have decided that Handles are more durable than native URIs (the URIs to which Handles redirect), and how they deal with the problem of downstream (post-redirection) citation and bookmarking. How useful is this sort of identifier scheme if your users never even see the supposedly more persistent URI for a resource?

As a former proponent of Handles and ARKs, this may seem like a hypocritical question to pose. If I had to answer my own question, I would say that Handles seem like a good option because they save you some work and headaches in the short-term; you don't need to get together with your web team and come up with a scalable and sustainable URI policy; just assign native URIs in the usual haphazard way and generate Handles to compensate for a lack of identifier policies.

But if you're already making an organizational commitment to identifier persistence — and if you're rolling out Handles, I'd wager that's likely — why not do so by minting carefully-considered cool URIs? Less management and technology overhead and less confusion for your users are two good reasons to consider it.

At long last, the paper that Ron Jantz and I wrote for the Journal of Archival Organization has been published in a special double issue. It's titled "Digital Archiving and Preservation: Technologies and Processes for a Trusted Repository" and is intended to be a fairly nitty-gritty piece on digital preservation (in the context of trusted repositories) for archivists. The abstract:

This article examines what is implied by the term "trusted" in the phrase "trusted digital repositories." Digital repositories should be able to preserve electronic materials for periods at least comparable to existing preservation methods. Our collective lack of experience with preserving digital objects and consensus about the reliability of our technological infrastructure raises questions about how we should proceed with digital-based preservation practices, an emerging role for academic libraries and archival institutions. This article reviews issues relating to building a trusted digital repository, highlighting some of the issues raised and possible solutions proposed by the authors in their work of implementing and acculturating a digital repository at Rutgers University Libraries.

This special double-issue of JAO will also be released in the manuscript, "Archives and the Digital Library."

Thanks to editors Bill Landis, Robin Chandler, Tom Frusciano, and Caryn Radick for seeing this through. And of course to Ron Jantz for getting me interested in this crazy stuff at a time when I had no direction or interest in my career.

A friend and former colleague asked if I would comment on a chapter in her upcoming book on digital rights management and I agreed. The chapter is about identification and authenticity of web resources. Throughout my review of the chapter, I kept coming back to a couple of very basic notions that underlie any effort to provide persistent identifiers for web resources. These notions are, to my mind, central to identifier persistence, and any other concerns rely upon this foundation:

1. Identifier persistence requires an organizational commitment. Persistence cannot be ensured by a few renegades in the skunk-works, nor can it be mandated from on high without the support of those who manage the identifiers or produce web resources. All individuals involved in the life-cycle of web resources must be committed to persistence in perpetuity if true persistence of identifiers is to be achieved.
2. No technology, no standard, no identifier scheme, no information architecture will get you persistence. Whether you choose native URIs, Handles, DOIs, PURLs, ARKs, UUIDs, or XRIs, you will never achieve identifier persistence without active management of your identifiers and web resources. This requires the aforementioned organizational commitment since such management cannot occur without sufficient resources. Management of web resources and identifiers requires time and due diligence and those don't come for free.

And, at the risk of being reductive, that's about it. Once you've got an organizational commitment and a person or team to manage your identifiers and web resources, the rest of the decisions are secondary. If you like semantically meaningful URLs that redirect, choose Handles; if you prefer opaque identifiers, go with ARKs; if you don't want to run your own software, consider PURLs. At that point, it really doesn't matter which scheme you choose, as long as its characteristics match your organization's values. You've already done the heavy lifting; rest easy.