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Apr 9, 2018

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What is an Enhanced Publication?

Apr 9, 2018

An enhanced publication (EP) is a totally new way of publishing in which a traditional publication (a book, an article or a report) is enriched with additional information. An enhanced publication relies on the linking possibilities of the web. A simple representation of an EP is given in Fig. 1


Fig.1: a traditional written text with its relationships to other enriching objects (Source:

The additional information plays an important role in the clarification of the context of the traditional publication. Datasets (primary research results), audio or video fragments may be added.

But enhancing publications goes beyond just adding material that was necessary for writing the traditional publication. Readers of an enhanced publication will have the opportunity to comment on it. These comments will be added to the EP as well. The components of an EP will therefore vary in time, transforming it into a dynamic object. By doing so, research becomes more transparent to society.

One of the challenges related to EPs is the development of easy to use tools for the creation of EPs.


The development of tools to compose EPs depends on the chosen architecture. OAI-ORE based architecture is very promising (ORE stands for Object Re-use and Exchange; for its symbol, see Fig.2). This architecture has been developed by Herbert van de Sompel and Carl Lagoze and can be used for describing composed objects together with the relationships between their components.

Fig. 2: the international symbol for OAI-ORE, indicating the relationships between objects

These composed objects are called aggregations.

It is the researcher who decides which components will be combined in the EP. Within OAI-ORE it is also possible to describe the aggregation and its composer. This is called a Resource Map.

To summarize: a Resource Map describes an Aggregation and an Aggregation describes an EP with all its components. Or as an image (see Fig. 3):


Fig.3: Relationships between a Resource Map (ReM-1), an aggregation (A-1) and the components of this aggregation (AR-1; AR-2; AR2). Source:


The Dutch scientific organisations working together within SURFfoundation see OAI-ORE as a de facto standard. One of the possibilities for serialisation of descriptions of EPs in OAI-ORE is RDF-XML (see Fig. 4).


Fig. 4: Example of a serialization of OAI-ORE in RDF/XML

In the Netherlands a preliminary data model has been designed that has been used by DANS to incorporate descriptions of EPs into its portal NARCIS. In other countries similar developments may be noticed. It is certainly worthwhile to discuss these Dutch developments within OpenAIREplus.

EPs are based on resources anywhere in the world. The change of the actual location of a resource may corrupt the EP (when one of the components of an EP is no longer accessible, the value of the total EP diminishes).
Therefore instead of using URLs in describing a component, it should be mandatory to use persistent identifiers (see Fig. 5 for application of a Persistent Identifier to a doctoral thesis).

Fig. 5: Doctoral Thesis as a component of an EP, with its Persistent Identifier (URN:NBN)

By doing so, the description of a resource will be separated from its actual (non-stable) location. A so-called resolver – like the DANS resolver –  ( leads a user from the Persistent URL to the actual location of a resource (see Fig. 6).


Fig. 6: The DANS-resolver referring a user from the Persistent Identifier to the actual URL

Role of the researchers

The average researcher has no knowledge of OAI-ORE, RDF/XML or Resource Maps. Therefore, tools are needed that give researchers the opportunity to compose EPs without the necessity to study the data model. One of these tools is the so-called ESCAPE tool, developed by Twente University (see Fig. 7).


ESCAPE automatically translates the components the researcher brings together as well as their relationships into a Resource Map with its Aggregation, described in RDF/XML.

Visualisation of Resource Maps

As explained earlier, Resource Maps and Aggregation may be serialised in – for instance – RDF/XML. But RDF/XML is not a very appealing format (see fig. 4). The strength of an EP lays in the intellectual work in bringing related resources together in a totally new, web-based format. By excellence the Internet may be used to visualise complex objects.

In the Netherlands, SURFfoundation and DANS have been working together to develop a visualisation tool for EPs that has been integrated into the NARCIS portal. This tool translates the RDF/XML of the EPs into clear, graphical representations (see fig. 8).

Fig. 8: Visualisation of an EP, showing the relationships between the aggregation and its component (in this case an article, 5 datasets, a conference and the creator).

Overview of the present infrastructure for EPs

The text above may be summarized in the following description of the necessary infrastructure for EPs:

A researcher uses an appropriate tool to compose EPs. This tool will translate the components of the EP with all their relationships into RDF/XML (OAI-ORE). To every single component of the EP as well as to the EP itself persistent identifiers will be assigned. The descriptions of EP will be stored in repositories that can be harvested by other parties. These other parties may be national aggregators (like NARCIS) or international aggregators (like OpenAIREplus). The aggregators have implemented a visualisation tool to provide their users with a graphical representation of the EPs. Finally, the composer of an EP may allow other researchers to add comments to the original EP. These comments will also be shown through the visualisation tool.

Maintenance of EPs

Maintenance of EPs is much more complicated than the maintenance of digital books, as datasets are often part of an EP. Unlike a digital book, access to datasets is often coupled to the usage of a specific software application. Thus, maintenance of EPs means the maintenance of datasets and their applications. This will cause a dramatic change in the activities of traditional information centres like libraries.

Of course, this new type of maintenance will lead to higher costs for permanent access. It is advisable to make these extra costs eligible for funding within OpenAIREplus.

Author: Arjan Hogenaar

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