(part of the InLOC work)

InLOC Technical Bindings

Introduction to the InLOC Technical Bindings report

The project work plan originally specified the production of a report on “Technical Bindings for the ELM Europass Application Profile specifications”. The CWA “InLOC — Application Profile of Europass Curriculum Vitae and Language Passport for Integrating Learning Outcomes and Competences” (see Europass CV and LP AP) already covers its own XML binding, but none of InLOC's three CWA outputs specifies bindings for the InLOC Information Model itself. This is a clear common intention, to allow implementers to choose their own binding, as long as it maps to the information model.

Now it is common good practice followed by many specifications in the learning technology domain to propose technical bindings, not as mandatory aspects of a standard, but as proposals towards facilitating standard implementations of the specification. The InLOC project team decided that it made sense, for this reason, to extend beyond the contract deliverables to provide general purpose technical bindings of the InLOC Information Model.

A "binding" here means the choice of specific technology for implementing an information model, and includes mapping the components of the model to components of the chosen technology. Bindings can be to any of a wide range of technologies. The InLOC team assessed that the most useful ones for the purposes of relevant stakeholders, and therefore presented together with this report, are:

For the future, not presented here, the next most likely desired binding could be RDFa in HTML5, as this will build on the RDF binding. When that is done, a binding to Microdata will be able to be inferred using the mapping from Microdata to RDFa.

A binding may constrain the possibilities of representing the model; and how to represent particular parts of a model in a particular binding may not be obvious, requiring some ingenuity. The different binding technologies also come with different approaches to validating a set of data to check whether it conforms to the constraints set out in the model specification. Binding technology also differs in how easy it is for a human to read a file, and to assess the content by eye.

Another important consideration, particularly for implementation of a specification, is that different bindings have very different sets of tools developed for use with information "bound" in any one way.

Justification of the binding technologies used

XML

This is currently a very well used and well known technology for web services. There are many tools and libraries already available to manipulate XML data and validate against an XML schema. XML Schemas can also sometimes be used to automate parts of the software engineering process. Europass has used XML for their CV and Language Passport (LP) since its first online release. Many other interoperability initiatives for learning technology (e.g. IEEE, Scorm, LOM) and HR technology (e.g. HR-XML) assume that XML is a core part of their architecture. The Workshop's own ELMO project is based around an XML binding.

The InLOC XML binding has been relatively well tested, and is offered here as a potentially stable binding.

RDF

RDF is a set of technologies used for the Semantic Web (see W3C and Wikipedia) and Linked Data (see Wikipedia and W3C). This is widely seen as a technology that will grow in importance in the medium term. Already it is important for repositories of public information, the UK being a good example. It is open and decentralised in nature, very well adapted to new and unforeseen applications, where rigid schemas might be obstacles.

The InLOC RDF binding has not been extensively tested, and is therefore offered as provisional, subject to future review and improvement.

JSON

JSON is increasingly popular as a means of transferring information between web applications. It has a tree-like structure, like XML, and so a JSON binding is easy to base on a corresponding XML binding. The Europass CV and LP software already implements JSON, with a JSON schema for validation. HR-XML provides a JSON schema and examples for their "Candidate" and "JOBPosting" specifications.

The InLOC JSON binding was an early draft.

The InLOC JSON-LD binding includes a semantic mapping, offering easy conversion to RDF and Linked Data.

What is available in each binding

The three bindings documents are presented together with this report. Each binding document includes, more or less:

  • a brief introduction to the technology used for the binding, with some links to further documentation on that technology;
  • links to associated InLOC documentation for the binding, such as:
    • a schema if available (XML Schema, JSON Schema);
    • some downloadable examples;
  • as appropriate, any necessary explanation of the binding approach use for InLOC, related to the InLOC Information Model, explaining the relationship with the other bindings;
  • any headers needed for each document bound in this way, including e.g. namespaces or links to schemas;
  • how to represent the LOCstructure root object;
  • how to represent LOCdefinitions and sub-structures;
  • how to represent each of the 6 types of LOCassociation:
  • any known issues;
  • further reading.

Conversion between different bindings

Various mechanisms have been or are being developed to convert InLOC information between these different bindings. Attached to the wiki are XSL Transform files for transforming:

The bindings

The three bindings are available in the same format as this report.

For PDF documents, see the documents presented together with this report.

For Wiki documents, follow the links to XML, RDF and JSON.