Alistair Miles

Category: web technology

SKOS and RDFa in e-Learning

The W3C’s Semantic Web Deployment Working Group is developing two new technologies which may be relevant to e-learning technology. These are the Simple Knowledge Organisation System (SKOS), and RDFa.

SKOS is a lightweight language for representing intuitive, semi-formal conceptual structures. So, for example, the figure below (taken from the SKOS Core Guide) depicts concepts with intuitive hierarchical and associative relationships to other concepts, and with preferred and alternative labels in one (or more) languages — these are the kinds of structures that can be expressed using SKOS. Once expressed in this form, conceptual structures can easily be published on the Web, shared between applications, linked/mapped to other conceptual structures and so on. Typically, these conceptual structures are used as tools for navigating around complex or unfamiliar subject areas, for retrieving information across languages, and for bringing together related information from different sources.

RDFa is a language for embedding richly structured data and metadata within Web pages. This allows a Web page to expose much of its underlying meaning to applications, enabling a range of new functionalities within Web clients, exchanging data between Web sites, services, and the users’ desktop applications. For example, a Web page about a new music album can use RDFa to embed structured data expressing facts about that album, such as the track listing, artist, links to sample media files etc. A Web browser with a suitable plugin or extension can use this data to offer new functions to the user, such as download the tracklisting with available samples to my music library, or compare prices from online vendors.

Both of these technologies are on the W3C Recommendation track, and are scheduled for completion in April 2008.

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Versioning and the Web

This post looks at some of the problems of identifying, decribing and linking “versions” of “digital objects”, from the point of view of the Web, drawing especially on the Architecture of the Web published by W3C. These thoughts were stimulated by the recent kickoff meeting of the new Version Information Framework (VIF) project, at which versioning was discussed in the context of adding value to digital repositories — I hope this post provides some useful input to the VIF project team.

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Issues in Ontology Development and Use

Yesterday I presented the paper on “Collaboration in the Value Grid for Semantic Technologies” at the workshop on “Issues in Ontology Development and Use” [download the presentation].

The workshop was part of the UK e-Science All Hands Conference, and the programme for the workshop can be found within the full conference programme, including links to all presented papers.

Other highlights were Ure et al.’s paper on “A Socio-technical Perspective on Ontology Development in HealthGrids“, Gacitua et al.’s paper on the “Ontology Acquisition Process: A Framework for Experimenting with different NLP Techniques”, and Lin et al.’s paper on “Ontology Building as Practical Work: Lessons from CSCW“.

RDFOO – Convert RDF Graphs into JSON Objects

I’ve written a small Java utility for converting any node in an RDF graph into a JSON object. You can download RDFOO 0.1 alpha or alternatively go to the RDFOO web page which has links to more documentation.

RDFOO is (more or less) an implementation of JDIL, using Jena and the Java classes for JSON from Given a resource in an RDF graph, RDFOO by default performs a shallow mapping to a JSON object, capturing only literal value properties. RDFOO can also be told to follow specific properties to a given (or unlimited) depth, to capture nested objects, and handles circular references.

If you find any bugs or have any comments I’d love to hear from you. I think the implementation is sensible, and it passes a reasonably complete test case, but then I’m no Java guru – you have been warned 🙂

Collaboration in the Value Grid for Semantic Technologies

I’ve submitted a final version of a paper for the e-Science All Hands Meeting this year, now entitled “Collaboration in the Value Grid for Semantic Technologies”. The main body of the paper is much the same as the previous version, although I’ve tried to emphasise the link between the two main sections on value and collaboration. See e.g. the following extract:

Ontologies are not the only means of articulating a shared conceptualisation, however. Controlled vocabularies, taxonomies, thesauri, classification schemes, topic maps, subject heading systems, semantic networks – to name a selection – are all specifications of a shared conceptualisation, albeit “informal” or “semi-formal”. These and many other types of product have to be considered, in order to design solutions to specific problems at reasonable cost; solutions that are feasible, scalable and part of a sustainable business model. This begs a number of questions. What possible paths exist from knowledge expressed informally (unstructured information) to formal ontologies? How can these paths be broken down into stages, and what does each stage produce? In what ways can these different products be exploited? What are the likely costs, benefits and risks associated with different paths and different stages? How much human effort will be required, and how can this effort be reduced by computation? How can the necessary human effort be organised into efficient work flows that enable collaboration? Does economic and practical scalability vary with different paths and different products?

This paper works towards answers to these questions, by viewing ontologies as products in a value grid of semantic technologies, and by examining collaboration as a critical component of all value-adding activities within this grid. The dual focus of this paper on value and collaboration is emphasised, because these points of view are complementary. Whereas the focus on value leads to a better understanding of products and the ways in which they can be broken down, planned and exploited, the focus on collaboration leads to a better understanding of processes and the ways in which they can be structured and managed.

Trac Moin Python Postgresql Apache Red Hat Enterprise Linux Installation and Dependency Hell

I’ve recently been helping out on a software development project in my department. I decided to try out Trac – a software project management tool – to see if it could help us manage the development process. So I downloaded the latest stable release (0.10.4), and set about installing it on a server. This is what happened next…

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Gardens of Meaning … or why the Semantic Web is for Vulcans

I gave a presentation entitled Gardens of Meaning … or why the Semantic Web is for Vulcans to the Oxfordshire Semantic Web Interest Group this week. The presentation works towards the motivation behind the Gardens of Meaning metaphor, via an informal and somewhat ironic poke at some of the hype associated with the Semantic Web vision. The joke is that the Semantic Web depends on people being able to share their “conceptualisations” with each other, and then express those conceptualisations formally using an ontology language, neither of which is easy … if only we were Vulcans, we could mind meld and, of course, we would have dedicated our lives to pure logic.

The Value Grid for Semantic Technologies

I’ve submitted a paper entitled “The Value Grid for Semantic Technologies” to the workshop on Issues in Ontology Development and Use to be held as part of the UK e-Science All Hands Meeting later this year. The paper is available for download from the following URL:


This paper situates formal ontologies as one of many products in a multi-tier value grid of semantic technologies. Incremental strategies for the exploitation of intermediate products in the value grid are discussed, as a possible step towards cost-effective, low-risk and scalable business models for the exploitation of semantic technologies. A case study is presented, illustrating a hypothetical value grid for the management of scientific data from a large-scale experimental facility. Suggestions are made for the design of predictable, repeatable collaborative processes for adding value in semantic technology value grids.

The Devil is in the Detail

I find something new in the RDF Semantics every time I read it …

“… it is possible to write RDF graphs which assert the existence of highly peculiar objects … with forked … tails, or multiple heads:

_:666 rdf:first  .
_:666 rdf:first  .
_:666 rdf:rest  .
_:666 rdf:rest rdf:nil .


New SKOS Web Site

I should have mentioned earlier … the SWDWG rolled out a new and improved SKOS web site a couple of weeks ago. We reorganised the web site a bit to make it easier to navigate, and also hopefully to provide a higher profile for the community areas such as the data zone, the tool shed and the mailing list.

Enterprise Search: Google vs. Exalead vs. Oracle

Some interesting discussion in the session “Latest Developments in Enterprise Search” at Online Information yesterday (day 2, track 2, session 1)…

Francois Bourdoncle presented the Exalead approach; Roger Ford presented Oracle Secure Enterprise Search (SES); Roberto Solimene presented Google OneBox.

All three speakers emphasised being able to search different types of both structured and unstructured information. Surprisingly, none of the speakers talked about how their products achieve high precision (relevancy). The discussion after the talks was perhaps most interesting, highlighting two major issues in enterprise search, relevancy and privacy … here’s my raw notes taken at the time…

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