Tag Archives: classification

Building bridges: Linking diverse classification schemes as part of a technology change project

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My paper about my work on the linking and migration of legacy classification schemes, taxonomies, and controlled vocabularies has been published in the Journal for Business Information Review.

Transforming and extending classification systems – UDCC Seminar

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Estimated reading time 2–3 minutes

This post is the last in a series about the UDC consortium international seminar in The Hague, 19-20 September, 2011

Joan S. Mitchell, OCLC (USA), and Marcia Lei Zeng, Kent State University (USA), supported by Maja Žumer, University of Ljubljana (Slovenia), talked about extending models for controlled vocabularies to classification systems: modelling DDC with FRSAD, which led to interesting discussions about their concepts of “nomen” and “thema”.

Along with my former colleague Andy Heather, now CTO at DODS Parliamentary Communications Ltd, I talked about our work on the data migration of classifications from a legacy database into new taxonomy management software, presenting our paper: Transformation of a legacy UDC-based classification system: exploiting and remodelling semantic relationships.

Conclusions

The key ideas I took away from the conference were:
1) Classifications and ontologies are not an either/or choice. They have different properties and different strengths and weaknesses and so should be chosen according to the task in hand.
2) It is difficult to turn a classification into an ontology, but easy to turn an ontology into a taxonomy, so if you don’t have either to start with and can’t decide, an ontology is a safer bet. If you already have a classification, you need to think carefully about whether it is worth turning it into a fully modelled ontology, as converting it to RDF or SKOS is likely to be much easier. However, at the moment, RDF and SKOS have limitations, especially in handling faceted taxonomies, so beware of losing semantic richness in the conversion process. Polyhierarchies offer a way of expressing facets in SKOS.
4) Vocabulary control and alignment continue to be significant issues for the Semantic Web.
5) Ontology curation, management, and semantic alignment will be increasingly important issues for the Semantic Web.

Slides and audio recordings of all 21 talks can be now downloaded from the conference website.

Conference proceedings are published by Ergon Verlag and can now be
purchased/ordered online from http://seminar.udcc.org/2011/php/proceedings.php.

Classification and ontology in specific subjects – UDCC Seminar

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Estimated reading time 3–5 minutes

Day two of the UDC consortium international seminar opened with two subject-specific talks – Wolfram Sperber described a classification of mathematics and Andrew Buxton showed how similar chemistry classification and ontologies are, using the ChEBI ontology. He also described the different ways classifications and ontologies could be used to support each other and about the lack of good graphical tools and visualisations to represent ontologies.

Categories and relations: key elements of ontologies – Categorial Distinctions

Roberto Poli, University of Trento (Italy) talked about the compliexisties of part-whole relationships. There are simple wholes, composed of a sum of their parts, but some parts of wholes cannot simply be added together – for example, the social, psychological, and physical aspects of a person. He also discussed the difference between science as epistemological – dealing with what can be known – and ontological – deraling with what exists.

Towards a relation ontology for the Semantic Web

Dagobert Soergel made a bold claim that the only way for the Semantic Web to deliver its promise is if we adopt a relation ontology and map each dataset to the standard, to allow interoperability. He pointed out that you “do not getting semantics from syntax alone”.

Relations in the notational hierarchy of the Dewey Decimal Classification

Rebecca Green from OCLC described the difficulties encountered when trying to automatically create ontologies from the Dewey Decimal Classification. These included semantic differences in the way subclasses had been defined, meaning that no single rule would handle them all appropriately.

Modelling concepts and structures in analytico-synthetic classifications

The eminent Ingetraut Dahlberg compared Aristotle and Ranganathan’s key facets and UDC and Colon Classification systems. She also presented a survey of academic subject areas analysed into facets.

Representing the structural elements of a freely faceted classification

Claudio Gnoli of the University of Pavia, talked about freely faceted classifications, in comparison with systems such as UDC. He emphasised the urgency of publishing classifications on line, but highlighted the limitations of SKOS and OWL to fully expressed faceted systems despite the fact that faceted systems are extremely good tools for obtaining precise search results. Faceted systems are also excellent for combining information across disciplines, allowing you to combine aspects of one subject areas with aspects of a different one, and interdisciplinarity is becoming increasingly important as an approach, as innovation often happens at the boundaries between disciplines.

He pointed out that a polyhierarchical approach can be modelled in SKOS as a way of representing facets, but that this approach is often overlooked. He also called for more work to be done on SKOS so that it can represent facets directly.

Facet analysis as a tool for modelling subject domains and terminologies

Vanda Broughton, University College London, offered the Bliss Classification as a useful tool for online subject classification, but called for help in how best to publish it for general use. Should it be released as a text document, database, or should work be done to convert it to an ontology – and if so, in what form?

She stressed how the logical approach of facet analysis and regular syntax makes it predictable and hence ideal for machine manipulation.

Analytico-synthetic approach for handling knowledge diversity in media content analysis

Devika P. Madalli, Indian Statistical Institute, DRTC (India), described the Living Knowledge project that used an analytico-synthetic approach in order to bring together around useful themes diverse content from different sources using varied means of expression. This supported a rich faceted search system.

Slides and audio recordings of all 21 talks can be now downloaded from the conference website.

Conference proceedings are published by Ergon Verlag and can now be
purchased/ordered online from http://seminar.udcc.org/2011/php/proceedings.php.

Classification meets the Web – UDCC Seminar 2011

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Estimated reading time 2–2 minutes

This post is 4th in a series about the UDC consortium international seminar in The Hague, 19-20 September, 2011.

Interoperability of knowledge organization systems with and through ontologies

Daniel Kless from the University of Melbourne pointed out that problems with ontologies arise when combining them, as errors in combination can have disastrous effects on subsequent reasoning. A well-defined modelling method is needed to minimise this. Standards such as OWL and RDF do not address the problems of methodology or terminology control.

Towards the integration of knowledge organization systems with the linked data cloud

Vincenzo Maltese of the University of Trento, Italy, explained how it is vital to make clear the semantics and purpose of any ontology when attempting to share Linked Data. Ontologies may differ in their scope, purpose, structure, terminology, language, coverage, formality, and conceptualization. He drew a distinction between descriptive ontologies and classification ontologies. It is very easy to convert a descriptive ontology to a classification ontology and the process can be automated, but extremely difficult to convert a classification ontology to a descriptive one and the process requires human intellectual and editorial effort.

Classification and reference vocabulary in linked environment data

Joachim Fock of the Federal Environment Agency (Germany) talked about how they transformed their keyword thesaurus to a Linked Data format.

Classifications and ontologies on their own terms – UDCC Seminar 2011

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Estimated reading time 2–2 minutes

This post is the third in a series about the UDC consortium international seminar in The Hague, 19-20 September, 2011.

Approaches to providing context in knowledge representation structures

Barbara Kwasnik, Syracuse University (USA), talked about ways that context can be used as a disambiguation tool, and described different kinds of contexts: warrant, scientific, educational, cultural, etc. However, interdisciplinary approaches can be difficult. It is easy to have different ontological commitments, but you need a mapping to know when and which bits need to work across domains. Ontologies will need updating as the world and world views shift and change, so we need ways of defining their scope, as well as provenance and mappings. There are also difficulties in establishing the neutrality of ontologies.

Interaction between elementary structures in universes of knowledge

Richard P. Smiraglia, University of Wisconsin (USA),
talked about how people want to turn the multidimensional world into a unidimensional top-down model. He pointed out that people tend to assume UDC is like Dewey, but it actually works far more like Ranganathan’s Colon Classification. He called for new theories of organizing knowledge in shifting contexts and theories about how to mediate between concepts and structures like UDC.

Demystifying ontology

Emad Khazraee, Drexel University (USA), talked about how ontological approaches are as old as literature itself, showing a picture of what I think was the ancient Sumerian king list. He talked about boundary objects and the overlap between different academic areas that are interested in knowledge organisation and learning. He also discussed the differences between ontology-as-categorial-analysis and ontology-as-technology.

Classification and Ontology – UDCC Seminar 2011

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Estimated reading time 2–4 minutes

I thoroughly enjoyed the third biennial International UDC Consortium seminar at the National Library of the Netherlands, The Hague, last Monday and Tuesday. The UDC conference website includes the full programme and slides and the proceedings have been published by Ergon Verlag.

This is a first of a series of posts covering the conference.

Aida Slavic, UDC editor-in-chief, opened the conference by pointing out that classification is supposed to be an ordered place, but systems and study of it are difficult and complex. We still lack terminology to express and discuss our work clearly. There is now an obvious need to instruct computers to use and interpret classifications and perhaps our work to make our classifications machine readable will also help us explain what we do to other humans.

On being the same as

Professor Patrick Hayes of the Florida Institute for Machine Learning and Cognition delivered the keynote address, pointing out that something so simple as asserting that one thing is the same as another is actually incredibly difficult and one of the problems facing the development of the Semantic Web is that people are asserting that two things are the same when actually they are merely similar.

He explained that the formalisms and logic underpinning the Semantic Web are all slimmed down versions of modern 20th century logic based on a particular world view and set of assumptions. This works very well in theory, but once you start applying such logics to the real messy and complex world with real objects, processes, and ideas, the logics are put under increasing stress.

In logic, when two things are referred to as the same, this means they are two different names for the same thing, not that there are two things that are logically equivalent. So, Paris, the city of my dreams, and Paris the administrative area, Paris throughout history, and Paris – the capital of France are not necessarily all the same. This means that in logic we have to separate out into different versions aspects of an idea that in ordinary language we think of as the same thing.

He described this as the problem of “logic versus Occam” (as in Occam’s razor). Logic drives us to create complexity, in that we have to precisely define every aspect of a concept as a different entity. In order for the Semantic Web to work, we need to be very clear about our definitions so that we don’t muddle up different aspects of a concept.

Linking classification schemes via rdf

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I was delighted to read an excellent blog post by Dan Brickley about the value of opening up classifications. It is lovely to read something like this from a technical expert who understands the power of innovation and new technology, but who also recognises the value of the information contained in classifications.

KO

A proposal to expand the design space of classification

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Estimated reading time 1–2 minutes

In Beyond retrieval: A proposal to expand the design space of classification, Melanie Feinberg argues that classifications are not just about efficient retrieval, but about mapping a conceptual space as an active part of problem-solving or design.

A classification highlights connections and contrasts, and fuzzy boundaries, so seems to me to be an obvious tool to help analysis. Comparing different classifications can also illustrate different aspects of an idea or domain. I am very used to the principle of building classifications, seeing how things fit, looking at the things that don’t fit, throwing the classification away, and starting again. You always learn a lot about the topic you are working with in the process.

There seem to be a lot of classifications in Human-Computer Interaction that are used as checklists (things like the DECIDE framework), rather than retrieval tools. It strikes me that library classifications are the special case, rather than “checklist classifications”, which are very common. But then that is just a question of how you classify classifications.

Sorting Things Out

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Estimated reading time 1–2 minutes

Sorting Things Out – Classification and its Consequences is a joy of a book, crammed with research and insights. It is very well written but is aimed at a serious academic audience, so pretty dense and packed with references. Bowker and Star examine in depth the development of the International Classification of Causes of Death, going back to 17th century archives and considering how something as apparently obvious and clearcut as death is in fact mired in political, religious, and economic biases. They go on to discuss the treatment of TB patients and the development of the Nursing Interventions Classification, again both of which would appear to be “objectively measurable” but are revealed to be complex intertwinings of various pressures. They then assess South Africa’s system of apartheid from the point of view of classification, showing how the arbitrary categorisation of people added to the brutality and cruelty of the regime. The book is not just a stark warning of how dominant regimes can use classification as a tool of oppression, but is also an important investigation of the powerplays involved in all categorisations.

Essential Classification

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Here’s a review of Essential Classification by Vanda Broughton, a core Library Studies textbook and very easy read. It’s a sound introduction to classification – very practical and really aimed at trainee librarians, but included enough background and theory to keep me interested, including some pointers to the biases in the big classification systems. I was also intrigued by the assertion that people find it easier to remember numbers, so numerical shelfmarks are generally more popular than those based on letters. I always thought it was easier to remember letters, because you can make them into little phrases, but perhaps that’s just me!