Cross-browsing subject gateways with the Dewey

Decimal Classification in the Renardus Service

Michael DayUKOLN, University of Bath

m.day@ukoln.ac.uk

JISC Terminology Services Workshop, London,13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

What is the Renardus service?

– A broker service that integrates access to European subject gateways

– Developed by a research project funded 2000-2002 by the European Commission as part of the Information Society Technologies (IST) programme

– Managed by participating gateways through the Renardus Consortium

– Operational service hosted by Goettingen State and University Library (SUB)

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

What are subject gateways?

• Discovery services that give access to high-quality Web resources:– Selective (defined criteria)– Based on resource description (metadata)– Search and browse facilities– Use subject classification for subject

browsing– Many examples:

• RDN (UK), EdNA Online (Australia), etc.

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Participating gateways

DAINet - German Agricultural Information Network DE

Denmark's Electronic Research Library (DEF) DK

DutchESS - Dutch Electronic Subject Service NL

Finnish Virtual Library (FVL), NOVAGate FI

Online dissertations (Die Deutsche Bibliothek) DE

Resource Discovery Network (RDN) UK

SSGFI gateways at SUB Goettingen (Anglistik Guide, Geo-Guide, History Guide, MathGuide)

DE

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Cross-searching

• Uses the Z39.50 protocol

• Renardus application profile:– Based on the Dublin Core Metadata

Element Set (DCMES)– Added element:

– Country

– Mandatory elements:– Identifier, Title, Description, Subject …

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Search example

• Simple search for "palaeontology"– Renardus searches each participating

gateway using the Z39.50 protocol– Retrieves hits from multiple gateways:

• RDN (129)• Geo-Guide (123)• NOVAGate (2)• DutchESS (1)• FVL (1)

– Displays results (detailed or brief)

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Linking to resources

– The results display the URL of the described resource as a hyperlink

– Users can also refer to the richer metadata record provided by the participating gateway

– The level of detail varies …– Examples from DutchESS and RDN

(Biome) follow …[Next two slides …]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004[Record from participating gateway (DutchESS)]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004[Record from participating gateway (RDN Biome)]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Advanced searching (1)

• Search options– Simple Boolean AND/OR searching on

the content of individual elements• Title, Subject, Description, Creator, DDC

Classification, Document Type

– Term selection help• For the elements: Title, DDC Classification,

Subject and Type, a "term selection window" opens in some browsers to indicate terms that are already included in gateway indexes

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Advanced searching (2)

• Other options:– Limit (filter) search by Document Type,

Language, or Country– Display options and search timeout– Select which gateways to search

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Cross-browsing (1)

• Enhanced subject access a key part of the services offered by subject gateways

• Subject gateways, however, use many different subject schemes– Some 'home-grown'– Others based on (or adapted from)

standards

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Cross-browsing (2)

• Subject schemes in use within Renardus:– Nederlandse Basisclassificatie - DutchESS– AGRIS main subject categories - NOVAGate– Göttinger Online-Klassifikation (GOK) - Geo-

Guide, Anglistik Guide, History Guide– DDC - parts of RDN– Universal Decimal Classification (UDC) - parts of

RDN– Mathematics Subject Classification (MSC) -

MathGuide– etc.

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Cross-browsing (3)

• Also much variation in the depth of browsing structure (between 1 and 5 levels), although most are shallow

• Given this variety, how could browsing across the content of gateways be done in the broker service?

• Answer = mapping local schemes to a universal classification scheme

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Cross-browsing (4)

• For this, the Renardus project chose the Dewey Decimal Classification (DDC):– Available online (WebDewey)– Covers all subjects, is frequently updated,

has global use, etc.– Negotiated a research license from OCLC

Forest Press

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Classification mapping (1)

• General approach:– Mapping to local browse system, not to

individual resources– The mapping is one-way only, from the

DDC to the local browsing system– Mappings move from top levels of browse

structures before moving progressively down it

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Classification mapping (2)

• Mapping relationships:– Simple equivalence between terms not

expected– Five mapping relationships

• Fully equivalent• Narrower equivalent• Broader equivalent• Major overlap• Minor overlap

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Classification mapping (3)

• Syntax: LN (Local classification notation)

LC (Local classification caption)RL (Relationship code, i.e. =, >, <, MJ, or MN)DN (DDC notation)DC (DDC caption)UR (Local browsing URL for the class)NT (Notes):RE: (Record end)

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Classification mapping (4)

• Technical solutions:– Mapping tool developed by the German

CARMEN project (CarmenX)– Participating gateways provide a machine-

readable version of the classification scheme in use

– The tool (with WebDewey) facilitates the production of the mapping information in the correct syntax

                                                             

JISC Terminology Services Workshop, London, 13 February 2004[Renardus Mapping Tool]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Using the mapping information

• In Renardus, the DDC mapping information provides:– The basis of the cross-browse feature– Information for the advanced search

feature, e.g. search by DDC Classification

• The DDC browse structure forms the core part of the Renardus Service Web page

[Next slide …]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Cross-browsing in Renardus

• Based on a two-step process– first browsing within the DDC structure on the

Renardus Web pages– Then linking directly to the browse structures in

local gateways– Called "Browse and jump"

• Interface issues– Visual inconsistency– No clear path back to Renardus from the local

gateways

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Browsing example (1)

• Browsing for information on 'mineralogy':– Select "science" in first browse level

• Note broader equivalent mapping to "Technology and Natural Sciences" (DEF)

– Then select "chemistry" …• Again, note narrower and broader equivalents

…

[Next three slides …]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Browsing example (2)

– Then select "mineralogy"• Fully equivalent to "Mineralogy: General" in

GOK (Geo-Guide), "Mineralogy" in FVL• A narrower equivalent is "Mineral

paragenesis" in GOK (Geo-Guide)• Major overlap with "Mineralogie, Boden-,

Gesteins- und Lagerstättenkunde" in DDB online dissertations

[Next slide …]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Browsing example (3)

– Selecting the link takes the user to the relevant part of the browse hierarchy in the local gateway

– This is known as "browse and jump"– Examples of the relevant local browse

hierarchies in FVL and DDB online dissertations follow …

[Next two slides …]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004[Finnish Virtual Library]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004[DDB]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Navigational support (1)

• Need for additional navigational support in large browsing structures

• Renardus developed some experimental features:– Searching for an start page– Graphical navigation overview– Merge

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Navigational support (2)

– Finding a different start-page• It is possible to find a different page in the

browse structure, by entering a term in the search box available on each browsing page

• This takes you to a results page that links to the HTML and graphical overview versions of the Renardus browse hierarchy

[Next three slides …]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Navigational support (3)

– Graphical Navigation Overview• Gives a 'fisheye' view of the DDC browse

hierarchy• Allows users to see the browse term

(highlighted in red) together with related terms in surrounding classes

• Terms with content (highlighted in blue) link to the relevant page in the Renardus browse hierarchy

[Next slide …]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Navigational support (3)

• Merge– A short cut to viewing individual resource

descriptions from all related collections– Similar to "DDC Classification" search in

advanced search feature

[Next two slides …]

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Issues

• Usability of broker:– Interface consistency– Navigation in large structures

• Maintenance issues:– Maintenance of mappings (subject

gateways are always changing)– Maintenance of links to browse hierarchy

in each gateway (e.g., when gateways restructure)

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

Future developments

• Multilinguality– Because DDC has been translated into

many languages, it is possible to add other language versions of the browse system into Renardus

– Successfully implemented in the Renardus testbed

• Automatic classification– Support for mapping process

                                                             

JISC Terminology Services Workshop, London, 13 February 2004

More information on Renardus:

– Renardus Service:http://www.renardus.org/

– Traugott Koch, Heike Neuroth & Michael Day, "Renardus: cross-browsing European subject gateways via a common classification system (DDC)," Subject retrieval in an networked world, OCLC, Dublin, Ohio, August 2001:http://www.lub.lu.se/~traugott/drafts/preifla-final.html