Presentation on theme: "Parallel Session on Metadata The Value of Metadata and how to Realise it.. Date 18 th June 2002 Facilitator: Dennis Nicholson Centre for Digital Library."— Presentation transcript:
Parallel Session on Metadata The Value of Metadata and how to Realise it.. Date 18 th June 2002 Facilitator: Dennis Nicholson Centre for Digital Library Research
Notes and Slides
Theme: Examine, Discuss: n.…the value of using metadata as a aid to reliable retrieval both within individual Web sites and across distributed sites n ….what the barriers to effective use of metadata are and how they can be overcome n ….Who should be responsible for creating and maintaining metadata - resource creators; web-masters; librarians?
Theme: Examine, Discuss: n ….Whether embedding and harvesting or a central database is the best approach. n …plus (if time allows): u A step beyond, the value of Content Management Systems n Focus: General n My background...
Responsibility to... n Stimulate: u Thought; Discussion; Debate n Draw out the important points n Impart ability to apply what weve discovered n Ensure participation n So…
Individual needs and circumstances?
Effective Retrieval n What is it? u Balance of precision and recall best suited to a given problem F High precision and low recall usually preferred but in some cases (e.g. patents) there may be an advantage in lowering precision to boost recall u Level of precision and recall should be under the users control not a side effect of poor metadata
Effective Retrieval n Why does it matter? u Costs University, public purse to create the material - a waste if the people it is aimed at cant find it u Strategic/PR considerations - If they cant find your courses or expertise registers or digital images for sale if and when you want or need them to they wont use you or talk or write about you
Effective Retrieval n When does it matter? u Only if it is stuff you want found u The bigger they come, the sooner they fail… F The more stuff you have, the more campuses, or organisations in a collaboration,the harder it is to ensure effective retrieval F Especially with no or poor metadata
What is metadata? n Metadata is data about data n Consists of things like: u Author; Title; Subject; Description; Level; Language; Viewer n Appropriate to function n The route to effective retrieval n Maybe...
What can go wrong? n Limited penetration (i.e. only some available documents covered) u Misleading results for users n Different metadata record formats u Can the software cope? Is there a cross-walk? n Incompatible core field sets u Cross-walk not possible
What can go wrong? n Different field sub-sets used (Both use DC but different field set) u Full service limited to common fields n Different fields used for same data element (I put subject headings in subject field and free form keywords in the keyword field but you put subject headings in the keyword field) u Misleading results
What can go wrong? n Different or no standards applied in creating data element content (e.g. Darwin, C. or Charles Darwin) u Reduced retrieval; varied results n Different or no subject schemes and/or category lists (Educational levels, LCSH v. UNESCO v. made up) u Reduced retrieval; varied results n Insufficient granularity (If everything physical is physics) u Poor precision, high recall
What can go wrong? n Varied or no methods of central co-ordination (2 sites or campuses) u Can cause some of the other problems listed above and below n Different sites index different fields (One has subjects, keywords in one index, another in separate indices) u Misleading for users
What can go wrong? n Missing indices (Nothing on the subject in the index or no subject index? (2 sites)) u Misleading retrieval n Humans can cope but machines cant (A machine finds it harder to spot different usages of the same word or alternative words for the same thing than a human does) u Semantic web wont work
Safeguards against: n Limited penetration u Policy? Training? DC Dot? Human monitor? n Different formats u Discover need, agree policy, set standards, ensure software can cope with formats n Incompatible core field sets u Identify formats (DC, IMS, MARC?) then agree core set of fields (e.g. 15 in DC base)
Safeguards against: n Different field sub-sets used u Agree, monitor, one core set n Different fields used for same data element u Templates and examples, Central co-ordination, Guidelines, Training
Safeguards against: n Different or no standards applied in creating data element content u Template with examples n Different or no subject schemes and/or category lists u Agree single schemes or lists, have drop down lists, upgrade centrally
Safeguards against: n Insufficient granularity u Agree usable level, training, examples n Varied or no methods of central co-ordination (2 sites or campuses) u Make sure it doesnt happen! n Different sites index different fields u Agree approach, implement and monitor standards
Safeguards against: n Missing indices u Agree not to do this, and warn users if you cant agree n Humans can cope but machines cant (semantic web) u Use standard schemes, ontologies in standard ways and map between different ones in a way that your software can process
Where to keep it? n Pros and Cons of: u Embedding and harvesting: F Metadata creation more likely? Harder to co-ordinate, easier to resource? More often out of date? Harder to ensure standardised metadata? u A central database F Easier to co-ordinate, more expensive to resource? Easier to maintain standards? How to ensure new stuff notified?
Where to keep it? n Pros and Cons of: u A mix of the two? F Worst of both worlds? Or best? How to ensure the latter? Optimise author input of embedded metadata but allow central upgrades by metatada experts? I this feasible? Is it cost-effective? u Depends on other factors? F A question of designing to be fit for purpose?
Whose Responsibility? n Candidates; Their pros and cons: u Resource creators? F Au fait with the resource; Labour saving u Web-masters? F Au fait with the technical landscape u Librarians? F Au fait with knowledge and metadata domains u Public Relations? F Au fait with the needs of the University u Anybody else? u All of the above? Co-ordinated by?
Other Related Issues n A CMS would ensure : u Currency; Accuracy; Legality; Authority of Content retrieved by metadata n Not to mention u Uniform look and feel control; easy total redesign and global changes; all content tracked; joint authorship across departments, units, different institutions; easy repurposing n All who have some responsibility can be involved in controlled way?
Facilities n It would provide: u Content authoring; collaborative authoring; editing and workflow; preventing unauthorised editing or creation; scheduling publication; tracking changes; personalising; repurposing; metadata creation; knowledge management through semantic control
Closing Discussion… n Who has/plans to have a CMS? n What does it/will it cost? n Are they: u Essential? Optional? Impractical? A threat to academic freedom? n Do they help solve the metadata problem?
Useful URLs n Metadata u (Why should we care?) u u materials/exercises/dc-dot/dc-dot.doc materials/exercises/dc-dot/dc-dot.doc u n Content Management Systems u (what are they?) u (Who needs them?) u (CMSs available)