2. Recall and Precision
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Recall illustrates the confidence that a search returns all the information you
are interested in.
Precision, is the confidence that the results of your search are relevant.
Web users are used to low recall and precision
Achieving high precision and recall when searching unstructured or semi-
structured data is a very difficult task.
Librarians and library OPAC users are used to, and require very high recall and
precision, especially recall.
Great care and consistent rules (such as AACR2) applied in creating structured
catalogue records.
Different Indexes Techniques are used to achieve high recall.
Recall is a real problem for Arabic Language! (Requires Special Arabic Indexer)
3. Arabic Recall Requirements
Arabic Support is not just Unicode Storage and
Retrieval
Normalizing and equating different shapes of Arabic
characters (ئ ؤ ،ـه ـة ،ي ى ،ا إ )أ and any other normalization
required
Detects and stem prefixes (ل ،و ،ك ،فـ ،بـ ،)ال
Detects and stem suffixes ( ـة ،ي ،ات ،ون ،ين ،)ان
Smart processor capable of realizing the order of
prefixes. (ولل ،كال،وبـ ،لل ،بال ،وال BUT NOT لبـ ،بلـ ،)بو،كف
Complete and customizable dictionary for prefixes and
suffixes handling.
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Essential Processes for UC
There are four essential processes for delivering
effective Union Catalogues: (4C)
Collect a knowledgebase of all members
Catalogues
Connect people with answers using the
best method
Correct the knowledgebase to maintain
accuracy
Control collections and workflows to
optimize value
5. Purposes of Union Catalogues
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Unified point of discovery
larger resources are better exposed in general
(single shop versus row of shops versus mall)
comprehensive resources are more attractive to
users
• more likely to use; more likely to contribute via WIKI
Ease load on local OPAC
Provide identity to a library cooperative
Discovery and Exposure
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Purposes of Union Catalogues
Increasing delivery options
Resource sharing
Sharing of users
Your users find resources elsewhere
Other’s users find your resources
Delivery becoming increasingly separated
from discovery
Increasing delivery options
Digitization on demand, reference look-up, purchase,
resolution
Union catalogues need to link to multiple providers
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Purposes of Union Catalogues
Librarians Perspective
Unified Efforts and Standards
Unify Standards
Unify Cataloguing efforts
Unify Systems
Minimize Cost
Consistent Recall and Precision
9. Physical UC – MODEL 1
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I- Union catalogue is the main catalogue for the participating libraries.
(Consortia Approach – Single System)
Jordanian Public Universities Libraries (JOPULS), OHIOLink, Oxford
University Union Catalogue (OLIS).
• Benefits:
Centralizes the cost of technical support.
Minimize Cataloging Cost sharing Bibliographic Records.
Consistent indexing and Searching policy.
Real-time locally volatile information such as circulation information
• Problems:
Problems in merging libraries which already have their own library systems.
Requires a greater degree of collaboration in terms of cataloguing and
indexing policies.
Requires increase in network speed and reliability; Difficult for
geographically dispersed unions.
10. Physical UC – Model 2
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II- Records are exported from local catalogues to the union catalogue .
COPAC service in the U.K (over 70 UK and Irish academic, national & specialist catalogues)
OCLC WorldCat
• Benefits:
Centralizes the cost of technical support.
Consistent indexing and Searching policy.
More freedom for libraries to adopt different Cataloging standards
• Problems:
Insists on Minimal Standards (MARC).
Can’t benefit Libraries with NO LIS
Duplicate records ; worse search experience.
Latency in updating Union Catalogue.
Large discrepancy between actual holdings and the Union Catalogue.
Cannot address locally volatile information such as circulation information.
11. Physical UC – Model 3
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III- Records are catalogued on union and imported to local catalogue .
OCLC Cooperative Online Resource Cataloging (CORC) Project
Partially Adopted by ARUC (ARUC is a mixture of models 2-3)
• Benefits:
Centralizes the cost of technical support.
Consistent indexing and Searching policy.
Better Quality of records (Maintained Standards)
• Problems:
Insists on Minimal Standards (MARC).
Some Discrepancy between actual holdings and the Union Catalogue.
Difficult to address locally volatile information such as circulation information.
12. Physical UC – Model 4
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IV- Dynamic Updates of both union and local catalogue .
Commercial Databases Systems
Z3950 Catalogue Update Service
Dynamic Proxy Update to both Union and Local Catalogues
• Benefits:
Consistent Updates to both Local and Union Catalogue
Consistent indexing and Searching polices on Union Catalogue
• Problems:
Quality of records (No Maintained Standards)
Duplicate records ; worse search experience.
Difficult to Adopt by Academic Libraries.
Difficult to maintain and update
13. Virtual Approach
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Local Catalogues are maintained as is
User Interface to search all Catalogues as if searching a single Catalogue
(Federated Search to Online Catalogues)
• Benefits:
Easier to Implement
Less Time and efforts required
Real time searching and retrieval in All Catalogues (Higher Accuracy)
• Problems:
Different Cataloging, Indexing and Searching Policies
Inconsistent Indexing/searching based on Local OPACs
Requires Online Accessible Catalogues for all Members
Slower in Retrieving results
Depends on Availability of local OPACs
14. Which Model to Select?
What are you trying to Achieve?
What are your current Members Using?
What Standards are Implemented?
What Services you like to offer?
Speed, Accuracy, or Recall & Precision comes First?
What Cs you target (Collect & Connect only, or also
Correct & Control)?
Answering the Above questions is the key to select the
best model for the Union Catalogue.
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15. Select Virtual Model Approach
Members Already have LIS Systems and Online Accessible
Catalogues.
Members uses different Systems, Cataloging Rules, and Standards.
Difficult to apply same standards and policies.
Target to support end users with greater exposer and additional
services
Accuracy is more important than speed , recall and precision
Virtual Union Catalogue Model is the Answer
New Federated Search Engines Provide Clustering, Ranking, and Sorting
Capabilities.
Possible to Integrated Digital subscriptions with Physical Collections.
Additional Services (ILL, Additional Delivery Options can be Achieved)
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16. Select Physical Model Approach
Some Members Don’t have LIS Systems and Online
Accessible Catalogues.
Target to Unify Cataloging Rules and Standards.
Target To minimize cost, and control Cataloging
At the same time target to support end users with greater
exposer and additional services.
Speed and Precision is more important than accuracy.
Own the appropriate network (Speed and reliability)
Physical Union Catalogue Model is the Answer
(Model 1 “Union catalogue is the main catalogue for the
participating libraries” is the best to select if feasible)
(Oxford, OHIOLink, JOPULS Model)
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