Citation Linking in Federated Digital Libraries
Eike Schallehn, Martin Endig, Kai-Uwe Sattler
Otto-von-Guericke-University MagdeburgInstitute for Technical and Business Information Systemshttp://wwwiti.cs.uni-magdeburg.de/
Third International Workshop on Engineering Federated InformationSystems (EFIS'2000)
19th-21st June 2000
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
2EFIS 2000
Overview
• Motivation• Architectural Overview
• Federation Service• Adapter Layer
• Citation Linking• Fundamentals• Implementation
• Conclusion
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
3EFIS 2000
Motivation
• Digital libraries and electronic catalogues can cover only limited amounts of publications
• Citation information offered by various sources• Current strategies:
• citation information only available for locally maintained publications
• minimum set of citation information for identifying non-local publications
• universal citation database• globally unique identifier for publications (DOI)
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
4EFIS 2000
Motivation II
• Integration of bibliographical metadata has to include citation data
• Advantages:• improves accesibility of publications• implicit knowledge becomes explicit and usable for
derivation of higher level information
• Major tasks:• common platform based on integration service for
bibliographical data required• global identification of objects
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
5EFIS 2000
Architectural Overview
Federation Layer
Adapter Layer
Federation Service
...
AdapterAdapterAdapterAdapter
Higher Level Services
Common Interface / Unified Representation
website ofpublisher 2
proprietarydata ...
database ofpublisher 1 ...
SourceLayer
ApplicationLayer
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
6EFIS 2000
Architecture Overview: Federation Service
• FRAQL - Federation Query Language• supports loosely coupled database federations• mechanisms for conflict resolution
• Import relations are provided by adapters• complex restructuring mechanisms including value
mappings
• Integration relations as global views• same-object identification and tuple reconcilation• definition based on schema elements possible
• ...
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
7EFIS 2000
Architecture Overview: Adapter Layer
• Adapters for websites and various databases
• special XML adapter for cooperative providers in WAN scenario
FRAQL Query Processor
QueryEvaluator
QueryTranslator XML
Parser
ResultTranslator
Sou
rce
Des
crip
tion
XS
LT
XML
XM
L A
dapt
er
Dat
a S
ourc
e
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
8EFIS 2000
Architecture Overview: Related Issues
• Source descriptions• various systems have limited query capabilities• aim: pass queries with a high as possible selectivity
through to data sources
• Integration of semi-structured data• Cooperative vs. non-cooperative providers
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
9EFIS 2000
Citation Linking:Fundamentals
• Simple target schema:Publ(Key, A1, ..., An, {Ref1, ...,
Refm})
• BibKey set of global identifiers • unique source name• OID set of locally unique identifiers
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
10EFIS 2000
Citation Linking:FRAQL Implementation
• FRAQL schema in first normal form types PubType and RefType
• Import relations according to the type definitions
create table Publ_1 of PubType as import from src1.Publ (
id is Key,source is “Publ_1“,title is Title,authors is Authors);
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
11EFIS 2000
Citation Linking:FRAQL Implementation II
• Mapping table MapPubl(key,id,source) from local reference keys to global keys is required
create table Ref_1 of RefType as import from src1.Publ (
id is Key,source is “Publ_1“,ref_id is
@MapPubl(References,key,id,References),ref_source is
@MapPubl(References,key,source,“Publ_1));
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
12EFIS 2000
Citation Linking:FRAQL Implementation III
• Integration relations can be defined using metadata facilities:
create table References of RefType as select t2.* from catalog.tables t1, $(t1.tablename) t2 where t1.type_name = “RefType“;
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
13EFIS 2000
Citation Linking:FRAQL Implementation IV
A d a9 8A d a9 8S co 9 8
D a tab asesD a tab asesD ig . L ib ra rie s
A d am sA d am sS co tt
S co 9 8M e y 9 2M o o 9 4
K ey Title A u tho rs R eferences
M o o 9 4……
S Q L……
M o o re……
………
K ey Title A u tho rs R eferences
M o o 9 4M e y 9 2
M o o 9 4M e y 9 2 a
P u b l_ 2P u b l_ 3
key id sou rce
A d a9 8S co 9 8
P u b l_ 1P u b l_ 1
D a tab asesD ig . L ib ra rie s
A d am sS co tt
id sou rce title au tho rs
M o o 9 4 P u b l_ 2 S Q L M o o re
id sou rce title au tho rsS co 9 8M e y 9 2 aM o o 9 4
id sou rce re f_ id re f_ source
A d a9 8A d a9 8S co 9 8
P u b l_ 1P u b l_ 1P u b l_ 1
P u b l_ 1P u b l_ 3P u b l_ 2
Local re lation src1.Publ Local re lation src2.Publ
M apping tableM apPubl
Im port re lation Publ_1Im port re lation R ef_1
Im port re lation Publ_2
19th - 21st June 2000
Eike Schallehn Martin Endig
Kai-Uwe Sattler
14EFIS 2000
Conclusion and Outlook
• Integration system for bibliographical data• based on FRAQL federation service• special adapter for this scenario
• Platform for the integration of citation linking information
• Outlook:• critical issue: efficient generation of mapping
table• integration of citation databases• integration with DOI mechanism