The MOMIS System - DBGroup - Università degli Studi di Modena e

DOTTORATO DI RICERCA IN
INGEGNERIA DELL’INFORMAZIONE
XVI ciclo di dottorato - II ciclo Nuova Serie
Dai Dati all’Informazione:
il sistema MOMIS
dott. ing. Francesco Guerra
tutore: prof. Sonia Bergamaschi
Francesco Guerra – DBGroup@unimo
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Outline
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Intelligent Integration of Information
Matching
The MOMIS system
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MOMIS in the Semantic Web
MOMIS as the basis of a virtual marketplace
MOMIS to manage collaborative processes (the WINK
project)
MOMIS as a semantic search engine (the SEWASIE
project)
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Intelligent Integration of Information
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Distinguishing elements:
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Kinds of managed sources
The Global-as-View vs. the Local-as-View
approach
Data Model
Building the Global View
Querying the Global View
Description Logics techniques
Updating the Global View
Francesco Guerra – DBGroup@unimo
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Intelligent Integration of Information
the systems
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Intelligent Integration of Information
the systems
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Matching comparison
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Distinguishing elements:

Different kinds of mappings representation
(granularity, cardinality)

Mappings extraction (structure-instances
analysis, lexical analysis, external tools
exploitation)
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Matching comparison
Extended from : E. Rahm and P.A. Bernstein. A survey of approaches to automatic schema matching, VLDB
Journal, 10(4):334-350,2001
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Matching comparison
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The MOMIS System

MOMIS (Mediator envirOnment for Multiple Information Sources)
is a framework to perform information extraction and integration from
both structured and semistructured data sources.
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An object-oriented language, with an underlying Description Logic, called
ODL-I3, derived from the standard ODMG is introduced for information
extraction. Information integration is then performed in a semi-automatic
way, by exploiting the knowledge in a Common Thesaurus and ODL-I3
descriptions of source schemas with a combination of clustering
techniques and Description Logics. This integration process gives rise
to a virtual integrated view of the underlying sources (the Global Virtual
View) for which mapping rules and integrity constraints are specified to
handle heterogeneity.
The MOMIS system, based on a conventional wrapper/mediator
architecture, provides methods and open tools for data management in
Internet-based information systems by using a CORBA-2 interface.
MOMIS was developed as a joint collaboration between the University of
Modena and Reggio Emilia and University of Milano and Brescia.
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The MOMIS System
Distributed information stored in multiple, heterogeneous sources
• Sources integration provides a Global Schema (which is a virtual view)
• the Global Schema allows the user to send a query and get a unified answer
from all the involved sources (transparently)
• All information in http://www.dbgroup.unimo.it
• INTERDATA (1999-2000); D2I (from Data to Information) (2001-2002) –
“Programmi di ricerca scientifica di rilevante interesse nazionale”; WINK (Weblinked Integration of Network-based Knowledge) (2002-2003); SEWASIE
(Semantic Webs and AgentS in Integrated Economies) (2002-2005)
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The MOMIS System- Architecture
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WRAPPING
COMMON THESAURUS
GENERATION
GVV GENERATION
SCHEMA DERIVED
RELATIONSHIPS
ODLI3
LOCAL SCHEMA 1
GLOBAL
CLASSES
LEXICON DERIVED
RELATIONSHIPS
Common
Thesaurus
…
…
ODLI3
LOCAL SCHEMA N
USER SUPPLIED
RELATIONSHIPS
MAPPING
TABLES
INFERRED
RELATIONSHIPS
MANUAL
ANNOTATION
SEMI-AUTOMATIC
ANNOTATION
SYNSET#
SYNSET4
SYNSET2
SYNSET1
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Local sources annotation

The integration designer has to manually choose the appropriate WordNet
(www.cogsci.princeton.edu/~wn/) meaning for each element of the
conceptual schema provided by wrappers.

Motivations of the annotation:
1.
Exploiting semantics associated with the names of the
schemas/structures of the information sources
2.
Having a well-known meaning for each term of the sources

The annotation phase is composed of two steps:
1.
Word Form choice. The WordNet morphologic processor aids the
designer by suggesting a word form corresponding to the given term.
2.
Meaning choice. The designer can choose to map an element on zero,
one or more senses. Notice that the user can choose a sense among the
existing ones in WordNet and he can add new senses in the DB.
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Global Virtual View annotation

The GVV has to be annotated to become ”exportable knowledge”.

Annotating a GVV means to provide Global Classes with a name and with
meanings.

By starting from annotations of local sources and mappings between the
GVV and the local ontologies, we have developed a semi-automatic
methodology to generate the annotations of the GVV.
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GVV annotation
Wordnet meanings
essay#1 = an analytic or interpretive literary composition
publication#2 = a copy of a printed work offered for distribution
article#1 = nonfictional prose forming an independent part of a publication
Annotated Local classes
CS.Essay=<essay, {essay#1}>
CS.Publication=<publication,{publication#2}>
UNI.Article=<article,{article#1}>
The CT relationships
UNI.Article
NT
CS.Publication
CS.Essay
NT
CS.Publication
A Global class
GlobalClass1
CS.Essay
CS.Publication
UNI.Article
broadest meaning
The annotated Global class
meanings
GlobalClass1 = <publication, {essay#1,publication#2, article#1}>
name
BLCGC={LCGC|  y GC, (LC NT y ) v (y BT LC)}
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Updating the GVV
A created GVV can change:
1) By adding a new source on the system
2) By updating an existing data source schema
3) By deleting a previously integrated source
Adding a new source: two possible scenarios
•
Integration from scratch: the integration process is applied again; in
this case only the Common Thesaurus of the previously GVV can be
exploited.
•
Integration with the GVV: the process exploits the “automatically
annotated” GVV and the Common Thesaurus.
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Adding a new source
Annotated
GVV
XML
RDB
New
OODB New
Common Thesaurus
– intra/inter schema relationships
(only new sources)
Sources’s
Common
Schema
– lexicon relationships
Thesaurus
ODLI3(GVV e new sources annotated)
– relationships inserted by user
– inferred relationships
Cluster
generation
New GVV
GloblalClass1
GloblalClass2
Mapping
Global schema/
Local schema
GloblalClass3
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Adding a new source

Three scenarions:

A new global class is composed of only one old global class and
one or more new local classes
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A global class of the new integrated schema is composed of
only new local classes
A global class of the new integrated schema is composed of
more than one global class of the old GVV and at least one local
class of the new source

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GVV- integrated ontology

A GVV may be thought of as a domain ontology for the integrated sources;
the usual approach in the Semantic Web is based on “a priori” existence of
an ontology connected by means of semantic markups to the sources
Semantic Web
MOMIS
Ontolog
y
Ontology Builder
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GVV- integrated ontology

The MOMIS ontology is composed of the following
components:
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Global Virtual View
Mapping Rules
Integrity constraint rules
Intensional and extensional inter and intra-schema
relationships (Common Thesaurus)
We express the ontology by using the ODLI3
language or an OWL file.
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Using the MOMIS system
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The MOMIS system was exploited:
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To create a virtual marketplace
To support collaborative processes within the
European Wink project
To build an advanced semantic search engine
within the European SEWASIE project (under
development)
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SEWASIE

SEWASIE (SEmantic Webs and AgentS in Integrated Economies) is a
research project funded by EU on action line Semantic Web (May 2002/April
2005)
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The consortium details
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Università degli Studi di Modena e Reggio Emilia (ITALY)
CNA SERVIZI Modena s.c.a.r.l. (ITALY)
Università degli Studi di Roma “La Sapienza” (ITALY)
Rheinisch Westfaelische Technische Hochschule Aachen (GERMANY)
Libera Università di Bolzano (ITALY)
Thinking Networks AG (GERMANY)
IBM Italia SPA (ITALY)
Fraunhofer-Gesellschaft Institut Angewandte Informationstechnik (GERMANY)
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SEWASIE Objectives
The SEWASIE project aims to develop an advanced search engine enabling
intelligent access to heterogeneous data sources on the web, via semantic
enrichment, to provide the basis for structured web-based communication.
The SEWASIE project pursues the following aims:
To develop an agent-based secure, scalable and distributed system architecture
for semantic search (based on ontologies) and for structured web-based
communication.
To develop a general framework for query management and information
reconciliation based on a semantically enriched data and trusted agent structure.
 To develop an information brokering component which includes methods for
collecting, contextualizing and visualizing data.
To provide the end-user with an efficient interface for formulating queries using
a graphical representation and for intelligent navigation through the semantically
information space.

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The SEWASIE architecture

The SEWASIE system realizes a virtual network, the SEWASIE Virtual Network (SVN),
whose nodes are SEWASIE Information Nodes (SINodes), multi-database mediatorbased systems, each including a Virtual Data Store, an Ontology Builder, and a Query
Manager

Brokering Agents maintain the knowledge related to the SEWASIE Virtual Network
and the user profiles.

In query solving phase, starting from a specified SINode, a Query Agent accesses
other SINodes and thus collects partial answers.

To select SINodes useful to solve a query, a Query Agent interacts with a/several
Brokering Agents.
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The SEWASIE architecture
user
Other
users user
user
User
Profile
Monitor
Profiles
OLAP
Reports
User Interface
Comm.
Agent
Visualisation
Monitoring
Comm. Interface
Query Interface
Metadata Interface Interface
Communication
Tool
Monitoring
Agent (MA)
Query Results
Brokering
Agent
(BA)
Ontology
Query
Query
QueryAgent
Agent
Agent
SINode
maps
Brokering
Agent (BA)
Ontology
maps
BA
SEWASIE
BA
Interconnectio
n
BA
infrastructure
Virtual Data Store
Query
Query
Manager
Metadata
Metadata
Repository
Repository
Ontology
Wrapper
Wrapper
Semantic
Enrichment
RDBs
Structured
Databases
Ontolog
y
builder
Wrapper
Wrapper
Semantic
…Enrichment
<XML>
<DATA>...
</DATA>
Semi- Structured
Databases
Wrapper
Wrapper
Wrapper HTML
XML Wrap
HTML→XML
The
information
layer
BA
OLAP
Tool
<HTML>
...Unstructured
Text documents
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Future Work
– Ontology evolution within an SINode
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Update of existing sources
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Deletion of previously integrated sources
– Extending WordNet
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If a source description element has no correspondent concept in
WordNet, the designer may add a new meaning and proper
relationships connecting them to existing meanings.
– Multilingual functionalities
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SEWASIE multilingual technologies will allow users to share
information and resources available all over the world, but also to
preserve their original local qualities.
Enrichment of multi-lingual lexicon ontology with the aid of statistical
analysis techniques for multilingual text corpora (for example with
techniques for the generation of multilingual dictionaries).
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Partecipazione a progetti di ricerca di
carattere nazionale ed europeo
• progetto D2I (From Data to Information) finanziato dal MIUR:
“Programma di ricerca scientifica di rilevante interesse nazionale
(2000-2001)”;
• progetto “Agenti software e commercio elettronico: profili
giuridici, tecnologici e psico-sociali”, finanziato dal MIUR
“Programma di ricerca scientifica di rilevante interesse nazionale”
(2001-2002)
• progetto “Tecnologie per arricchire e fornire accesso a contenuti”
finanziato con il Fondo Speciale Innovazione 2000 (2001-2002)
• progetto SEWASIE (SEmantic Web and AgentS in Integrated
Economies) finanziato dalla Comunità Europea (2002-2005)
• progetto WINK (Web-linked Integration of Network-based Knowledge)
finanziato dalla Comunità Europea (cluster EUTIST-AMI). (2002-2003)
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Pubblicazioni
Riviste Internazionali (RI) e Capitoli in libri Internazionali (CLI)
[RI1] S. Bergamaschi, G. Cabri, F. Guerra, L. Leonardi, M. Vincini, F. Zambonelli, Exploiting Agents
to Support Information Integration, Special Issue of the International Journal on Cooperative
Information Systems vol. 11(3-4): 293-314, 2002, ISSN 0218-8430
[RI2] I. Benetti, D. Beneventano, S. Bergamaschi, F. Guerra, M. Vincini, An Information Integration
Framework for E-Commerce, IEEE Intelligent Systems Magazine, Jan/Feb 2002, pp. 18-25,
[RI3] D. Beneventano, S. Bergamaschi, F. Guerra, M. Vincini, Synthesizing an Integrated Ontology,
IEEE Internet Computer, September-October 2003, 42-51, ISSN 1089-7801
[RI4] I. Benetti, S. Bergamaschi, F. Guerra, M. Vincini, Soap-enabled web services for knowledge
management to appear in Int. J. Web Engineering and Technology, InderScience Publishers.
[RI5] D. Beneventano, F. Guerra, S. Magnani, M. Vincini A Web Service based framework for the
semantic mapping between product classification schemas, to appear in Journal of Electronic
Commerce Research, ISSN 15266133.
[CLI1] D. Beneventano, S. Bergamaschi, J. Gelati, F. Guerra, M. Vincini: MIKS: an agent framework
supporting information access and integration, Intelligent Information Agents - The AgentLink
Perspective, (editor S. Bergamaschi, M. Klusch, P. Edwards, P. Petta) - March 2003, Lecture Notes in
Computer Science N. 2586 - Springer Verlag, pp. 22-49 ISSN 0302-9743 ISBN 3-540-00759-8
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Riviste Nazionali (RN)
[RN1] G. Gelati, F. Guerra, M. Vincini, Agents Supporting Information Integration: the MIKS
Framework, AI*IA Notizie, Periodico dell’Associazione Italiana per l’Intelligenza Artificiale, AnnoXIV,
Francesco Guerra – DBGroup@unimo
N.4, Dicembre 2001
Pubblicazioni
Congressi Internazionali (CI)
[CI1] D. Beneventano, S. Bergamaschi, I. Benetti, A. Corni, F. Guerra, G. Malvezzi, SI-Designer: a
tool for intelligent integration of information, 34th Annual Hawaii International Conference on
System Sciences (HICSS-34), January 3-6, 2001, Maui, Hawaii - Track 9. IEEE Computer Society
[CI2] D. Beneventano, S. Bergamaschi, F. Guerra, M. Vincini,The Momis approach to Information
Integration, IEEE and AAAI International Conference on Enterprise Information Systems (ICEIS01),
Setùbal, Portugal, 7-10 July 2001, pp.194-198, ISBN 972-98050-2-4
[CI3] I. Benetti, D. Beneventano, S. Bergamaschi, F. Guerra, M. Vincini, SI-Designer: an Integration
Framework for E-Commerce, IJCAI*01 Workshop on E-Business & the Intelligent Web Seattle, USA
* August 5 2001
[CI4] S. Bergamaschi, G. Cabri, F. Guerra, L. Leonardi, M. Vincini, F. Zambonelli, Supporting
information integration with autonomous agents, Fifth International Workshop CIA-2001 on
COOPERATIVE INFORMATION AGENTS September 6 - 8, 2001 Modena, Italy pp, 88-99.
[CI5] D. Calvanese, S. Castano, F. Guerra, D. Lembo, M. Melchiori, G. Terracina, D. Ursino, M.
Vincini, Towards a comprehensive methodological framework for integration, 8th International
Workshop on Knowledge Representation meets Databases (KRDB-2001), Roma, Italy, 2001
[CI6] S. Bergamaschi, F. Guerra, M. Vincini, A Data Integration Framework for E-commerce
product classification, 1st International Semantic Web Conference (ISWC2002), Sardegna, Italy, 912 June 2002, LNCS 2342 Springer 2002, ISBN 3-540-43760-6, pp. 379-393, ISBN 3-540-43760-6
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Pubblicazioni
[CI7] S. Bergamaschi, F. Guerra, Peer to Peer Paradigm for a Semantic Search Engine, in
proceedings of the International Workshop on Agents and Peer-to-Peer Computing, Bologna, 15 July
2002, LNCS 2530, Springer ISBN 3-540-40538-0
[CI8] S. Bergamaschi, F. Guerra, M. Vincini, Product Classification Integration for E-Commerce,
Second International Workshop on Electronic Business Hubs - WEBH 2002 in conjunction with DEXA
2002, September 2-6 2002, Aix En Provence, France, published by IEEE Computer Society, Los
Alanitos (CA), ISBN 0-7695-1668-8, pp. 861-867
[CI9] D. Beneventano, S. Bergamaschi, S. Castano, V. De Antonellis, A. Ferrara, F. Guerra, F. Mandreoli,
G. Ornetti, M. Vincini, Semantic Integration and Query Optimization of Heterogeneous Data
Sources, 1st Int.l Workshop on Efficient Web-based Information Systems (EWIS), 2002, Montpellier,
France, pp.154-165.
[CI10] S. Bergamaschi, F. Guerra, M. Vincini, A peer-to-peer information system for the semantic
web, in proceedings of the International Workshop on Agents and Peer-to-Peer Computing, in AAMAS
2003 Melbourne, Australia, July 14, 2003
[CI11] D. Beneventano, S. Bergamaschi, F. Guerra, M. Vincini: Building an Ontology with MOMIS, in
proceedings of the Semantic Integration Workshop within the Second International Semantic Web
Conference, October 20, 2003 Sundial Resort, Sanibel Island, Florida, USA.
[CI12] D. Beneventano, S. Bergamaschi, F. Guerra, M. Vincini, Building an integrated Ontology
within SEWASIE system, in proceedings of the First International Workshop on Semantic Web and
Databases, Co-located with VLDB 2003 Berlin, Germany, (2003)
[CI13] S. Bergamaschi, G.Gelati, F. Guerra, M. Vincini, WINK: a Web-based Enterprise System for
Collaborative Project Management in Virtual Enterprises, 4th International Conference on Web
Information Systems Engineering, Roma Italy, 10-12 December 2003
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Pubblicazioni
Congressi Nazionali (CN)
[CN1] D. Beneventano, S. Bergamaschi, F. Guerra, M. Vincini, Exploiting extensional knowledge for
query reformulation and object fusion in a data integration system, Proceedings of SEBD2001,
Venezia, 27-29 June, 2001, pp. 257-271
[CN2] G. Gelati, F. Guerra, M. Vincini, Agents Supporting Information Integration: the MIKS
Framework, Proc. AIIA and TABOO Workshop: From Object to Agents, Pitagora Editrice, Bologna, ISBN
88-371-1272-6, September 2001
[CN3] D. Beneventano, S. Bergamaschi, D. Bianco, F. Guerra, M. Vincini, SI-Web: a Web based
interface for the MOMIS project, Proceedings of SEBD2002, 19-22 June, 2002, pp. 407-411
[CN4] D. Beneventano, S. Bergamaschi, D. Gazzotti, G.Gelati, F. Guerra, M. Vincini, The WINK Project
for Virtual Enterprise Networking and Integration, Proceedings of SEBD2002, 2002, pp. 283-290
[CN5] D. Beneventano, S. Bergamaschi, M.Felice, D. Gazzotti, G.Gelati, F. Guerra, M. Vincini,. An Agent
framework for Supporting the MIKS Integration, Proc. AIIA and TABOO Workshop: From Object to
Agents, 18-19 Novembre 2002, Milano Università Bicocca
[CN6] D. Beneventano, S. Bergamaschi, A. Fergnani, F. Guerra, M. Vincini, D. Montanari, A Peer-toPeer Agent-Based Semantic Search Engine, Proceedings of SEBD2003, Cetraro (CS),2003, pp.283290
[CN7] S. Bergamaschi, G. Gelati, F. Guerra, M. Vincini, A Experiencing AUML for the WINK MiltiAgent System, Proc. AIIA and TABOO Workshop: From Object to Agents, 10-11 Settembre 2003,
Villasimius (CA)
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Global Instance Computation

For the definition of a Global Class we have to
define the following elements:



Mapping Table: define the mapping between the global
class attributes and the local classes attributes
Join condition: we assume that there is a Join Condition
between each pair of overlapping relations to identify
tuples corresponding to the same object and fuse them
Full disjunction: the GC contains a unique tuple
containing a unique tuple resulting from the merge of all
different tuples representing the same real world object.
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Global Instance Computation
S(l1)= (firstn, lastn, year, e_mail)
S(l2)= (name, e_mail, dept_code, s_code)
L1
L2

Name
firstn and lastn
name
E_mail
E_mail
E_mail
Section
null
S_code
Year
year
null
Dept
null
dept code
Two functions:


Global function: renaming the attributes of the
local classes into attributes of the global class
Local Function: converting a tuple of elements of
a local classby suitable functions such as string
concatenations ….
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Global Instance Computation

Semantic Homogeneity property condition
Join Attribute
Join Attribute
Full Disjunction
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Global Instance Computation

Semantic Homogeneity property condition not
verified:

Resolution functions:



Random
Priority
User defined function
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Example
University source (relational)
Department(dept_code,dept_name,budget)
Research_Staff(name,e_mail,dept-code,s_code)
FK dept_code REF Department, s_code REF Section
School_Member(name,school,year,e_mail)
Section(s_code,section_name,length,room_code)
FK room_code REF Department, s_code REF Room
Room(room_code,seats_number,notes)
Tax_Position source (XML)
<!ELEMENT ListOfStudent (Student*)>
<!ELEMENT Student (name,s_code,school_name,e_mail,tax_fee)>
<!ELEMENT name (#PCDATA)>
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Example
Computer_Science source (object)
CS_Person(first_name,last_name)
Professor:CS_Person(belongs_to:Division,rank)
Student:CS_Person(year,takes:set<Course>,rank,e_mail)
Division(description,address:Location)
Location(city,street,number,country)
Course(course_name,tought_by:Professor)
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Source Acquisition Module
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Common Thesaurus (Domain Ontology)
Set of terminological relationships between classes and
attributes names (terms)
expresses both intra-schema and inter-schema knowledge
Relationships added to Common Thesaurus:
(1)
schema derived
(2)
lexicon derived
(3)
designer supplied
(4)
inferred exploiting ODB-Tools capabilities
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Schema-derived relationships
Terminological and extensional intra-schema relationships
 RT relationships derived from
foreign keys in a relational schema
UNI.Section RT UNI.Department
 BT/NT relationships derived from
inheritance relationships in a object-oriented schema or
integrity constraints in relational schema
CS.Student NT CS.CS_Person
CS.Professor NT CS.CS_Person
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Schema Derived Relationships
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Lexicon-derived relationships
Extracted from WordNet lexical database (Princeton Un.)
129625 lemma organized in 99759 synonym set (synset)
Synonymy
Polysemy
Tax_position_xml.Student.name SYN
University.School_member.name
CS.Professor NT CS.CS_Person
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Lexicon Derived Relationships
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Lexicon Derived Relationships
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Lexicon Derived Relationships
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Lexicon Derived Relationships
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Lexicon Derived Relationships
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Inferred relationships
Exploiting Description Logics techniques (ODB-Tools system)
a new set of terminological relationships are inferred
University.Research_Staff RT CS.Course
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Common Thesaurus
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Mediator global schema
Global schema generation
(interaction with ARTEMIS module):
Affinity calculation
Cluster generation
Global attributes and mapping table generation
A global class gci is generated for each cluster Cli
SI-Designer builds the attributes set to be associated
to the cluster:
–Union of the attributes of all classes belonging to the cluster
–Fusion of “similar attributes”
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Affinity tree and Cluster
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Affinity tree and Cluster
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Affinity tree and Cluster
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Mapping table example
– each global class includes mapping rules between global and
local attributes (and/or relationships, default/null values)
– a mapping is generated for each global class gci
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Mapping table
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Mapping table
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