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Francesco Guerra – 1 DOTTORATO DI RICERCA IN INGEGNERIA DELLINFORMAZIONE XVI ciclo di dottorato - II ciclo Nuova Serie Dai Dati allInformazione:

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Presentation on theme: "Francesco Guerra – 1 DOTTORATO DI RICERCA IN INGEGNERIA DELLINFORMAZIONE XVI ciclo di dottorato - II ciclo Nuova Serie Dai Dati allInformazione:"— Presentation transcript:

1 Francesco Guerra – 1 DOTTORATO DI RICERCA IN INGEGNERIA DELLINFORMAZIONE XVI ciclo di dottorato - II ciclo Nuova Serie Dai Dati allInformazione: il sistema MOMIS dott. ing. Francesco Guerra tutore: prof. Sonia Bergamaschi

2 Francesco Guerra – 2 Outline Intelligent Integration of Information Matching The MOMIS system 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)

3 Francesco Guerra – 3 Intelligent Integration of Information Distinguishing elements: 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

4 Francesco Guerra – 4 Intelligent Integration of Information the systems

5 Francesco Guerra – 5 Intelligent Integration of Information the systems

6 Francesco Guerra – 6 Matching comparison Distinguishing elements: Different kinds of mappings representation (granularity, cardinality) Mappings extraction (structure-instances analysis, lexical analysis, external tools exploitation)

7 Francesco Guerra – 7 Matching comparison Extended from : E. Rahm and P.A. Bernstein. A survey of approaches to automatic schema matching, VLDB Journal, 10(4): ,2001

8 Francesco Guerra – 8 Matching comparison

9 Francesco Guerra – 9 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. 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.

10 Francesco Guerra – 10 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 INTERDATA ( ); D2I (from Data to Information) ( ) –Programmi di ricerca scientifica di rilevante interesse nazionale; WINK (Web- linked Integration of Network-based Knowledge) ( ); SEWASIE (Semantic Webs and AgentS in Integrated Economies) ( )

11 Francesco Guerra – 11 The MOMIS System- Architecture

12 Francesco Guerra – 12 SYNSET 2 SYNSET # SYNSET 4 SYNSET 1 MANUAL ANNOTATION SEMI-AUTOMATIC ANNOTATION INFERRED RELATIONSHIPS LEXICON DERIVED RELATIONSHIPS SCHEMA DERIVED RELATIONSHIPS Common Thesaurus COMMON THESAURUS GENERATION USER SUPPLIED RELATIONSHIPS ODLI3 LOCAL SCHEMA N WRAPPING ODLI3 LOCAL SCHEMA 1 … … GVV GENERATION MAPPING TABLES GLOBAL CLASSES

13 Francesco Guerra – 13 Local sources annotation n n 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. n n The annotation phase is composed of two steps: 1. 1.Word Form choice. The WordNet morphologic processor aids the designer by suggesting a word form corresponding to the given term 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. n n Motivations of the annotation: Exploiting semantics associated with the names of the schemas/structures of the information sources Having a well-known meaning for each term of the sources

14 Francesco Guerra – 14 Global Virtual View annotation n n The GVV has to be annotated to become exportable knowledge. n n Annotating a GVV means to provide Global Classes with a name and with meanings. n n 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.

15 Francesco Guerra – 15 GVV annotation UNI.ArticleNTCS.Publication CS.EssayNTCS.Publication CS.Essay= CS.Publication= UNI.Article= CS.Essay= CS.Publication= UNI.Article= GlobalClass1 = GlobalClass1 = The annotated Global class Annotated Local classes The CT relationships name meanings essay#1 = an analytic or interpretive literary composition essay#1 = an analytic or interpretive literary composition publication#2 = a copy of a printed work offered for distribution publication#2 = a copy of a printed work offered for distribution article#1 = nonfictional prose forming an independent part of a publication article#1 = nonfictional prose forming an independent part of a publication essay#1 = an analytic or interpretive literary composition essay#1 = an analytic or interpretive literary composition publication#2 = a copy of a printed work offered for distribution publication#2 = a copy of a printed work offered for distribution article#1 = nonfictional prose forming an independent part of a publication article#1 = nonfictional prose forming an independent part of a publication Wordnet meanings GlobalClass1 CS.Essay CS.Publication UNI.Article GlobalClass1 CS.Essay CS.Publication UNI.Article A Global class broadest meaning BLC GC ={LCGC|y GC, (LC NT y ) v (y BT LC)}

16 Francesco Guerra – 16 Updating the GVV A created GVV can change: 1) 1)By adding a new source on the system 2) 2)By updating an existing data source schema 3) 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.

17 Francesco Guerra – 17 Adding a new source Common Thesaurus Common Thesaurus Cluster generation Cluster generation XML AnnotatedGVV OODB RDB Sourcess Schema ODL I 3 GloblalClass 3 GloblalClass 1 GloblalClass 2 Mapping Global schema/ Local schema New GVV Common Thesaurus –intra/inter schema relationships (only new sources) (only new sources) –lexicon relationships (GVV e new sources annotated) (GVV e new sources annotated) –relationships inserted by user –inferred relationships Common Thesaurus –intra/inter schema relationships (only new sources) (only new sources) –lexicon relationships (GVV e new sources annotated) (GVV e new sources annotated) –relationships inserted by user –inferred relationships New New

18 Francesco Guerra – 18 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 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

19 Francesco Guerra – 19 GVV- integrated ontology n n 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 Ontolog y Ontology Builder Semantic Web MOMIS

20 Francesco Guerra – 20 GVV- integrated ontology The MOMIS ontology is composed of the following components: 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.

21 Francesco Guerra – 21 Using the MOMIS system The MOMIS system was exploited: 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)

22 Francesco Guerra – 22 SEWASIE n SEWASIE (SEmantic Webs and AgentS in Integrated Economies) is a research project funded by EU on action line Semantic Web (May 2002/April 2005) n The consortium details n Università degli Studi di Modena e Reggio Emilia (ITALY) n CNA SERVIZI Modena s.c.a.r.l. (ITALY) n Università degli Studi di Roma La Sapienza (ITALY) n Rheinisch Westfaelische Technische Hochschule Aachen (GERMANY) n Libera Università di Bolzano (ITALY) n Thinking Networks AG (GERMANY) n IBM Italia SPA (ITALY) n Fraunhofer-Gesellschaft Institut Angewandte Informationstechnik (GERMANY)

23 Francesco Guerra – 23 SEWASIE Objectives The SEWASIE project pursues the following aims: n n To develop an agent-based secure, scalable and distributed system architecture for semantic search (based on ontologies) and for structured web-based communication. n n To develop a general framework for query management and information reconciliation based on a semantically enriched data and trusted agent structure. n n To develop an information brokering component which includes methods for collecting, contextualizing and visualizing data. n n 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. 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.

24 Francesco Guerra – 24 The SEWASIE architecture The SEWASIE system realizes a virtual network, the SEWASIE Virtual Network (SVN), whose nodes are SEWASIE Information Nodes (SINodes), multi-database mediator- based 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.

25 Francesco Guerra – 25 The SEWASIE architecture Other users Query Results Communication Tool Query Agent Query Agent Query Agent Comm. Agent user Brokering Agent (BA) Ontology maps Monitoring Agent (MA) User Interface Comm. InterfaceQuery InterfaceMetadata Interface Visualisation User Profile OLAP Tool OLAP Reports Monitoring Interface Monitor Profiles SINode … Ontology Structured Databases RDBs Wrapper Semantic Enrichment Query Metadata Repository Semi- Databases Wrapper Semantic Enrichment... Wrapper Unstructured Text documents... Virtual Data Store Ontology Structured Databases RDBs Wrapper Semantic Enrichment Query Manager Metadata Repository Databases Wrapper Semantic Enrichment... Wrapper... Ontolog y builder Virtual Data Store The user interface layer SEWASIE Interconnectio n infrastructure Ontology maps Brokering Agent (BA) BA The information layer The intermediaries layer Structured Wrapper HTML XML Wrap HTML XML

26 Francesco Guerra – 26 Future Work –Ontology evolution within an SINode n n Update of existing sources n n Deletion of previously integrated sources –Extending WordNet n n 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 n n SEWASIE multilingual technologies will allow users to share information and resources available all over the world, but also to preserve their original local qualities. n n 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).

27 Francesco Guerra – 27 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 ( ); progetto Agenti software e commercio elettronico: profili giuridici, tecnologici e psico-sociali, finanziato dal MIUR Programma di ricerca scientifica di rilevante interesse nazionale ( ) progetto Tecnologie per arricchire e fornire accesso a contenuti finanziato con il Fondo Speciale Innovazione 2000 ( ) progetto SEWASIE (SEmantic Web and AgentS in Integrated Economies) finanziato dalla Comunità Europea ( ) progetto WINK (Web-linked Integration of Network-based Knowledge) finanziato dalla Comunità Europea (cluster EUTIST-AMI). ( )

28 Francesco Guerra – 28Pubblicazioni 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): , 2002, ISSN [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 , [RI3] D. Beneventano, S. Bergamaschi, F. Guerra, M. Vincini, Synthesizing an Integrated Ontology, IEEE Internet Computer, September-October 2003, 42-51, ISSN [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 [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 Springer Verlag, pp ISSN ISBN Riviste Nazionali (RN) [RN1] G. Gelati, F. Guerra, M. Vincini, Agents Supporting Information Integration: the MIKS Framework, AI*IA Notizie, Periodico dellAssociazione Italiana per lIntelligenza Artificiale, AnnoXIV, N.4, Dicembre 2001

29 Francesco Guerra – 29 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 [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 , ISBN [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 [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, [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, June 2002, LNCS 2342 Springer 2002, ISBN , pp , ISBN

30 Francesco Guerra – 30 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 [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 , Aix En Provence, France, published by IEEE Computer Society, Los Alanitos (CA), ISBN , pp [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 [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. Semantic Integration WorkshopSemantic Integration Workshop [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) VLDB 2003VLDB 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, December 2003

31 Francesco Guerra – 31 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, June, 2001, pp [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 , 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, June, 2002, pp [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 [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, Novembre 2002, Milano Università Bicocca [CN6] D. Beneventano, S. Bergamaschi, A. Fergnani, F. Guerra, M. Vincini, D. Montanari, A Peer-to- Peer Agent-Based Semantic Search Engine, Proceedings of SEBD2003, Cetraro (CS),2003, pp [CN7] S. Bergamaschi, G. Gelati, F. Guerra, M. Vincini, A Experiencing AUML for the WINK Milti- Agent System, Proc. AIIA and TABOO Workshop: From Object to Agents, Settembre 2003, Villasimius (CA)

32 Francesco Guerra – 32 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.

33 Francesco Guerra – 33 Global Instance Computation S(l1)= (rstn, lastn, year, e_mail) S(l2)= (name, e_mail, dept_code, s_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 ….

34 Francesco Guerra – 34 Global Instance Computation Semantic Homogeneity property condition Join Attribute Full Disjunction

35 Francesco Guerra – 35 Global Instance Computation Semantic Homogeneity property condition not verified: Resolution functions: Random Priority User defined function

36 Francesco Guerra – 36 Clusters generation Clustering Algorithm (Hierarchical clustering techniques - Heveritt) 1. Compute all pair-wise Global Affinity coefficients GA(c ji,c hk ). 2. Place each class into a separate cluster 3. Repeat Select pair c ji,c hk of current cluster with the highest GA in M(h,k) = max i,j M(i,j) Form a new cluster by combining c h,c k Update c ji,c hk by deleting the rows and columns corresponding to c h and c k Define a new row and column (h+k) for the new cluster c h,k. until rank of M is greater than 1. Affinity Matrix Clustering Algorithm Cl 1 Cl 2 Cl 5 Cl 6 Cl 3 Cl 7 Cl 8 Cl 9 Cl 4 Cl 10 Cl 11

37 Francesco Guerra – 37 Affinity evaluation Two names have Affinity when connected through a path in the Thesaurus The Structural Affinity of two classes measures the affinity of their Attributes (Dices function) The Global Affinity of two classes measures the affinity computed as the weighted sum of the Name and Structural Affinity Extensional evaluation

38 Francesco Guerra – 38 ODB-Tools Schema Validator: automatically builds the class taxonomy and preserves the coherence with respect to the inheritance and aggregation hierarchies. Query Optimizer: executes the semantic expansion of the query Available at

39 Francesco Guerra – 39 Example 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) University source (relational) Tax_Position source (XML)

40 Francesco Guerra – 40 CS_Person(first_name,last_name) Professor:CS_Person(belongs_to:Division,rank) Student:CS_Person(year,takes:set,rank,e_mail) Division(description,address:Location) Location(city,street,number,country) Course(course_name,tought_by:Professor) Computer_Science source (object) Example

41 Francesco Guerra – 41 Source Acquisition Module

42 Francesco Guerra – 42 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

43 Francesco Guerra – 43 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

44 Francesco Guerra – 44 Schema Derived Relationships

45 Francesco Guerra – 45 Lexicon-derived relationships Extracted from WordNet lexical database (Princeton Un.) lemma organized in synonym set (synset) Synonymy Polysemy Tax_position_xml.Student.name SYN University.School_member.name CS.Professor NT CS.CS_Person

46 Francesco Guerra – 46 Lexicon Derived Relationships

47 Francesco Guerra – 47 Lexicon Derived Relationships

48 Francesco Guerra – 48 Lexicon Derived Relationships

49 Francesco Guerra – 49 Lexicon Derived Relationships

50 Francesco Guerra – 50 Lexicon Derived Relationships

51 Francesco Guerra – 51 Inferred relationships Exploiting Description Logics techniques (ODB-Tools system) a new set of terminological relationships are inferred University.Research_Staff RT CS.Course

52 Francesco Guerra – 52 Common Thesaurus

53 Francesco Guerra – 53 Mediator global schema Global schema generation (interaction with ARTEMIS module): Affinity calculation Cluster generation Global attributes and mapping table generation A global class gc i is generated for each cluster Cl i 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

54 Francesco Guerra – 54 Affinity tree and Cluster

55 Francesco Guerra – 55 Affinity tree and Cluster

56 Francesco Guerra – 56 Affinity tree and Cluster

57 Francesco Guerra – 57 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 gc i

58 Francesco Guerra – 58 Mapping table

59 Francesco Guerra – 59 Mapping table


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