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L ogics for D ata and K nowledge R epresentation

L ogics for D ata and K nowledge R epresentation. Towards Infrastructure, Methodology and Principles for Ontology Development. Fausto Giunchiglia and Biswanath Dutta Fall - 2011. Outline. Introduction Knowledge Representation (KR) Ontology Domain Facet DERA Mapping Methodology

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L ogics for D ata and K nowledge R epresentation

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  1. Logics for Data and KnowledgeRepresentation Towards Infrastructure, Methodology and Principles for Ontology Development Fausto Giunchiglia and Biswanath Dutta Fall - 2011

  2. Outline • Introduction • Knowledge Representation (KR) • Ontology • Domain • Facet • DERA • Mapping • Methodology • Principle • Demo : Domain Modeling

  3. Knowledge Representation (KR) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • “…is about building models of the world, of a particular domain or problem, which allow automatic reasoning and interpretation” • Fundamental Goal • is to represent knowledge in a manner that facilitates inferencing new knowledge (i.e. drawing conclusions) from the knowledge base

  4. Knowledge Representation Properties INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • According to (Crawford & Kuipers, 1990): • It must have a reasonably compact syntax. • It must have a well defined semantics so that one can say precisely what is being represented. • It must have sufficient expressive power to represent human knowledge. • It must have an efficient, powerful, and understandable reasoning mechanism • It must be usable to build large knowledge bases. Crawford, J. M. & Kuipers, B. (1990). ALL: Formalizing Access Limited Reasoning. Principles of semantic networks: Explorations in the representation of knowledge, Morgan Kaufmann Pub., 299-330.

  5. Knowledge Representation Issues INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • KR issues: • How do people represent knowledge? • What is the nature of knowledge? • Do we have domain specific schema or generic, domain independent schema? • How much it needs to be expressive?

  6. Ontology INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • “formal, explicit specification of a shared conceptualisation” – Gruber, 1993 • Models a domain consisting of shared vocabulary with the definition of objects and/or concepts and their properties and relations • A structural framework for organizing information, and • used as a form of KR in the fields like, AI, SW, Lib. Sc., Inf. Architecture, etc. • Ontology as a language resource

  7. Ontology Properties INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • Some of the ontological properties are: • Extendable • Reusable • Flexible • Robust • …

  8. Domain INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • An area of knowledge or field of study that we are interested in or that we are communicating about • Example: • Computer science, Artificial Intelligence, Soft computing, Social networks, …Library science, Mathematics, Physics, Chemistry, Agriculture, Geography, … • Music, Movie, Sculpture, Painting, …Food, Wine, Cheese, …Space,…

  9. Domain (contd…) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • A domain can be decomposed into its several constituents, and • Each of them denotes a different aspect of entities • An example from Space domain: by region, by body of water, by landform, by populated places, by administrative division, by land, by agricultural land, by facility, by altitude, by climate,… • Each of these aspects is called facet

  10. Facet INTRODUCTION:: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • A hierarchy of homogeneous terms describing an aspect of the domain, where each term in the hierarchy denotes a different concept • E.g., • Body of water(e.g., River, Lake, Pond, Canal), Landform (e.g., mountain, hill, ridge), facility (e.g., house, hut, farmhouse, hotel, resort), etc. • language facet (e.g., English, Hindi, Italian,), property facet, author facet, religion facet (e.g., Christian, Hindu, Muslim), commodity facet, etc.

  11. DERA INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • Is a Facet based knowledge organization framework • It is is independent from any specific domain • Allows building domain specific ontologies • Is logically sound • Has mapping to Description Logic • Decidable • Designed by the UniTn KnowDive group

  12. DERA Surface Structure INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • In the surface level, it has the following components: • D – Domain • E – Entity • R – Relation • A – Attribute

  13. Domain (D) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • A DERA domain is a tuple of, D = <E, R, A>

  14. Entity (E) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • an elementary component that consist of entity classes and their instances, having either perceptual correlates or only conceptual existence in a domain in context E = <{C} + {E'}> • Where, • C = Entity class – consists of core classes representing the entities; • E' = Entity (also called object) – consists of real world named entities, that is the instantiation of the entity classes C.

  15. Entity (E) (contd…) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • Entity class (C) : • Represents the essence of the domain under consideration; • Consists of the core classes representing a domain in context • E.g., Consider the following classes in context of Space domain: • Mountain, Hill, Lake, River, Canal, Province, City, Hotel,...

  16. Entity (E) (contd…) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • Entity (E') : • Are the real world named entities • An extension of the real world entities • E.g., • The Himalaya, Monte Bondone, Lake Garda, Trento, Povo, Hotel America,...

  17. Entity (E) (contd….) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO E.g., An example from a domain Space

  18. Relation (R) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • An elementary component consists of classes defining the relations between entities R = <{r}> • A relation is a link between two entities (E') • Builds a semantic relation between the entities • E.g., • Some relations (spatial) from Space domain: near, adjacent, inside, before, center, sideways, etc.

  19. Attribute (A) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • An elementary component consists of classes expressing the characteristics of entities A = <{A'}, {C}> • An attribute is any property, qualitative, quantitative or descriptive measure of an entity

  20. Attribute (A) (contd…) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • Datatype Attribute (A'): • A datatype attribute includes the attribute classes that accounts the quality or quantity of an entity within a domain • E.g., • latitude, longitude (of a place): • 450 N, 180 S • altitude (of a mountain): • 8000ft, 2400m. • high, low • depth (of a lake): • deep, shallow • 100ft., 20m.

  21. Attribute (A) (contd…) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • Descriptive Attribute (C): • It includes the attribute classes that describe the entities under a domain in consideration • The value of a descriptive attribute could consists of a single string or a set of strings • E.g., • natural resource (of a place): • coal, natural gas, oil, … • architectural style (of a castle): • {Classical architecture, Greek architecture, Roman architecture, Bauhaus, etc.} • history (of a place) • ………. • climbing route (to a mountain) • ……………….

  22. Mapping INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • From DERA to DL • Entity classes (C) -> Concepts • Relation (R) -> Roles • Datatype attribute (A') -> Roles • Descriptive attribute (C) -> Roles • Entity (E') -> Individuals

  23. Methodology INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • Step 1: Identification of the atomic concepts • Step 2: Analysis (per genus et differentiam) • Step 3: Synthesis • Step 4: Standardization • Step 5: Ordering • Following the above steps leads to the creation of a set of facets. They constitute a faceted representation scheme for a domain

  24. Ontological Principle INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • Relevance (e.g.,breed is more realistic to classify the universe of cows instead of by grade) • Ascertainability (e.g., flowing body of water) • Permanence (e.g., Spring- a natural flow of ground water) • Exhaustiveness (e.g., to classify the universe of people, we need both male and female) • Exclusiveness (e.g., age and date of birth, both produce the same divisions) • Context (e.g., bank, a bank of a river, OR, a building of a financial institution) • Important: helps in reducing the homographs • Currency (e.g., metro station vs. subway station) • Reticence (e.g., minority author, black man) • Ordering • Important: ordering carries semantics as it provides implicit relations between the coordinate terms

  25. Step 1: identification of the atomic concepts INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • Sources of the concepts • WordNet • GeoNames (357/663 classes) • TGN • Literature

  26. Step 1: identification of the atomic concepts (2) INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO • Some of the relevant sub-trees in WordNet are: • location • artifact, artefact • body of water, water • geological formation, formation • land, ground, soil • land, dry land, earth, ground, solid ground, terra firma Note: not necessarily all the nodes in these sub-trees need to be part of the space domain. For example, the descendants of artifact, like, article, anachronism, block, etc. are not.

  27. INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO Analysis Mountain River Hill Stream • the well defined elevated land • formed by the geological formation (where geological formation is a natural phenomenon) • altitude in general >500m • the well defined elevated land • formed by the geological formation, where geological formation is a natural phenomenon • altitude in general <500m • a body of water • a flowing body of water • no fixed boundary • confined within a bed and stream banks • a body of water • a flowing body of water • no fixed boundary • confined within a bed and stream banks • larger than a brook

  28. INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO Synthesis Landform Natural depression Oceanic depression Oceanic valley Oceanic trough Continental depression Trough Valley Natural elevation Oceanic elevation Seamount Submarine hill Continental elevation Hill Mountain Body of water Flowing body of water Stream Brook River Stagnant body of water Pond * each term in the above has gloss and is linked to synonym(ous) terms in the knowledge base

  29. INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO Facets and sub-facets • Space [Domain] • by geographical feature [Entity class] • by water formation • by land formation • by land • by administrative division • … • by relations [Relation] • spatial relation • direction, internal, external, longitudinal, sideways, etc. • functional relation (e.g., primary inflow, primary outflow) • … • by attribute • [Datatype attribute] • latitude • Longitude • dimension • … • [Descriptive attribute] • Natural resource • Architectural style • Time zone • ph • History • … Log-in: http://uk.disi.unitn.it/resources/html/UKDomain.html

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