LDK R Logics for Data and Knowledge Representation Towards Infrastructure, Methodology and Principles for Ontology Development Fausto Giunchiglia and Biswanath Dutta Fall

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

Knowledge Representation (KR)  “…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 3 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., Knowledge Representation Properties INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

Knowledge Representation Issues  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? 5 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

Ontology  “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 6 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

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

Domain  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,… 8 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

Domain (contd…)  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 9 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

Facet  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. INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

DERA  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 11 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

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

Domain (D)  A DERA domain is a tuple of, D = 13 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

Entity (E)  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 =  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. 14 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

Entity (E) (contd…)  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, INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

Entity (E) (contd…)  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, INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

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

Relation (R)  An elementary component consists of classes defining the relations between entities 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. 18 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

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

Attribute (A) (contd…)  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):  45 0 N, 18 0 S  altitude (of a mountain):  8000ft, 2400m.  high, low  depth (of a lake):  deep, shallow  100ft., 20m. 20 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

Attribute (A) (contd…)  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)  ………………. 21 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

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

Methodology  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 23 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

Ontological Principle 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 24 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

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

Step 1: identification of the atomic concepts (2)  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. 26 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

HillStream River 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 Mountain Analysis 27 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO

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

 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  … Facets and sub-facets 29 INTRODUCTION :: DOMAN :: FACET :: DERA :: MAPPING :: METHODOLOGY :: PRINCIPLE :: DEMO Log-in: