Yi Hong Department of Computer Sciences University of Leicester
A Crash Course in Ontology Modelling for Archaeologists Process to
create a Slide 2 How we describe knowledge? as archaeologists
Unstructured free-form text natural language human readable, highly
expressive no universally-agreed terminology reflect individual
interpretations and explanations of archaeological evidence
Archaeology is the search for fact... not truth. If it's truth
you're looking for, Dr. Tyree's philosophy class is right down the
hall. Indiana Jones Slide 3 How we describe knowledge? as computer
scientists Formal Specification programming language, metadata
machine readable and executable controlled vocabulary, Limited
expressivity well-defined, highly uniform mathematical symbols and
notations Computer language design is just like a stroll in the
park. Jurassic Park, that is. -Larry Wall inventor of Perl Slide 4
How people structure data traditionally.. Slide 5 Traditional
Identified/linked by Relational Database approach Table Fields
Record Primary/Foreign Keys row values Slide 6 Form List fields
(columns) Group fields Link tables(foreign keys) Relational
Database approach Add records Step 1. paper-based or electronic
form Create tables & columns Process to create a database Slide
7 Relational Database approach Inventory Number, Excavation Date,
Site name, Site description, Material, Weight, Catalog, Images,
Object Description Step 2. List all fields Form List fields
(columns) Group fields Link tables(foreign keys) Add records Create
tables & columns Process to create a database Slide 8
Relational Database approach o Object o Inventory Number o
Excavation Date o Material o Weight o Catalog o Images o Object
description Step 3. Group fields, give a group name o Site o Site
name o Site description . Form List fields (columns) Group fields
Link tables(foreign keys) Add records Create tables & columns
Process to create a database Slide 9 Relational Database approach
Form List fields (columns) Group fields Link tables(foreign keys)
Add records Create tables & columns Step 4. create tables,
columns Process to create a database Slide 10 Relational Database
approach Form List fields (columns) Group fields Link
tables(foreign keys) Add records Create tables & columns Step
4. create tables, columns with MS Access tables, fields (columns)
primary-foreign key pairs Process to create a database Slide 11
Relational Database approach Form List fields (columns) Group
fields Link tables(foreign keys) Add records Create tables &
columns Step 4. Data entry Process to create a database Slide 12
Example Relational Database Design Ontology Modeling Scenario :
Requirement: (1)Every course module can only be taught by one
Lecturer (2)A Lecturer can teach many courses.. (3)An student must
enrol in at least 3 courses. (4)Max enrolment number for a course
is 100. Design a data structure for Course Modules Selection *
Every student has a unique student ID * Every staff has a unique
staff ID Slide 13 Relational Database Approach Form 2 (Lecturer)
Form 3 (Student) Student Course Lecturer Student IDName. Course
IDCourse Name. Staff IDName. ModuleSelection Course IDStaff
IDStudent ID Form 1 Course List Tables * Many to many relation
Slide 14 Think Ontologically Slide 15 Ontology 15 An ontology is a
formal specification of a conceptualization Thomas Gruber Slide 16
Relational Database vs Ontological Database Schema (SQL) (table,
field) Ontology (RDF/OWL) (class, property) RecordsTriples/ axioms
Define Structure Basic elements Products/ Editor Relational DB
OntoDB (Triple store) Microsoft Access, FileMaker, Oracle, MySQL
etc Protge, SWOOP Virtuoso, Jena SDB, TDB etc. Slide 17 Closed
world assumption Web Ontology Language Open world assumption Assume
knowledge is completed everything we dont know is false Assume
knowledge is incompleted everything we dont know is undefined Yi
eats chicken tikka boiled rice potato salads tofu Can vegetarian
eat Tofu? Question: No OWA Data Vegetarian: someone who does not
eat meat. We know Alessandro eats pasta boiled rice potato salads
hash browns YiAlessandro Closed world assumption No Yes No
Undefined Vegetarian? Open World Assumption (OWA) Slide 18 Think
Ontologically Ontology Outside the box Identified/linked by Class
Property Individual (URI) Uniform Resource Identifier Instance
ofrestrict has value for Slide 19 Class (Concept) Think
Ontologically Class (Concept) A template of definition of a
particular kind of object Identify domain concepts Identify
properties Add triples Object properties Data type properties
Organise classes into hierarchies Slide 20 Class (Concept) A
template of definition of a particular kind of object e.g. Person,
Ceramic Pot, Excavation Site, Color Think Ontologically Identify
domain concepts Identify properties Add triples Object properties
Data type properties Organise classes into hierarchies Slide 21
Describe Class with Description Logic Think Ontologically
Description Logic Circular terracotta loom weight Excavation site
Settlement Examples Slide 22 Individual Individual (object)
Individuals are instance of class Red is an instance of Color
Example: Instance of RedColor Think Ontologically Identify domain
concepts Identify properties Add triples Object properties Data
type properties Organise classes into hierarchies Slide 23
Individual Individual (object) Individuals are instance of class
Alessandro is an instance Person Example: Instance of
PersonAlessandro Think Ontologically Identify domain concepts
Identify properties Add triples Object properties Data type
properties Organise classes into hierarchies Slide 24 Individual
Individual (object) Individuals are instance of class A two holes
disc loom weight found at Satriano is an instance of loom weight
Example: Instance of Think Ontologically Identify domain concepts
Identify properties Add triples Object properties Data type
properties Organise classes into hierarchies Slide 25 Class
Hierarchy Class hierarchy (subclass: IS A relationship)
-Vessel(Bowl) - Ceramic vessel - wooden vessel Vessel(Bowl) wooden
vessel Ceramic vessel sub class of Think Ontologically Identify
domain concepts Identify properties Add triples Object properties
Data type properties Organise classes into hierarchies Vessel(Bowl)
Ceramic vessel Wooden vessel supercalss subclass Slide 26 Class
Hierarchy Class hierarchy Female Craft worker sub class of Craft
workerWoman sub class of multiple inheritance Think Ontologically
Identify domain concepts Identify properties Add triples Object
properties Data type properties Organise classes into hierarchies
Slide 27 Class Hierarchy Class hierarchy sub class of ManWoman sub
class of multiple inheritance Disjoined class Think Ontologically
Identify domain concepts Identify properties Add triples Object
properties Data type properties Organise classes into hierarchies
?? Slide 28 Think Ontologically Common mistakes in organising class
hierarchy Example: Ontology for Education .. Sub class relationship
must be is a relationship UoL is an indiviual of class University,
not a class .. University Staff Student University University of
Leicester University of Glasgow National University Private
University Person Staff Student (1)(2) Slide 29 Property an element
that takes a value and is associated with an object. It defines
attributes of a concept and relations between concepts. Data type
property Object property e.g. Person, Excavation Site, Ceramic Pot,
Color Class hierarchy (sub class) -Vessel(Bowl) - Ceramic vessel -
wooden vessel Think Ontologically Identify domain concepts Identify
properties Add triples Object properties Data type properties
Organise classes into hierarchies Slide 30 Data Type Property Data
type property (attribute) A Data type property is an element that
takes a value and is associated with an object (properties for
which the value is a data literal) e.g. Person, Excavation Site,
Ceramic Pot, Color Class hierarchy (sub class) -Vessel(Bowl) -
Ceramic vessel - wooden vessel String Number Date Think
Ontologically Identify domain concepts Identify properties Add
triples Object properties Data type properties Organise classes
into hierarchies Slide 31 Data Type Property Data type property
(attribute) A Data type property is an element that takes a value
and is associated with an object (properties for which the value is
a data literal) e.g. Person, Excavation Site, Ceramic Pot, Color
Class hierarchy (sub class) -Vessel(Bowl) - Ceramic vessel - wooden
vessel e.g. Ceramic Pot Weight: 1.4kg Description: Beautiful Year
of Excavation: 1980 Think Ontologically Identify domain concepts
Identify properties Add triples Object properties Data type
properties Organise classes into hierarchies Slide 32 Object
Property (relation) An Object property is a direct binary relation
between two classes e.g. Person, Excavation Site, Ceramic Pot,
Color Class hierarchy (sub class) -Vessel(Bowl) - Ceramic vessel -
wooden vessel Pot was found at Site owned by Person Think
Ontologically Identify domain concepts Identify properties Add
triples Object properties Data type properties Organise classes
into hierarchies Slide 33 Property Property hierarchy e.g. Person,
Excavation Site, Ceramic Pot, Color Class hierarchy (sub class)
-Vessel(Bowl) - Ceramic vessel - wooden vessel Think Ontologically
Identify domain concepts Identify properties Add triples Object
properties Data type properties Organise classes into hierarchies
has parent has mother has father Slide 34 Domain & Range
Property Domain: A domain of a property limits the individuals to
which the property can be applied. Range: The range of a property
limits the individuals that the property may have as its value e.g.
Person, Excavation Site, Ceramic Pot, Color Class hierarchy (sub
class) -Vessel(Bowl) - Ceramic vessel - wooden vessel Think
Ontologically Identify domain concepts Identify properties Add
triples Object properties Data type properties Organise classes
into hierarchies Slide 35 Domain & Range Property Domain: A
domain of a property limits the individuals to which the property
can be applied. Range: The range of a property limits the
individuals that the property may have as its value ArtefactPerson
owned by teaches Teacher Student domain range Think Ontologically
teaches Slide 36 Domain & Range Property Domain: A domain of a
property limits the individuals to which the property can be
applied. Range: The range of a property limits the individuals that
the property may have as its value Class Person Domain & range
can be the same class Is a friend of Think Ontologically Slide 37
Cardinality cardinality specifies the occurances of a relationship
A property can have: Exact cardinality Min cardinality Max
cardinality Think Ontologically Univ Staff Mother [email protected]
has_CFS _Id child min 1 exactly 1 Bus max 60 has_child
has_passenger Slide 38 Inverse Property Property Inverse Property
One property may be stated to be the inverse of another property.
If the property P1 is stated to be the inverse of the property P2,
then if X is related to Y by the P2 property, then Y is related to
X by the P1 property Pot Person (P1) owned by (p2) hasChild Child
(P2) has_personal_belongings (p1)hasParent Parent Think
Ontologically Slide 39 Characteristics of a property Property Data
Type Property Object Property Functional Property Transitive
Property Symmetric Property InverseFunctional Property Slide 40
Characteristics of a property If John has a driving licence (No.)
Functional Property has husband biologicalMotherOf Inverse
Functional Property Slide 41 Characteristics of a property
Transitive Property is part of overlaps with Symmetric Property is
part of Early Bronze Age Bronze Age is part of EBA 1 3300 3000 BC
3300 - 2100 BC 3300 - 1200 BC Iron Age Roman period overlaps with
Slide 42 Many other properties . http://www.w3.org/TR/owl-ref/
Slide 43 Triple Triple (RDF triple) A Triple is conventionally
written in the order subject, predicate, object. The predicate is
also known as the property of the triple. e.g. Person, Excavation
Site, Ceramic Pot, Color Class hierarchy (sub class) -Vessel(Bowl)
- Ceramic vessel - wooden vessel Identify domain concepts Identify
properties Add triples Object properties Data type properties
Organise classes into hierarchies Slide 44 Triple Outside the box
e.g. Person, Excavation Site, Ceramic Pot, Color Class hierarchy
(sub class) -Vessel(Bowl) - Ceramic vessel - wooden vessel Subject
Predicate Object Basic element contains three parts: subject,
predicate and object. Individual Property Slide 45 Triple Triple
Graph A set of triples become a graph An ontology-based database is
a graph house was destroyed by fire Populating ontology Slide 46
Example Scenario : Requirement: (1)Every course module can only be
taught by one Lecturer (2)A Lecturer can teach many courses.. (3)An
student must enrol in at least 3 courses. (4)Max enrolment number
for a course is 100. Design a data structure for Course Modules
Selection * Every student has a unique student ID * Every staff has
a unique staff ID Slide 47 Ontological approach Student Course
Lecturer Identify concepts Slide 48 Ontological approach Student
Course Lecturer Organise classes into hierarchies Slide 49 Making
relationships explicit and clear Student Course Lecturer Person
Organise classes into hierarchies Enable reuse of domain knowledge
Slide 50 Student Course Lecturer Ontological Approach Person Enable
reuse of domain knowledge Ontological approach Can be taken from
other ontology Slide 51 Student Course Lecturer Ontological
Approach Person Add Data Type Property Name Staff ID Student ID
Course ID Ontological approach Slide 52 Ontological Approach
Student Course Lecturer Person Name Staff ID Student ID Course ID
Ontological approach Add Object Property Slide 53 Ontological
Approach Student Course Lecturer Person Name Staff ID Student ID
Course ID Ontological approach Object Property Slide 54 Ontological
Approach Student Course Lecturer Person Ontological approach Object
Property Add ObjectProperty Slide 55 Ontological Approach Student
Course Lecturer Person teaches Ontological approach Object Property
Add ObjectProperty Slide 56 Ontological Approach Student Course
Lecturer Person teaches Ontological approach enrol in Object
Property Add ObjectProperty Slide 57 Ontological Approach Object
Property Student Course Lecturer Person teaches enrol in
Ontological approach Add ObjectProperty Slide 58 Ontological
Approach Object Property Student Course Lecturer Person teaches
enrol in is taught by has registered student Add Inverse Property
Ontological approach Slide 59 Ontological Approach Object Property
Student Course Lecturer Person teaches enrol in is taught by has
registered student =1 min. 3 max. 100 =1 Specify cardinality
Ontological approach Slide 60 Ontological Approach Object Property
Student Course Lecturer Person teaches enrol in is taught by has
registered student (functional) (inverseFunctional) =1 min. 3 max.
100 =1 Identify type of property Ontological approach Slide 61
Ontological Approach Object Property Student Course Lecturer Person
teaches enrol in is taught by has registered student (functional)
(inverseFunctional) =1 min. 3 max. 100 =1 Done! Ontological
approach Slide 62 Ontological Approach Add triple course lecturer
student L1 C1 enrol in teaches Ontological approach Slide 63
Ontological Approach Add triple L1 C1 Ontological approach teaches
course lecturer student enrol in teaches Slide 64 Ontological
Approach Add triple L1 C1 S1 Ontological approach teaches course
lecturer student enrol in teaches enrol in Slide 65 Why use
ontology? Ontological Approach Add triple L1 C1 C2 C3 C4 C5 L2 S1
S2 S3 Ontological approach course lecturer student enrol in teaches
Slide 66 Explore implicit relationship Ontological Approach
Reasoning L1 C1 S1 studied under the supervision of if Student S
studies course C if Lecturer L teaches course C course lecturer
student enrol in teaches Slide 67 Explore implicit relationship
Deductive reasoning Reasoning L1 C1 S1 studied under the
supervision of if Student S enrolled in course C AND Lecturer L
teaches course C THEN Student S studied under the supervision of L
(?s rdf:type Student) (?s rdf:type Student)(?s enrolled ?c) (?l
teaches ?c) (?s studies_under the supervision of ?l) teaches
enrolled studied under the supervision of course lecturer student
enrol in teaches Slide 68 Classification Class hierarchy Reasoning
L1 C2 C1 C2 Student Lecturer Person Lazy Lecturer Hardworking
Lecturer C2 Define Hardworking Lecturer: A Lecturer who teach more
than 4 courses using Description Logic Class(Hardworking Lecturer,
subClassOf(Restriction(hasCourse, min-cardinality(4)))) course
lecturer student enrol in teaches Slide 69 69 Ontology Editor
http://protege.stanford.edu/ Protg Download Protge 3.4.7
http://protege.stanford.edu/download/r egistered.html
http://protege.stanford.edu/download/r egistered.html Download
example in this slide: http://www.tracingnetworks.ac.uk:443/
wiki/index.php/File:Course.owl.zip
http://www.tracingnetworks.ac.uk:443/
wiki/index.php/File:Course.owl.zip Try it?
