o n t o p e d i a the identity of everything identity steve pepper [email protected] oslo...
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O N T O P E D I AThe Identity of Everything
Identity
Steve [email protected]
Oslo University College, 2008-10-27
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O N T O P E D I AThe Identity of Everything
Course agenda
Week 37 – 09-08 Introduction to Topic Maps – Part 1 Week 38 – 09-15 Creating a topic map Week 39 – 09-22 Introduction to Topic Maps – Part 2 Week 42 – 10-13 Modelling issues (LTM) Week 43 – 10-20 Ontology-driven editing Week 44 – 10-27 Identity Week 48 – 11-24 (Semantic Web)
– Move to end of Week 47???
Terminology:– Topic Maps: The technology and the standard
– topic maps: The artefacts (documents) we create
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O N T O P E D I AThe Identity of Everything
Today’s agenda
Identity– Subject identifiers and subject descriptors
– (subject locators)
– (item identifiers)
Discussion of group projects
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O N T O P E D I AThe Identity of Everything
Identity: The all-important issue
What makes merging possible?– NOT the use of names, which are notoriously unreliable
– Names are not unambiguous (the homonym problem)
– Many topics have multiple names (the synonym problem)
Achievement of the collocation objective– Only possible through the use of unique global identifiers
The issue of identification of subjects is therefore crucial
– If subjects have unique identifiers, people can be free to use whatever names they like – and machines can still aggregate information
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O N T O P E D I AThe Identity of Everything
Subjects and Topics
Topics are surrogates, or “proxies” (inside the computer) for the ineffable subjects that you want to talk about, such as Puccini, love, these slides, or the second law of thermodynamics
A subject in the real world
TA topic in the computer domain
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O N T O P E D I AThe Identity of Everything
The identity of subjects
Topics exist in order to allow us to talk about subjects
– The relationship between the two is sometimes called intentionality
We need to know exactly which subject a topic represents
– That is, we need to establish its subject identity
– The collocation objective depends on knowing when applications are talking about the same thing
Lucca
Tosca
Puccini
MadameButterfly
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O N T O P E D I AThe Identity of Everything
Life, the Universe and Everything
The Computer Domain
The Topic Map Domain
Subject identifiers
The identity of most subjects can only be established indirectly
– An information resource can provide an indication of the subject’s identity to a human
– Such a resource is called a subject descriptor
A subject descriptor has an address,even though the subject it indicatesdoes not
– Computers can use the address of thesubject descriptor to establish identity
– Such addresses are calledsubject identifiers
Subject descriptors and subject identifiers are the two sides ofthe human-computer dichotomy
subject
Giacomo Puccini, Italian composer, b. Lucca 22nd Dec 1858, d. Brussels, 29th Nov 1924. Best known for his operas, of which Tosca is the most . . .
subject descriptor
Puccini
http://
psi.o
ntoped
ia.n
et/P
uccin
i
subject identifier
topic
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O N T O P E D I AThe Identity of Everything
Published Subjects
In order for identifiers to be reused, they must made publicly available
– A subject identifier that has been made available for use outside one particular application is called a published subject identifier (PSI)
– Its descriptor is called a published subject descriptor (PSD)
Anyone can publish PSI sets– Adoption of PSI sets will be an evolutionary process based on trust
– It will lead to greater and greater interoperability – between topic map applications, between Topic Maps and RDF, and across information and knowledge management in general
– Check out http://psi.ontopedia.net (under development)
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O N T O P E D I AThe Identity of Everything
Advice on subject identifiers
Always use them for your typing topics– Makes your ontology more portable
The more serious your application, the more extensively you should use them for instances
– Merging with other topic maps will not be successful without identifiers
LTM code for subject identifiers– See previous lecture and opera.ltm
– Example:– [composer = "Composer"
@"http://psi.ontopedia.net/Composer"]
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O N T O P E D I AThe Identity of Everything
Identifiers
Use an identifier for every typing topic– Use the prefix http://psi.ontopedia.net/– Reuse existing identifiers wherever possible
Choice of suffix for topic types and role types:– A short name, preferably the same as Wikipedia uses– Start with a capital letter; accented letters are OK– Replace spaces by underscores– Examples: Composer, Fairy_tale, Work_of_art, Place
For association types, occurrence types and name types:– Use a verb (association types) or a noun (occurrence and name types)– Start with a lower-case letter (to indicate a property)– Examples: composed_by, date_of_birth, given_name
Check Norwegian Opera for examples– Do not use the Italian Opera Topic Map – its conventions are outdated
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O N T O P E D I AThe Identity of Everything
More tips for your ontology
Provide a description for every topic type:– Give a short definition– Comments (if necessary) on the way in which the type is (intended to be)
used in the topic map– http://www.ontopedia.net/omnigator
For examples of recommended best practice– Refer to the Norwegian Opera Topic Map
See http://www.ontopedia.net/NorwegianOpera/ontology.jsp
– Use the Omnigator version listed under Topic Maps at www.ontopedia.net Download it to your machine using the Export plug-in
– This query lists all subject identifiers for typing topics:
select $TYPE, $SID from{ instance-of($T, $TYPE) | type($T, $TYPE) },subject-identifier($TYPE, $SID)order by $TYPE?
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O N T O P E D I AThe Identity of Everything
Role types
select $AT, $RT1, $RT2 fromassociation-role( $A, $R1 ),association-role( $A, $R2 ),type($A, $AT),type($R1, $RT1),type($R2, $RT2),$R1 /= $R2order by $AT?
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O N T O P E D I AThe Identity of Everything
Project Groups
African Nations Cup 2008African WritersDILL ProgramHIO DatabasesNorwegian Feature FilmsThe Nobel Prize
Topic Maps BibliographyTopic Maps ToolsWhisky
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O N T O P E D I AThe Identity of Everything
Groups
A. Phuong, Nga, Szu-PingHIO Databases
B. Andrea, Juan-Daniel, Mehrnoosh, SaraDILL Program
C. Pussadee, Roriana, WachirapornNobel Prizes
D. Nickson, Florence, MonicaTopic Maps Bibliography
E. Alice, Barulaganye, EstherAfrican Writers
F. Muluken, YibeltalTopic Maps Tools
G. Anja, Clara, Kanita, TrudeNorwegian Feature Films
H. Isaac, WilfredAfrican Nations Cup
J. ChristianWhisky
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O N T O P E D I AThe Identity of Everything
Semester Assignment
The assignment is to create a topic map using Ontopoly.It will be judged on the following criteria:
– Accuracy of modelling type hierarchy other hierarchies appropriate role types appropriate naming
– Consistency of names assertions
Appropriate size:
– Topics: 250–1,000 TTs: 10–35
– Associations:500–2,500 ATs: 10–45
– Occurrences:500–2,500 OTs: 10–25
– Degree of interest sufficient number of topics rich set of interconnections large number of interesting
occurrences of different types
– Documentation every typing topic should have
a PSI and a description
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O N T O P E D I AThe Identity of Everything
Statistics from 2007
Including system types
Excludingsystem types Total TAOs
Topic Map TT AT OT TT AT OT Topics Assocs Occs
Beethoven’s Concerti 34 20 17 19 12 12 297 513 571
Dante's Inferno 30 23 19 15 15 14 701 1334 950
Digital Libraries 30 33 31 15 25 26 289 803 929
Dog Breeds 25 17 17 10 9 12 325 1756 1681
Donald Duck 25 37 17 10 29 12 281 955 678
Historical Monument 31 17 15 16 9 10 284 450 470
JLI Faculty 33 25 20 18 17 15 234 517 381
Christiania Bohemians 28 25 18 13 17 13 597 1147 1561
Norwegian Christmas 50 51 21 35 43 16 987 2312 2239
StreetStyle 33 24 19 18 16 14 480 987 562
Wine 33 25 16 18 17 11 413 1024 1120
Averages 32 27 19 17 19 14 444 1073 1013
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O N T O P E D I AThe Identity of Everything
Home assignment
Finalize the ontology– Document it by providing a short description of each typing topic
– Send me the XTM file by email before November 3
Populate the topic map– Make a note of any issues that arise for discussion in class on
November 10
Prepare a presentation– Thesis seminar: November 28