This document provides an overview of the semantic web stack. It defines the semantic web as an extension of the current web that gives information well-defined meaning, allowing computers and people to better cooperate. The document then outlines several layers of the semantic web stack including RDF, RDF Schema, and Ontologies. It provides examples of expressing semantics through RDF triples and serializing RDF in formats like Turtle.
Forms part of a training course in ontology given in Buffalo in 2009. For details and accompanying video see http://ontology.buffalo.edu/smith/IntroOntology_Course.html
GRC Integration And Management Of Diverse Environmental Data SetsCybera Inc.
Cameron Kiddle
Research Fellow, Grid Research Centre
University of Calgary
Presented at the Cybera/CANARIE National Summit 2009, as part of the session "New Frontiers in Data Integration." This session showcased a selection of leading-edge initiatives that are breaking new ground and setting new precedents around the collection and integration of data.
Forms part of a training course in ontology given in Buffalo in 2009. For details and accompanying video see http://ontology.buffalo.edu/smith/IntroOntology_Course.html
GRC Integration And Management Of Diverse Environmental Data SetsCybera Inc.
Cameron Kiddle
Research Fellow, Grid Research Centre
University of Calgary
Presented at the Cybera/CANARIE National Summit 2009, as part of the session "New Frontiers in Data Integration." This session showcased a selection of leading-edge initiatives that are breaking new ground and setting new precedents around the collection and integration of data.
The future of the MARC format in the light of the development of RDA and the future of bibliographic control. Presented at the CCS Forum, ALA Annual Chicago, Friday, July 10, 2009.
A presentation to Digital Sparks North West's Transmissions event on 21 July 2010 [http://transmission6.eventbrite.com/].
This presentation covers Linked Data and the Semantic Web, and uses the example of companies such as TripIt to demonstrate that a little semantics can go a long way. The presentation then explores more formal approaches, such as those underway within the UK Government, and asks whether or not this is feasible in a commercial context.
The Internet is full of Web Services, everyday more and more. Some services offer API (application programming interface) that developers use to build new applications (mash-ups). One of the most known and used technology for the machine-to-machine communication is SOAP (Simple Object Access Protocol) but in the last years we can use another paradigm, ReST (Representational State Transfer). How does it work?
"Why the Semantic Web will Never Work" (note the quotes)James Hendler
This talk refutes some criticisms of the semantic web, but also outlines some research challenges we must overcome if we are to ever realize Tim Berners-Lee's original Semantic Web vision.
Neno/Fhat: Semantic Network Programming Language and Virtual Machine Specific...Marko Rodriguez
• The Semantic Web is a distributed, flexible modeling framework.
• The Semantic Web is primarily descriptive in nature. The Semantic Web is used to describe web-pages, services, systems, etc.
• Neno is an object-oriented language that was designed specifically for the Semantic Web.
• Fhat is a virtual machine represented in the Semantic Web.
• With Neno/Fhat the Semantic Web now has a procedural component. The Semantic Web now includes object methods, algorithms, and computing machines.
• The Semantic Web can be made to behave like a distributed, general-purpose computer. Not just an information repository.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
The future of the MARC format in the light of the development of RDA and the future of bibliographic control. Presented at the CCS Forum, ALA Annual Chicago, Friday, July 10, 2009.
A presentation to Digital Sparks North West's Transmissions event on 21 July 2010 [http://transmission6.eventbrite.com/].
This presentation covers Linked Data and the Semantic Web, and uses the example of companies such as TripIt to demonstrate that a little semantics can go a long way. The presentation then explores more formal approaches, such as those underway within the UK Government, and asks whether or not this is feasible in a commercial context.
The Internet is full of Web Services, everyday more and more. Some services offer API (application programming interface) that developers use to build new applications (mash-ups). One of the most known and used technology for the machine-to-machine communication is SOAP (Simple Object Access Protocol) but in the last years we can use another paradigm, ReST (Representational State Transfer). How does it work?
"Why the Semantic Web will Never Work" (note the quotes)James Hendler
This talk refutes some criticisms of the semantic web, but also outlines some research challenges we must overcome if we are to ever realize Tim Berners-Lee's original Semantic Web vision.
Neno/Fhat: Semantic Network Programming Language and Virtual Machine Specific...Marko Rodriguez
• The Semantic Web is a distributed, flexible modeling framework.
• The Semantic Web is primarily descriptive in nature. The Semantic Web is used to describe web-pages, services, systems, etc.
• Neno is an object-oriented language that was designed specifically for the Semantic Web.
• Fhat is a virtual machine represented in the Semantic Web.
• With Neno/Fhat the Semantic Web now has a procedural component. The Semantic Web now includes object methods, algorithms, and computing machines.
• The Semantic Web can be made to behave like a distributed, general-purpose computer. Not just an information repository.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
1. Wissenstechnologie WS 08/09
Michael Granitzer
IWM TU Graz & Know-Center
Know Center
http://kmi tugraz at
http://kmi.tugraz.at http://www.know-center.at
http://www know center at
This work is licensed under the Creative Commons Attribution 2.0 Austria License.
To view a copy of this license, visit http://creativecommons.org/licenses/by/2.0/at/.
2. Today
The Semantic Web
h b
Stack (rep )
(rep.)
Semantics &
Ontologies
RDF S h
Schema (RDFS)
2
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WS 08/09 Wissenstechnologie @ kmi.tugraz.at
3. The Semantic Web
Stack (rep.)
Definition „Semantic Web“
The Semantic Web is an extension of the current Web in
which information is given well-defined meaning, better
enbaling computers and people to work in cooperations.
[Berners-Lee et al. 2001]
http://www.sciam.com/print_version.cfm?articleID=00048144-
10D2 1C70 84A9809EC588EF21
10D2-1C70-84A9809EC588EF21
3
http://kmi.tugraz.at
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4. The Semantic Web
Stack (rep.)
The Vision as Application Scenario
Plan a trip via the internet using your personal agent
Agent searches automatically for
Suitable flight
Suitable hotels
Alternative routes
Also, the software agent tells you why it made this decision!
4
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5. The Semantic Web
Stack (rep.)
How to Express Semantics
A small example
John Lennon
Is A
Is Member Band
The B tl
Th Beatles
Is Member
Paul McCartney Founded in
Is born in Query: all bands from England
Ist in
Liverpool England ?All bands with English artists?
Inferenz & Reasoning: 5
English i P h i
E li h artists := Person who is an artist and born in England
i db i E l d
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6. The Semantic Web
Stack (rep.)
Semantic Web Stack
a.k.a. SW Layer Cake
y
a.k.a. SW Tower
6
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7. The Semantic Web
Stack (rep.)
Semantic Web Stack
Unicode
URI
7
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8. The Semantic Web
Stack (rep.)
Semantic Web Stack
XML
XML Schema
Namespaces
8
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9. The Semantic Web
Stack (rep.)
Drawbacks of XML
9
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10. The Semantic Web
Stack (rep.)
Drawbacks of XML
No semantic/meaning of tags
Tree-like structure makes it hard to combine decentral
stored information
<Person> <lecture>
<name> x</name> <name> x</name>
/
<lecture> <Person>
… …
</lecture> </Person>
/
</Person> </lecture>
10
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11. The Semantic Web
Stack (rep.)
Semantic Web Stack
RDF
11
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12. The Semantic Web
Stack (rep.)
Goal of RDF
Description of (Web) resource via metadata
Historically focused on web sites
E t d d t „general“ resources
Extended to l“
For
Classification of resources
Classification of relationships between resources
Unambigious description
12
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13. The Semantic Web
Stack (rep.)
RDF Statements (Triples)
A small example
http://en.wikipedia.org/wiki/John_Lennon
htt // iki di / iki/J h L http://dbpedia.org/property/associatedActs
http://dbpedia org/property/associatedActs
http://en.wikipedia.org/wiki/The_Beatles
http://en.wikipedia.org/wiki/Paul_McCartney
http://dbpedia.org/property/associatedActs
rdfs:label
„Paul McCartney“
Subject
j Predicate Object
j
http://en.wikipedia.org/wiki/J http://dbpedia.org/property/a http://en.wikipedia.org/wiki/T
ohn_Lennon ssociatedActs he_Beatles
http://en.wikipedia.org/wiki/P http://dbpedia.org/property/a http://en.wikipedia.org/wiki/T
aul_McCartney ssociatedActs he_Beatles
http://en.wikipedia.org/wiki/P Rdfs:label “Paul McCartney”
13
aul_McCartney
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14. The Semantic Web
RDF – Serialisation Stack (rep.)
Turtle Example - Extended
# Define some namespaces
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix dc: <http://purl.org/dc/elements/1.1/> .
@prefix ex: <http://example org/terms/> .
<http://example.org/terms/>
<http://www.example.org/index.html>
dc:creator <http://www.example.org/staffid/85740> .
# write all statements in short form
<http://www.example.org/staffid/85740>
ex:name quot;John Smithquot;;
ex:age quot;27quot; .
14
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15. The Semantic Web
Stack (rep.)
RDF Extended Concepts
Blank Nodes
Container & Collections
Reification
Syntactical abbreviations, no extension of expressiveness
But how to define meaning?
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16. Semantics & Ontologies
Ontologies & Semantics
What is an Ontology?
Greek: „The study of being“
The being
Branch of Philosophy
W can narrow it d
We down t th d fi iti
to the definition of concepts i
f t in
the world and their relationship
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17. Semantics & Ontologies
Ontologies
What are Concepts in our purpose?
Semiotic Triangle [Ogden & Richards 1923]
Concept
Refers to
Symbolizes
Term / Word
Thing
/URI
Stands for
St d f
‚Apache‘ 17
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18. Semantics & Ontologies
Ontologies & Semantics
How to describe concepts?
Intensional Description: Conditions and properties of a
concept
Natural World: textual summary
y
Logics:
– NNecessary and sufficient conditions
d ffi i di i
– constraints on things
Extensional Description: List of all objects belonging to a
p j g g
concept
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20. Semantics & Ontologies
Ontologie (Gruber)
Definition in Computer Science
explicit specification of a conceptualization
conceptualization is an abstract, simplified view of
p , p
the world that we wish to represent for some purpose
Definitions associate the names of entities in the
universe of discourse with human readable text
human-readable
describing what the names mean, and formal axioms
that constrain the interpretation and well-formed use
of these terms
terms.
Formally, an ontology is the statement of a logical
theory
20
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21. Semantics & Ontologies
Ontologie (Gruber)
Ontologies are often equated with taxonomic
hierarchies of classes, but class definitions, and the
subsumption relation, but ontologies need not be
limited to these forms. … To specify a
forms
conceptualization one needs to state axioms that
do constrain the possible interpretations for the
d fi d terms.
defined t
21
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22. Semantics & Ontologies
Ontologie (Guarino)
Language vs. Conceptualization
An ontology is a logical theory accounting for the
gy g y g
intended meaning of a formal vocabulary, i.e. its
ontological commitment to a particular conceptualization
of the world. The intended models of a logical language
using such a vocabulary are constrained by its ontological
commitment. An ontology indirectly reflects this
commitment (and the underlying conceptualization) by
h d d d l
approximating these intended models.
an ontology is language-dependent
a conceptualization is language-independent
22
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23. Semantics & Ontologies
Ontologie (Sowa)
Formalization level of Ontologies
An informal ontology may be specified by a
catalog of types that are either undefined or
defined
d fi d only b statements in a natural l
l by t t t i t l language.
A formal ontology is specified by a collection of
names for concept and relation types organized
in a partial ordering by the type-subtype relation.
23
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24. Semantics & Ontologies
Ontologie (Obrst)
With respect to definitions of ontologies, I hope to send a portion
of a briefing I made at the Army Knowledge Management
Conference in Ft. Lauderdale late Aug/early Sept of 2004, that
takes you through the ontology spectrum, from taxonomy (weak
spectrum
and strong) to thesaurus (a strong term taxonomy) to
conceptual model (weak ontology) to logical theory (strong
ontology).
The first is unstandardized the second and third each has a
unstandardized,
set of standards associated with them, the third and fourth
have multiple representation languages supporting them,
and the last has some logic behind the representation language,
typically ranging from a description logic (OWL) to first-order
first order
logic (KIF, Common Logic) to a higher order logic.
A logical theory is a formal ontology. The others range from
informal to semi-formal. Other informal ontologies can be
document.
natural language sentences in a document The key point
about formal ontologies (logical theories) is that they are
machine-interpretable, i.e., semantically interpretable by
machine. The others are not, are only interpretable by 24
human beings, though they may be machine-readable and
machine readable
machine-processable. http://kmi.tugraz.at
WS 08/09 Wissenstechnologie @ kmi.tugraz.at
25. Semantics & Ontologies
Summary of Definitions
A Ontology is a model (of the world)
t l
A ontology d ib
describes a particular (k
ti l (knowledge) d
l d ) domain
i
A ontologie defines words/terms/signs for describing
Concepts
A ontologie puts concepts into relation to each other
A ontologie uses axioms to put constraints on particular
concepts
25
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26. Semantics & Ontologies
Components of an Ontology
Classes general things of a domain
Instances special things of a domain
R l ti
Relations b t
between thi
things
Properties of things
26
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27. Semantics & Communication Semantics & Ontologies
Why do we need Ontologies in the Web?
Java based C# based
Exchange Semantics
Intelligent Agent on the basis of an Intelligent Agent
agreed Ontology
Q: Is Paul McCartney member of a Rock Band?
27
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28. Semantics & Ontologies
Semantics & Communication
Language must allow to express the semantics in an
implementation/algorithmic independent way
Usually done via a Vocabulary
Topic oriented vocabulary (e.g. Friend of a friend)
Schema Knowledge/Terminological Knowledge
g g g
– Special vocabulary to make statements over topic oriented
vocabulary (i.e. the termonologie used in a domain)
– A general set of rules independent of the domain
– Defines the expressiveness of a language
28
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29. Semantics & Ontologies
Semantics & Communication
Example
Topic Vocabulary: Elephant, Mammal, Animal
Schema:
isSubClassOf defines an transitiv IS-A relationship
IS A
Define that: isSubClassOf(Elephant, Mammal)==true
Define that: isSubClassOf(Mammal, Animal)==true
isSubClassOf(Elephant,Animal)==true
Independent of implementation and applyable to
abritrary vocabularies:
isSubClassOf(A, B)
isSubClassOf(B, C)
isSubClassOf(A,C)==true
29
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30. Semantics & Ontologies
Semantics & Communication
Example
„Rules
Similar „Rules“ exist in natural language
Fact 1: „An elephant is a mammal“
„Mammals like for example elephants“
Fact 2: „A mammal is an animal“
Based on our formal knowledge we conclude that an
g
„elephant is an animal“.
Note: Exploitable in Ontology Learning from Text
30
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31. Semantics & Ontologies
Ontology Spectrum (McGuinness)
..or how much semantic expresses
Thesauri
“narrower Formal Frames Selected
t
term”” i
is-a (properties) Logical
Catalog/
relation Constraints
ID (disjointness,
inverse, …)
Informal Formal General
Terms/ is-a instance Value Logical
glossary Restrs. constraints
http://ontolog.cim3.net/file/work/OntologySummit2007/workshop/McGuinness_NIST-interop-ontology-summit_20070423.ppt
Originally from AAAI 1999- Ontologies Panel by Gruninger, Lehmann, McGuinness, Uschold, Welty;
– updated by McGuinness.
31
Description in: www.ksl.stanford.edu/people/dlm/papers/ontologies-come-of-age-abstract.html
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33. RDF Schema
(RDFS)
RDF Schema (RDFS)
http://www.w3.org/2000/01/rdf-schema#
http://www w3 org/2000/01/rdf-schema#
Allows to express terminological knowledge over RDF
Application of RDFS
Defines a new vocabulary for giving meaning
independent of program logic
Allows to define „lightweight“ Ontologies and basic
g g g
Reasoning capabilities
http://www.w3.org/TR/rdf-schema/
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34. RDF Schema
(RDFS)
RDF Schema & Object-Orientierted
Languages
j p
RDFS uses object-oriented Concepts:
Classes
Properties of the classes
But not classes have properties (e.g. Java)
Properties are assigned to classes:
Easier to extend vocabulary
Easier to assign properties to classes
Take care on uniqueness of Properties
q p
34
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35. RDF Schema
(RDFS)
RDF Schema
Notation
<http://www.w3.org/2000/01/rdf schema#>.
@prefix rdfs <http://www w3 org/2000/01/rdf-schema#>
@prefix rdf <http://www.w3.org/1999/02/22-rdf-syntax-ns#>.
For the following slides we define this namespace
35
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36. RDF Schema
(RDFS)
RDF Schema
Classes
rdfs:Resource Class of all resources
rdfs:Literal Class of literals (Strings)
rdf:XMLLiteral Class of XML Literals
rdfs:Class Class of classes
rdf:Property Class of properties
rdfs:Datatype Class of datatypes (e g integer etc.)
(e.g. etc )
rdf:Statement Class of RDF Statements
rdfs:Container Class of containers
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37. RDF Schema
(RDFS)
RDF Schema
Properties
rdf:type Subject is an instance of a class
rdfs:subClassOf Subject is a subclass of a class
rdfs:subPropertyOf Subject is a sub property of a property
rdfs:domain A possible class for a subject of a property
rdfs:range A possible class for an object of a property
rdfs:label human readable label of an resource
rdfs:comment human readable comment of an resource
…
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38. RDF Schema
(RDFS)
RDF Schema
Instances,
Instances Classes
Typing: Individuals are assigned to classes (multiple
assignments possible)
rdfs:Class
rdf:type
#MyBMW
#Car
rdf:type rdfs:subClassOf
rdfs:Resource
Note: Sometimes it is domain dependent what an instance is
and what not (modelling aspect) 38
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41. RDF Schema
(RDFS)
RDF Schema
Domain & Range
rdf:Domain and rdf:Range allow to specify which
classes of subjects (==domain) and which classes of
object (
bj t (==range) a property can connect
) t t
<ex:has> rdf:domain <#Car>
<ex:has>rdf:Range <rdf:Resource>
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43. RDFS Semantics
RDFS Semantics
Model theoretic
Model-theoretic semantics (subfield of formal semantics)
Entailment: Given a graph the graph is transformed according
to the rules of RDFS
Implicit knowledge (i.e. not explicitly modelled)
#Means of #Means of
Transportation Transportation
rdfs:subClassOf rdf:type
yp rdfs:subClassOf
#MyBMW
#Car #MyBMW #Car
rdf:type
rdfs:subClassOf rdf:type
df rdfs:subClassOf
df bCl Of
#BMW #BMW
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44. RDFS Semantics RDFS Semantics
Deductive Rules/Entailment
The RDF Semantics Document defines a list of 44 Entailment
Rules:
s1 K sn
if s1 K sn are valid statements, add statement s
lid dd
s
“do that recursively until the graph does not change
do change”
“this can be done in polynomial time for a specific graph”
We have means for how statements should be
interpreted
We
W can express “meaning” of URI’s using RDFS
“ i ” f URI’ i
http://www.w3.org/TR/rdf-mt/ 44
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45. RDFS Semantics RDFS Semantics
Entailment Example
u, x,
u x v …. URI‘s or Blank Nodes
URI s
u rdfs : subtype rdfs : Class.
u rdfs : subClassOf rdfs : Re source.
rdfs:subtype
rdfs:Class
#Car rdfs:subClassOf
rdfs:Resource
#Means of
u rdfs : subClassOf v. v rdfs : subClassOf x. Transportation
u rdfs : subClassOf x. rdfs:subClassOf
#Car
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rdfs:subClassOf
#BMW
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46. RDFS Semantics RDFS Semantics
Drawback/Restriction of RDF
Open world assumption: false statements must be
specified
Closed world assumption: if a statement is missing, it is
p g,
assumed to be false
No negation in RDFS possible
• ex:michael rdf:type ex:nonsmoker
• ex:michael rdf:type ex:smoker
Does not lead to a contradiction!
No l
N rules over individuals e.g. ex:Humans = All
i di id l H
ex:Women and All ex:Men
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No Counting: “An Elephant has 4 legs”
An legs
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47. Summary
Classes, Instances,
Ontology = Classes Instances Properties and
Relationships
RDFS as terminological vocabulary over RDF
g y
RDF Schema (RDFS):
First step in increasing semantics
No negation and restricted logic capabilities
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48. Points you should take away from this
lecture
• What are Ontologies in Computer Science?
• What adds RDFS to the semantic expressiveness of RDF
• Wh i RDFS not enough?
Why is t h?
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49. That‘s it for today…
Thanks for your attention
Questions/comments?
mgranitzer@tugraz.at
i @
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50. License
This work is licensed under the Creative Commons
Attribution 2.0 Austria License.
To view a copy of this license, visit
http://creativecommons org/licenses/by/2 0/at/
http://creativecommons.org/licenses/by/2.0/at/.
Contributors:
Mathias Lux
Peter Scheir
Klaus Tochtermann
Michael Granitzer
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