The document discusses the Semantic Web and ontologies. It begins by explaining that the current web was built for humans, not machines, and the Semantic Web aims to make data machine-readable to allow computers to work on our behalf. It then discusses ontologies as a formal specification of a shared conceptualization of a domain that introduces vocabulary and specifies meaning. Finally, it provides examples of how the Semantic Web could enable applications and intelligent agents to interact with distributed data sources.

1. Semantic Web and Ontology
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2. Knowledge and
Data Collections
Facilitates
Knowledge-to-
Knowledge
interaction
Web of Knowledge (Semantic Web, Web 3.0)
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3. Communication between people
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4. Towards the Semantic Web
• WWW now
– Humans do everything
– Computers as tools
– Problems abound
• WWW in the future
– Computers do a lot
more
– Computers work on
our behalf
– Fewer problems…
How do we get there…?
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5. The More or Less Global Agreement about Standard
Terminology and Conceptual Hierarchy for a Domain
Description is Necessary for the Interoperability in the
Intelligent Web
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6. Motivation: machine-friendly data
• Natural Language
• XML – represent structures
• Semantic Web - represent more semantics
– represent structures
– enable common vocabulary
– associate symbols with logic interpretation for
inference
Li Ding is a person
<person>Li Ding</person>

<>  </>
as seen by a person
as seen by a person as seen by a machine
as seen by a machine
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7. Where we are Today: the Syntactic
Web
[Hendler & Miller 02]
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8. i.e. the Syntactic Web is…
• A place where
– computers do the presentation (easy) and
– people do the linking and interpreting (hard).
• Why not get computers to do more of the hard
work?
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9. Today’s Web
• Currently most of the Web content is suitable
for human use.
• Typical uses of the Web today are
information seeking, publishing, and
searching for people and products, shopping,
reviewing catalogues, etc.
• Dynamic pages generated based on
information from databases but without
original information structure found in
databases.
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10. What is the (Proposed) Solution?
Now... that should clear up a few things around here
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11. Semantic Web: Motivation & Features
• Current WWW was built for humans, not for machines
• Hyperlinks with meaning
– agents can navigate the WWW by following semantic
links
• What will happen when data comes with semantics?
– data from different sources can be combined
• new, perhaps unforeseen opportunities and
functionality will result
– machines can meaningfully use the WWW and
perform tasks on our behalf (“machine-
understandable” content)
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12. –“An extension of the current Web in which
information is given well-defined meaning,
better enabling computers and people to
work in cooperation.”
• Sir Tim Berners-Lee et al., Scientific American, 2001:
tinyurl.com/i59p
–“…allowing the Web to reach its full
potential…” with far-reaching consequences
–“The next generation of the Web”
What is the Semantic Web?
Scientific American Article 2001
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13. Some Definitions from the W3C
“The Semantic Web is the representation of
data on the World Wide Web. It is a
collaborative effort led by W3C with
participation from a large number of
researchers and industrial partners. It is
based on the Resource Description
Framework (RDF), which integrates a variety
of applications using XML for syntax and URIs
for naming.”
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14. Semantic Web Layers
Web
Aspect
Semantic
Aspect
HTTP
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15. The Semantic Web Vision
Semantic Web
Turning the WWW into a machine
understandable knowledge base
Ontologies
Knowledge
Markup
Intelligent
Agents
Applications
Documents
Databases
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16. What is an Ontology?
A model of (some aspect of) the world
• Introduces vocabulary
relevant to domain, e.g.:
– Anatomy
– Cellular biology
– Aerospace
– Dogs
– Hotdogs
– …
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17. What is an Ontology?
A model of (some aspect of) the world
• Introduces vocabulary
relevant to domain
• Specifies meaning (semantics)
of terms
Heart is a muscular organ that
is part of the circulatory system
• Formalised using suitable logic
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18. Studer(98): Formal, explicit specification of a shared conceptualization
Machine
readable
Concepts, properties,
functions, axioms
are explicitly defined
Consensual
knowledge
Abstract model of
some phenomena
in the world
What is an ontology?
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19. Ontologies – Example
OntologyF-Logic
similar
city
NeckarZugspitze
Geographical Entity (GE)
Natural GE Inhabited GE
countryrivermountain
instance_of
Germany
BerlinStuttgart
is-a
flow_through
located_in
capital_of
flow_through
flow_through
located_in
capital_of
367
length (km)
2962
height (m)
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20. SW: Use cases
Booking a flight
Interaction between office computer, flight company, travel agency, shuttle services, hotel,
my calendar
Finding a restaurant
Interaction between mobile device, map service, recommendation service, restaurant
reservation service
Web search
Combining information from different sources to figure out whether to hire Innova
Intelligent home
Fridge knows my calendar, orders food if I am planning a dinner
Intelligent cars
Car knows my schedule, where and when to get gas, how not to
hit other cars, what are the legal regulations
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21. Role of Semantic Web
• Semantic Web representation mechanisms -
ideally suited to
– describing people and the objects that link them
together
– recording and representing the heterogeneous ties
involved.
• Semantic Web -useful platform for
– performing operations on diverse, distributed person-
and object-related data.
• Object-centered networks and user-centric
services for generating collaborative content can
serve as rich data sources for Semantic Web
applications.
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24. Semantic Web vs. Web 2.0 (Ora Lassila)
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