Transcript Lecture 4 - The University of Texas at Dallas

Trustworthy Semantic Webs
Dr. Bhavani Thuraisingham
The University of Texas at Dallas
Lecture #4
Vision for Semantic Web
Outline
 Today’s Web
 From web to semantic web
 Applications and Technologies
 Layered Approach
 Reference: Chapter 1 of the book
A semantic web primer: Antoniou and van Harmlen
Today’s Web
 High recall, low precision: Too many web pages resulting in
searches, many not relevant
 Sometimes low recall
 Results sensitive to vocabulary: Different words even if they mean
the same thing do not results in same web pages
 Results are single web pages not linked web pages
From Today’s Web to the Semantic Web
 Machine understandable web pages
 Activities on the web such as searching with little or no human
intervention
 Technologies for knowledge management, e-commerce,
interoperability]
 Solutions to the problems faced by today’s web
- Retrieving appropriate web pages, sensitive to vocabulary etc.
- Semantic web applications including
Knowledge Management
 Corporation Need
- Searching, extracting and maintaining information, uncovering
hidden dependencies, viewing information
 Semantic web for knowledge management
- Organizing knowledge, automated tools for maintaining
knowledge, question answering, querying multiple documents,
controlling access to documents
Business to Consumer E-Commerce
 Users shopping on the web; wrapper technology is used to extract
information about user preferences etc. and display the products to
the user
 Use of semantic web: Develop software agents that can interpret
privacy requirements, pricing and product information and display
timely and correct information to the use; also provides information
about the reputation of shops
 Future: negotiation among the behalf of the user
Business to Business E-Commerce
 Organizations work together and carrying out transactions such as
collaborating on a product, supply chains etc. With today’s web lack
of standards for data exchange
 Use of semantic web: XML is a big improvement, but need to agree
on vocabulary. Future will be the use of ontologies to agree on
meanings and interpretations
Personal Agents
 John is a president of a company. He needs to have a surgery for a
serious but not a critical illness. With current web he has to check
each web page for relevant information, make decisions depending
on the information provided
 With the semantic web, the agent will retrieve all the relevant
information, synthesize the information, ask John if needed, and
then present the various options to John and also makes
recommendations
Semantic Web Technologies
 Explicit metadata
- XML, RDF, etc.
 Ontologies
 Logic
 Agents
Explicit metadata
 Metadata is data about data
 Need metadata to be explicitly specified so that different groups and
organizations will know what is on the web
 Using metadata, one can then carry out various activities such as
searching, integration and executing actions
 Metadata specification languages include XML and RDF
Ontologies
 Explicit and formal specification of conceptualization describes a
domain of discourse
 Consists of concepts and prelateships between them
 Web searches can exploit ontologies to facilitate the search process
 Ontology languages include XML, RDF, OWL
Logic
 Logic can be used to specify facts as well as rules
 New facts and derived from existing facts based on the inference
rules
 Descriptive Logic is the type of logic that has been developed for
semantic web applications
Agents
 Agents are essentially processes that have evolved from
object-oriented programming; agent is an active objects
 Agents will use metadata to find resources on the web;
ontologies will be used to interpret statements; logic will be
used for drawing conclusions
 Agents will not completely replace humans; but will make the
tasks of the humans much easier.
Semantic Web vs Artificial Intelligence
 Goal of Artificial Intelligence is to build an intelligent agent exhibiting
human-level intelligence
 Goal of the semantic web is to assist the humans in their day to day
online activities
Layered Approach: Tim Berners Lee’s Vision
www.w3c.org