Semantic Web - Sharif University of Technologyce.sharif.edu/.../01-MortezaAmini-SemanticWebIntro.pdfSemantic Technology & Semantic Layer Cake 3 Introduction to Semantic Web - Morteza

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Semantic Web

Morteza Amini

Introduction to Semantic Web

Sharif University of Technology Fall 95-96

Outline

Thinking and Intelligent Applications

The World Wide Web History

The Problem with the Web

Machine-Processable Data

Semantic Technology & Semantic Layer Cake

Sharif Univ. of Tech. Introduction to Semantic Web - Morteza Amini 2

Outline








Thinking is the most important aspect of human existence: Aristotle describes Human as Rational Animals

But what is thinking? Thought or thinking generally refers to any mental or intellectual

activity. In general, thinking can be a complex process that uses concepts,

their interrelationships, and inference or deduction, to produce new knowledge.

However, thinking is often used to describe such disparate acts as memory recall, Arithmetic calculations, creating stories, decision making, and so on.

Sharif Univ. of Tech. 4 Introduction to Semantic Web - Morteza Amini


Intelligence has been defined in many different ways including, but not limited to, abstract thought, understanding, self-awareness,

communication, reasoning, learning, having emotional knowledge, planning, and problem solving.

The term intelligence can be applied to nonhuman entities as we do in the field of Artificial Intelligence (AI).

But frequently we mean something somewhat different than in the case of human intelligence.



Turing Test: Suppose there is a questioner. A machine with true intelligence will pass the Turing Test by providing responses that are sufficiently human-like that the questioner cannot determine which responder is human and which is not.

Increasingly, software applications perform tasks that are sufficiently complex and human-like that the term intelligent may be appropriate.

AI can be seen as the science of machines that behave intelligently (or simulate intelligent behavior)

The concept of intelligent applications entails the efforts to take advantage of AI technologies to enhance applications and make them act in more intelligent ways.


Outline



The Problem with the Webs





The history of the Web extends back more than 55 years.

Early signs of network architecture in the 1960s by ARPANET project. A network between universities and research laboratories.

The ARPANET was a success right from the very beginning.

Few years later, the network developed New sites (nodes) New capabilities and features (such as software) New protocols to facilitate email and file transfers



The mid-1980s marked a boom in the personal computer and superminicomputer industries.

Internet used to communicate with each other and with their customers.

By 1990, the ARPANET was decommissioned, leaving only the vast network-of-networks called the Internet with

over 300,000 hosts.

Three events fueled the Internet: the introduction of the World Wide Web, the widespread availability of the graphical browsers, the unleashing of commercialization.


The World Wide Web

World Wide Web is a system of interlinked hypertext documents accessed via the Internet. Developed by 1990. With a web browser, one can view web pages that may contain

text, images, videos, and other multimedia, and navigate between them via hyperlinks.

Some Standards and Protocols of WWW: HTTP (how to transfer data)

GET /index.html

URI (how to identify or address data) http://www.sharif.ir/

HTML (how to mark up data for human reader) <html><head><title>.....


Outline








Billions of pages with static/dynamic data representations that are designed for direct human.

Problems in: Search and retrieving documents Extracting relevant data from retrieved documents Combining information from different sources to achieve a

particular goal


Search and Retrieving Documents

How can we find some documents on a subject in this huge volume of non-specified information?

Which book is about security?


Extracting Information

What is the price of the book?


Combining Information

Where can I find the cheapest copy of “Computer Security”?


Outline







The Solution

Instead of or beside publishing static represented data in natural language, publish machine-processable data!

Publish information in terms understandable for a machine.

Ask questions in terms understandable for a machine

And: make sure all machines understand your terms!

This is what envisioned as Semantic Web.


Machine-Processable Data (1)

Publishing: B related-to A C related-to A D related-to C

Querying (give me all things related to A): ?x related-to A Answer:

?x = B ?x = C


Machine-Processable Data (2)

Publishing (related-to is transitive): B related-to A C related-to A D related-to C ?x related-to ?y and ?y related-to ?z ⇒ ?x related-to ?z

Querying (give me all things related to A): ?x related-to A Answer:

?x = B ?x = C ?x = D


Outline







Semantic Technology

Semantic Technology (by Davis's definition) semantic technology is "a collection of software standards and

methodologies that are aimed at providing more explicit meaning for the information in a computational environment".

Semantics in semantic technology is interpreted as the mapping between the structured data or concepts and the set of objects. In this way, it provides a common understanding and interpretation

about the concepts for machines and humans.

Semantic technology encodes meanings (semantics) in an abstract layer by describing the structure of the knowledge we have about them. separately from data and content files, and separately from

application code.


Semantic Web

Semantic Web= Semantic Technology + Web

According to W3C The Semantic Web provides a common framework that allows

data to be shared and reused across application, enterprise, and community boundaries

By encouraging the inclusion of semantic content in web pages, the Semantic Web aims at converting the current web,

dominated by unstructured and semi-structured documents into a "web of data“.

The term was coined by Tim Berners-Lee for a web of data that can be processed by machines.


Semantic Layer Cake (1)

The semantic layer cake provides a framework to present a variety of approaches to provide the meta-data that describe the abstract layer (semantics or meaning of underlying resources and information).

More upper layer provides more vocabulary and thus more meaning (semantics).


Semantic Layer Cake (2)

We talk more about the different layers of the semantic layer cake, during this course.

A semantic data model, which is more often used to represent and share knowledge in a distributed world using semantic technology, is ontology.

So, our main focus will be on ontologies. Ontology languages (based on Description Logics) Ontology engineering Ontology alignment and matching


Any Question... [email protected]
