WWW and Semantic Web

Chapter3 WWW and semantic web

Introduction to World Wide Web: components: URIs, HTTP. HTML

The World Wide Web (WWW) is a network framework to distribute/retrieve information resources. It relies on the following three elements:
- A uniform naming scheme for locating resources on the Web (e.g., URIs).
- An access protocol to named resources over the Web (e.g., HTTP).
- A document standard to easily navigate among resources (e.g., HTML).

HTTP: hypertext transfer protocol:

Initial request line, initial response line (status line)

Initial Request Line

• A request line has three parts, separated by spaces: a method

name, the local path of the requested resource, and the

version of HTTP being used.

• Atypical request line is:

GET /path/to/file/index.html HTTP/1.0

• GET(uppercase) is the most common HTTP method; it

says "give me this resource". Other methods include

POST and HEAD.

• The path is the part of the URL after the host name, also

called the request URI (a URI is like a URL, but more

general).

• The HTTP version always takes the form "HTTP/x.x",

uppercase.

Initial Response Line (Status Line)

• The initial response line has three parts separated by spaces:

the HTTP version, a response status code that gives the

result of the request, and an English reason phrase

describing the status code.

• Typical status lines are:

HTTP/1.0 200 OK

HTTP/1.0 404 Not Found

HTML, How to add a tag

What is a Web Page?

• Web pages are text files containing HTML

• HTML –Hyper Text Markup Language

• A notation for describing

• document structure (semantic markup)

• formatting (presentation markup)

• Looks like: A Microsoft Word document

• The markup tags provide information about the page content

structure

HTML Structure

• HTML files are just normal text files.

• They usually have the extension of .htm, .html, or .shtml.

• HTML documents havetwo parts: the head and the body.

• The head ofthedocument contains the document's title

and similar information, and the body contains most

everything else.

HTML is comprised of “elements” and “tags”

• Begins with <html> and ends with </html>

• Elements (tags) are nested one inside another.

• Tags have attributes:

• HTML describes structure using two main sections: <head>

and <body>

HTML Tags

• HTML tags are used to mark-up HTML elements

• HTML tags are surrounded by the two characters < and >

• The surrounding characters are called angle brackets

• HTML tags normally come in pairs like <b> and </b>

• The first tag in a pair is the start tag, the second tag is the end

tag

• The text between the start and end tags is the element

content

• HTML tags are not case sensitive, <b> means the same as <B>

Semantic Web

Introduction to Semantic Web

The Semantic Web is the next generation of the internet, designed to integrate various resources and devices to facilitate knowledge sharing among machines.
Its purpose is to leverage the economies of scale by enabling machines to process, integrate, and analyze information autonomously.
By specifying resources, concepts, and knowledge in a machine-readable format,
the Semantic Web allows machines to acquire and share knowledge, make decisions, and collect insights.
Examples of Semantic Web applications include intelligent personal assistants, and improved search engines that understand context and intent.

HTML, XML, RDF and OWL: compare, progressive

HTML, XML, RDF and OWL

• HTML

• HTML stands for Hyper Text Markup Language

• An HTML file is a text file containing small markup tags

• The markup tags tell the Web browser how to display the

page

• XML

• XML stands for eXtensible Markup Language

• XML is a markup language much like HTML

• XML was designed to carry data, not to display data

• XML tags are not predefined. You must define your own