SEMANTIC WEB ABSTRACT: This topic introduces one of the toughest problems that the web is facing today. Search engines now a day’s depends and search only depending on the key words. Humans are capable of using the Web to carry out tasks such as finding the Finish word for "monkey", reserving a library book, and searching for a low price for a DVD. However, a computercannot accomplish the same tasks without human direction because web pages are designed to be read by people, not mac hine s. The sema ntic web is a visi on of informa tion that is understan dable by computers, So that they can perform more of the tedious work involved in finding, sharing, and combining information on the web . Semantic Web which is machine friendly and makes the computer to know what the user wants. Once your computer can understand a person a place and event days it can help you interact with those things.This topic introduces the semantic web concepts and how to implement it using RDFa (Resource Description Framework) and foaf(friend of a friend) vocabulary on your webpage. So the Semantic Web makes our life easier by helping computers helps us get what we want. However Sema ntic Web technologies are still very much in their infancies, and the future ofthe project in general appears to be bright. Electronics & Computer Engineering, P.V.P.S.I.T 1
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SEMANTIC WEB
ABSTRACT:
This topic introduces one of the toughest problems that the web is facing today.
Search engines now a day’s depends and search only depending on the key words. Humans
are capable of using the Web to carry out tasks such as finding the Finish word for "monkey",reserving a library book, and searching for a low price for a DVD. However, a computer
cannot accomplish the same tasks without human direction because web pages are designed
to be read by people, not machines. The semantic web is a vision of information that is
understandable by computers, So that they can perform more of the tedious work involved in
finding, sharing, and combining information on the web. Semantic Web which is machine
friendly and makes the computer to know what the user wants. Once your computer can
understand a person a place and event days it can help you interact with those things.This
topic introduces the semantic web concepts and how to implement it using RDFa (Resource
Description Framework) and foaf(friend of a friend) vocabulary on your webpage. So the
Semantic Web makes our life easier by helping computers helps us get what we want.
However Semantic Web technologies are still very much in their infancies, and the future of
the project in general appears to be bright.
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1.INTRODUCTION:
Currently the focus of a W3C working group, the Semantic Web vision was
conceived by Tim Berners-Lee, the inventor of the World Wide Web. The World Wide Web
changed the way we communicate, the way we do business, the way we seek information and
entertainment – the very way most of us live our daily lives. Calling it the next step in Web
evolution, Berners-Lee defines the Semantic Web as “a web of data that can be processed
directly and indirectly by machines.”
In the Semantic Web data itself becomes part of the Web and is able to be processed
independently of application, platform, or domain. This is in contrast to the World Wide Webas we know it today, which contains virtually boundless information in the form of
documents. We can use computers to search for these documents, but they still have to be
read and interpreted by humans before any useful information can be extrapolated.
Computers can present you with information but can’t understand what the
information is well enough to display the data that is most relevant in a given circumstance.
The Semantic Web, on the other hand, is about having data as well as documents on the Web
so that machines can process, transform, assemble, and even act on the data in useful ways.
The semantic web is comprised of a philosophy, a set of design principles,
collaborative working groups, and a variety of enabling technologies. Some elements of the
semantic web are expressed as prospective future possibilities that have yet to be
implemented or realized. Other elements of the semantic web are expressed in formal
specifications. Some of these include Resource Description Framework (RDF), a variety of
data interchange formats (e.g. RDF/XML, N3, Turtle, N-Triples), and notations such as RDF
Schema (RDFS) and the Web Ontology Language (OWL), all of which are intended to
provide a formal description of concepts, terms, and relationships within a given knowledge
The vision of the Semantic Web is a “web of data” that not only harnesses the
seemingly endless amount of data on the World Wide Web, but also connects that
information with data in relational databases and other non-interoperable information
repositories, for example, EDI systems. Considering that relational databases house the
majority of enterprise data today, the ability of Semantic Web technologies to access and
process it alongside other data from Web sites, other databases, XML documents, and other
systems increases the amount of useful data available exponentially. In addition, relational
databases already include a great deal of semantic information. Databases are organized in
tables and columns based on the relationships between the data they house, and theseRelationships reveal the meaning (the semantics) of the data. Data integration applications
offer the potential for connecting disparate sources, but they require one-to-one mappings
between elements in each different data repository. The Semantic Web, however, allows a
machine to connect to any other machine and exchange and process data efficiently based on
built-in, universally available semantic information that describes each resource. In effect, the
Semantic Web will allow us to access all the information listed above as one huge database.
Semantics ?
When I searched the dictionary for the meaning of the word semantics I discovered
that it is an adjective and it meaning is as follows
1. Of or relating to meaning, especially meaning in language.
2. Of, relating to, or according to the science of semantics.
So Semantics is an adjective which gives the meaning of something. Semantics is
actually related to syntax. In most languages syntax is how you say something. Semantics isthe meaning behind what you have said. Let’s take a phrase “I Love technology” as an
example. The syntax is all the letters, words, punctuation marks in the sentence. The
semantics is what the sentence actually mean. In this case that means you enjoy learning
about and using new technology. Now if we would change the sentence using different
symbol for the word love we are changing the sentence however note that the semantics of
the sentence still the same. When you write “I ♥ technology” it still means that you enjoy
learning and using new technology.
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The Internet
When we talk about the syntax and semantics what we really talking about is
communication when you want to communicate with somebody else you use your voice to do
so. The internet created a standard way to communicate with each other. In other words itgave a voice to the computer so that they may talk to each other and exchange information.
However much like a parrot mimic you and sounds without understanding them. Computer
nearly mimic the human information to one another so while the internet enables computer to
talk to one another it was not designed to teach them what the information actually means.
The Web
When the web came along and created a very quick and easy way for us to retrieve
and view information. You can think web as a huge document storage and retrieval system.
When you put a website address into your browser so it sends the request to a website. The
request basically states that you would like the document located at the address that you gave.
The website retrieves the document and sends it back to your web browser. This document is
written in a language called HTML. The html language that defines syntax that computer can
understand. It tell the computer how to display the document to you so the two really needed
things that the web did is create a way to get any document on the internet and also created asyntax called html that is used to display the documents for you.
2.1 The Problem
Data that is generally hidden away in HTML files is often useful in some contexts, but
not in others. The problem with the majority of data on the web that is in this form at the
moment is that it is difficult to use on large scale, because there is no global system for
publishing data in such a way as it can be easily processed by anyone. Technically WWWmeans a set of protocols and languages driven by a strong standards approach namely URI,
HTTP, HTML, and HML.
The principles involved are the
1) Implementation and platform independence crucial and
2) World Wide Web consortium the most prominent.
Google –Market Cap: 72.45 $
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In comparison shopping also, the Market cap is 502.70$. Also in WWW who can you
trust to send you e-mail and how can we know for sure if a transaction really occurred. So
what’s the big deal. We have the internet that talks to each other we have the web that store
and retrieve any documents on the internet and the search engines which can find any of the
website that we want. The web is already pretty good how we are going to make it any better
the answer lies in semantics. ”Remember computer today just blindly retrieves and shows
information that’s the problem”. Computers don’t understand the meaning behind the
WebPages that they are showing us. While they may understand the syntax the semantics last
on them. Now if we can get computers to recognize what in a webpage they could learn want
they are interested in if they know that they can help us get what we want. They would
change passively helping us to actively helping us.
About 3,660,000 Results were returned....
2.2 A web of Things
This is what semantic web is all about it help the computer understand the meaning
behind the web page. The web of today is about documents where as semantic web is about
things. When I say things I mean anything, people, places, events, music, movies and just
about any concept that you think of. The semantic web is not only about pointing things out
to a computer but also about letting computers know how this are related to each other. There
are several pouncing technologies that are in use today that can embed semantics in a html
document too the more popular ways are called
1. Micro formats
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2. RDFa
RDFa
RDFa is based on RDF, RDF stands for Resource Description Framework. That’s the
fancy way of saying that it can describe any concept relationship or thing that exists in the
universe the idea RDF is sample and it does very easy to grasp. RDF has features that
facilitate data merging even if the underlying schemas differ, and it specifically supports the
evolution of schemas over time without requiring all the data consumers to be changed. RDF
extends the linking structure of the Web to use URIs to name the relationship between things
as well as the two ends of the link (this is usually referred to as a “triple”).
Using this simple model, it allows structured and semi-structured data to be mixed,
exposed, and shared across different applications. This linking structure forms a directed,
labeled graph, where the edges represent the named link between two resources, represented
by the graph nodes. This graph view is the easiest possible mental model for RDF and is
often used in easy-to-understand visual explanations. There are three things in RDF subjects,
predicates and objects. If you remember to your elementary school English classes this
should sound pretty familiar to you the subject, object and predicate approach how most
western languages create basic semantics. The subject refers to the thing you are describing
the predicate usually refers to an attribute of a thing that you are describing and the object is
the thing which you are referring to with the predicate.
Consider a basic example
“Avinash likes sweets”
In the above statement Avinash is the subject, likes is the predicate and sweets is the object.
Using this simple idea we can describe anything so that is basically what RDF enables us to
do.
URI :( Uniform Resource Identifier)
RDF uses URI’s to specify subjects and predicates. URI stands for Uniform ResourceIdentifier. And is how we Identify things on the web. You're probably already familiar with
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one form of URI: the URL or Uniform Resource Locator . A URL is an address that lets you
visit a webpage, such as: http://www.w3.org/Addressing/. If you break it down, you can see
that a URL tells your computer where to find a specific resource (in this case, the W3C's
Addressing website). Unlike most other forms of URIs, a URL both identifies and locates.
Contrast this with a "mid:" URI. A "mid:" URI identifies an email message, but it isn't able to
Some of the challenges for the Semantic Web include vastness, vagueness, uncertainty,
inconsistency, and deceit. Automated reasoning systems will have to deal with all of these
issues in order to deliver on the promise of the Semantic Web.
Vastness: The World Wide Web contains at least 24 billion pages as of this writing(June 13, 2010). The SNOMED CT medical terminology ontology contains 370,000 class
names, and existing technology has not yet been able to eliminate all semantically
duplicated terms. Any automated reasoning system will have to deal with truly huge
inputs.
Vagueness: These are imprecise concepts like "young" or "tall". This arises from the
vagueness of user queries, of concepts represented by content providers, of matching
query terms to provider terms and of trying to combine different knowledge bases with
overlapping but subtly different concepts. Fuzzy logic is the most common technique for
dealing with vagueness.
Uncertainty: These are precise concepts with uncertain values. For example, a patient
might present a set of symptoms which correspond to a number of different distinct
diagnoses each with a different probability. Probabilistic reasoning techniques are
generally employed to address uncertainty.
Inconsistency: These are logical contradictions which will inevitably arise during the
development of large ontologies, and when ontologies from separate sources are
combined. Deductive reasoning fails catastrophically when faced with inconsistency,
because "anything follows from a contradiction". Defensible reasoning and Para
consistent reasoning are two techniques which can be employed to deal with
inconsistency.
Deceit: This is when the producer of the information is intentionally misleading the
consumer of the information. Cryptography techniques are currently utilized to alleviate
Things get really exciting when we start exploring to explore the possibilities of the
semantic web. Once your computer understand a person a place and a event days, it can help
you interacting with those things 6 for example if a birthday party is marked up as an event
With a date and a place you can tell your computer to save the date in your calendar. Another
example is in the world of music blogs, Music blogs usually list songs and album reviews on
their front page. If the blog marked up the song in the artist semantic web technology you can
tell page to search the internet for other albums by the same artist. Search engines would also
become a great deal more accurate than they are today. When you search you can search for
any person, place or any particular song. Search engine could then refer to you a website with
a far more accuracy, because it wouldn’t have just depend on keyword in WebPages any
more it could also depends on the semantics on the webpage so that semantic web holds a
great deal of proms and making our life’s easier by helping computers help us get what you
want.
6.1 Web-services
Among the most important web resources on the Semantic Web are those so called web-
services. Here, web-services refers to "web sites that do not merely provide static information
but allow one to effect some action or change in the world". The Semantic Web will enable
users to locate, select, employ, compose, and monitor web-services automatically
• Automatic web-service discovery. Since semantic descriptions of web-services are
registered with some public registries, intelligent mobile agents might migrate from
one service registry to another to find desirable web-services as specified by a user.
There has been some work in agent-assisted browsing of the web. For example,
Letizia is a user interface agent that assists a user browsing the World Wide Web
based on the user's profile. Letizia can learn the profile of a user based on the user'sbrowsing history. This idea can be applied to web-service discovery as well. For
example, a server might provide web-services at different levels or with different
values towards different users, and an agent might find a web-service based on the
user's profile.
• Automatic web-service invocation. Currently most web-services require human's
intervention during their execution. For example, to buy a book
at http://www.amazon.com, the website requires a user to fill out a form, and then
click a button to execute the service. Usually, multiple interactions between a user and
a web-service are needed to complete the execution of that web-service . The
capability of automatic web-service invocation implies that a software agent will be
able to perform these invocations on behalf of a user, who only needs to tell the agent
to "go to Amazon and buy a book titled The Semantic Web with no more than $50",
and the agent will interact with the web-service with appropriate input data via
computer interpretable APIs.
• Automatic web-service composition and interoperation. Given a library of web-
services and an objective, one might be able to automatically select and compose a
new web-service to achieve the new objective. The prerequisites and consequences of
individual web-services need to be described in a formal way, and the technology for
automatic workflow generation) might be used to generate web-services
automatically.
• Automatic web-service execution monitoring. For long-running complex web-
services, it is desirable to be able to track and query the status of the execution of each
service as well as its components.
The industry has already seen the potential market enabled by web-services and some efforts
have been put to the development of standards for electronic commerce, in particular for the
description of web-services. For example, Microsoft, IBM and Ariba proposed UDDI(Universal Description, Discovery, and Integration, 2000) to describe a standard for an online
registry, and the publishing and dynamic discovery of web-services offered by businesses;
Microsoft and IBM proposed WSDL (Web Service Definition Language) as an XML
language to describe interfaces to web-services registered with a UDDI database; the DAML
Services Coalition proposed DAML-S (Darpa Agent Markup Language - Service, 2001) as
an ontology to describe web-services; and OASIS and the United Nations developed ebXML
(Electronic Business XML Initiative, 2000) to describe business interactions from a workflow
perspective. A number of communication protocols have been developed for the invocation
worth mentioning that some systems that use ontologies to enhance web search engines have
been developed. Since ontologies are built on a domain basis, web search engines might be
also built on a domain basis, and hence metasearch engines, which interface with multiple
remote search engines and select and rank remote search engines intelligently, might be very
useful.
6.4 Semantics-based digital libraries
Digital multimedia data in various formats has increased tremendously in recent years on the
Internet. With the development of digital photography, more and more people are able to
store their personal photographs on their PCs. Sharing of picture albums and home videos on
the Internet become more and more popular. Furthermore, many organizations have largeimage and video collections in digital format available for online access. Film producers want
to advertise movies through interactive preview clips. Travel agencies are interested in digital
achieves of holiday resorts photographs. Hospitals would like to build medical image
databases. These emerging applications for multimedia digital libraries require
interdisciplinary research in the areas of image processing, computer vision, information
retrieval and database management. Semantics-based retrieval of multimedia digital content
is important for efficient use of the multimedia data repositories. Traditional content-based
multimedia retrieval techniques describe images/videos based on low level features (such as
colour, texture, and shape) and support retrieval based on these features. However, human
typically does not view images/videos in terms of low-level features. A semantics-based
query capability is highly desirable. For example, one might want to formulate a query like
"return all the scenes in clip 1 in which a boy is riding a bicycles". Retrieving images/videos
based on low-level features cannot provide satisfactory results. Effective and precise
multimedia retrieval by semantics remains an open and challenging problem.
Recently, ontologies begin to be used in the context of digital libraries. For example,
ScholOnto is an ontology-based digital library that supports scholarly interpretation and
discourse, and ARION, another ontology-based digital library that supports search and
navigation of geospatial data sets and environmental applications.
We believe that various digital libraries will become another major web resource of the
Semantic Web. The challenges here are: (1) The development of efficient and effective
classification and indexing mechanism for each type of digital library, and (2) The semantic