Semantic Web

By | June 16, 2017

The web today enables people to access documents and services on the Internet but today’s methods require human intelligence. The semantic web augments the current web with formalized knowledge and well-formatted data that can be processed by computers. 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, combining, and acting upon information on the web. Data that is generally hidden away in HTML files is often useful in some contexts, but  there is no global system for publishing data in such a way that  it can  be easily processed by  anyone.  This makes Semantic Web a rational solution for the problem. This will  enable computers to assist human users  in tasks and understand data the way they cannot today. The layered architecture serves as the basic building block of the system and supports the vision of a Web imbued with meaning. The similarities that it shares with the object oriented programming language has made the Unified Modelling Language usable by both object-oriented Programming and semantic web development and the Semantic Web Browsers, extend the notion of  the Web browser into the Semantic Web. There will also be creation of more open market in information processing and computer services enabling the creation of new applications and services from combinations of existing service.


Semantics is the study of meaning. It’s as old as the ancient Greeks. For most of us it was a deadly dull sub-discipline of philosophy, to be avoided. But it turns out that we can’t avoid it. We are drowning in a sea of data which occasionally is generously referred to as information‚ but the truth is that almost all of it must be interpreted  by humans to be  of  any use. The growth and availability of data and, therefore, our need to consider it in decision-making and planning is growing exponentially, and  our systems, rather than helping with this, are for the most part contributing to the problem. The Semantic Web is  a web that is able to describe things in a way that computers can understand. The Semantic Web is not about links between web pages. The Semantic Web describes  the relationships between things (like A is a part of B and Y is a member of Z) and the properties of things (like size, weight, age, and  price). In an evolving  development of the World Wide Web  in which the meaning (semantics) of information and services on  the web  is  defined, making  it possible  for  the web  to “understand”  and satisfy  the requests of people and machines to use the web content. It derives from World Wide Web Consortium director Sir Tim Berners-Lee’s vision of the Web as a universal  medium for data, information, and knowledge exchange.

Implementing  the Semantic Web requires adding semantic  metadata, or data  that describes  data, to  information  resources. This  will  allow machines to effectively  process the data based on the semantic information  that  describes  it.  When  there  is enough  semantic information associated with data, computers can make inferences about the data, i.e., understand what a data resource is and how it relates to other data. At its core,  the  semantic web comprises  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 are yet to be implemented. 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 domain.


Humans are capable of using the Web to carry out tasks  such  as  finding  the  Finnish  word  for  “monkey”,  reserving a library book, and searching for a ow 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,  combining,  and  acting  upon  information on the web. The  idea  of  a  ‘semantic  web’  necessarily  coming  from some marking code other than simple HTML is built  on  the assumption  that  it  is not  possible  for  a machine  to  appropriately  interpret  code  based  on  nothing  but  order  relationships of letters and words. If this is not true, then it  may be possible to build a ‘semantic web’ on HTML alone,  making  a  specially  built  ‘semantic  web’   coding  system  unnecessary.

The  Semantic Web  takes  the  solution  further.  It involves publishing  in  languages  specifically designed  for  data:  Resource Description Framework (RDF),  Web  Ontology  Language  (OWL),  and  Extensible  Mark-up Language  (XML).  HTML describes documents  and  the links  between  them. RDF, OWL, and XML,  by  contrast,  can describe arbitrary things Such as people, meetings, or airplane parts. Tim Berners-Lee calls the resulting network of Linked Data  the Giant Global Graph, in contrast  to the  HTML-based World Wide Web. These  technologies  are  combined  in  order to  provide descriptions that supplement or replace the content of Web  documents.  Thus, content may manifest  itself  as  descriptive  data  stored  in Web-accessible databases, or as mark-up  within  documents  (particularly,  in  Extensible  HTML (XHTML)  interspersed with XML, or, more often, purely  in  XML,  with  layout  or  rendering cues  stored  separately).  The  machine-readable  descriptions enable content managers  to add meaning  to  the  content,  i.e.,  to   describe the structure of the  knowledge we have about that content.  In  this way, a machine  can  process  knowledge  itself,  instead  of  text,  using  processes  similar  to  human deductive reasoning and inference, thereby obtaining more   meaningful  results  and  helping  computers  to  perform  automated information gathering and research.


The common use of  the  term Semantic Web  is  to  identify  a  set  of  technologies,  tools  and  standards which  form  the  basic building  blocks  of  a system  that  could  support  the  vision  of  a Web  imbued  with meaning.  The  Semantic Web has been developing a  layered architecture,  which  is  often represented  using a  diagram  first proposed   by Tim Berners-Lee, with many variations since.

Symantec web layered architecture

Figure gives a typical representation of this diagram.

While  necessarily  a  simplification which  has  to  be  used with some caution, it nevertheless gives a reasonable conceptualisation  of  the  various components  of  the   semantic Web. We describe briefly these layers.

A. Unicode and URI:

Unicode,  the Standard  for computer   character  representation,  and  URIs,  the  standard  for identifying  and  locating resources  (such  as  pages  on  the  Web),  provide  a  baseline  for  representing  characters  used  in most of  the  languages  in the world, and  for  identifying  resources.

B.  XML:

XML  and  its  related  Standards,  such  as  Namespaces,  and  Schemas,  form  a  common  means  for  structuring data on the Web but without communicating the  meaning of  the data. These are well established within  the  Web already.

C. Resource Description Framework:

RDF is the first layer   of  the  Semantic Web  proper.  RDF  is  a  simple metadata  representation  framework,  using  URIs  to  identify  Web- based  resources  and  a  graph  model  for  describing relationships  between  resources.  Several  syntactic  representations  are  available,  including  a  standard  XML  format. RDF Schema:    a  simple  type modelling  language  for describing classes of  resources and  properties between  them  in  the  basic  RDF  model.It  provides  a  simple  reasoning framework for inferring types of resources.

D.  Ontologies:

a  richer  language  for  providing  more  complex  constraints  on  the  types  of  resources  and  their  properties.

E.  Logic  and  Proof:

an  (automatic)  reasoning  system  provided  on  top  of  the  ontology  structure  to  make  new  inferences. Thus, using such a system, a software agent can  make  deductions  as  to  whether  a  particular  resource  satisfies its requirements (and vice versa).

F. Trust:

The  final  layer  of  the  stack  addresses  issues  of  trust  that  the Semantic Web can  support. This component  has not progressed  far beyond a vision of allowing  people to  ask  questions  of  the  trustworthiness  of  the  information  on the Web, in order to provide an assurance of its quality.


A. Semantic Web Browser

Semantic Web Browsers,  extend  the notion  of  the Web  browser  into  the Semantic Web  by  allowing  the  RDF annotations of resources to be read and presented in a  structured  manner.  For  example,  the  Haystack  Web- browser  from  MIT,  it  aggregates  RDF  from  multiple  arbitrary  locations and presents it  to  the user  in a human- readable fashion, with point and click semantics that let the  user  navigate  from  one  piece  of  Semantic  Web  data  to  other, related  pieces.

A  user  can  load  RDF  annotations  from  other  websites,  and  also  catalogue  information  from  his  or  her  own  file-store or e-mail accounts. The structured  searches  can  be made  based  on  this  annotation,  and  links  between  information  can  be  created  and  presented  based  on  the  connections  between resources embodied in the RDF.

Figure  gives a typical view of Haystack in practice.


There  exist  similarities  between  the  Semantic  Web  and  object-oriented  programming  (OOP).  Both  the  semantic  web  and object-oriented programming  have  classes  with  attributes  and  the  concept  of  instances  or  objects.  Linked  Data  uses Dereference  able  Uniform  Resource  Identifiers  in  a  manner  similar  to  the  common  programming concept of pointers or “object  identifiers”  in  OOP. Dereference  able  Uris  can  thus  be  used  to  access  “data   by  reference”.  The Unified Modelling Language  is  designed  to  communicate  about  object-oriented  systems,  and can thus be used for both object-oriented programming  and semantic web development.

A. Future Development

We have  seen  in  this paper  that  there has been  significant and enthusiastic effort over the last few years to   explore  and develop  the  technology,  shared  vocabularies and ideas which are turning Tim Berners-Lees vision into  a reality. There is a long way to We have seen in this paper  that  there has been significant and enthusiastic effort over the last few years to explore go until it is a standard part of  the  Web  Infrastructure  but,  nevertheless,  there  has  been  startling  progress  in  the  last  few years.  Semantic  technologies  have  become  central  to  a  broad  range  of  research  and  development  initiatives.  This diagram visualizes  the  intersections  of  four  major  development  themes  in  the  semantic wave:  networking  (e.g., semantic web,  grid  &  p2p),  content  (e.g., knowledge  extraction, semantic  enhancement,  executable  content,  semantic search),  services  (e.g.,  composite  applications,  semantic  web services), and cognition (e.g. semantic UI, knowledge  computing, intelligent agents).

B. Challenges to the development:

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 achieve


Web  is  most  likely  to  make  an  impact:  information  management,  digital  libraries,  virtual  communities, and e-learning.

A.  Information Management:

the Semantic Web  enhances  the capabilities of those tools which form a familiar part of the  current  Web  so  that  they  can  become  useful  information management  tools  in  their own  right. A more  structured  and  directed  approach  to  managing  this  information  space,  within  institutions  can  make  this  information more useful, with less wasted effort, and more  capacity to measure the quality of information.

B.  Digital  Libraries:

the  impact  on  digital   libraries,  combined with  the Open Access  Initiative  and  the  rise  of  open  archiving  is  likely  to  be  quite  profound.  Libraries  become  ‘value-added’  information annotators and collators  rather  than  the archivists of externally published  literature and the holders of the published output of institutions.

C.  Building  communities  and  collaborations:

a  major impact  is  likely  to  occur  in  the  way  that  academic communities work  together. The  tools  for  forming  virtual communities  and  sharing information  across  that  community  are  simple  and  lightweight,  and,  if  the  development of blogs and  the use of RSS  is an  indication, can enhance the interaction of an interested community by  an enormous amount

D.  E-Learning:

all  of  the  above  can  influence  e-learning.   However, we should also consider specifically, support for the  presentation  and  delivery  of  course materials  and  for  assisting and  assessing  students. Again,  the  impact  of  the  Semantic Web  is  likely  to  mean  that  these  can  be  more  closely tailored to the needs of the user.


The Semantic Web has great potential, and with  direct  application  to  education  and  business  sector.   however, it has been a long time in development and does  require an investment of time, expertise and resources. But,  the  time does  seem  right  to  start  to  think how  best  to use  the simpler applications of the technology.

So what should institutions and industries consider  doing  now?  Institutional  libraries  should  be  considering  joining  collaborations  to  explore  how Semantic Web  can  best be investing in training staff, with a view to providing  Semantic Web solutions within the next two to three years.  Information  science professionals  and  academics working  in  particular  fields  should  work  together  to  provide  the  vocabularies  and  domain  ontologies  required  to  support  particular fields.

In  the  future  the  Semantic Web  may  not  even  be  noticeable.  The  tools  of  the  Semantic  Web  will  be  integrated  into Virtual Learning Environments and Virtual  Research  Environments  on  our  desktops,  as  well  as  in  browsers and search engines. What we will have is a richer  experience  of  IT  that  is better  able  to  deliver  the  right  information at the right time in the right way, so we can get  on with the serious business of research and teaching.

Author: Ravi Bandakkanavar

A Techie, Blogger, Web Designer, Programmer by passion who aspires to learn new Technologies every day. It has been 6 years since I have been publishing articles and enjoying every bit of it. I want to share knowledge and build a great community with people like you.

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