Semantic Web-Creation
Prof. Vidya S. Dandagi
Department of MCA
KLE DR. M.S.Sheshagiri College of Engg.& Technology, Belgaum , India
vsdandagi@yahoo.co.in
Dr. Nandini Sidnal
Department of Computer Science and Engineering
KLE DR. M.S.Sheshagiri College of Engg.& Technology,Belgaum , India
nandini.sidnal@gmail.com
Abstract—Semantic Web is a system that enables machines to
"understand" and respond to complex human requests based on
their meaning. Semantics is a study of the meaning of data. It
focuses on the relationship between the words, symbols, phrases
and signs. The Resource Description Format (RDF) is a set of
individual objects used to represent information also a set of
connections among those objects. RDF is one of the pillars of the
Semantic Web. This paper describes the creation of a semantic
web using RDF, and how it can queried using the SparQL query
language to get accurate results.
Index Terms—Resource Description Framework (RDF), SparQL,
Ontology, Semantic Web, URIs metadata.
I. INTRODUCTION
The World Wide Web is composed of documents written in
HTML (Hyper Text Markup Language). It is a language that
is useful for visual presentation. HTML contains a set of
“markup” symbols for display on the web browser .Most of
the information on the Web is designed only for human
utilization. Humans can read Web pages and understand them,
but their natural meaning is not shown in a way that allows
their interpretation by computers [1]. The present day search
engines are quite powerful, but still return irrelevant results .
Semantics is study of the meaning of data. It focuses on the
relationship between the words, symbols, phrases and signs.
The Semantic Web is a system that enables machines
to "understand" and respond to complex human requests based
on their meaning. Semantic Web is an advanced version of
existing web which claims to be a solution toward currently
faced web problem of formatting data in machine process able
format to take advantage in information retrieval [2]. The
Semantic web is a mesh of data representing meanings
through connectivity, expressing multiple viewpoints and use
business rules logic is making models to share information
across applications. The goal of the semantic web is to
structure the meaningful contents of unstructured data and
involve knowledge management in making more advanced
knowledge modeled management systems [3].
Semantic Web (SW) is defined as an extension of the
current web. The information is presented in a well-defined
manner enabling computers and people to work in
cooperation. Data in the Semantic Web is linked in a way that
can be used for more effective; it can be shared and processed
by automated tools.
A. Purpose of Semantic Web
1.
The main purpose of the Semantic Web is driving the
evolution of the current Web by enabling users to
search, distribute, and mix information more easily.
2.
The Semantic Web is a system that enables machines
to "understand" and respond to complex human
requests based on their meaning.
Web pages are designed to carry out tasks, searching
for a lowest price of a DVD, finding the French word
for a “folder”, these tasks cannot be performed
without human direction. Web pages are designed not
to be read by machines but by people.
3.
The paper is organized as follows. In section II, the
explanation of the architecture of Semantic web is discussed.
Section III deals with the explanation of tools for generating
ontology using RDF. In section IV we discuss the
implementation procedure. Results and discussions are given
in Section V. Section VI deals with the conclusion.
II. ARCHITECTURE OF SEMANTIC WEB
Interpretation by machines is the vision of the semantic web ,
so machines can carry out more of the tedious work involved
in searching combine and act upon the information on the
web. Berners-Lee's vision, the semantic network constituted
of seven levels is constituted of a layered architecture (Fig.
1).[4]
The first layer of URI and Unicode is the basis for the
structure of the entire system. Unicode is a unique number for
every character independent of the underline language.This
layer is responsible for encoding of the resources . URI is
responsible for resource identification, and allows precise
retrieval of information .
The Second layer of XML + NS (Namespace) +
XML Schema, is used to identify common syntax in semantic
web .XML namespace specifies different markup
vocabularies.
The third layer of RDF + RDF Schema, which
provides a semantic model used to describe the information on
the Web in the graph form .
The fourth layer of ontology vocabulary layer is
responsible for the definition of shared knowledge and
describes the semantic relationships between the various kinds
of information to reveal the semantic between the information
itself. Ontology provides knowledge and reusable web
content.
The fifth layer of logic layer responsible for
providing axioms and inference principles to provide the basis
for intelligent services. This layer enhances the writing of
application specific declarative knowledge .
The sixth layer of Proof to verify statements to draw
conclusion .
The seventh layer of trust is responsible for providing
authentication and trust mechanisms. To enhance web security
digital signatures and encryption technology are used to detect
changes in the document..
XML, RDF (S) and the Ontology are its core in the
Semantic web architecture.
.
Fig. 1 Architecture of Semantic Web.
III. WHAT IS ONTOLOGY?
Ontology is a formal direct description of concepts
describing various features and attributes of the concept in a
domain of discourse (classes), properties of each class
describe various features and attributes of the concept.
Ontology with a set of individual instances of classes
constitutes a knowledge base The term “ontology” is used in
different ways by different people. Pidcock writes that
“People use the word to mean different things, e.g.: glossaries
and data dictionaries, thesauri and taxonomies, schema and
data models, and formal ontologies and inference”, and
according to Uschold: “An ontology may take a variety of
forms, but necessarily it will include a vocabulary of terms,
and some specification of their meaning”. This includes
definitions and an indication of how concepts are inter-related
which collectively impose a structure on the domain and
constrain the possible interpretations of terms [5].Ontology
function is to provide the knowledge base needed for the user
to search .[6]
A. RDF
A core support for Semantic Web is Resource
Description Framework (RDF). RDF is a standard available
by W3C .RDF is a framework for representing information
about resources in a graph form. It was primarily proposed for
representing metadata about WWW resources, such as the
name, address, and modification date of a Web page, but it can
be used for storing any data. It is supported on triples subjectpredicate-object that forms a graph of data. Knowledge
represented using RDF standard is machine understandable .
[7].. Anyone can define vocabulary of terms used for more
detailed description. A RDF Schema (RDFS) is created with
its formal semantics within RDF. RDFS provides domain
specific classes and properties which are used to create
lightweight ontologies.
Knowledge can be represented so that it can be used
in a scalable form .Decomposition of knowledge into small
pieces, depending on simple rules knowing about the
semantics of these pieces . Simple and flexible, structured
enough to express any fact, that computer applications can
operate with the expressed knowledge.
The following are the key components:
• Statement
• subject and object resources
• Predicate
A statement is a given small piece of knowledge .
Knowledge (or information) is expressed as a list of
statements, each statement takes the form of SubjectPredicate-Object, and this order is never changed.
Fig. 3 Generation of Ontology using RDF.
Fig. 2 Graph structure of RDF statement
The information is stored graphically as shown below in Fig.
4.
The subject and object are names for two things in
the world, with the predicate being the name of a relation
that connects these two things. Semantic web uses RDF to
extract the relevant information by identifying subject
predicate and object.
IV. IMPLEMENTATION
The software used for the implementation is Jena,
which is the Semantic Web Framework for Java. Joseki is a
Web-based SPARQL endpoint.
Fig. 4 Information Storage.
A. Creating a Semantic Web
We have gathered information of all the staff members of
Department of Computer Science and Engineering, KLE
Dr.M.S.Sheshagiri College of Engineering and Technology,
Belgaum, and information of the doctors of the Dr. KLES
Prabhakar Kore Medical College, name ambiguity details was
entered and using SPARQL retrieved the correct page.
In Fig. 4, Person is the subject and has a predicate and the Last
Name is the object.
B. Creating the RDF for a single person
Algorithm: RDF creation.
Input:
The flow chart shown in Fig 3 is generating an ontology
using RDF, and then using SPARQL to retrieve the results.
Output:
Step-1: Start
Step-2: Create a model.
Model model= ModelFactory.createDefaultModel();
model.setNsPrefix("rdfs",RDFS.getURI());
model.setNsPrefix("foaf",FOAF.getURI());
Step-3: Create the resource for the model.
Resource subject=model.createResource
rdf:predicate
{
rdf:resource="http://xmlns.com/foaf/0.1/Group");
?Person foaf:givenname ?Givenname.
Step-4: Add the properties to the created resource.
?Person foaf:title ?Title.
subject.addProperty(FOAF.name,"Rashmi G");
subject.addProperty(FOAF.title,"Assprof.");
.subject.addProperty(RDF.type,FOAF.Person);
Step-5: Direct the output to the required file.
For Example:d://f6.rdf
Step-6: Stop.
RDF created by Single person as shown below:
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" >
<rdf:Description rdf:nodeID="A0">
<rdf:predicate
rdf:resource="http://xmlns.com/foaf/0.1/Group"/>
<foaf:mbox>Rashmi4mahendrakar@gmail.com</foaf:mbox>
<foaf:phone>9448130159</foaf:phone>
<foaf:topic>10Am-1pm</foaf:topic>
<foaf:birthday>mon-sat</foaf:birthday>
<foaf:member>CSE</foaf:member>
<foaf:name> Rashmi G</foaf:name>
<foaf:title>Assprof.</foaf:title>
</rdf:Description>
}
V. RESULTS AND DISCUSSIONS
The paper deals with creating a semantic web using RDF to
ease the process of human-computer interaction .The proposed
system used real time data collected from two colleges in
Belgaum.Information of the staff members of KLE
Dr.M.S.Sheshgiri such as name,designation,email etc,was
collected and the information of the Doctors of KLEs
Dr.Prabhakar Kore Hospital such as name ,specialization and
working hours etc,was taken and RDF is generated for all
staff members And SPARQL is used to retrieve the query
results. Taking into consideration name ambiguity the search
is more effective. For example Dr.Rashmi Medicine from
Dr.Prabhakar Kore hospital of medical college and Dr.Rashmi
from CSE department of KLE Dr.M.S.Sheshgiri.
The below figure 1 illustrates the main menu .
C. SPARQL
SPARQL is an RDF query language and data access
protocol for the Semantic Web. SPARQL is a query language
that we can use to query the RDF data content.[8]
FOAF represents a project called Friend of a Friend.
The goal of the FOAF project is to build a social network
using the Semantic Web technology so that we can do
experiments with it and build applications that are not easily
built under traditional Web [9]. The core element of FOAF
project is the FOAF ontology, a collection of terms that can be
used to describe a person: name, home page, e-mail address,
interest, and people he/she knows, etc.[10]
Anyone can create an RDF document to describe
himself/herself by using this FOAF ontology, and he/she can
join the friend’s network as well.
Triplestore is a Database Management systems for the storage
and retrieval of triples . Native Triplestore exploit the RDF
data model to efficiently store and access the RDF data .
Sample Sparql Query for Querying the RDF
prefix foaf: <http://xmlns.com/foaf/0.1/>
select *
from <c://f6.rdf>
where
Fig 1
Query if given in SPARQL as Rashmi isa Medicine then the
details of Dr.Rashmi will be retrieved. The below figure 2
shows the query entered .
Fig 2
The details of the employee Rashmi isa Medicine are
displayed . A triplestore is database for the storage and
retrieval of triples, a triple being a data entity composed of
subject-predicate-object The below figure 3 illustrates it .
Fig 3
Semantic web is the future web were retrieval is faster and
accurate .
The study can be further extended for efficient building of
semantic web for large organization so that retrieval of
information is faster and efficient .
VI. CONCLUSION
Semantic Search Engine is, in no doubt, the future
of World Wide Web. In this paper, we have shown the
creation of a semantic web.
In future we will be generating a search within a
search to retrieve relevant results so that search becomes
faster.
ACKNOWLEDGEMENTS
The authors are immensely thankful to the valuable
guidance provided by the department of MCA, KLE
DR.M.S.Sheshgiri College of Engineering and Technology,
Belgaum, Karnataka, India.
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