Semantic Query Optimisation with Ontology Simulation

International journal of Web & Semantic Technology (IJWesT) Vol.1, Num.4, October 2010
DOI : 10.5121/ijwest.2010.1401 1
Semantic Query Optimisation with Ontology
Simulation
Siddharth Gupta1
and Narina Thakur2
1
UG Research Scholar, 2
Asst. Professor
1,2
Department of Computer Science, Bharati Vidyapeeth’s College of Engineering,
New Delhi, India
siddharth_bvcoe@hotmail.com
narinat@gmail.com
ABSTRACT
Semantic Web is, without a doubt, gaining momentum in both industry and academia. The word
“Semantic” refers to “meaning” – a semantic web is a web of meaning. In this fast changing and result
oriented practical world, gone are the days where an individual had to struggle for finding information
on the Internet where knowledge management was the major issue. The semantic web has a vision of
linking, integrating and analysing data from various data sources and forming a new information stream,
hence a web of databases connected with each other and machines interacting with other machines to
yield results which are user oriented and accurate. With the emergence of Semantic Web framework the
naïve approach of searching information on the syntactic web is cliché. This paper proposes an optimised
semantic searching of keywords exemplified by simulation an ontology of Indian universities with a
proposed algorithm which ramifies the effective semantic retrieval of information which is easy to access
and time saving.
KEYWORDS
Semantic Query, Ontology, RDF, SPARQL, XML, Keyword Searching
1. INTRODUCTION
The World Wide Web is a congregation of billion web pages which are adhered to each other
through hyperlinks. In 1989 Tim Barners-Lee [1] invented the World Wide Web and marked the
advent of Web 1.0 in which all the web pages were published with no user interaction. Web 2.0
based on equal user participation, collaboration; inter personal connectivity, interconnected
applications [4]. Some of the applications are blogging, Facebook, Flickr, MySpace, Google,
and YouTube where both producer and consumers can interact with each other [3]. The major
drawback of Web 2.0 is its lack of interpretability between machines. Because of the lack of
metadata and knowledge management crisis, powerful and complex algorithms are required by
the search engines in order to parse the keywords requested by the user. The future web,
semantic web is based on the principal of interoperability between machines and giving them
power to think [5], aims at attaching metadata, specifying relations between web resources and
knowledge management, in order to process and integrate data by the users. Hence semantic
web is a web of databases and not of documents, queried by SPARQL [12]. RDF attaches
metadata specify relations between the resources based on XML. Ontologies are another major
semantic web technology built above RDF aims at providing strong semantics and vocabulary
[6]. They link the data on the basis of logical reasoning, common vocabulary and analytical
thinking. This paper elucidates searching of information based on semantic understanding of
words with simulation of Ontology of Indian Universities using protégé is a tool. An algorithm
based on semantic searching of information is exemplified by an example. The main idea
behind it is to collectively manage all the related information of Indian universities on a single
platform which aggregates the information related to conferences, inter-college competitions,

2
exchange of ideas, interaction among the students hence knowledge management and sharing on
a single platform.
The Semantic Web is an extension of the World Wide Web with new technologies and
standards that enable interpretation and processing of data and useful information for extraction
by a computer[15]. The Web contains a huge amount of data but computers alone cannot
understand or make any decisions with this data. The solution is the Semantic Web. The
Semantic Web is not a separate Web but an extension of the World Wide Web, in which
information is given well defined meaning, better enabling computers and people to work in
cooperation. [9] Sometimes it is said that the semantic web will make data become “smart”.
What would it mean, for data to be smart? Smart data means that the web of information
becomes so richly interconnected that it can become much smarter than humans. [10]
With the emergence of Semantic Web framework the naïve approach of searching information
on the syntactic web is cliché. The World Wide Web is a congregation of billion web pages
which are adhered to each other through hyperlinks. Many internet users daily activity is web
search only and these users end up in an endless quench to retrieve relevant information
pertaining to the user in shortest possible time A Web 2.0 based search engine is having major
drawback as it lacks interpretability between machines, metadata and knowledge management
crisis [4]. Powerful and complex algorithms are required by the search engines in order to parse
the keywords requested by the user. The future web, semantic web is based on the principal of
interoperability between machines and giving them power to think [3][7], aims at attaching
metadata, specifying relations between web resources and knowledge management, in order to
process and integrate data by the users.
For e.g. Let a user types a keyword set X. Then by looking at the texts found by means of X,
some other words related to X can be determined like antonyms and synonyms. Obviously,
these texts may not include any query word and they include merely one related word or more
[1]. This aims at finding the probabilities of the keywords with the maximum likelihood
occurrence if keywords in a set. This method which will help us in assigning priority to the web
pages based on the high probability.
Fig.1 Evolution of WEB 3.0
This paper discusses them in detail with simulation of ontology of Indian universities using
protégé which shows how the sematic web works on the whole.

3
2. SEMANTIC WEB ARCHITECTURE
The first layer URI/IRI (Uniform Resource Identifier / International Resource Identifier) is a
string of standardized form in order to uniquely identify resources/documents. URL (Uniform
Resource Locator) is a subset of URI. IRI is an internationally accepted form. XML layer with
the XML namespace and XML schema ensures that there is common syntax used in the
semantic web. XML is the key for platform independence and exchange data using a common
language[13][15]
The core format for representation of data in semantic web is RDF which is based on triples
(subject – predicate – object) and forms a graph pertaining to the given data in the same form
[7]. It is the grammar of the document whereas XML is the words understood by machines.
OWL (Web ontology Language) uses description logics and provides strong semantics. For
querying RDF and OWL ontologies, SPARQL is used which acts as a query tool similar to SQL
[8]. The correct logics with the rules implied proves the ontologies which then intertwined with
trusted inputs to yield trusted outputs. Digital signatures and cryptography is applied in order to
maintain security while information exchange.
Fig 2. Semantic web architecture [7].
RDF
Resource Descriptive Framework (RDF) is the backbone of semantic web, which is the standard
model for data interchange on the web. It is linked with the other resources via URI which
uniquely identifies the documents. It works on the XML technology hence making data in each
database understood by each other in XML form and hence platform independent. The RDF
model is based on the idea of triple. It breaks down the data into three parts namely resource,
property and property-value which are nothing but subject, predicate and object in simple
grammar [7] [8].
For example:
Sentence 1: Bharti Vidyapeeth has a student, Siddharth Gupta
Here, Bharti Vidyapeeth is the subject (resource), student is the predicate (property) and
Siddharth Gupta is the object (property-value).
Subject: http://bvcoend.ac.in/info#BhartiVidyapeeth

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Predicate: http://bvcoend.ac.in/info#student
Object: Siddharth Gupta
Sentence 2: Siddharth Gupta has a nickname Sid
Here, Siddharth Gupta is the subject (resource), nickname is the predicate (property) and Sid is
the object (property-value).
where, http://bvcoend.ac.in/info# is the URI which uniquely identifies the resources. Standard
URI for RDF is
http://www.w3.org/1999/02/22-rdf-syntax-ns#
Fig 3. RDF graph tree
The graph shows a FOAF (Friend of a Friend) who describes Siddharth Gupta. We examine the
graph is in triplets of subject – predicate – object. There is an other language called RDFS (RDF
schema) which uses vocabulary to define resources. Other triple formats are: N3, turtle, N-
Triples. The XML is hence generated depending on the graph.
<rdf:RDF
xmlns:rdf=”http://www.w3.org/1999/02/22-rdf-syntax-ns#”
xmlns:info=”http://www.bvcoend.ac.in/info#”
xmlns:foaf=”http://xmlns.com/foaf/0.1/“>
<rdf:Description rdf:about=
”http://www.bvcoend.ac.in/info#College-“BhartiVidyapeeth”>
<info:student rdf:resource=
”http://me.bvcoend.us/foaf.rdf#me”/>
</rdf:Description>
</rdf:RDF>
OWL
OWL is a stronger language as compared to RDF and has much greater machine interpretability.
Thomas Gruber defines it as “explicit specification of conceptualisation” [9], which are the
relationships that concepts, objects and other entities hold with each other. According to Barry
smith “the ontology is a classification of entities, represented by nodes in a hierarchal tree” [10].

5
The ontologies are derived form the real world conceptualisation shared by humans as a
knowldege base and implemented in digital described through machine readable languages such
as OWL, XML. Everything is derived from <owl:Thing> under which we have the classes,
properties and instances. The main component of ontology is Class which describes concepts in
the domain. Secondly are the properties which are further classified into object properties and
datatype properties which describes various features and attributes of the concepts and then
individual instances of the classes are made which in together makes a knowledge-base.
The results plotted are based on logical reasoning and linking
Fig 4. Interconnection between machines exchanging data
SPARQL
SPARQL (Simple Protocol and RDF Query Language) is similar to SQL and used to access
native graph based RDF stores and extract data from the traditional databases, hence yielding
perfect results.
An example of a SELECT query follows:
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?college ?university
WHERE { ?name foaf:college ?college .
?name foaf:universtity ?university . }
Fig 5. Querying RDF stores with SPARQL

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3. ONTOLOGY OF INDIAN UNIVERSITIES
Using protégé [11], which is a free, open source platform for constructing, visualizing and
manipulating domain models and knowledge based applications with ontologies we have
simulated ontology of Indian Universities. It implies that if different Indian colleges websites
providing information about various events, services, information are published and shared
under same ontology in terms they all use, then computer agents can share and aggregate
information from these websites and hence provide a more viable solution to the user query
about Indian universities/ colleges. The domains of the ontology defined can be reused by other
ontology, thus integrating several existing ontologies under one large ontology describing a
large domain.
The name of my ontology representing unique URI:
http://www.indianuniversities/ourontology1.owl
Defining Classes:
We define three main classes namely Universities, Courses and States. The University class has
been further subclassed into Colleges. The instances of these classes will be defined later.
The courses class contains a list of all the courses as its subclasses and states contain a list of
states.
All the classes are subclassed under one class <owl:Thing> which is the root of all the classes.
Defining properties:
The properties of the classes are hence defined which includes Object properties and Datatype
properties.
TABLE 1
Object Properties Domain
hasChiefMinister State
hasColleges University
hasCourses University
hasPrincipal Colleges
hasViceChancellor University
Fig 6. Object Properties
And now the domain of each property is defined to show which class they are pertaining to.
Example: the domain for Datatype property hasCollegeName is Colleges and domain of Object
property hasColleges is University.

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TABLE 2
Datatype Properties Domain
hasUniversityName Universities
hasCollegeName Colleges
hasCourseName Courses
hasStateName States
hasPhoneNumber Universities
Fig 7. Datatype Properties
The assertions are made using assertion browser and new instances of the classes can be created
with the details according to the properties defined.
The following subclasses were made and its instances using instance browser, which shows a
column wise creation of assertions of the classes:
TABLE 3
Universities Colleges Courses States
IP
University
BVCOE BTECH New Delhi
Delhi
University
DCE MTECH Mumbai
IIT IIT Chennai MBA Chennai
IIT Delhi MCA Kolkata
IIT Mumbai MEDICAL
NSIT
MAIT
The results are hence plotted on the graphs using OWLViz tool and following simulations were
done which shows the interconnection between the classes and the domain defined.
The fig 4. Shows the class hierarchy which shows the base class as <owl:Thing> and all the
classes subclassed under it.

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Fig 8. Class hierarchy
The figure 5 shows the classes and the individual tree of the classes and its instances in a radial
layout. Hence we can see the instances of the Universities class and has a subclass Colleges
which has its own set of instances and how they are interconnected with the State and Courses
classes all under one root <owl:Thing>.
Fig 9 Radial Layout

9
Algorithm ( semantic search )
Input : Search := { x1, x2, x3, x4…. Xn }
Output : Set O := { semantic retrieval }
Procedure :
Let Set I := Φ , Set P := Φ
for every keyword set Searchi in web database
if Search ∩ Searchi ≠ Φ then add Searchi to I;
Let I := {search1, search2, search3… searchn}
P:= search1 ∪
∪
∪
∪ search1 ∪
∪
∪
∪ search1 ∪
∪
∪
∪ …
…
…
…. searchn
C := count number of keywords in Set P
O(Pi) :={ Occurrence, Prioritise Keysets with the probability of occurrence }
The above algorithm illustrates the semantic searching of words on the web. As we
know present scenario of searching depends on heavy parsing algorithms in order to
yield results as computer cannot understand the meaning of the documents. Here we
have retrieved all the keysets related to the search query in the database and the union of
all the keysets are taken in another set[14]. The probability of occurrence was found and
according to that priority was given to it as a perfect search result.
Example :
Search Query= { “Indian Universities” }
Let Keyword sets obtained were :
Search1 = { “Indian”, “Courses”, “AIU”, “Universities”, ”UGC”, ”Top”, “Colleges”, “States”}
Search2 = { “Indian”, “UGC”,”AIU”, “List”, “Exams”, “Top”, “Universities”}
Search3 = { “Universities”, “UGC”, “Colleges”, ”Top”, “Indian”, “Ranking” }
Search4 = { “Indian”, “States”, “AIU”, “Universities”, ”Questions”, ”Ranking “}
Search5 = { “Indian”, “Courses”, ”Ranking”, ”UGC”, “States”, “Universities”}
Now we have a set P in which union of all the keysets are taken
P = { “Indian”, “Universities”, “Courses”, “AIU”, “UGC”, “Top”, “Colleges”, “States”, “List”,
“Exams”, “Ranking”, “Questions” }
Now as we see Indian Universities occur in every search hence the comparison is made with
reference to these two keywords.
Occurrence (Pi) = {Φ, Φ, 2, 3, 4, 3, 2, 2, 1, 1, 3, 1 }
According to the observation probability of UGC is more than other keywords hence, it is given
higher priority and then AIU. Though computer doesn’t understand the meaning, but we can
assign priorities in order to yield semantic search as keywords with higher priority occurs in
greater number of keysets and implies that it is closely related to the search query. The order of
occurrence on the basis of priority is : UGC ,AIU, Top, Ranking, Courses, Colleges, states, List,
Exams, Questions.
Now, on a standard google search of Indian Universities yields app.8,820,000 web pages. As we
know, most of them are irrelevant to the user, hence according to our problem we can infer that
if we discard the relevancy of web pages containing the keywords – List, Exams and Questions

10
because of the lowest assigned priorities found above, we can discard almost 15% of the web
pages consisting of these keywords i.e 7,497,000 pages can be considered and further refined
according the assigned priorities and hence making the search more efficient.
4. FUTURE SCORE AND CONCLUSION
This paper focuses on how the future web might look like and the interaction between the
sources of information to yield perfect and real time results with unique power of intelligence
by interpreting the best possible solution for the query. Ontologies are the bases of semantic
web and can be further expanded. An example ontology was simulated using protégé and results
were analysed. The keywords were given priority and bases on that we have discarded certain
percentage of web pages hence making the search more compact and efficient. The main idea is
to collaborate the search for Indian Universities to be more informative and provide it an
intellicense in order to retrieve user oriented results. The future scope of this method is that
Firstly, the current ontology can be integrated into large domains resulting in expansion of
knowledge base. Secondly, Information of all the universities and their corresponding colleges
will be assorted under one ontology hence interoperability as well as interpretability. Thirdly,
The web will be a collection of databases with a common vocabulary for exchanging and
interpreting information between machines.
REFERENCES
[1] Dean Allemang, Rule-based intelligence in the Semantic Web, TopQuadrant Inc. IEEE 2006
[2] Ora Lassila, James Hendler, Embracing “Web 3.0”, Nokia Research centre and Rensselaer Polytechnic Institute.
IEEE 2007
[3] Radha Guha, Towards the Intelligent Web Systems, Coimbator(India), IEEE 2009
[4] LI yuan, ZENG jianqiu, Web 3.0: A real personal web! Beijing China, IEEE 2009
[5] A Semantic Web primer by Grigoris Antoniou and Frank Ven Harmelen, MIT PRESS 2008
[6] XML Databases and Semantic Web by Bhavani Thuraisingham, 2002
[7] Programming the Semantic Web by Toby Segaran, Colin Evans, Jamie Taylor, O’REILLY 2009
[8] OWL:http://protege.stanford.edu/publications/ontology_development/ontology101-noy-mcguinness.html
[9] A guide to Future of XML, Web Services and Knowledge Management by Michael C.Daconta, Leo J. Obrst,
Kevin T.Smith, 2003
[10] Protégé : http://protégé.stanford.edu/download
[11] Li BAI, Min LIU, “A Fuzzy –set based Semantic Similarity Matching Algorithm for Web-Services” CIMS
Research Centre, IEEE 2008
[12] Tim Berners-Lee, Jim Hendler, and Ora Lassila. “The semantic web” [Online]. Available:
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[13] Samantha K. Rajapaksha and Nuwan Kadogoda “Internal Structure and Semantic Web Link Structure Based
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Zhongshan University, IEEE 2004
[15] Yashihiro Tohma et al “The Estimation of Parameters of the Hypergeometric Distribution and its Application to
Software Reliability Growth Model”, IEEE Vol 17, No 5, 1991

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