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Abstract— The main research areas in web services
are related to security, quality of service and
composition. Among all these areas, web services
composition turns out to be a challenging one, because
it supports business-to-business or enterprise
application integration. It provides an effective
solution to complex web application. In recent days
with the emergence of semantic web the scope for
semantic based web services composition increases as
it provides better results compared to the traditional
method of discovering candidate services for
composition. Along with the semantics the nature of
composition also needs to be dynamic as the web
services and its parameters are changing frequently
INTRODUCTION
Web services are considered as self-contained, selfdescribing
modular applications that can be published,
located and invoked across the web. There are mainly two
reasons for switching from middleware technologies to
web services those are (i) involves whole learning curve
and (ii) they don’t adopt standard rules and specifications.
Another important characteristic for web services are they
are loosely coupled. Due to the dynamic nature of the
web, and rapid development across the internet a large
number of web services are emerged in the present day
internet. However a single web service i.e. published on
the web can not satisfy single user request. The increasing
number of web services facilitates not only new
technology but also poses new challenges on how to
compose or collaborate.
As the core technology web service composition provides
an effective solution to complex web application.
Challenges related to web services composition include
constant changes in business rules, high diversity and
heterogeneity of web services [1]. Still the research is
going on finding the appropriate services from a set of
candidate services, building of compound services,
invocation of atomic services and execution of compound
services. The description of web service is lack of
semantic information due to this web service composition
is lack of uncertainty Due to this reason research is
towards semantic web.
The necessity for fast service composition systems is
directly connected with the emergence of ServiceOriented
Architectures (SOA). A SOA is the ideal
architecture for such systems [2],[3]. Service oriented
architectures allow us to modularize the business logic
and to implement it in the form of services accessible in a
network. Services are building blocks for service
processes which represent the workflows of an enterprise.
They can be added, removed, and updated at runtime
without interfering with the ongoing business. A SOA can
be seen as a complex system with manifold services as
well as n:m dependencies between services and
applications:
An application may need various service
functionalities.
Different applications may need the same service
functionality.
Certain functionality may be provided by multiple
services Semantic Web [3] is the crucial step for Web
services composition. The functionality of a Web service
needs to be described with further information, either by a
semantic explanation of what it does or by a functional
annotation of how it behaves [6]. The semantic Web is
also an expansion of the current Web in which
information is given well defined meaning, as a result
better enabling computer and human to work in
cooperation .Semantic Web aims to add machineinterpretable
information to Web content in order to
provide intelligent access.
Ontologies are used to capture knowledge about some
domain of interest. Ontology describes the concepts in the
domain and also the relationships that hold between those
concepts. Different ontology languages provide different
facilities. The most recent development in standard
ontology languages is OWL from the World Wide Web
Consortium (W3C) .It has a richer set of operators - e.g.
intersection, union and negation. It is based on a different
logical model which makes it possible for concepts to be
defined as well as described. Complex concepts can
therefore be built up in definitions out of simpler
concepts. Furthermore, the logical model allows the use of
a reasoner which can check whether or not all of the
statements and definitions in the ontology are mutually
consistent and can also recognize which concepts fit under
which definitions. The reasoner can therefore help to maintain the hierarchy correctly. This is particularly
useful when dealing with cases where classes can have
more than one parent
II. RELATED WORK
In [6], an ontology based Web service composition
method is proposed. Instead of a standard web ontology
language such as OWL-S, they propose an ontology
model for web service composition in order to define
service attributes such as message, service, quality,
operation and parameter. In METEOR-S [7], a web
service composition framework with features such as
dynamic failure handler and reconfiguration is proposed.
To handle data mismatches between different suppliers, it
includes an ontology mediator which handles the mapping
between ontologies. Our work puts emphasis on semantic
In [8] and [9], in order to add semantic capabilities, a
mapping is defined between OWL-S document and UDDI
registry record. However they do not propose a complete
mechanism for semantic queries. In this work, we propose
a different approach for adding semantic capabilities. It is
based on the proposed concept matching approach. In [9],
a new semantic similarity algorithm is proposed. It defines
various degrees on similarity on the basis of the
inheritance relation in ontology model. The proposed
semantic matching algorithms extend this approach with
new features. COSS [10] is context aware web service
composition system. For service discovery and matching,
context information is utilized. Context input is provided
by implemented context providers. However
implementing or finding a previously developed context
providers are difficult in real applications and thus not
practical.
Word Net [11] is a semantic model that captures semantic
relations in English words. It has similar features to the
proposed semantic domain model. However proposed
semantic domain model is for composition purpose and
has many different features. service discovery, matching
and modeling guidance in composition context.
To describe semantic meanings, various semantic Web
service description models are proposed by researchers.
One research trend in semantic Web services is to enhance
WSDL with semantic descriptions. Semantic Annotations
for WSDL and XML Schema (SAWSDL) [12] is a W3C
recommendation to annotate semantics to WSDL and
XML. SAWSDL provides mechanisms to associate
semantic models (e.g., Ontologies) to WSDL and XML
schema components. The semantic models are defined
outside the WSDL document. SAWSDL does not denote
any specific language for representing the semantic
models. Sivashanmugam et al. [13] use the extensibility
supported by WSDL specification to add semantic
descriptions to WSDL. Miller et al. [14, 15] create a
language called WSDL-S to extend WSDL with semantic
descriptions. Miller et al. assume that the semantic models
already exist. The semantic models are maintained outside
of WSDL documents and referenced from the WSDL
document through WSDL extensibility elements. Another research trends of semantic Web services is to create a full
framework for semantic Web services. Ankolekar et al.
[16] use a DAML+OIL based ontology, named DAML-S,
to describe the semantic meanings of Web services.
OWL-S is the successor of DAML-S. OWL-S provides an
OWL-based framework for describing semantic Web
services. The OWL-S ontology is written in Ontology
Web Language (OWL). OWL-S uses the class ―Service‖
to describe the knowledge about a Web service, such as
what the service does, how to use the service, and how a
service client can access the service. Each published Web
service is mapped to an instance of ―Service‖. Instead of
providing the concrete specification of how to access
services, OWL-S uses a class named ―Service Grounding‖
to construct the mapping between the semantic description
of services and the concrete specification of how to access
the services (e.g., WSDL). Except OWL-S, WSMO is
another prominent semantic description model. WSMO
defines four major components to describe semantic Web
services: (1) Ontologies, which provides the terminology
used by all other components; (2) Web Services, which
describe the capabilities, interfaces and internal working
of the Web services; (3) Goals, which represent the
objectivities that a client can achieve by executing the
Web service; and (4) mediators, which define elements to
overcome interoperability problems between different
WSMO components