Model transformation and formal verification for Semantic Web Services
composition
Yue Ni
a,b,
*
, Yushun Fan
a
a
Department of Automation, Tsinghua University, 100084 Beijing, China
b
Guilin Air Force Academy, 541003 Guilin, China
article info
Article history:
Received 6 July 2009
Received in revised form 15 January 2010
Accepted 19 January 2010
Available online 26 February 2010
Keywords:
Semantic Web Services
Services composition
OWL-S
Coloured Petri Nets
abstract
Web services composition is becoming more and more important in today’s service oriented business
environment. We need to compose services from different providers together to fulfill the business goals
that cannot be satisfied by any single service. However, different services often have semantic inconsis-
tencies which may lead to the failure of the services composition. In order to verify the correctness of the
Semantic Web Services composition, this paper proposed a composition model of Coloured Petri Nets
which is transformed from OWL-S model. This model can express the logical relations among the sub-
processes of the services composition explicitly, and verify the correctness of the services composition
using formalized methods of Coloured Petri Nets. This paper presented the verification algorithms for
the reachability, boundness and semantic consistency of composed services. Furthermore, an example
of collaborating design process was given to simulate and execute the model.
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
Web services composition has become the most popular ap-
proach to build business processes with the prosperity of the
Web services in intranet and internet. Generally, a single Web ser-
vice cannot fulfill the demands of business process, so we need to
combine interrelated Web services together to achieve different
business goals. Obviously, it will be great if Web services composi-
tion can be done automatically. However, it is still a challenge for
automatic Web service composition because there is no machine
readable information in Web services until the emergence of
Semantic Web Service (SWS). SWS brings semantics into Web ser-
vices, which makes automatic Web services composition, discov-
ery and invocation possible.
Some efforts have been purposed to specify SWS in order to en-
able automatic service discovery, composition and execution. The
major efforts are Web Ontology Language for Services (OWL-S),
Web Service Modeling Ontology (WSMO) and Semantic Annota-
tions for WSDL and XML Schema (SAWSDL). OWL-S has been sub-
mitted to World Wide Web Consortium (W3C) in November, 2004,
which is the first submission in the area of SWS, it describes the
properties and capabilities of Web services in unambiguous,
computer-interpretable form [1]. WSMO has been submitted to
W3C in June, 2005, it provides a conceptual framework and a
formal language for semantically describing all relevant aspects
of Web services in order to facilitate the automation of discovering,
combining and invoking electronic services over the Web [2].
SAWSDL has been published as a recommendation by W3C in Au-
gust, 2007, which defines how semantic annotation is accom-
plished using references to semantic models [3].
However, some serious problems still exist in Web services
compositions, such as composition deadlock, processes incompat-
ibility and Quality of Service (QoS) inconsistency.
In order to solve these problems, some efforts have been taken.
Petri Nets (PN) has been widely used to analyze the correctness of
services composition such as the deadlock and liveness, bound-
ness, reachability, safeness and soundness due to their benefits
on graphic and formal representations. There are many mature
tools for PN-based model checking.
But for semantic verification of Web services composition, cur-
rent methods are not effective enough. Consequently, we consider
the transformation from Semantic Web Service composition to PN-
based models, and then existing research efforts on PN can also be
used to verify the correctness of Semantic Web Services.
Some efforts have been dedicated to this topic. A transformation
tool – DaGen was implemented to transform DAML-S descriptions
to high level Petri Nets [4], but DaGen did not support the transfor-
mation from process ontologies to Petri Nets. A DAML + OIL meth-
od was mentioned in [5] to describe Web services and an
automatic transformation was given to translate composition
0965-9978/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.advengsoft.2010.01.005
* Corresponding author. Address: Department of Automation, Tsinghua Univer-
sity, 100084 Beijing, China. Tel.: +86 13718827120; fax: +86 10 62789650.
E-mail addresses: afnyer@gmail.com, niy04@mails.tsinghua.edu.cn (Y. Ni).
Advances in Engineering Software 41 (2010) 879–885
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