by
Jorge Cardoso1 and
Amit Sheth2
1University
of
The Web coupled with contemporary
E-commerce and E-services is enabling a new networked economy [1]. The scope of
activities that processes span has moved from intra-enterprise workflows
coordinating multiple applications, predefined inter-enterprise and B2B processes,
to dynamically defined Web processes among cooperating organizations.
Components of technical aspect of the solutions involve the technologies for
information exchange (from EDI to XML), software componentization (from CORBA
to Web Services), and workflow coordination and collaboration.
Semantics is the new
component to this mix, as observed at the Amicaola
workshop [2], which could enable support both the scalability and increasingly
more dynamic nature of these Web processes. To these Semantics-enabled and
empowered Web processes we call Semantic Web Processes.
This tutorial presents
what can be achieved by symbiotic synthesis of two of the hottest R&D and
technology application areas: Web services and the Semantic Web. It presents some of the promises and challenges in
applying semantics to each of the steps in the Semantic Web Process lifecycle. In
particular we present the role of semantics in annotation (Semantic Annotation
of Web Services), discovery (Semantic Web Service Discovery), composition (Semantic
Process Composition), process execution/enactment (Semantic Web Process
Orchestration), and quality of service of Semantic Web Processes. We also review
ongoing frameworks and initiatives such as Semantic Web Service Initiative
(SWSI) and DAML-S, as well as results from key projects such as the METEOR-S
which build upon research, technology and current standards in workflow
processes, Semantic Web, Web services and simulation [6].
In dynamic markets and environments,
the selection of the most appropriate Web services to accomplish a
pre-established goal becomes a challenge. Web services need to be dynamically
identified, selected, and integrated to form a Web process that meets user’s objectives.
Today, Web service specifications
are based on standards that only define syntactic characteristics. Examples
include WSDL, SOAP, and UDDI. The syntactic approach to service description is
relatively simple and commonly used in other areas. Unfortunately, it is
insufficient, since the interoperation of Web services is an important issue
for Web processes and cannot be successfully achieved based only on syntactic
descriptions.
Interoperability problems
have lead to research which has involved a steady progress from syntax, to
representation and structure, and to semantics [3]. One of the most recognized
solutions to solve interoperability problems is to enable systems and
applications to understand methods and data by adding meaning to them. Therefore,
Web service can be enhanced semantically by annotating their descriptions.
Emergent trading models, such as
e-commerce, have evoked the development of systems and infrastructures to
support the concept of Web services. An organization’s functionality is
encapsulated with an appropriate interface and advertised as a Web service.
The search of Web services to
model e-commerce applications – such as business-to-business,
business-to-customer, and customer-to-customer processes – differs from the search
of tasks to model traditional process. One
of the main differences is in terms of the number of activities (i.e., Web
services) available to the composition process. In traditional processes, the
number of available tasks to compose a process is relatively small. Usually
only a few hundreds of tasks are available from repositories. On the other
hand, potentially thousands of Web services are available during the composition
of a Web process. Therefore, one of the problems that need to be solved is how to efficiently discover Web services [5].
One possible approach is to use semantic information to describe Web services.
This additional information can then be use to enhance the discovery process.
While in some cases Web services
may be utilized in an isolated form, it is normal to expect that Web services
will be integrated as a part of Web processes. Compared to traditional process
tasks, Web services are highly autonomous and heterogeneous.
As a result sophisticated
methods are indispensable to support,
facilitate, and assist the composition and orchestration of Web process [5]
involving Web services. Here again, one possible solution is to explore the use
of semantics to enhance interoperability among Web services.
New trading models, such as
e-commerce, bring a new set of challenges and requirements that need to be
explored and answered. In such processes, trading agreements between suppliers
and customers include the specification of QoS items such as products or
services to be delivered, deadlines, quality of products, and cost of service.
The correct management of such QoS requirements directly impacts the success of
the organizations participating in e-commerce and also directly impacts the
success and evolution of e-commerce itself. The composition of Web services,
and therefore of Web processes, cannot be undertaken while ignoring the
importance of quality of service measurements.
The good management of QoS directly impacts the success of organizations [4]
participating in e-commerce activities by better fulfilling customer
expectations and achieving customer satisfaction. To enable adequate QoS
management, research is required to develop mechanisms that semantically specify,
compute, monitor, and control the QoS of the products or services to be
delivered.
[1] Amit Sheth,
[2] Amit Sheth and R. Meersman, “Amicalola Report: Database and Information Systems Research
Challenges and Opportunities in Semantic Web and Enterprises,” SIGMOD Record,
31 (4), December 2002, pp. 98-106.
[3] Amit Sheth. (1998). Changing Focus on Interoperability
in Information Systems: From System, Syntax, Structure
to Semantics. Interoperating Geographic Information Systems.
Eds. M. F. Goodchild, M. J. Egenhofer,
R. Fegeas and C. A. Kottman
(eds.), Kluwer, Academic Publishers: 5-30.
[4] Jorge Cardoso, Amit Sheth and
John A. Miller, "Workflow Quality of Service," Enterprise Inter- and
Intra-Organizational Integration - Building International Consensus, K. Kosanke, R. Jochem, J. Nell and
A. Bas, Editors (November 2002) pp. 303-312. Book Series: IFIP International
Federation for Information Processing: Vol. 236, Kluwer
Academic Publishers,
[5] Jorge Cardoso, and Amit. Sheth, Semantic e-Workflow Composition. Journal of Intelligent Information Systems (JIIS), 2003 (to appear).
[6] METEOR-S: Semantic Web Services and Processes - Applying
Semantics in Annotation, Quality of Service, Discovery, Composition, Execution,
http://lsdis.cs.uga.edu/proj/meteor/SWP.htm
Note: The tutorial will build upon
a broad variety of information, not only those authored by the tutorial
presenters. For this, a Web based
resources will provide tutorial attendees with broad coverage of research,
technologies and learning resources on related topics (example of such a
resource appears at:
http://lsdis.cs.uga.edu/lib/presentations/SWSP-tutorial-resource.htm)
The intended audience of this tutorial
is any person interested in business processes, Web processes and services, and
semantics. This tutorial is of particular interest to e-service systems architects
and Web process designers, as well as to researchers from the fields of
business process re-engineering, e-commerce applications, and interoperability
of Web services. Exposure to Web
Services is assumed.
Jorge Cardoso (jcardoso@uma.pt)
received a B.A. (1995) and a M.S. (1998) in Computer Science from the
His research work
concentrated on workflow QoS management and semantic composition of workflows.
Research results were implemented in the METEOR project at the LSDIS lab.
METEOR system is a workflow process management system oriented to support
mission-critical enterprise applications requiring high scalability and
robustness. It is fully distributed, scalable and includes multilevel security
mechanisms.
He
published several papers on workflow systems, workflow QoS, and semantics
composition of workflow. More information is at: http://dme.uma.pt/jcardoso