Information Technology Reference
In-Depth Information
being promoted as a standard through OASIS (BPEL). The work of the workflow
management coalition WfMC (WFMC) with the resulting XPDL standard (XPDL) provides a
higher level of abstraction of workflow and aims to provide a format for process design. The
focus of BPEL, and most business-oriented workflow languages, is control flow. Extensive
research on workflow control patterns has shown that all languages have limitations in
terms of what can be easily expressed (AALST, 2003). This insufficient expressivity and lack
of rigorous semantics to allow automated checks on correctness and completeness mean that
BPEL and related languages are unlikely to be a suitable foundation for ISISEMD.
The scientific community has also conducted considerable research into information and
data processing applications that have similarities to some of the ISISEMD applications.
However, these languages and tools do not support the constructs needed in ISISEMD and
are not designed for Business to Business (B2B) applications that require distributed
management, and trust and security based on the emerging industry Web Service standards.
Beyond this, comes research into intelligent, autonomous, goal-oriented and knowledge-
based service infrastructures. These infrastructures include facilities for: dynamic
negotiation, adaptation and configuration; intelligent scheduling, resource and service
selection; and optimised job execution and management. The infrastructure itself is able to
decide on how to react in case of unexpected situations using self-organisation, self-
management, etc. Of particular relevance to ISISEMD is the use of semantic service
descriptions to facilitate autonomic discovery, composition and use of services, for example
within an organisation as an approach to resource management.
ISISEMD makes heavy use of emerging web service standards, including the areas of
semantic service descriptions, SLAs and agreements, workflow and orchestration,
management, trust and security, and transport and messaging. A significant research
element of the work includes determining exactly how to apply and extend these standards
in order to support ISISEMD applications. A particular challenge is balancing the use of
industry standards, which are the key to meeting business to business needs and hence
exploitation of the ISISEMD results. The standards that ISISEMD consider and engage with
are manifold. Competing proposals from industry vendors may eventually converge
through consolidation, but whilst this has the potential to improve interoperability, it often
does so at the expense of compromising the specification.
In particular, ISISEMD adopts WS-Convergence where possible and evaluate/build
upon/adapt the standards used for management, in particular to enable distributed
management of networks of services that deliver real time applications in inter-organisation
value-chains. Moreover, it uses Simple Knowledge Organisation System (SKOS) and Web
Ontology Language (OWL), for formally describing SLA terms and their relationships,
including QoS attributes of e-care applications. In particular, we address the problem of
mapping high-level business objectives to low-level resource provisioning policies in a more
automated, robust and verifiable way.
4.2 Potentials of ISISEMD services and limitations
Summarising the key features and comparing them with the existing solutions available in
the market, ISISEMD service platform has the following advantages:
