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text. Several types of agents have been considered
namely composite-service-agents for composite ser-
vices, master-service-agents for Web services, and
service-agents for Web service instances. The dif-
ferent agents have been aware of the context of their
respective services in the objective to devise com-
posite services on-the-fly. To reach this objective,
three types of context have been used: I-context, W-
context, and C-context. Conversations between agents
have also featured the composition of Web services.
Before Web service instances are created, agents en-
gage conversations to decide if service instances can
be created and annexed to a composite service. Such
a decision is based on several factors among them the
maximum number of service instances that can be de-
ployed at the same time and the availability of these
instances for a certain period of time.
Our ongoing work is decomposed into several
thrusts. A security is one them as it is important to
make sure that services do not misuse the comput-
ing resources on which they will be performed. An-
other thrust consists of composite service adaptabil-
ity by allowing composite-service-agents to carry out
some run-time modifications by for instance adding
new component services, removing certain compo-
nent services, or replacing certain component ser-
vices. Therefore, the assessment of the effects of
adaptation is deemed appropriate. Another thrust con-
sists of refining the update operations that occur be-
tween contexts. We already pointed out the support
of Tuple Spaces to such operations.
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