To: seminaire@pauillac.inria.fr
From: Francois.Pottier@inria.fr
Subject: SEM - INRIA : Moscova - 19/10/05 - Paris - FR

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                             S E M I N A I R E
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                          I N R I A - Rocquencourt
                         Amphi Turing du bâtiment 1

                         Mercredi 19 octobre, 10h30

                               -------------
                               Ugo Montanari
                               -------------

              Dipartimento di Informatica, University of Pisa

            ===================================================
            Models and Languages for Service Oriented Computing
            ===================================================

In Service Oriented Computing (SOC), applications are composed of
services. These are heterogeneous software components which manage
resources and which can be orchestrated or coordinated to yield new
services. They may run on different devices ranging from PCs to PDAs
to mobile phones. Applications are usually open ended and adaptive,
namely they should be able to accommodate at some extent unforeseen
changes regarding their clients and their context. Service activities
include directory posting, contract negotiation, compensation and
monitoring. Contracts specify requirements and properties known as
service level agreements (SLA). SLA Quality of Service (QoS) includes
various non functional properties like response time, availability,
security, etc. which can have an important impact  on the whole
software architecture.

This scenario is extremely challenging from both the practical and
the theoretical viewpoint. In fact, it requires on the one side to
redesign in most cases the software architectures of the relevant
applications, and on the other it makes the existing foundations of
computer science often inadequate in terms of generality,
expressiveness, efficient implementation, and verification methods.
In this talk we will focus on some of the new requirements web
services impose on models of computation and specification languages,
and on some existing proposals for their fulfillment.

We will focus on issues concerning the handling of names, which may
denote channels, locations, events, nonces, continuations, or other
entities. We will also discuss how to model the negotiation process,
which consists of several related activities concluded by some commit
operation or interrupted by some abort and compensation step.
Finally, we will consider QoS attributes, how they can be abstractly
represented and handled, and how the constraints posed by them can be
solved.