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That's absolutely right Tom. I've changed the subject to better reflect
where this thread is heading. That is, to assume that we are at some
point in the future where the Semantic Web has arrived, and to pose a
scenario in which the capabilities of the Semantic Web can be leveraged
in dynamic discovery of Web services.
My aim is to have as wide a range of feedback as possible - so to me,
"It can never be done" is just as valuable as "It can be done", or "It
can be done with the following caveats". I'd like to uncover the
potential challenges (such as how Web services may be rated), so that we
can think of how (if at all) these challenges may be overcome.
Below I've reproduced the original scenario I proposed, for those who
may be joining this thread at this point:
- A travel agency needs to access hotel reservation Web services when
making reservations. Rather than have a fixed list of Web services that
it always accesses, the travel agency would like to instead dynamically
discover Web services at each transaction. This allows the travel agency
to avoid having a pre-negotiated agreement with each Web service.
- This dynamic approach allows the travel agency to be able to
dynamically include newly available Web services (i.e. those not
available on a previous transaction), and exclude existing Web services
that may no longer be available.
- It is assumed that dynamic discovery is through means described by the
various Semantic Web-related initiatives taking place (i.e. a Web
service can discover another Web service that - for instance - accepts a
given credit card, offers fligts by a given airline, etc.).
- Since there is no pre-negotiated agreement in this scenario, the
travel agent needs a way of determining whether a given Web service is
"legitimate" or not. This goes beyond the security/trust realm that can
be covered by security tokens, to encompass whether or not the business
behind the Web service is legitimate, and not a front for a phony
operation. This could be done through the use of a third-party Web
Service "certification" authority that is "trusted" by the travel agent.
Once the travel agent's Web service agent sees this certification on a
Web service, it moves farther with that Web service in its discovery
- Additionally, the Web services (those that the travel agent's Web
service attempts to discover) could have some sort of "quality rating"
that reflects various factors such as reliability (i.e. whether or not
the Web service offers a reliable messaging feature), up time, etc.
- Assuming that the travel agent's Web service has initiatlly "selected"
a Web service based on its legitimacy and quality rating: the travel
agent's Web service may have a list of criteria specific to its request
(hotel reservation) that are required of the discovered Web service, and
at various levels (weights). These may reflect the travel agency's
business policies. For instance, the travel agency may (for whatever
reason) require a 3-day (more lenient) cancellation policy (instead of
1-day notice). Therefore, the requesting Web service may require that
any discovered Web service provide information on its cancellation
policy - and it subsequently "rates" that policy.
- The requesting Web service calculates an overall "weighted score" for
each discovered Web service, and returns to the travel agency
information from the Web services with the top X scores (X is determined
by the travel agency's policies). The aggregated results are then
organized according to the travel agency's policies (e.g. sorted by
price in ascending order).
Booz | Allen | Hamilton
"Thomas B. Passin" wrote:
> [Nicolas Toper]
> > My first question is OK you could invoke dynamically web services, but how
> > would you find about it? a UDDI directory? OK but does it tell you what is
> > the web service in a way the computer could understant?
> Joe is thinking about a future in which Semantic Web technologies allow
> incredibly capable discovery capabilities ... right, Joe (in view of our
> discussion earlier this evening)?
> Tom P
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org:Booz | Allen | Hamilton;IT Digital Strategies Team
adr:;;8283 Greensboro Drive;McLean;VA;22012;
fn:Joseph M. Chiusano