Download Web Services as a new Concept for enterprise application integration

Semantic Web Services:
Hype or Reality
Ling Liu
College of Computing
Georgia Institute of Technology
Web, Web Services and Semantic
Web Services

Web today:
 Presents
a computing architecture of the Web geared
towards delivering information for human-browsing.

Web Services:
 Presents
a computing architecture of the Web geared
towards exchanging information between
applications.

Semantic Web Services:
 Promises
a computing architecture of the Web
towards intelligently exchanging information between
applications.
My Panel Statement

Can semantic web services become a
reality?
 Semantic
Web Services can play a critical role
in the rapid deployment of service oriented
applications.
 However, this will happen only if
the use of semantics will not add extra burden on
both the developers and the users of Web services;
 And yet demonstrate real value in terms of
productivity.

The History of AI

Provides many examples of two
weaknesses:
 Over-promising

by insiders
Intelligent Agents, “a breakthrough in enthusiasm”
 Over-optimism
by outsiders
[Henry S. Thompson, 2000]

SWS: What should we learn
 Risk:
vulnerable to the same criticism
The History of KR

The representation and exploitation of
knowledge has been the ultimate grand
challenge for Artificial Intelligence since its
inception
Human intelligence v.s. machine intelligence

Lessons learned

 Designing
apparently expressive notations is easy,
making them do actual work is much harder
 designing an approach to KR without first designing
an inference engine  can be ‘a waste of time’
 User-friendly and Expressive  how to tradeoff
[adopted from Henry S. Thompson 2000]
The Success Story of DBMSs

Relational data model
 Mechanisms
for capturing simple but powerful
semantics (more declarative)
 Prevailed over Hierarchical data model and
Network data model (more procedural)

RDBMS: ANSI SPARC architecture
Three Levels: External, Conceptual, Internal
 Binding between external and conceptual  Logical
data independence
 Binding between conceptual and internal  Physical
data independence

Web Services: an Analogy

Location-independent distributed computing model
 Functionality



Facilitate rapid design and deployment of service oriented
applications
Enabling effective creation, execution, and composition, as well as
automated discovery and classification, of Web services
Productivity and Ease of Deployment
 Three



tier architecture
User Level, Service Level, Execution Level
Binding between user and service  Service Location
Independence
Binding between service and execution  Service Execution
(interface/invocation) Independence
Web Services: On the Move

Web Services as a Software Architecture

connect computers and devices with each other through the Web
infrastructure and exchange and combine Web data dynamically
 enable software to be delivered as continuous streams of services as
opposed to packaged products.

Web Services as a new Concept for enterprise
application integration


The integration of data, information, knowledge; processes;
applications; and business
Web Services as a Web programming technology


today: Remote Procedure Calls (RPC) over HTTP, powered by
WSDL, UDDI, SOAP, BPEL etc.
Tomorrow: location-independent distributed computational
model, powered by three tier distributed service computing
architecture
Take Home Message:

Research and Standardization should
focus on methodology and technologies
that encourage and enable the use of
semantics to increase the productivity
of both the developers and the users of
Web services and applications
The Web Services Stack
(state of Art)
Protocols
Description
Discovery
(Communication&
Representation )
(What and How)
(Location and
binding)
SOAP Blocks
Agreements
SOAP/XMLP
Process
XML
WSDL Extensions
HTTP/SMTP/BEEP
WSDL
Registry (UDDI)
TCP/IP
XML
Inspection
Courtesy of James Snell ([email protected]) “Transactional Web”
WS as Software Architecture

A distributed Service Computing Architecture
 Web
Services connect computers and devices with
each other through the Web infrastructure and
exchange and combine Web data dynamically
 Web Services enable on-the-fly software creation
through the use of loosely coupled, reusable software
components.
 Web Services enable software to be delivered as
continuous streams of services.
WS as Software Architecture
“Web services are a new breed of Web application.
They are self-contained, self-describing, modular
applications that can be published, located, and
invoked across the Web. Web services perform
functions, which can be anything from simple requests
to complicated business processes. …
Once a Web service is deployed, other applications
(and other Web services) can discover and invoke the
deployed service.”
IBM web service tutorial
WS as Software Architecture
(today)

Service-oriented Architecture
a
model to depict Web services
interactions, comprising
relationships among three
Publish
entities:



a
Bind
A Web service provider;
A Web service requestor; and a
Service
A Web service broker.
generic model describing
service collaboration, not
specific to individual Web
services.

Service
provider
broker
Find
Service
requestor
See http://www106.ibm.com/developerworks/webservi
ces/
(Courtesy of IBM Corporation)
WS as Software Architecture (tomorrow)
Service requestors
Service providers
Web services networks act as intermediaries
in Web services interactions
Network of Web Services:
Security, Reliability
QoS, Trust, Billing
[XML and Web Services Unleashed
by Ron Schmelzer et.al]
WS as a New Concept for
Enterprise Application Integration

Enterprise Application Integration

The integration of data, information, knowledge; processes; applications;
and business
 State of Art: emerging as a major share of the overall spent IT expenses


State of Art: many companies trying to solve their integration needs by
adhoc integration projects


> 30% of all IT budgets  > a trillion dollar per year world wide
do not scale, need Silver bullet to solve the growing problem, serious
investment of dollars and time
Challenge:



Goal-driven (structure efforts in the context of business processes)
Extensible (extension in response to changed or new business needs)
Reusable (create a vendor and platform independent software integration
platform)
WS as a New Programming
Technology

State of the art


Web Services are Remote Procedure Calls (RPC) over HTTP
Key Components:

WSDL defines services as collections of network endpoints or
ports.




A port is defined by associating a network address with a binding; a
collection of ports define a service.
SOAP is a message layout specification that defines a uniform
way of passing XML-encoded data, a technology to allow for
“RPC over the web”.
UDDI provides a mechanism for clients to find web services, in
some way similar to ‘a DNS service’ for business applications.
BPEL4WS (BPEL) - Business process language to orchestrate
interactions between Web services. (IBM, Microsoft, BEA, SAP, etc.)
Semantic Web Services

Vision
 Transform
the Web from a static collection of
information into a distributed device of
computation, making content within the WWW
machine-processable and machineinterpretable.

A Conceptual modeling framework +
associated conceptual architecture
Semantic Web Services
"Semantic differences, remain the primary roadblock to
smooth application integration, one which Web Services
alone won't overcome. Until someone finds a way for
applications to understand each other, the effect of Web
services technology will be fairly limited. When I pass
customer data across [the Web] in a certain format using
a Web Services interface, the receiving program has to
know what that format is. You have to agree on what
the business objects look like. And no one has come up
with a feasible way to work that out yet -- not Oracle,
and not its competitors..."
--- Oracle Chairman and CEO Larry Ellison