Semantic Web Services

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22 Οκτ 2013 (πριν από 4 χρόνια και 6 μήνες)

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Agent Model for Interaction with
Semantic Web Services

Ivo Mihailovic



About Semantic Web

About Web Services

About Semantic Web Services

The model of the agent

eGovernment example


An attempt to demystify the Semantic Web to
the author

Agent for interaction with Semantic Web

Integration of eGov services: providing a
single access point to all government
services, the increase in their interoperability
without affecting their autonomy, approach
oriented towards citizens

Semantic Web

Web Services

The W3C defines a
Web service

as a software
system designed to support interoperable Machine
to Machine interaction over a network.

Require three basic components: A messaging
service for communicating between resources on the
Web (SOAP), An interface description language
(WSDL), A registration service so that clients looking
for a service can find them (UDDI).

Semantic Web Services

Semantic Web Services

are self
semantically marked
up software resources
that can be interacted with in a task driven
automatic way.

Dynamic part of the semantic web.

Semantic Web Services

Automated Web Service Discovery

Automated Web Service Invocation

Automated Web Service Composition

Automated Web Service Monitoring

Automated Web Service Verification

Automated Web Service Simulation

Semantic Web Services

WSDL can specify the operations available
through a web service and the structure of

WSDL cannot specify semantic meaning of
the data or semantic constraints on the data.





describe all relevant concepts and
relations among them

Web Services

describe capabilities, interfaces and
internal working of the Web service


describe the capability the user would like to
have and the interface he would like to interact with


define mappings between components


S Service Profile

Service Profile

describes what the service does,
used for the discovery

Intended to be published in a WS registry

Classification through the creation of a subclass
hierarchy (one WS can belong to multiple classes)

IOPEs represent Web service’s capabilities, they
describe the service

Other features: contact information, category, quality
rating etc.

S Process Model

Process Model

describes how the service
works, its operation, control and data flow

Used for selection, invocation, interoperation,
composition, and monitoring of the WS

Process types: atomic, simple, composite

S Grounding

Grounding specifies how to access the
service in terms of communication protocols
and message descriptions

Mapping from Process Model to WSDL

Agent model

Example: The user wants to book a flight.

He should find a service that sells tickets, check if it
accepts his credit card and book the flight

The agent can automate this using an ontology of
Web services

Agent tries to resolve the semantics of the user with
the semantics of the service

User provide goals, agent try to map them to actions

Agent model

: Goal

to go on a business trip.

to book a flight, a taxi to the hotel
and a hotel room

: Goal

the change of address.

Agent needs two ontologies:

First to map user’s requests to available

Second to map goals to Web services

Scenario of operation

Step 1) User enters the query

Step 2) Agent maps user’s requirements to

The hard part

needs NLP, needs to be able
to interpret user’s constraints

Book me a flight if the weather’s nice.

Scenario of operation

Step 3) Agent tries to discover a service for
each goal

Step 4) If it cannot find an integrated service
for a goal it tries to decompose it

Step 5) After making the plan of actions the
agent invokes the services

Area of application: e

Integration of services, increased
interoperability, not affection the autonomy of
government organizations

Government is a dynamic area, things
constantly changing (especially in countries
in transition)

Services easily changed, added or removed

Area of application: e

Government Domain Ontology encodes
organizational, legal, economic, business etc.

Web services ontology should categorize services to
enable discovery

Registry of Web services with the service

A change of the service requires the update of the

Service discovery


comparing Goals to Web Service


using the Service Profile

Service classification by creating a hierarchy
of subclasses of Service Profile

SWS yellow pages

a class

Service discovery

Classification by serviceProduct and
serviceCategory properties

Mapping to an OWL specification of
UNSPSC (United Nations Standard Products
and Services Code)

Also can be connected to a classification
outside of OWL

Service composition

AI planning to form service composition

A planning problem P is a 3
tuple < I, G, A >


description of the initial state


description of the goal state


set of actions for state transformations

An action sequence (a plan) S is a solution to
P if S can be executed from I and the
resulting state of the world contains G.

Service composition

States formed from user’s goals and services
preconditions and results

Actions are descriptions of Web services
which show how their execution modifies the
state of the world

STRIPS algorithm

Gov ontology

Needs to represent the viewpoint of citizens
as well as government

Connecting terms from common language
with their legal jargon counterparts

Descriptions of non web
based services as

Planner could make hybrid composition

Thank you!