The Semantic Web Week 18: Part 4 Introduction to Web Services and Intelligent Web Agents - PowerPoint PPT Presentation

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The Semantic Web Week 18: Part 4 Introduction to Web Services and Intelligent Web Agents

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Horoscope (!) Other agents exist that have tangible effects eg. Online Product Sales. Reservations / Bookings. Exercise: map these to Agent capabilities ... – PowerPoint PPT presentation

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Title: The Semantic Web Week 18: Part 4 Introduction to Web Services and Intelligent Web Agents


1
The Semantic WebWeek 18 Part 4Introduction to
Web Services and Intelligent Web Agents
  • Module Website
  • http//scom.hud.ac.uk/scomtlm/chs2533
  • Practical this week

2
Recap
  • Acquiring content for the semantic web needs tool
    support.
  • Some tools exist (eg Protégé) to acquire
    knowledge in SW form ie OWL ontologies
  • There are methods / platforms to acquire
    knowledge accurately and validate it to a high
    standard (eg CPS)
  • BUT the semantic web needs populating with
    content how can this be done given people in
    general dont understand description logic / FOL
    ???????

3
Content Acquisition
  • There are two types of content
  • A. NEW knowledge
  • B. OLD information in existing, structured
    formats
  • We concentrated on A most content initially at
    least will be through B - we will return to this
    later

4
Intelligent Agents - Overview
  • Basic Intelligent (Web) Agents are
  • Programs capable of flexible, autonomous
    behaviour in dynamic, unpredictable environments
  • SO they should be able to
  • generate plans to solve goals,
  • execute plans,
  • observe, sense and gather information,
  • communicate,
  • negotiate and
  • co-operate with other agents.
  • adapt and learn ie improve their behaviour
  • IA make decisions when achieving goals in DYNAMIC
    and SOCIAL environments

5
Types of IA
  • There are many dimensions
  • Planning Agents vs Reactive Agents
  • MOBILE vs Static Agents
  • INFORMATION Agents

6
WEB SERVICES
  • .. can be considered as
  • agents as they provide services to other agents
  • (they are not necessarily intelligent agents
    though)
  • actions as they have preconditions and
    effects

7
CURRENT WEB SERVICES
  • The main web (internet) service is .. EMAIL!!
  • Examples of types of information agents their
    effect is to increase our knowledge
  • Weather forecasts
  • Travel Timetables, Journey Planners
  • Search Engines
  • Horoscope (!)
  • Other agents exist that have tangible effects eg
  • Online Product Sales
  • Reservations / Bookings
  • Exercise map these to Agent capabilities

8
Example - Mobile Virtual Agent
A
D
Booking Service
B
E
MV Agent
Virtual Bank Service
Action Book-theatre(T) Pre seat-price(T,X)resour
ce(Y)Y gt X atbooking-service(T) Effects
resoiurce(Y)resource(Y-X)have_ticket(T)
9
Semantic Web Services
  • Requirement
  • A computer-interpretable declarative description
    of the Service ie its syntax, effect and other
    information
  • Agents need to be able to find (discover) the
    relevant web services that may satisfy their
    goals with published costs/resources required
    to use the service
  • Agents need to be able to understand the Service
    protocol so that they can execute the service
  • Agents need to be able to reason with the
    published capabilities of a service to

10
OWL-S upper level ontology OWL-S is a
language for describing web services. It is built
from DAML-S and is written in OWL. There are 3
parts to a web service specification
Service
supports
presents
describedby
ServiceProfile
ServiceModel
ServiceGrounding
11
OWL-S
  • Service Profile
  • What it does, what it offers
  • Who is offering it
  • What it requires of the client (eg business
    contact information, payment), and what effect it
    makes.
  • What service category
  • The information here should be sufficient for an
    agent to discover the service
  • this is like the yellow pages entry

12
OWL-S
  • Service Model
  • How does it work? This contains a model of the
    PROCESS of the Service and a concrete
    definition of
  • Inputs
  • Outputs
  • Preconditions
  • Effects
  • Example we could get a service to book our
    theatre seat for us
  • Service Book-theatre(T)
  • Preconditions seat-price(T,X)resource(Y)Y gt X
    atbooking-service(T)
  • Effects resoiurce(Y)resource(Y-X)have_ticket(T
    )

13
OWL-S
  • Service Grounding
  • How is it used? Maps the service (process) model
    description and its parameters to
    communication-level protocols and message
    descriptions in the WSDL

14
Exercises
  • 1. Catch up with any practical exercises you have
    missed this term.
  • 2. Complete the mobile agent example with actions
    for getting resource (money) and logging Into a
    network. (Use your imagination). You could add
    some information adding actions! Finally write a
    plan using the actions you have decided.
  • 3. Look at some web services and try to capture
    there behaviour using pre- and post conditions
  • Eg
  • Look at the National Rail journey planner.
  • put the INPUTS into precondition logic
  • write the OUTPUTS as logical effects
  • 4. Internet Info Look at www.agentcities.org
    and www.agentcities.net for a website on agents.
  • What are agent cities? Look at www.daml.org/servic
    es for a website on semantic web services
  • 5. To dwell on What is the difference between an
    (Intelligent) Agent and
  • A program or (Unix) process
  • An operating system
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