Processes

1
Processes
Chapter 3

• Part IV
• Software Agents

2
Software Agents

• There is a lot of controversy on what a software
  agent is
• Getting increasingly important in distributed
  systems

3
Broad Definition

• A software agent is an autonomous process that
  can
• React to and
• Initiate changes in
• its environment (possibly) by collaboration with
  other agents or users

4
Characterization of Agents - Collaborative

• Multi-agent systems a collection of agents that
  collaborate to a achieve a common goal
• Collaborative agent part of a multi-agent system
• Cooperation and autonomy
• Examples
• Agents for meeting arrangements
• Agents for contract negotiation

5
Characterization of Agents - Mobile

• Mobile agent can move between different places
• Mainly require strong mobility
• Can also be useful with weak mobility
• Examples
• Agents that travel to extract information
• BOTs

6
Characterization of Agents - Interface

• Interface agent assists a user in the use of
  applications
• Can learn through interaction with users
• Examples
• Agents for contract negotiation
• Agents for match-making

7
Characterization of Agents - Information

• Information agent manages information from
  different resources
• Order, filter, can collate information
• Examples
• email agent
• Agents for monitoring Web sites

8
Software Agents in Distributed Systems

• Some important properties by which different
  types of agents can be distinguished.

9
Agent Technology

• Separate general (common) components between
  different agents into a separate layer
• FIPA (Foundation for Intelligent Physical Agents)
  is working on such a generic model

10
FIPA agent platform

• The general model of an agent platform (adapted
  from fipa98-mgt).

11
Management Component

• Keeps track of agents
• Provides facilities for managing agents
• Create
• Delete
• Lookup (naming and locating agents)

12
Directory Service

• Yellow pages for agents
• Lookup agents by attributes
• Can be accessed by remote agents (those sitting
  on a different platform)

13
Agent Communication Channel

• Agents (mainly) communicate by messages
• ACC looks after (inter-platform) communication
  between agents
• Can be implemented as a communication server

14
Agent Communication Language

• Agents communicate through an application-level
  communication protocol, called ACL
• ACL separates the purpose and content of a
  messages

15
Purpose and Content of Messages

• Examples of different message types in the FIPA
  ACL fipa98-acl, giving the purpose of a
  message, along with the description of the actual
  message content.

16
Application-Level Protocol

• Agents must agree on an understanding of message
  purpose
• Purpose of a message determines the reaction of
  the receiver

17
Example Message

• A simple example of a FIPA ACL message sent
  between two agents using Prolog to express
  genealogy information.