Working Together-Multiagent Systems-Lecture Slides, Slides of Multiagent Systems

Prof. Balkishan Sachin delivered this lecture at Aliah University for Multiagent Systems course. Its main points are: Working, Together, Benevolent, Self-interested, Agents, Cooperative, Distributed, Problem, Solving, Conflict

Typology: Slides

2011/2012

Uploaded on 07/16/2012

samrti
samrti 🇮🇳

4.5

(2)

37 documents

1 / 139

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
LECTURE 9:
Working Together
9-1
docsity.com
pf3
pf4
pf5
pf8
pf9
pfa
pfd
pfe
pff
pf12
pf13
pf14
pf15
pf16
pf17
pf18
pf19
pf1a
pf1b
pf1c
pf1d
pf1e
pf1f
pf20
pf21
pf22
pf23
pf24
pf25
pf26
pf27
pf28
pf29
pf2a
pf2b
pf2c
pf2d
pf2e
pf2f
pf30
pf31
pf32
pf33
pf34
pf35
pf36
pf37
pf38
pf39
pf3a
pf3b
pf3c
pf3d
pf3e
pf3f
pf40
pf41
pf42
pf43
pf44
pf45
pf46
pf47
pf48
pf49
pf4a
pf4b
pf4c
pf4d
pf4e
pf4f
pf50
pf51
pf52
pf53
pf54
pf55
pf56
pf57
pf58
pf59
pf5a
pf5b
pf5c
pf5d
pf5e
pf5f
pf60
pf61
pf62
pf63
pf64

Partial preview of the text

Download Working Together-Multiagent Systems-Lecture Slides and more Slides Multiagent Systems in PDF only on Docsity!

LECTURE 9:

Working Together

9-

Working Together

  • Why and how do agents work together?
  • Important to make a distinction between:
    • benevolent agents
    • self-interested agents

9-

Self-Interested Agents

  • If agents represent individuals or organizations, (the more general case), then we cannot make the benevolence assumption
  • Agents will be assumed to act to further their own interests, possibly at expense of others
  • Potential for conflict
  • May complicate the design task enormously

9-

Task Sharing and Result

Sharing

  • Two main modes of cooperative problem solving:
    • task sharing : components of a task are distributed to component agents
    • result sharing : information (partial results, etc.) is distributed

9-

Recognition

  • In this stage, an agent recognizes it has a problem it wants help with. Agent has a goal, and either… - realizes it cannot achieve the goal in isolation — does not have capability - realizes it would prefer not to achieve the goal in isolation (typically because of solution quality, deadline, etc.)

9-

Announcement

  • In this stage, the agent with the task sends out an announcement of the task which includes a specification of the task to be achieved
  • Specification must encode:
    • description of task itself (maybe executable)
    • any constraints (e.g., deadlines, quality constraints)
    • meta-task information (e.g., “bids must be submitted by…”)
  • The announcement is then broadcast

9-

Awarding & Expediting

  • Agent that sent task announcement must choose between bids & decide who to “award the contract” to
  • The result of this process is communicated to agents that submitted a bid
  • The successful contractor then expedites the task
  • May involve generating further manager-contractor relationships: sub-contracting

9-

Issues for Implementing Contract

Net

  • How to…
    • …specify tasks?
    • …specify quality of service?
    • …select between competing offers?
    • …differentiate between offers based on multiple criteria?

9-

Cooperative Distributed Problem Solving

(CDPS)

  • Neither global control nor global data storage — no agent has sufficient information to solve entire problem
  • Control and data are distributed

9-

CDPS System Characteristics and

Consequences

  • Communication is slower than computation
    • loose coupling
    • efficient protocol
    • modular problems
    • problems with large grain size

9-

Four Phases to Solution, as Seen in

Contract Net

  1. Problem Decomposition
  2. Sub-problem distribution
  3. Sub-problem solution
  4. Answer synthesis

9-

The contract net protocol deals with phase 2.

Contract Net• The collection of nodes is the “contract net”

  • Each node on the network can, at different times or for different tasks, be a manager or a contractor
  • When a node gets a composite task (or for any reason can’t solve its present task), it breaks it into subtasks (if possible) and announces them (acting as a manager), receives bids from potential contractors, then awards the job (example domain: network resource management, printers, …)

9-

Idle Node Listening to Task

Announcements

9-

Manager
Manager
Manager
Potential
Contractor

Node Submitting a Bid

9-

Manager
Potential
Contractor
Bid