Intelligent Agents: Technology and Applications Agent Teamwork

1
Intelligent Agents Technology and
ApplicationsAgent Teamwork

• IST 597B
• Spring 2003
• John Yen

2
Learning Objectives

• Given an application that involves a group of
  agents, be able to identify its major
  characteristics (e.g., adhoc vs structured team
  etc).

• For a specific types of agent team applications,
  be able to identify major issues related to the
  design of such agent teams.

• Given an agent team applications, be able to
  determine whether a particular agent teamwork
  model/architecture (i.e., CAST) is suitable for
  the application.

3
Problem 1

• Consider the following five applications
  involving agent teams, identify several key
  characteristics that are important for these
  applications. Use a table to compare the
  similarities and differences of these
  applications along these characteristics.

4

1. A team of agents that play Robot Soccer together.
2. A team including robots, soldiers, and software
   agents (for information fusion/delivery) in the
   battle field.
3. A team of software agents that support/automate
   the information exchanges and/or transactions of
   business partners (e.g., supplier of parts,
   manufacturers of products, distributors, ...) in
   a supply chain.
4. A group of agents that assist the companies they
   each represent to form coalitions for business
   opportunities.
5. A group of agents, each represent a user,
   interacts in an e-auction marketplace.

5
Characteristics

• Team membership Static vs dynamic
• Shared goals vs individual goals
• Benevolent vs selfish
• Hierarchical vs Egalitarian
• Homogenous vs Heterogeneous
• Level of Trust
• Coordination vs competition

6
Key Characteristics for Agent Teamwork

• Benevolent (shared goals) vs selfish (individual
  goals)
• Capabilities Homogenous vs Heterogeneous
• Membership of the Team Static vs dynamic
• Structure of the Team Completely predefined,
  partially defined by roles, completely
  unspecified.
• Types of the structure Hierarchical vs
  Egalitarian
• Process of the Team Completely predetermined,
  partially specified, dynamically generated.
• Human agent-software agent relationship
  boss-assistant, peer, trainee-coach.
• Relationship between members of the Group
  Cooperative, partially cooperative, competitive.
• The level of trust

7
Homework 3 (15, team assignment, due April 8th)

• Compare the similarities and differences of the
  five agent teams using the key characteristics
  identified in class. Describe a (sixth) agent
  team application and characterize it using the
  characteristics.

8
Problem 2 (5)

• What are important issues related to these
  characteristics?

9
Related Issues - Team Structure

• How to form a team? How to determine the
  structure of a team?
• Important if the structure of the team is
  dynamically determined.
• How to specify roles and assign responsibilities
  based on roles?
• Important if the team structure is partially
  specified by roles.
• How to reconfigure a team?
• Important if members of the team may die or be
  overloaded
• How to resolve conflicts in a team?
• Important if the team does not have a
  hierarchical structure.

10
Related Issues - Team Process

• How to specify, coordinate, and execute a team
  process?
• If the process is partially/fully specified.
• How to generate a team process (through
  planning)?
• If the process is dynamically generated.
• How to make sure emergent behavior achieves
  expected effects?
• If the process is not specified.

11
Related Issues - Human-agent Relationship

• How to give human users adequate control of
  agents?
• If agents are assistant to human
• How to enable agents to understand the mental
  states of human and the context of the
  interactions?
• If agents are peer and (to some degree)
  assistant.
• How much can users trust agents?
• How to design friendly interface to enables
  agents and user interact more effectively?
• How to make agents human-like?

12
Related Issues - Cooperative/Competitive

• How to enable agents to negotiate with others?
• If agents are partially cooperative partially
  competitive
• How does an agent balance intentions of others
  with intentions of self when they are
  conflicting.
• If agents are not selfish less (I.e., partially
  self-centered).

13
Related Issues - Trust

• How to establish/guarantee/revise trust?
• Important if trust is important

14
Two Conflicting Objectives of Teamwork Models

• Efficiency
• Higher team performance
• Reduced communications
• Flexibility/Adaptability
• Adapt the structure of the team
• Adapt the process of the team
• Adapt the responsibility assignment

15
Goals for CAST Teamwork Model

• Achieves a high-level of efficiency with a
  reasonable degree of adaptability for
  applications with role-based structure and
  process.

16
Motivation

• Psychological Studies about Effective Human
  Teamwork Indicated that
• Team members can anticipate needs of team mates
• Team members can offer relevant information
  proactively.
• These teamwork behaviors are based on an
  overlapping shared mental model.

17
Shared Mental Model

• Shared Ontology
• Shared Goals
• Shared Team Structure
• Shared Team Collaboration Process
• Shared Belief about the Team
• Shared Belief about the World
• Shared Hypotheses about the Enemy

18
CAST Agent Architecture

• Use a high-level language to describe teamwork
  knowledge
• Capture shared mental model about team
  structure and process
• Infers information needs (from SMM)
• induces proactive information exchanges

19
Anticipating Information Needs of Teammates
Dynamic Task Allocation
Team Plan
Responsibilities of Tasks
Preconditions of Tasks
Who
needs what
Information Needs
20
Dynamic Task Allocation
Team Plan
Roles of Agents in the Team
Dynamic Task Allocation
Constraints for Task Allocation
My Belief about The World
My Belief about Teammates
21
Proactive Information Delivery
Information Needs
Information
Match ?
My Belief about Teammates
Does he/she know ?
How to inform him/her?
Communication Strategy
22
CAST Agent Architecture
Belief Update
Information
Team Knowledge (MALLET)
Responsibility Selection
Belief
Responsibilities (Petri Nets)
Domain Knowledge
Identify Info Needs
Information Needs
Act on Info Needs
23
Shared Mental Model in CAST

• Prolog knowledge base belief
• MALLET High-level language for representing team
  knowledge
• Petri Nets An agents internal representation of
  the dynamic teamwork processes and related
  information requirements

24
Relationships between SMM Components
MALLET Compiler
MALLET Knowledge Base
Petri Net (team process)
query
Prolog Knowledge Base (belief)
CAST Kernel
reply
25

• (team-plan T1 ()
• (process (par (kill-wumpuses) (collect-gold))))
• (team-plan kill-wumpuses ()
• (agent-bind ?s (play-role ?s scout))
• (agent-bind ?f (play-role ?f fighter)(closest
  ?f wumpus))
• (process (while ((wumpus ?x) (not (dead ?x))))
• (seq (do ?s (find-wumpus ?x))
• (do ?f (move-to-wumpus ?x))
• (do ?f (shoot-wumpus ?x)))))
• (team-plan find-gold ()
• (agent-bind ?c (play-role ?c carrier))
• (process (while (true) (if (see ?any-agent
  glitter)
• (do ?c (carrier-pickup gold))))

wumpus exists
start
find
shoot
move
done
pickup
glitter
no wumpuses left
26
CAST Development Environ.
Circles are places and hold tokens denoting
current execution state. Red indicates the
presence of a token. Rectangles are transitions
and are tested and executed when preceding places
have tokens.
27
Two Types of Information needs

• Action-performing information needs
• enables an agent to perform certain (complex)
  actions, which contributes to an agent's
  individual commitments to the whole team.
• Goal-protection information needs
• allows an agent to protect a goal from potential
  threats that may result in a conflict with the
  goal.

28
Applications

• Training for AWACS-like synthetic task (AFOSR
  MURI)
• Support Agent-based Collaborative Mission
  Planning (Army Research Lab)
• Simulating Digital TOC (STRICOM)
• Negotiation among Agent Teams for Engineering
  Design (NSF)

29
Conclusion

• A computational shared mental model is critical
  for developing agents that support a team
  involving both agents and human.
• (PSU-TAMU) CAST enables proactive information
  delivery by anticipating needs of teammates.
• MALLET facilitates the reuse of teamwork
  knowledge
• CAST achieves efficiency using shared team plans
  and shared policy
• CAST achieves adaptability by dynamic assignment
  of agent responsibility