Lecture 4 – Bond Agents
What is a software agent?
Mobility
The Bond Agent Model.
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What is a software agent
It depends whom you ask:
Someone from the distributed objects
community: “ a software agent is an active
mobile object”.
 An AI person: “A software agent is code
capable to exhibit autonomous and intelligent
behavior:

Infer new facts given a set of rules and facts.
 Plan
 Learn.


Us: a software agent is a mobile entity capable
of intelligent behavior.
2
Agent dimensions
Agency - autonomous behavior
Mobility
Intelligence
- inference
- planning
- learning
3
Agent-world interactions
Reflex Agents
perceptions
reflex actions
Goal-Directed Agents
Model of the
World
Real World
perceptions
goal-directed actions
4
Mobility
Physical Mobility
Code Mobility
5
6
7
Code mobility
Strong mobility:
anywere,
 anytime.

Weak mobility:
only to some places
 only at specific moments of time

8
Objectives for the design of Bond
Assemble dynamically an agent from
reusable components.
Create an open-ended environment for
agents.
Support concurrency.
Allow changes in the agent behavior.
Support weak agent mobility.
9
Bond components
Multi-plane state machines  different
facets of activity:
User-interractions
 Reasoning…..

Strategies: code executable when an agent
enters a state.
Model of the word  shared memory
allowing strategies in the same plane or in
different planes to communicate.
10
From agent description, to agent
creation and to execution
Blueprint: an agent description language.
An agent factory interprets the agent
description and generates an internal data
structure that controls the run-time
behavior of the agent.
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Blueprint of an
Agent
Internal
Representation of
an Agent
State Machines:
-states
-transitions
Strategies
Agent
Factory
Model of the
World
Agenda
12
The structure of a strategy
Strategy
Start strategy
install() {
}
action() {
}
action() {
}
action() {
}
uninstall() {
End strategy
}
13
Local Host
Blueprint
Repository
Blueprint
Repository
Strategy
Data Base
Resident
A
C
S
Tuple
Space
Web
Server
Agent Factory
Multi-plane Agent
N
E
T
W
O
R
K
S2
S1
A
C
S
S3
Agent Control Structure
Model
Agent
Semantic Engine
Action Scheduler
14
15
Agent surgery
Dynamic modification of an agent.
The agent factory uses a surgical blueprint
to modify the agent, then generates a
modified blueprint.
16
17
Agent migration
Done at the request of a beneficiary who
may supply a migration blueprint.
12 step process desribed in the text at
page 511-512.
18
Original
Blueprint
Surgical
Blueprint
Resident
A
C
S
Modified
Blueprint
Resident
A
C
S
Agent Factory
Original Multi-plane Agent
Original Agent
Control Structure
Semantic Engine
Modified Multi-plane Agent
S2
S1
A
C
S
Agent Factory
S1
S2
A
C
S
S3
Model
Action Scheduler
Modified Agent
Control Structure
Semantic Engine
Model
Action Scheduler
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Beneficiary
(i) migrate-agent
(xi) success
(xii) control-agent
Blueprint
Resident
Agent Factory
A
C
S
(iv) migrate-agent
(x) start-agent
Resident
A
C
S
Multi-plane Agent
Agent Factory
Multi-plane Agent
S1
S2
A
C
S
S3
Model
S2
S1
A
C
S
Model
Agent Control Structure
S3
Agent Control Structure
shadow
of model
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