1. Agent Oriented Software Development
References
© Eric Yu 2001

2. Agent-Oriented Software
Situated / Pro-active
sense the environment and perform actions that change the environment
Autonomous
have control over their own actions and internal states
can act without direct intervention from humans
Flexible
responsive to changes in environment, goal-oriented, opportunistic, take initiatives
Social
interact with other artificial agents and humans to complete their tasks and help others
Jennings, Sycara, Wooldridge (1998) A Roadmap of Agent Research & Development. Autonomous Agents & Multi-Agent Systems journal.
© Eric Yu 2001

3. But why Agent Orientation?
The “world” (application environment) has become more distributed, autonomous, networked…
I.e. the agent properties are being found in the world.
E.g. E-commerce, e-health, e-learning, groupwork, kn mgt
Question is: how to make the software systems meet these desired properties (in the world)
That’s the job of RE (and SE).
But previously, no way of expressing these properties.
RE languages need to be social, intentional.
Most AOSE methodologies focus the system, not on relationship to the world
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4. Requirements Engineering
relationship between system and environment.
Bubenko (1980), Greenspan (1982), Jackson (1983)…
Traditional focus:
consistency, completeness, …
e.g., “Three Dimensions of RE” Pohl (1993)
informal -> formal (representation)
opaque -> complete (specification)
personal view -> common view (agreement)
Suitable for a more stable, non-distributed world
Recent:
goals, scenarios, agents
See overview in van Lamsweerde (ICSE 2000)
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5. Ubiquity
The continual reduction in cost of computing capability has made it possible to introduce processing power into places and devices that would have once been uneconomic
As processing capability spreads, sophistication (and intelligence of a sort) becomes ubiquitous
What could benefit from having a processor embedded in it…?
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6. Interconnection
Computer systems today no longer stand alone, but are networked into large distributed systems
The internet is an obvious example, but networking is spreading its ever-growing tentacles…
Since distributed and concurrent systems have become the norm, some researchers are putting forward theoretical models that portray computing as primarily a process of interaction
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7. Intelligence
The complexity of tasks that we are capable of automating and delegating to computers has grown steadily
If you don’t feel comfortable with this definition of “intelligence”, it’s probably because you are a human
© Eric Yu 2001

8. Computers are doing more for us – without our intervention
Delegation
Computers are doing more for us – without our intervention
We are giving control to computers, even in safety critical tasks
One example: fly-by-wire aircraft, where the machine’s judgment may be trusted more than an experienced pilot
Next on the agenda: fly-by-wire cars, intelligent braking systems, cruise control that maintains distance from car in front…
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9. Human Orientation
The movement away from machine-oriented views of programming toward concepts and metaphors that more closely reflect the way we ourselves understand the world
Programmers (and users!) relate to the machine differently
Programmers conceptualize and implement software in terms of higher-level – more human-oriented – abstractions
© Eric Yu 2001

10. Global Computing
What techniques might be needed to deal with systems composed of 1010 processors?
Don’t be deterred by its seeming to be “science fiction”
Hundreds of millions of people connected by / Social Networks even over the phone once seemed to be “science fiction”…
Let’s assume that current software development models can’t handle this…
© Eric Yu 2001

11. Where does it bring us?
Delegation and Intelligence imply the need to build computer systems that can act effectively on our behalf
This implies:
The ability of computer systems to act independently
The ability of computer systems to act in a way that represents our best interests while interacting with other humans or systems
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12. Interconnection and Distribution
Interconnection and Distribution have become core motifs in IT
But Interconnection and Distribution, coupled with the need for systems to represent our best interests, implies systems that can cooperate and reach agreements (or even compete) with other systems that have different interests (much as we do with other people)
© Eric Yu 2001

13. Agents, a Definition
An agent is a computer system that is capable of independent action on behalf of its user or owner (figuring out what needs to be done to satisfy design objectives, rather than constantly being told)
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14. Multiagent Systems, a Definition
A multiagent system is one that consists of a number of agents, which interact with one-another
In the most general case, agents will be acting on behalf of users with different goals and motivations
To successfully interact, they will require the ability to cooperate, coordinate, and negotiate with each other, much as people do
© Eric Yu 2001

15. Spacecraft Control
When a space probe makes its long flight from Earth to the outer planets, a ground crew is usually required to continually track its progress, and decide how to deal with unexpected eventualities. This is costly and, if decisions are required quickly, it is simply not practicable. For these reasons, organizations like NASA are seriously investigating the possibility of making probes more autonomous — giving them richer decision making capabilities and responsibilities.
This is not fiction: NASA’s DS1 has done it!
© Eric Yu 2001

16. Air Traffic Control
“A key air-traffic control system…suddenly fails, leaving flights in the vicinity of the airport with no air-traffic control support. Fortunately, autonomous air-traffic control systems in nearby airports recognize the failure of their peer, and cooperate to track and deal with all affected flights.”
Systems taking the initiative when necessary
Agents cooperating to solve problems beyond the capabilities of any individual agent
© Eric Yu 2001

17. A typical process model
Automobile insurance claims example
… but we need deeper understanding!
© Eric Yu 2001

18. … a deeper understanding about processes
Car owner wants car to be repaired
Insurance company wants to minimize claims payout
Car owner wants fair appraisal of repairs
Insurance agent wants to maintain good customer relations
© Eric Yu 2001

19. Modelling Strategic Actor Relationships and Rationales. - the i
Modelling Strategic Actor Relationships and Rationales the i* modelling framework
Strategic Actors
have goals, beliefs, abilities, commitments
depend on each other for goals to be achieved, tasks to be performed, resources to be furnished
are semi-autonomous -- not fully knowable / controllable
© Eric Yu 2001

20. Strategic Dependency Relationship
I want …
Actor B
I can …
Actor A D
Car Be Repaired
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21. i* objectives, premises, key conceptsD
Actors are semi-autonomous, partially knowable
Strategic actors, intentional dependencies
have choice, reasons about alternate means to ends
wants and
abilities
means-ends
alternatives
© Eric Yu 2001

22. i* modeling explicit intentionality  goals
2. implicit intentionality  agents
functional
decomposition
means-ends
alternatives
wants and
abilities
inputs
outputs D
© Eric Yu 2001

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28. Development-World model refers to and reasons about…
Strategic Rationale Model
Development-World model refers to and reasons about…
Alt-1
Alt-2
To-be
As-is
Operational-World models
Strategic Dependency Models
© Eric Yu 2001

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32. Softgoal Operationalizations: Contribution Relationship
Side-effects to softgoals: Correlation Relationship
© Eric Yu 2001

33. Analysis and Design Support
opportunities and vulnerabilities
ability, workability, viability, believability
insurance, assurance, enforceability
node and loop analysis
design issues
raising, evaluating, justifying, settling
based on qualitative reasoning [Chung Nixon Yu Mylopoulos (2000) Non-Functional Requirements in Software Engineering. Kluwer Academic Publishers.]
© Eric Yu 2001

34. Another Example: Meeting Scheduler
From: E. Yu. Towards Modelling and Reasoning Support for Early-Phase Requirements Engineering   
3rd IEEE Int. Symp. on Requirements Engineering (RE'97) Jan. 6-8, 1997, Washington D.C., USA. pp
© Eric Yu 2001

35. “Strategic Dependency” Model
[Yu RE97]
Meeting Scheduling Example
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36. Revealing goals, finding alternatives
Ask “Why”, “How”, “How else”
© Eric Yu 2001

37. Scheduling meeting …with meeting scheduler
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38. “Strategic Rationale” Model with Meeting Scheduler
SR2
© Eric Yu 2001

39. Analyzing vulnerabilities
Example of enforcement mechanism
Reciprocal dependency
Loop analysis
© Eric Yu 2001

40. Strategic Modelling for Enterprise Integration
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41. Consider one very successful enterprise...
important organizational and social aspects are missing in conventional models
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42. A Strategic Dependency Model
actor
goal dependency
task dependency
resource dependency
softgoal dependency
LEGEND
© Eric Yu 2001

43. Wants and Abilities
I want ...
I can provide ...
© Eric Yu 2001

44. Some strategic dependencies between IKEA and its customers
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45. Roles, Positions, Agents
LEGEND
agent
position
role
A Strategic Dependency model showing reward structure for improving performance, based on an example in [Majchrzak96]
© Eric Yu 2001

46. For downloading OME: http://www. cs. toronto
For downloading OME:                    When prompt for username and password, please enter the following information.        username: yorku        password: ome4you
© Eric Yu 2001