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Chapter 17:Organizations
Service-Oriented Computing: Semantics, Processes, Agents– Munindar P. Singh and Michael N. Huhns, Wiley, 2005
Chapter 17 2Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Highlights of this Chapter
Contracts Spheres of Commitment Achieving Collaboration via
Conventions Policies Negotiation
Chapter 17 3Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Ethical Abstractions
Agents that are members of a society must have an ethics and a philosophy. This requires the development of components for
Deontological ethics Teleological ethics Consequentialism Duties Obligations Applying ethics
Chapter 17 4Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Motivation
The ethical abstractions help us specify agents who act appropriately
Intuitively, ethics is just the basic way of distinguishing right from wrong
It is difficult to separate ethics entirely from legal, social, or even economic considerations
Chapter 17 5Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Right and Good
Right: that which is right in itself Good: that which is good or
valuable for someone or for some end
Chapter 17 6Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Deontological vs. Teleological
Deontological theories right before good being good does not mean being right ends do not justify means
Teleological theories good before right something is right only if it maximizes
the good ends justify means
Chapter 17 7Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Deontological Theories
Constraints negatively formulated narrowly framed
e.g., lying is not not-telling-the-truth narrowly directed at the agent’s
specific action not its occurrence by other means not the consequences that are not
explicitly chosen, i.e., only works for consequences that are explicitly chosen
Chapter 17 8Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Double Effect
Deontological theories distinguish intentional effects from foreseen consequences
An action is not wrong unless the agent explicitly intends for it to do wrong legitimizes inaction even when inaction
has predictable (but unintended) effects shut down bank ATM for diagnostics even
if that might leave someone without cash
Chapter 17 9Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Kant’s Categorical Imperative Whatever maxim an agent uses
must be universalizable, i.e., in the society of agents respect for others (no lying or
coercion) so they can consent false promising is unacceptable,
because if all did, their society would not function
agents’ maxims are uncertainly inferred from their actions
Chapter 17 10Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Teleological Theories
Based on how actions satisfy various goals, not their intrinsic rightness comparison-based preference-based
Chapter 17 11Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Consequentialism
An agent should promote whatever values it adopts
actions are instrumental in the promotion
honor the values only if doing so promotes them
Chapter 17 12Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Utilitarianism
This is the view that a moral action is one that is useful
must be good for someone good may be interpreted as
pleasure: hedonism preference satisfaction: microeconomic
rationalism (assumes each agent knows its preferences)
interest satisfaction: welfare utilitarianism aesthetic ideals: ideal utilitarianism
Chapter 17 13Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Prima Facie Duties
What agents need to decide actions are not just universal principles (each can be
stretched) not just consequences but also a regard for their promises and duties
Agents have prima facie duties to help others, keep promises, repay kindness,...
no ranking among these highly defeasible conclusions, e.g., steal to
feed kids
Chapter 17 14Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Obligations
Obligations are for deontological theories, those
that are impermissible to omit for teleological theories, those that
most promote good for contract-based theories, those
that an agent accepts
Chapter 17 15Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Applying Ethics/1
The ethical theories are theories of justification not of deliberation
An agent can decide what basic “value system” to use under any approach
Chapter 17 16Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Applying Ethics/2 The deontological theories
Are narrower Ignore practical consideration But are only meant as incomplete
constraints (out of all right actions, the agent can choose any)
The teleological theories Are broader Include practical considerations But leave fewer options for the agent, who
must always choose the best available alternative
Chapter 17 17Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Applying Ethics/3
The ethical approaches are single-agent in orientation implicitly encode other agents
An explicitly multiagent ethics would be an interesting topic for study
Chapter 17 18Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Legal Abstractions
Contracts Directed obligations Hohfeldian concepts Compliance
Chapter 17 19Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Legal Concepts
Because law involves the interactions of citizens with one another and with the government, the legal abstractions have been richer in multiagent concepts
Traditional formalisms for legal reasoning, however, are often single-agent in orientation, e.g., deontic logic (the logic of obligation, “obliged to do p”)
Chapter 17 20Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Contracts
Much of the law is about the creation and manipulation of contracts among legal entities people corporations governmental agencies
The law is the study of how to break contracts!
Chapter 17 21Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Motivation
The legal abstractions provide a basis for agents to enter into contracts, e.g., service agreements, with each other
Contracts are about behavior important in open environments
Chapter 17 22Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Directed Obligations
Contracts lead naturally to one party being obliged to another party more precise notion of obligation than
in traditional deontic logic two-party concept has a more
multiagent flavor
Chapter 17 23Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Rights
The rights or claims a party has, as opposed to the right (ethical) thing to do.
The claims of one party are the duties of another: claim is a correlate of duty
Chapter 17 24Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Hohfeldian Concepts/1
Hohfeld discovered that “right” is used ambiguously and proposed a uniform terminology to distinguish the various situations. Sixteen concepts result: Four main concepts Their correlates Their negations Their negations’ correlates
Chapter 17 25Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Hohfeldian Concepts/2
Claim-duty: as above Privilege-exposure: freedom from
the claims of another agent Power-liability: when an agent can
change the claim-duty relationship of another agent
Immunity-disability: freedom from the power of another agent
Chapter 17 26Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Organizations
Organizations are larger-scale than single agent, goal-oriented, and with knowledge and memory beyond individual
Organizations help overcome the limitations of agents in
reasoning capabilities perception lifetime and persistence
Concretely, organizations consist of agents acting coherently
Abstractly, organizations consist of roles and commitments among the roles – these form a sphere of commitment
Chapter 17 27Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Coherence and Commitments
Coherence is how well a system behaves as a unit. It requires some form of organization, typically hierarchical
Social commitments among agents are a means to achieve coherence. An agent’s commitment to another agent or to its society
Is unidirectional Arises within a well-defined scope or
context Is revocable with restrictions Enables coordination through the
ordering and occurrence of actions by the agents
Chapter 17 28Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Commitments for Contracts
Commitments capture contracts. Importantly, commitments are
Public (unlike beliefs and intentions) Can be used as the basis for compliance Contracts apply between parties, in a
context Other approaches are:
Single-agent focused, e.g., deontic logic Don’t handle organizational aspects of contracts Don’t accommodate manipulation of contracts
Chapter 17 29Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Manipulating Commitments
Operations on commitments: Create Discharge (satisfy) Cancel Release (eliminate) Delegate (change debtor) Assign (change creditor)
Metacommitments constrain the manipulation of commitments
Chapter 17 30Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
SoCom: Sphere of Commitment
An organization that provides the context or scope of commitments among relevant roles (abstract) or agents (concrete) Serves as a witness for the
commitment, i.e., knows that the commitment exists
Helps validate commitments and test for compliance
Offers compensations to undo members’ actions
Chapter 17 31Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Virtual Enterprises (VE)
Two sellers come together with a new proxy agent called VE
Example of VE agent commitments: Notify on change Update orders Guarantee the price Guarantee delivery
date
Chapter 17 32Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
A Selling VECustomer Virtual Enterprise Hose Seller Valve Seller
I would like to buy a valve with inputdia of 43, two matching hoses, andof price up to $50.00
Order placed; 1 valve idia = 43Odia = 43. 2 hoses dia = 43Charge = $14.83 Sell two 43 dia hoses
Order is ready
Order revised; 1 valve idia = 43odia = 21, hose dia = 43, andhose dia = 21. Charge = $14.83
Order processed
valve input dia = 43, output dia 43 discontinuedvalve input dia = 43, output dia 21 recommended
Cancel previous order
Sell one valve with input dia 43, output dia 21
Order is ready
Yes
Two 43 dia hoses in stock?
One valve with input dia 43, output dia 43 in stock?
Yes
One 43 dia & one 21dia hose in stock?
Yes
Sell one 43 dia & one 21dia hose
Order is ready
Chapter 17 33Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Teams
Tightly knit organizations Shared goals, i.e., goals that all
team members have Commitments to help team-
members Commitments to adopt additional
roles and offer capabilities on behalf of a disabled member
Chapter 17 34Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Teamwork
When a team carries out some complex activity Negotiating what to do Monitoring actions jointly Supporting each other Repairing plans
Chapter 17 35Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Negotiation
Negotiation is central to adaptive, cooperative behavior
Negotiation involves a small set of agents
Actions are propose, counterpropose, support, accept, reject, dismiss, retract
Negotiation requires a common language and common framework (an abstraction of the problem and its solution)
Chapter 17 36Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Negotiation Mechanism Attributes
Efficiency Stability Simplicity Distribution Symmetrye.g., sharing book purchases, with
cost decided by coin flip
Chapter 17 37Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Negotiation among Utility-Based Agents
Problem: How to design the rules of an environment so that agents interact productively and fairly, e.g.,
Vickrey’s Mechanism: lowest bidder wins, but gets paid second lowest bid (this motivates telling the truth?? and is best for the consumer??)
Chapter 17 38Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Negotiation
A deal is a joint plan between two agents that would satisfy their goals
The utility of a deal for an agent is the amount he is willing to pay minus the cost to him of the deal
The negotiation set is the set of all deals that have a positive utility for every agent. The possible situations for interaction are
conflict: the negotiation set is empty compromise: agents prefer to be alone, but will agree
to a negotiated deal cooperative: all deals in the negotiation set are
preferred by both agents over achieving their goals alone
Chapter 17 39Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Negotiation Mechanism
The agents follow a Unified Negotiation Protocol, which applies to any situation. In this protocol,
The agents negotiate on mixed-joint plans, i.e., plans that bring the world to a new state that is better for both agents
If there is a conflict, they “flip a coin” to decide which agent gets to satisfy his goal
Chapter 17 40Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Problem Domain Hierarchy
Worth-Oriented Domains
State-Oriented Domains
Task-Oriented Domains
Chapter 17 41Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Task-Oriented Domains
A TOD is a tuple <T, A, c>, where T is the set of tasks, A is the set of agents, and c(X) is a monotonic function for the cost of executing the set of tasks X
Examples deliveries: c(X) = length of minimal path that visits X
postmen: c(X) = length of minimal path plus return
databases: c(X) = minimal number of needed DB ops
Chapter 17 42Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Task-Oriented Domains (2)
A deal is a redistribution of tasks Utility of deal d for agent k is
Uk (d) = c(Tk) - c(dk) The conflict deal, D, is no deal A deal d is individual rational if d>D Deal d dominates d’ if d is better for at least
one agent and not worse for the rest Deal d is Pareto optimal if there is no d’>d The set of all deals that are individual rational
and Pareto optimal is the negotiation set, NS
Chapter 17 43Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Monotonic Concession Protocol Each agent proposes a deal If one agent matches or exceeds what
the other demands, the negotiation ends Else, the agents propose the same or
more (concede) If no agent concedes, the negotiation
ends with the conflict dealThis protocol is simple, symmetric, distributed, and guaranteed to end in a finite number of steps in any TOD. What strategy should an agent adopt?
Chapter 17 44Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Zeuthen Strategy
Offer deal that is best among all deals in NS Calculate risks of self and opponent
R1=(utility A1 loses by accepting A2’s offer) (utility A1 loses by causing a conflict)
If risk is smaller than opponent, offer minimal sufficient concession (a sufficient concession makes opponent’s risk less than yours); else offer original deal
If both use this strategy, they will agree on deal that maximizes the product of their utilities (Pareto optimal)
The strategy is not stable (when both should concede on last step, but it’s sufficient for only one to concede, then one can benefit by dropping strategy)
Chapter 17 45Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Deception-Free Protocols
Zeuthen strategy requires full knowledge of
tasks protocol strategies commitments
Hidden tasks Phantom tasks Decoy tasks
P.O. A1 (hidden)
A1 A2
Chapter 17 46Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and
Michael Huhns
Chapter 17 Summary