Chapter 17:
Organizations
Service-Oriented Computing: Semantics, Processes, Agents
– Munindar P. Singh and Michael N. Huhns, Wiley, 2005
Highlights of this Chapter
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Chapter 17
Contracts
Spheres of Commitment
Achieving Collaboration via Conventions
Policies
Negotiation
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Why Organizations?
Serious applications of services require
interactions structured in subtle ways
 Organizations consist of agents (business
partners) providing or using services
 Organizations
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Chapter 17
Relate well to human organizations
Promote coherence in service interactions
Offer a conceptually natural, high-level basis for
understanding and designing service interactions
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Organizations
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Organizations nest naturally (not
necessarily as trees)
 All organizations are agents
 Some agents are organizations
Organizations help overcome
limitations of individuals in
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Reasoning
Capabilities
Perception
Lifetime, persistence
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Three Kinds of Organizations
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Concrete: agents playing roles
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Configured, run-time concept
Abstract (templates): roles and relationships
among roles
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Design-time concept
Institutions: part abstract and part concrete
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Run-time concept, but the membership can change
Example: eBay, where buyers and sellers can
change but eBay itself is a fixed participant
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Legal Abstractions
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Chapter 17
Contracts
Directed obligations
Hohfeldian concepts
Compliance
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Contracts
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Contracts structure interactions among
autonomous parties
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People and corporations
Governmental agencies
Compare with contracts in programming
Key questions: how to create, modify,
perform, or monitor contracts
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Motivation for Contracts
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Provide a basis for service agreements
Crucial in open environments
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Chapter 17
Emphasize behavior: observable by others
Constrain behavior: limit autonomy
Mostly disregard internal implementations,
thus facilitating heterogeneity
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Legal Concepts
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Inherently multiagent: about
interactions among autonomous parties
Directed obligations
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Contrast with traditional deontic logic
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Chapter 17
One party being obliged to another party
Multiagent flavor
Zero-agent: it is obliged that …
One-agent: you are obliged to do …
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Rights
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The rights or claims a party has on
another party
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Chapter 17
Not the right (ethical) thing to do
The claims of one party are the duties
of another: claim is a correlate of duty
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Hohfeldian Concepts: 1
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The term right is used ambiguously
Sixteen concepts distinguish the main
situations:
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Chapter 17
Four main concepts
Their correlates
Their negations
Their negations’ correlates
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Hohfeldian Concepts: 2
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Chapter 17
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
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Commitments
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A commitment
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Involves three parties: a debtor commits to a
creditor within a context
Is scoped by its (organizational) context
May be manipulated, subject to additional
commitments
is public (unlike beliefs)
Commitments provide
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Chapter 17
Flexible interactions, thus promoting coherence
A basis for judging compliance
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Manipulating Commitments
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Operations on commitments:
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Create
Discharge (satisfy)
Cancel
Release (eliminate)
Delegate (change debtor)
Assign (change creditor)
Metacommitments constrain the
manipulation of commitments
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Commitments for Contracts
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A contract is a set of related commitments
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Provides a notional context to the commitments
Applies between specified parties, in a context
(e.g., UCC, real-estate, Internet commerce)
In contrast to commitments, other
approaches:
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Chapter 17
Single-agent focused, e.g., deontic logic
Don’t handle organizational aspects of contracts
Don’t accommodate manipulation of contracts
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SoCom: Sphere of Commitment
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A computational abstraction based on
organizations
An institution with additional features
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Chapter 17
Involves roles (abstract) or agents (concrete)
A witness for the commitment
A locus for testing compliance and enforcing
corrections (e.g., compensation)
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SoComs and Structure
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A SoCom inherits policies from
surrounding (contextual) SoCom
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E.g., UCC applies to commercial
interactions
Inherited policies can conflict because of
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Nonunique nesting
When agents play multiple roles
- Munindar Singh and Michael Huhns
Virtual Enterprises (VE)
A VE offers commitments
beyond those of its members
 Sellers come together with a
new proxy agent called VE
 Example of VE agent
commitments:
 Entertain order updates
 Notify on change of order
 Price guarantee
 Delivery date guarantee
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A Selling VE (Composition Example)
Customer
Virtual Enterprise
I would like to buy a valve with input
dia of 43, two matching hoses, and
of price up to $50.00
Hose Seller
Valve Seller
Two 43 dia hoses in stock?
One valve with input dia 43, output dia 43 in stock?
Yes
Order placed; 1 valve idia = 43
Odia = 43. 2 hoses dia = 43
Charge = $14.83
Yes
Sell two 43 dia hoses
Order is ready
valve input dia = 43, output dia 43 discontinued
valve input dia = 43, output dia 21 recommended
Cancel previous order
Order revised; 1 valve idia = 43
odia = 21, hose dia = 43, and
hose dia = 21. Charge = $14.83
One 43 dia & one 21
dia hose in stock?
Yes
Sell one 43 dia & one 21
dia hose
Sell one valve with input dia 43, output dia 21
Order processed
Chapter 17
Order is ready
Order is ready
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Teams
Tightly knit organizations
 Goals shared by all team members
 Commitments to help team members
 Commitments to adopt additional roles
and offer capabilities on behalf of a
disabled member
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Teamwork
When a team carries out some complex
activity
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Chapter 17
Negotiating what to do
Monitoring actions jointly
Supporting each other
Repairing plans
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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)
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Negotiation Mechanism Attributes
Efficiency
 Stability
 Simplicity
 Distribution
 Symmetry
E.g., sharing book purchases, with cost
decided by coin flip
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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
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Chapter 17
This motivates each bidder to bid its true
valuation
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Negotiation
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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
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Chapter 17
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
Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns
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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
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Problem Domain Hierarchy
Worth-Oriented Domains
State-Oriented Domains
Task-Oriented Domains
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Task-Oriented Domains: 1
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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
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Task-Oriented Domains: 2
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Chapter 17
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
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Monotonic Concession Protocol
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Chapter 17
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 deal
This protocol is simple, symmetric,
distributed, and guaranteed to end in a finite
number of steps in any TOD. What strategy
should an agent adopt?
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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)
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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)
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Deception-Free Protocols
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Zeuthen strategy requires full
knowledge of
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Tasks
Protocol
Strategies
Commitments
P.O.
Hidden tasks
Phantom tasks
Decoy tasks
A1
Chapter 17
A1 (hidden)
A2
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Chapter 17 Summary
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Organizations are a natural metaphor
for understanding and designing
systems of services
Organizations provide a basis for
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Chapter 17
Legal and contractual concepts such as
commitments
Teamwork
Understanding and formalizing negotiation
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