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Page 1
Protocols, Strategies andArchitectures for
Automated Negotiation
Claudio BartoliniHP Labs Bristol
Bologna, November 17,2000
Page 2
Outline
Part I – Definition of theNegotiation Process
Part II – Importance of Negotiationin the New Economy
Part III – Negotiation Protocols andStrategies
Part IV – Agent-based SoftwareArchitectures for Negotiation
Page 3
Part I - Definition of the Negotiation Process
Page 4
NegotiationA regulated process, aimed to theformation of an agreement amongthe participants to the process
Page 5
Negotiation Protocols
The set of rules which govern theinteraction:
• Permissible types of participants(negotiators and third parties
• Negotiation states (acceptingbids, negotiation closed)
• Events that cause states tochange (no more bidders, bidaccepted)
• Valid actions of participants inparticular states (which messagescan be sent by whom, to whom,at what stage)
Page 6
Examples ofnegotiation
One to one bargaining
Auctions
Request for quotes (RFQ)
…
Page 7
Part II - Importance of Negotiation in theNew Economy
Page 8
Commerce meets theWeb
First generation E-Commerce
• Amazon.com, E-Bay, Priceline.com
Second generation E-Commerce
• B2B Exchanges: e-Steel,PaperExchange
Page 9
Importance ofNegotiation
Business-to-Business tradingneeds negotiation
Negotiation can be multi-party
Difficult to automate
Page 10
Are all E-CommerceNegotiations
Auctions?
The difference between auctions andnegotiation mechanisms hasblurred with the arrival of theInternet and E-Commerce
Are auctions negotiations? Arenegotiation auctions?
Mechanisms such as logrolling andsimultaneous improvements arenot easily expressed in auctiontheory
Our argument: auctions can be seenas negotiation, whereas there’smore to negotiation than what canbe expressed in an auctionframework
Page 11
Dimensions ofComplexity inNegotiation
Mechanisms
Multiple parameters of thegood/service being negotiated over
Multiple goods sold/bought
Page 12
Mechanisms
One-to-one
One-to-many (auctions, reverseauctions)
Many-to-many (double auctions)
Page 13
Multiple Parameters
Not only price
Pricing policy
Delivery procedure
Timing constraints
Payment methods
Page 14
First generation E-Commerce
Sales via the Internet haveincreased dramatically
Some companies (Amazon) sellonly via the Internet
Other companies use the net as amarketing tool
Page 15
E-bay
Most famous Internet Auction Site
Not only auctions:
• Free insurance
• Escrow service
• Traders rating service
• Authentication
• Investigation
• Dispute resolution
Page 16
Priceline.comBuyer make their own price, sellerswill match
Airline tickets, hotel rooms…
Page 17
Agents in ElectronicCommerce
First generation: Focussedprimarily on consumer trading
Second generation: realize thatnegotiation is important forbusiness to business
Page 18
Stages in Trading
What do I need?
What products provide this?
Where can I buy them?
At what price?
How do I pay?
How will it be delivered?
What post-sales support can I get?
Page 19
Shopbots andPricebots
Shopbots: agents that automaticallysearch the Internet to obtaininformation about prices andother attributes of goods andservices.
Pricebots -- adaptive, price-settingagents which firms may wellimplement to combat, or eventake advantage of, the growingcommunity of shopbots.
Study by Greenwald and Kephart:what does the proliferation ofelectronic agents induce: pricewars and pricebots earning higherprofits than game-theoreticalequilibrium
Page 20
Firefly
‘Collaborative filtering’ agent
Helps decide what CD or movie tobuy
Compares your tastes with others
Proposes you try out a CD enjoyedby people with similar tastes to you
Firefly was acquired by Microsoftin 1998
Page 21
BargainFinder
The first price search agent
Finds the cheapest suppliers of agiven CD
Some traders wanted to ban it(CDLand), others welcomed it in
Page 22
SmartBidder
Simple agent in internet auctions
Bids on your behalf up to yourmaximum price
Bids just above the previous bidder
Page 23
Agent-BasedAutomated Trading
Suppliers and consumers delegateto agents
Agents negotiate with each otherto determine prices
Pricing is affected by supply anddemand
24x7 trading based on currentinformation – agent always present
Page 24
Advantages of theWeb
Reduced sales overhead (noshopfront)
Potential international market
Ease of providing large amount ofinformation
Page 25
Second GenerationE-Commerce
Business-to-Business (B2B) sales
General supplies (e.g. paper,electronic components)
Specialised contracts
Services (e.g. contractprogramming, translation)
Page 26
B2B E-CommerceCatalog aggregators
B2B Exchanges
Page 27
B2B CatalogAggregators
Streamlines purchasing byaggregating the productcatalogues of each supplier in oneplace and one format
Examples:
• e-Chemicals, Chemdex,Metalsite, PlasticsNet
Technology providers:
• Ariba
• CommerceOne
• Other 126 listed byB2BBusiness.net under thecategory Enablers and Builder ->Auctions and Exchanges onNovember 15, 2000!
Page 28
A SampleTechnology Provider:
Trading Dynamics
Bought by Ariba in 2000 for 100M$
Now commercialised as AribaDynamic Trade
Fully integrated auction andexchange application
The solution allows marketparticipants to trade based on abroad range of factors, includingprice, product quality, paymentterms, service levels and deliveryoptions
Other similar solutions fromTradeAccess and Exterprise
Page 29
B2B Exchanges
Categories of B2B Exchanges
• Trading Hubs
• Post and Browse
• Auction Markets
• Fully-automated Exchanges
Page 30
Part III - Negotiation Protocols andStrategies
Page 31
Auction Theory andGame Theory
Auction theory is a type of appliedgame theory that is concerned withallocation of goods if valuation ofthe buyers for the goods areunknown
Page 32
Standard types ofauction
Ascending-bid auction (English)
Descending-bid auction (Dutch)
First-Price sealed-bid auction
Second-Price sealed-bid auction(Vickrey)
Page 33
Ascending-bidAuction
Also known as English Auction
Price is successively raised until onlyone bidder remains
That bidder wins the object at thefinal price
Its continuous version is calledJapanese Auction by someeconomists
Subject to the winner’s curse: theparadox that the winning bid in anauction is greater than theproduct’s market evaluation
Page 34
Descending-bidAuction
Also known as Dutch auction, socalled after the flower market
Price is successively lowered untila bidder calls out that they wantthe object at that price
Page 35
First-Price sealed-bidauction
Each bidder independently submitsa single bid without seeing others’bids
The object is sold to the bidderwho makes the highest bid
The price the bidder pays is howmuch they bid for
Page 36
Second-Price sealed-bid auction
Also known as Vickrey auction
Each bidder independently submitsa single bid without seeing others’bids
The object is sold to the bidderwho makes the highest bid
However, the price the bidder paysis the price of the second highestbid
Page 37
Revenue-Equivalence
Theorem
Vickrey 1961;
Regardless of the type of auction(Dutch, English, First-pricesealed-bid or Vickrey), the highestprice paid by a group of rationalbidders is on average the same
The result is based on convenientassumptions. Under more realisticassumptions, differences in themechanisms entail difference inprices.
Page 38
Multi-unit auctions
Simultaneous auctions – shareauctions
• e.g. radio spectrum, TVfrequencies…
Sequential auctions
• Items are sold sequentially
Combinatorial auctions
• Bidder expresses preferences forcomplementary and substitutableitems
• Complex algorithms might benecessary for winnerdetermination
Page 39
Reverse auctions
Dual case of the auction so farpresented
A single buyer, rather than a singleseller, controls the tradingmechanism
Sellers submit asks, rather thanbuyer submitting bids
Page 40
Double auctions
Buyers and sellers are treatedsymmetrically
Buyers submit bids and sellerssubmit asks
Structured process rather thanmulti-party bargaining
Example: the NYSE rule
Page 41
Agents whichnegotiate
An agent needs…
• A representation of thegoods/services to be traded
• An understanding of the trader’sgoals (utility function)
• A strategy for negotiation
Page 42
Utility Function
A utility function is a mathematicaldescription of the preferences of arational trader. The function mapsalternative choices into numericscores, such that the higher thescore, the more desirable thechoice
Multi-attribute Utility Theory analysespreferences with multipleattributes
Problems: preference extraction,uncertainty analysis
Page 43
NegotiatingStrategies
A negotiating strategy consists incarrying out the negotiationprocess so as to maximise atrader’s utility function, under theconstraints imposed bynegotiation rules and otherplayers’ behaviours
Multiple approaches:
• Rule-based
• Game theory
• Adaptive behaviour
• Genetic algorithms
Page 44
Part IV - Agent-based SoftwareArchitectures for Negotiation
Page 45
Why The AgencyParadigm Suits
Negotiation
Weak notion of Agency(Wooldridge, 1992):
• Autonomy
– No human intervention
• Social ability
– Interact with other agents
• Reactivity
– Perceive the “world” and react
• Situatedness
– Exhibit some goal-oriented behaviour
Page 46
Issues thatdevelopers face
Wooldridge and Jennings (1995):
• Agent Theories
– What is an agent
– Mathematical formalism to representand reason about the properties ofagents
• Agent Architectures
– From specification to implementationof software and hardware systems
• Agent Languages
– Software communication systems forprogramming and experimenting withagents
Page 47
Agent-OrientedSoftware Architecture
Need to define (GAIA, Wooldridge,Jennings, Kinny, 2000):
• Abstract concepts
– Roles– Permissions– Responsibilities– Protocols– Activities– Liveness properties– Safety properties
• Concrete concepts:
– Agent Types– Services– Acquaintances
• Plus: organizational abstractions(Zambonelli, Jennings, Wooldridge2000)
– Organizational Rules– Organizational Structures– Organizational Relationships
Page 48
Example: TheFishmarket
Noriega (1997)
• Electronic Auction house
• Agent Testbed
• The Fishmarket Tournaments
Page 49
Bibliography
Negotiation
• N. Jennings, S. Parsons, C. Sierra,P. Faratin (2000): AutomatedNegotiation, PAAM 2000
• G. Kersten, S. Noronha, J. Teich(2000) : Are All E-CommerceNegotiation Auctions? –Proceedings of COOP2000 – FourthInternational Conference on theDesign of Cooperative Systems
Page 50
Bibliography
Agents in electronic commerce:
• M. Wooldridge (1992): The LogicalModelling of Computational Multi-Agent Systems, PhD Thesis,University of Manchester
• M. Wooldridge, N. Jennings (1995):Agent Theories, Architectures andLanguages: A Survey, In IntelligentAgents (ATAL 94)
Page 51
Bibliography
Agents in electronic commerce:
• P. Noriega (1997) – Agent MediatedAuctions: the Fishmarket Metaphor,PhD Thesis, Universitat Autonomade Barcelona
• A. Greenwald and J. Kephart (1999)– Shopbots and Pricebots, inProceedings of IJCAI '99
Page 52
Bibliography
Agent-Oriented SoftwareEngineering:
• M. Wooldridge, N. Jennings, D.Kinny (2000): The GaiaMethodology for Agent-OrientedAnalysis and Design in AutonomousAgents and Multi-Agent Systems,Vol 3. Number 3, September 2000
• F. Zambonelli, N. Jennings, M.Wooldridge (2000) : OrganizationalAbstractions in the Analysis andDesign of Multi-Agents Systems,ICSE 2000
Page 53
Bibliography
Auctions:
• W. Vickrey (1962) : Auction andBidding Games – In Recentadvances in game theory (pp. 15-27) Princeton, New Jersey: ThePrinceton University Conference
• P. Klemperer (1999) : AuctionTheory: a guide to the literature – InJournal of Economic Surveys (Vol13-3, pp. 227-286)
Page 54
BibliographyB2B Exchanges:
• A. Sculley, W. Woods (1999) B2BExchanges, ISI publications
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