A Comparison of some Negotiation Algorithms using a Tournament-Based Approach

This paper provides some results and analysis of several negotiation algorithms. We have used a tournament-based approach to evaluation and applied this within a community of Buyers and Sellers in a simulated car hire scenario. An automated negotiation environment has been developed and the various negotiation algorithms made to compete against each other. In a single tournament, each algorithm was used as both a Buyer-negotiator and a Seller-negotiator. Each negotiating algorithm accommodates the parameters for negotiation as a set of desirable goals, represented as examples of product specifications. It was the task of each negotiating algorithm to get the best deal possible from every one of their opposites (i.e. Buyer versus Seller) in the sense of being close to the examples they were given as goals. One algorithm proved to be superior to the others against which it was made to compete

Eighth Workshop and Tutorial on Practical Use of Coloured Petri Nets and the CPN Tools, Aarhus, Denmark, October 22-24, 2007

This booklet contains the proceedings of the Eighth Workshop on Practical Use of Coloured Petri Nets and the CPN Tools, October 22-24, 2007. The workshop is organised by the CPN group at the Department of Computer Science, University of Aarhus, Denmark. The papers are also available in electronic form via the web pages: http://www.daimi.au.dk/CPnets/workshop0

Automatic negotiation of multi-party contracts in agricultural supply chain

Orientador: Edmundo Roberto Mauro MadeiraTese (doutorado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Uma cadeia produtiva agropecuária 'e constituída por diversos tipos de atores que estabelecem uma rede de relacionamentos bastante complexa. Estes relacionamentos variam de ad hoc e de curta duração até altamente estruturado e de longa duração. As cadeias produtivas agropecuárias possuem algumas particularidades, tais como, regulamentação estrita e dependência cultural, e possuem relevância social e econômica. A utilização de contratos 'e a forma natural para expressar os relacionamentos entre os membros de uma cadeia. Desta forma, contratos e a atividade de negociá-los são de grande importância numa cadeia produtiva. Esta tese propõe um modelo para cadeias produtivas agropecuárias que integra suas principais características, incluindo seus aspectos estruturais e sua dinâmica. Em particular, a tese propõe um formato para contratos multi-laterais e um protocolo de negociação que os constrói. Contratos multi-laterais são importantes neste contexto, pois vários atores de uma cadeia produtiva podem construir alianças que compreendem direitos e obrigações mútuos. Um conjunto de contratos bi-laterais não 'e adequado para tal propósito. A tese também apresenta uma implementação do protocolo de negócio baseado em serviços Web e numa máquina de workflow (YAWL)Abstract: An agricultural supply chain comprises several kinds of actors that establish a complex net of relationships. These relationships may range from ad hoc and short lasting ones to highly structured and long lasting. This kind of chain has a few particularities like strict regulations and cultural influences, and presents a quite relevant economical and social importance. Contracts are the natural way of expressing relationships among members of a chain. Thus, the contracts and the activity of negotiating them are of major importance within a supply chain. This thesis proposes a model for agricultural supply chains that integrates seamlessly their main features, including their structure and their dynamics. Specifically, the thesis proposes a multi-party contract format and a negotiation protocol that builds such kind of contracts. Multi-party contracts are important in this context because several actors of a supply chain may build alliances comprising mutual rights and obligations. A set of bilateral contracts is not well-fitted for such a purpose. The thesis also presents an implementation of the negotiation protocol that builds on Web services and a workflow engine (YAWL)DoutoradoSistemas de ComputaçãoDoutor em Ciência da Computaçã

Simulation of automated negotiation

Durch die Automatisierung von Verhandlungen sollen bessere Verhandlungsergebnisse erzielt werden können als bei Verhandlungen zwischen Menschen und neue Koordinationsformen für autonome Agentensysteme ermöglicht werden. Diese Arbeit beschäftigt sich mit der Simulation solcher Systeme für automatisierte Verhandlungen, da operative Systeme zur Zeit noch nicht verfügbar sind. Die Arbeit basiert auf einer Erhebung und Diskussion der aktuellen Literatur im Bereich der Simulation automatisierter Verhandlungen. Existierende Ansätze weisen einige Unzulänglichkeiten bezüglich deren praktischer Umsetzbarkeit in einer offenen Umgebung wie dem Internet auf, wo automatisierte Verhandlungen nicht nur sehr schnell durchgeführt werden sondern sich auch Software-Agenten und Verhandlungsprobleme ändern können. Diese Defizite thematisierend werden Verhandlungssysteme für automatisierte Verhandlungen vorgeschlagen. Diese bestehen zum einen aus Software-Agenten, die generische Angebots- und Konzessionsstratgien verfolgen, zum anderen aus Interaktionsprotokollen, die es Agenten erlauben ihre Strategien vorübergehend oder permanent auszusetzen. Ergebnisse der Simulation dieser Systeme, mit Verhandlungsproblemen aus Verhandlungsexperimenten mit menschlichen Probanden als Input, werden für unterschiedliche Ergebnisdimensionen -- Übereinkunftshäufigkeit, Fairness, individuelle und kollektive Effizienz -- zwischen Systemen und auch mit den Ergebnissen der Experimente verglichen. Trotz fundamentaler Zielkonflikte zwischen den einzelnen Ergebnisdimensionen erzielen einige Systeme konsistent bessere Ergebnisse sowohl im Systemvergleich als auch verglichen mit den Ergebnissen der Experimente. Diese Systeme bestehen aus Software-Agenten die systematisch Angebote mit monoton abnehmendem Nutzen unterbreiten und erste Konzessionensschritte tätigen solange der Opponent bisherige Konzessionen erwidert hat. Das verwendete Interaktionsprotokoll zeichnet sich dadurch aus, dass es den Agenten erlaubt ungünstige Angebote zurückzuweisen und damit neue Angebote des Opponenten einzufordern, durch diese Unterbrechung der eigenen Angebotsstrategie können ungünstige Verhandlungsergebnisse vermieden werden.Automated negotiation is argued to improve negotiation outcomes by replacing humans and to enable coordination in autonomous systems. As operative systems do not yet exist scholars rely on simulations to evaluate potential systems for automated negotiation. This dissertation reviews the state of the art literature on simulation of automated negotiation along its main components - negotiation problem, interaction protocol, and software agents. Deficiencies of existing approaches concerning the practical application in an open environment as the Internet - where automated negotiation proceeds fast, with changing opponents, and for various negotiation problems - are identified. To address these deficiencies we develop and simulate automated negotiation systems, consisting of software agents that follow generic offer generation and concession strategies and protocols that allow these agents to interrupt their strategy to avoid exploitation and unfavorable agreements. Outcomes of simulation runs are compared across systems and to human negotiation along various outcome dimensions - proportion of agreements, dyadic and individual performance, and fairness - for various negotiation problems derived from negotiation experiments with human subjects. Though there exist trade-offs between the different outcome dimensions, systems consisting of software agents, that systematically propose offers of monotonically decreasing utility and make first concession steps if the opponent reciprocated previous concessions, and an interaction protocol that enables to reject unfavorable offers - without immediately aborting negotiations - in order to elicit new offers from the opponent, performed best. These systems performed very well in all outcome dimensions when compared with other systems and were the only that outperformed negotiation between humans in all dimensions