To make automated negotiation widely used in real scenarios, it is necessary
to develop advanced software systems that are able to carry out such negotiation in those
scenarios. However, although much work has been done in automated negotiation, most of
these efforts have been focused on the development of negotiation protocols and strategies
and only a few are centred on software frameworks for automated negotiation. We are
concerned with the engineering aspect of automated negotiation. Specifically, we detail a
software framework to develop automated negotiations of service level agreements. Unlike
other proposals, we provide a detailed description of elements for full decision-making
support including evaluating offers, strategy selection, building a market and opponents
model, and creating counterproposals

Corchuelo Gil, Rafael

Fernández Montes, Pablo

Resinas Arias de Reyna, Manuel

English

idUS. Depósito de Investigación Universidad de Sevilla

XV Jornadas de Ingenieŕıa del Software y Bases de DatosJISBD 2006José Riquelme - Pere Botella (Eds)c©CIMNE, Barcelona, 2006ENGINEERING AUTOMATED NEGOTIATIONSManuel Resinas1∗, Pablo Fernandez1 and Rafael Corchuelo11: Dpto. Lenguajes y Sistemas InformaticosETS Ingenieria Informatica, Universidad de Sevilla, Avda. Reina Mercedes, s/n, 41012 Sevillae-mail: resinas@us.es, web: http://www.tdg-seville.infoPalabras clave: software architectures, web engineering, SLAs, negotiationResumen. To make automated negotiation widely used in real scenarios, it is necessaryto develop advanced software systems that are able to carry out such negotiation in thosescenarios. However, although much work has been done in automated negotiation, most ofthese efforts have been focused on the development of negotiation protocols and strategiesand only a few are centred on software frameworks for automated negotiation. We areconcerned with the engineering aspect of automated negotiation. Specifically, we detail asoftware framework to develop automated negotiations of service level agreements. Unlikeother proposals, we provide a detailed description of elements for full decision-makingsupport including evaluating offers, strategy selection, building a market and opponentsmodel, and creating counterproposals.1 INTRODUCTIONAn automated negotiation process can be understood as a search, in the space of possibleagreements, of a mutually acceptable agreement by the parties that are carrying outthe negotiation. In this work, we focus on SLA negotiations1. The goal of this kind ofnegotiation is to reach an agreement between a service provider and a service consumerabout the terms and guarantees of the service consumption. In the last years, much workhave been done on the development of new decision-making algorithms or the constructionof new protocols that present certain desirable characteristics for automated negotiations[5]. However, much less attention has been paid to the software artefacts that are necessaryto carry out this automated negotiation.In this paper, we are concerned with the software engineering aspect of automatednegotiation. Namely, we report on a software framework to build automated negotiationsystems. The novelty of our proposal lies in two characteristics. First, we use a service-oriented approach to precisely define the elements (services and data) of the framework.Second, unlike other proposals, we cover all required elements that are necessary to create1Also known as service-oriented negotiations [10]1Manuel Resinas, Pablo Fernandez and Rafael CorchueloStrategyBilateralNegotiatorStrategySelectorPerformativeSelectorArchiverBargainingCoordinatorCommitHandlerCommitAdvisorEstimatorEstimatorsRepositoryPoliciesGenerator1 *InformantProtocolEnforcerInquirerFigura 1: Services overviewa complex automated negotiation system including world modelling, decision-making,preferences, negotiation protocols and negotiation object [8].The structure of this paper is the following. First, in Section 2 we detail the softwareframework. Next, we report on related work in Section 3, and we conclude in Section 4.2 A SOFTWARE FRAMEWORK FOR AUTOMATED NEGOTIATIONOF SLAsIn this work, we focus on the particular case of concurrent proposal-based bilateralnegotiations of SLAs. That is, there are two participants and the information exchangedconsists exclusively in agreement proposals. The rationale is: (i) proposal-based bilateralnegotiations are a very well studied field and mature enough to start developing softwaresystems that work in a real scenario; (ii) it is aligned with recent efforts of the industry inthis area, such as WS-Agreement [1], and (iii) other approaches are not well suited to dealwith complex SLAs with multiple terms (e.g. auctions) or may lead to complex systemswith less techniques developed for them (e.g. argumentation-based approaches).The goal of the proposed software framework is to provide engineering support for soft-ware developers to build automated negotiation systems that implement the conceptualframework for automated negotiations described in [8], including support for negotiationobject, preferences, world modelling, negotiation protocol and decision-making. The soft-ware framework developed uses a service-oriented approach. Figure 1 depicts an overviewof the services2 that compose the framework and their relationships. The boxes representthe services of the framework; the circles, the interfaces, and the arrows represent a re-lationship between the services. The framework provides a specification for each serviceand a reference implementation for two of them: bilateral negotiator and bargaining coor-dinator. The remaining services are intended to be implemented following the algorithmsalready developed in the automated negotiation literature.2Note that not all relations are depicted in the diagram.2Manuel Resinas, Pablo Fernandez and Rafael CorchueloFigura 2: Data structures2.1 Negotiation object and preferencesFigure 2 depicts the data structures implemented in the framework to support thenegotiation object and the preferences of the user. The negotiation object is an agreementthat it is composed of the parties involved in it and a set of terms that define its content.A term includes the counterparty to whom it is applied, constraints to specify functionalor non-functional descriptions or guarantees of the service, and, optionally, compensationsthat must be paid if the term is not fulfilled.The agreement preferences are composed of a set of statements that expresses featuresand requirements about the service and the desired characteristics of the negotiationprocess, and an assessment mechanism that is used to evaluate the proposals received. Astatement is an expression, usually rules or constraints, that can be applied over a service,a party or the negotiation process itself, and that it is linked to a set of languages thatgive semantics to the vocabulary used in it.2.2 Protocol managementThe software framework gives support for the negotiation protocol as follows: on theone hand, the information exchanged is expressed by the proposal data structure (seeFigure 2). A proposal extends the agreement data structure by including a negotiationperformative and allowing for the terms of the proposal to be left opened in order to berefined later on. A negotiation performative is the expression of the intention of the senderof a message about it. The minimum subset of performatives is accept, reject proposal,reject negotiation, and propose. On the other hand, the protocol enforcer (the whitebox in Figure 1) service acts as a proxy between the bilateral negotiator service and thecounterparty, it adapts the concrete protocol messages into the proposal data structure3Manuel Resinas, Pablo Fernandez and Rafael Corchueloand vice versa, it provides the performatives that can be used in a certain moment of thenegotiation, and ensures that the protocol rules [2] are obeyed.2.3 World modelling servicesThe goal of these services is to build a world model that is necessary for the decision-making services to carry out their tasks. There are five types of world modelling services(the light grey boxes in Figure 1). The inquirer service directly polls the informantservice of other counterparty to obtain objective information about it. The estimatorservices build models based on subjective information about other participants [13], themarket [11] and the service domain. Therefore, an automated negotiation system may usea reputation estimator service, an opponent behaviour estimator service, or a proposalssimilarity estimator service [3]. These estimators may be internal to our organisationor implemented by third parties. Estimator services must implement a query interfaceand may implement an update interface to upgrade their information about the world.Alternatively, they may use other sources of information such as querying the archiverservice. The archiver service serves as a storage of the history of all negotiations thathave been developed by the system. Finally, the estimators repository service decouplesthe services of the framework from a certain estimator service by acting as an intelligentregistry of estimator services.2.4 Decision-making servicesThe decision-making services (the dark grey boxes in Figure 1)defined by the softwareframework provide mechanisms to support the binding decision and response generation.Response generation The services for response generation can be divided into twogroups: negotiation services and coordination services. There are four negotiation ser-vices: the bilateral negotiator service coordinates all other negotiation services in orderto carry out a proposal-based bilateral negotiation with one counterparty. Specifically,it firstly uses a performative selector service to choose which response shall be sent tothe counterparty amongst all possible performatives. Then, if a counterproposal has tobe built, it uses a strategy service. This service builds a counterproposal given the lastproposal submitted by the counterparty and the models provided by world modelling ser-vices. In addition, a strategy selector service may be previously used to choose the mostappropriate strategy service. Therefore, this service can be seen as an intelligent registryof strategy services.There are a number of approaches to coordinate several negotiations. In [7], the co-ordinator indicates which strategy must be used in each negotiator and it is informed ofeach proposal received from the counterparty. Instead, here we propose a more decoupledapproach. The bargaining coordinator service coordinates several bilateral negotiators andacts as a bridge between them and the binding services. It periodically receives informa-4Manuel Resinas, Pablo Fernandez and Rafael Corchuelotion about the status of the negotiations and it provides them with policies that guidestheir behaviour (e.g. “be more agressive”). To obtain these policies, it uses the policiesgenerator services.Binding decision Two types of services provide support for the binding decision. Thecommit handler service has the final decision on when a binding proposal must be sub-mitted and whether a binding proposal that has been received should be accepted. Inaddition, it must establish when these decisions are going to be made. The commit han-dler service may use commit advisor services (e.g. a capacity planner) in order to obtainadvise about the convenience of committing to an agreement proposal.3 RELATED WORKWhile much work has been done in the development of negotiation protocols andstrategies, the work on software frameworks that supports automated negotiation hasbeen much more limited. Moreover, most of them only deal with negotiation protocolsand do not give support for world modeling and decision-making. This is the case of [2, 9].In [2], Bartolini et al. present a rules taxonomy for negotiation protocols and a softwareframework that uses the rules to deal with them. In [9], a service-oriented architectureis used to manage several negotiation protocols. Therefore, these works can be seen aspossible implementations of our protocol enforcer service.There have been other proposals [12, 4, 6] of software frameworks for automated ne-gotiation that do provide some limited support to decision-making and world modeling.In [6], a framework for automated negotiation of service level agreements in service gridsis presented. This framework builds on WS-Agreement and provides a protocol serviceprovider and a decision making service provider to deal with the negotiation process.However, it lacks world modelling support and all decision-making has to be implementedin one unique service decreasing the reusability.PANDA [4] is a framework that mixes utility functions and rules to carry out thedecision-making process. The decision-making component is composed of rules, utilityfunctions and an object pool with several estimation libraries, the negotiation history andthe current offer. However, elements like the object pool are vaguely specified. Moreover,it does not support querying other parties to get information either. Another drawbackis that information related to the negotiation process is not managed.DynamiCS is an actor-based framework developed by Tu et al. [12]. This frameworkmake a neat distinction between negotiation protocol and decision making model and theyuse a plug-in mechanism to support new protocols and strategies. Nevertheless, it does nottake into account external factors in the binding decision (e.g. resources available in theprovider), and its world modeling capabilities are very limited: no subjective informationis managed, querying information to other parties is not supported, no market models arebuilt and it does not create models based on the analysis of previous interactions.5Manuel Resinas, Pablo Fernandez and Rafael Corchuelo4 CONCLUSIONSThe work in automated negotiation in the last ten years has lead to a variety of decision-making algorithms and protocols. From these works, we extract two conclusions: (i) foran automated negotiation system to work in an open environment such as the Internet,it is necessary to give support to a number of negotiation protocols; (ii) the most appro-priate negotiation strategy depends on the context and, hence, the system must supporta variety of negotiation techniques and select the best one in each moment. Therefore,it is convenient to have a software framework that provides engineering support for soft-ware developers to build automated negotiation systems. In this paper, we present aservice-oriented software framework for concurrent proposal-based bilateral negotiationsof SLAs. Unlike other proposals, our framework offers full support for world modellingand advanced decision-making, including changing dynamically of negotiation strategydepending on the negotiation context and support for an advanced binding decision.REFERENCIAS[1] A. Andrieux, K. Czajkowski, A. Dan, K. Keahey, H. Ludwig, T. Nakata, J. Pruyne, J. Rofrano, S. Tuecke, and M. Xu.WS-Agreement Specification, 2004.[2] C. Bartolini, C. Preist, and N. R. Jennings. A Software Framework For Automated Negotiation. In Software Engi-neering For MAS III: Research Issues and Practical Applications, pages 213–235. Springer Verlag, 2005.[3] P. Faratin, C. Sierra, and N. R. Jennings. Using Similarity Criteria to Make Trade-Offs in Automated Negotiations.Artificial Intelligence, 142:205–237, 12 2002.[4] H. Gimpel, H. Ludwig, A. Dan, and B. Kearney. PANDA: Specifying Policies For Automated Negotiations of ServiceContracts. In ICSOC 2003, Lecture Notes in Computer Science, pages 287–302. Springer-Verlag, 2003.[5] N. R. Jennings, P. Faratin, A. R. Lomuscio, S. Parsons, M. Wooldridge, and C. Sierra. Automated Negotiation:Prospects, Methods and Challenges. Group Decision and Negotiation, 10:199–215, 3 2001.[6] A. Ludwig, P. Braun, R. Kowalczyk, and B. Franczyk. A framework for automated negotiation of service levelagreements in services grids. In Business Process Management Workshops: BPM 2005, volume 3812 of Lecture Notesin Computer Science, pages 89–101. Springer, Feb. 2006.[7] T. Nguyen and N. Jennings. Managing commitments in multiple concurrent negotiations. Electronic CommerceResearch and Applications, 4:362–376, 2005.[8] M. Resinas, P. Fernandez, and R. Corchuelo. A conceptual framework for automated negotiation systems. In Proceed-ings of IDEAL 06, Lecture Notes in Computer Science, page To appear. Springer, 2006.[9] S. Rinderle and M. Benyoucef. Towards the automation of e-negotiation processes based on web services - a modelingapproach. In Web Information Systems Engineering - WISE 2005, volume 3806 of Lecture Notes in Computer Science,pages 443–453. Springer, 2005.[10] C. Sierra, P. Faratin, and N. R. Jennings. A Service-Oriented Negotiation Model Between Autonomous Agents. InProc. of the 8th Europ. Workshop On Modelling Auton. Agents in a Multi-Agent World, pages 17–35. Springer-Verlag,1997.[11] K. M. Sim and E. Wong. Toward market-driven agents for electronic auction. Systems, Man and Cybernetics, PartA, IEEE Transactions on, 31(6):474–484, 2001.[12] M. Tu, C. Seebode, F. Griffel, and W. Lamersdorf. Dynamics: An actor-based framework for negotiating mobileagents. Electronic Commerce Research, 1(1 - 2):101–117, Feb. 2001.[13] D. Zeng and K. Sycara. Bayesian Learning in Negotiation. Int. J. Hum.-Comput. Stud., 48(1):125–141, 1998.6

Engineering automated negotiations

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