@techreport{TR-IC-09-44,
   number = {IC-09-44},
   author  =  {E.  Bacarin  and E.R.M. Madeira and C.M.B. Medeiros and
                   W.M.P. van der Aalst},
   title  = {{SPICA's Multi-party Negotiation Protocol: Implementation
                   using YAWL}},
   month = {November},
   year = {2009},
   institution = {Institute of Computing, University of Campinas},
   note = {In English, 46 pages.
    \par\selectlanguage{english}\textbf{Abstract}
       A  supply chain comprises several different kind of actors that
       interact  either  in an ad hoc fashion (e.g., an eventual deal)
       or  in  a  previously well planned way. In the latter case, how
       the  interactions  develop  is  described in contracts that are
       agreed  on  before  the  interactions start. This agreement may
       involve several partners, thus a multi-party contract is better
       suited than a set of bi-lateral contracts. If one is willing to
       negotiate  automatically such kind of contracts, an appropriate
       negotiation  protocol  should be at hand. However, the ones for
       bi-lateral   contracts   are   not   suitable  for  multi-party 
       contracts,  e.g.,  the way of achieving consensus when only two
       negotiators  are haggling over some issue is quite different if
       there  are  several  negotiators involved. In the first case, a
       simple  bargain  would  suffice,  but  in  the  latter a ballot
       process  is  needed. This paper presents a negotiation protocol
       for  electronic multi-party contracts which seamlessly combines
       several  negotiation  styles.  It  also  elaborates on the main
       negotiation  patterns  the  protocol  allows  for: bargain (for
       peer-to-peer  negotiation),  auction (when there is competition
       among the negotiators) and ballot (when the negotiation aims at
       consensus).  Finally,  it  describes  an implementation of this
       protocol  based on Web services, and built on the YAWL Workflow
       Management System.
  }
}