Normative and Trust-Based Systems as Enabler Technologies for Automated Negotiation

In this chapter we elaborate on the specification and exploitation of a software agent-based Electronic Institution, embedding both a Normative Environment and a Computational Trust service which, when used in tandem, lead to an enhanced process of selection of potential business partners and enable automatic contract negotiation. We introduce a formalization of a Normative Environment, which accommodates the establishment of e-contracts and provides a contract monitoring facility. Contracts are established and enacted by contractual partners previously selected through an automatic negotiation process. While monitoring contracts at run-time, the Normative Environment makes use of a reporting mechanism to inform relevant contract enactment events to interested parties. In our work, we benefit from this reporting function by exploiting it as an input to a computational trust mechanism. We also present the built-in Computational Trust service, a key element of the Electronic Institution. This service includes two main components: the Contractual Evidences Manager, which generates contractual evidences from contract enactment events; and the Trust Aggregation Engine, a situation-aware trust aggregator that takes into account properties of the dynamics of trust and the contractual context under assessment. We then discuss and propose the potential exploitation of trustworthiness estimations in B2B negotiation processes, including the stages of preselection of partners and contract drafting. Using our computational trust approach, we have implemented a trust-based preselection mechanism included in an agent-based automatic negotiation process. We performed an empirical evaluation of our proposal, by running a set of experiments in an experimental setting enriched with realistic negotiation elements. The results obtained allow us to point to specific conditions under which the preselection of partners based on trust is beneficial.

Keywords: Electronic Institution, B2B Negotiation, Automatic Negotiation, Normative Environment, Electronic Contracts, Norms, Contract Drafting, Computational Trust, Trust and Contrating, Multi-agent Systems.