Automated service negotiation between autonomous computational agents.
Multi-agent systems are a new computational approach for solving real world, dynamic and open system
problems. Problems are conceptualized as a collection of decentralised autonomous agents that collaborate
to reach the overall solution. Because of the agents autonomy, their limited rationality, and the distributed
nature of most real world problems, the key issue in multi-agent system research is how to model interactions
between agents. Negotiation models have emerged as suitable candidates to solve this interaction
problem due to their decentralised nature, emphasis on mutual selection of an action, and the prevalence of
negotiation in real social systems.
The central problem addressed in this thesis is the design and engineering of a negotiation model for
autonomous agents for sharing tasks and/or resources. To solve this problem a negotiation protocol and
a set of deliberation mechanisms are presented which together coordinate the actions of a multiple agent
In more detail, the negotiation protocol constrains the action selection problem solving of the agents
through the use of normative rules of interaction. These rules temporally order, according to the agents'
roles, communication utterances by specifying both who can say what, as well as when. Specifically,
the presented protocol is a repeated, sequential model where offers are iteratively exchanged. Under this
protocol, agents are assumed to be fully committed to their utterances and utterances are private between
the two agents. The protocol is distributed, symmetric, supports bi and/or multi-agent negotiation as well
as distributive and integrative negotiation.
In addition to coordinating the agent interactions through normative rules, a set of mechanisms are presented
that coordinate the deliberation process of the agents during the ongoing negotiation. Whereas the
protocol normatively describes the orderings of actions, the mechanisms describe the possible set of agent
strategies in using the protocol. These strategies are captured by a negotiation architecture that is composed
of responsive and deliberative decision mechanisms. Decision making with the former mechanism is based
on a linear combination of simple functions called tactics, which manipulate the utility of deals. The latter
mechanisms are subdivided into trade-off and issue manipulation mechanisms. The trade-off mechanism
generates offers that manipulate the value, rather than the overall utility, of the offer. The issue manipulation mechanism aims to increase the likelihood of an agreement by adding and removing issues into the
negotiation set. When taken together, these mechanisms represent a continuum of possible decision making
capabilities: ranging from behaviours that exhibit greater awareness of environmental resources and less to
solution quality, to behaviours that attempt to acquire a given solution quality independently of the resource
The protocol and mechanisms are empirically evaluated and have been applied to real world task
distribution problems in the domains of business process management and telecommunication management.
The main contribution and novelty of this research are: i) a domain independent computational model
of negotiation that agents can use to support a wide variety of decision making strategies, ii) an empirical
evaluation of the negotiation model for a given agent architecture in a number of different negotiation environments,
and iii) the application of the developed model to a number of target domains. An increased
strategy set is needed because the developed protocol is less restrictive and less constrained than the traditional
ones, thus supporting development of strategic interaction models that belong more to open systems.
Furthermore, because of the combination of the large number of environmental possibilities and the size of
the set of possible strategies, the model has been empirically investigated to evaluate the success of strategies
in different environments. These experiments have facilitated the development of general guidelines
that can be used by designers interested in developing strategic negotiating agents. The developed model
is grounded from the requirement considerations from both the business process management and telecommunication
application domains. It has also been successfully applied to five other real world scenarios.