Arguing over Goals for Negotiation: Adopting an Assumption-Based Argumentation Decision Support System - Efficient Decision Support Systems: Practice and Challenges from Current to Future - page 233

S are the presumptions of an argument deriving the conclusion C and this argument is in a
subjectively admissible set.

Example 11 (Usage) . Figure 3 depicts our example, as described in Section 3.2, in the MARGO
syntax.
admissible([cheap, fast, good], AG, AD) returns:

AG = [cheap, fast]

AD = [s(d)]
admissibleArgument(cheap,P,S) returns:

P = [s(c), price(c,low), reply(accept)]
S = [s(c),reply(accept)]
MARGO has been used for service composition and orchestration within the ARGUGRID
project 5 . As discussed in (Toni et al., 2008), the ArguGRID system contains a semantic
composition environment, allowing users to interact with their agents, and a grid middleware
for the actual deployment of services. Service-oriented computing is an interesting test
bed for multi-agent system techniques, where agents need to adopt a variety of roles
that will empower them to provide services in open and distributed systems. Moreover,
service-oriented computing can benefit from multi-agent systems technologies by adopting
the coordination mechanisms, interaction protocols, and decision-making tools designed for
multi-agent systems, e.g. MARGO.
Bromuri et al. (Bromuri et al., 2009) have demonstrated the use of a fully decentralised
multi-agent system supporting agent-automated service discovery, agent-automated service
selection, and agent-automated negotiation of Service Level Agreements (SLAs) for the
selected services.
Requester agents select services according to their suitability to fulfil high-level user
requirements. These agents use argumentation in order to assess suitability and identify
“optimal” services. They argue internally using our concrete argumentation system linking
decisions on selecting services, (a possibly incomplete description of) the features of these
services, the benefits that these features guarantee (under possibly incomplete knowledge).
The ArguGRID system uses the MARGO tool for multi-attribute qualitative decision-making
to support the decision on suitable services.
As soon as the requester agents identify a suitable service, it engages in a negotiation process
with the provider agent for that service. The negotiation aims at agreeing a SLA on the
usage of the identified service, and is conducted using a realisation of the minimal concession
strategy of (Morge & Mancarella, 2010). According to this, agents start the negotiation with
their best offers. During the negotiation, an agent may concede or stand still. It concedes
minimally if the other agent has conceded in the previous step or it is making a move in the
third step of the negotiation (after offers by both agents have been put forward). It stands
still if the other agent has stood still in the previous step. This strategy has useful properties:
it is guaranteed to terminate and it is in symmetric Nash equilibrium. Both requester and
provider agents use MARGO, during negotiation, in order to decide their offers and whether
to concede or stand still.

5 http://www.argugrid.eu