Faculdade de Ciências, Campo Grande, 1700 Lisboa, Portugal, new proposals without changing problem structure, and (iii) re-

3 Faculdade de Ciências, Campo Grande, 1700 Lisboa, Portugal, new proposals without changing problem structure, and (iii) re-

hcoelho@di.fc.ul.pt.

definition of current problem structure. The mechanism is generic and flexible (see subsection 5.1).

Proceedings of the ECAI 2000 Workshop 13 "Agent Technologies and Their Application Scenarios in Logistics" edited by I. J. Timm et al. page 61

The second contribution is to describe an approach for defining Manufacturing Enterprise

a structure for negotiation problems. A negotiation problem struc- ture (NPstruct) is defined as a hierarchical And-Or tree expressing

a relationship between negotiation goals and issues. NPstruct is

Agent

generated from an incompatible plan. It represents a natural link between planning and negotiation and allows the direct integration of these two cognitive capabilities into a control architecture for

Resource Management

Scheduler

intentional agents. Also, problem structure generation acknowl-

Supplier n

Agent

Customer n

edges the role of conflict as a driving force for negotiation. The third contribution is to describe a method for proposal gen-

Key:

eration A negotiation proposal is defined as a set of facts (leaves

- agent;

Dispatcher

of NPstruct) with logical values (true, false, or any). A fact is a

- agent

tuple with two components, namely a negotiation issue and a value interaction. for the issue. Proposal generation is based on the resolution of

Figure 1. Simplified multi-agent supply chain system

NPstruct and supports cooperative and non-cooperative negotia- tion behavior.

problem of integrating such isolated functions into a complete, The fourth contribution is to introduce a method for generating

global supply chain.

counterproposals without making concessions. The method, called The coordination of the supply chain functions has been an- bargaining issue manipulation , consists mainly of adding to a

other active area of research. Also, most research addresses the proposal negotiation issues considered superfluous, in the hope

coordination of two or more supply chain functions, such as pro- that the other parties will feel strongly about these issues.

duction-distribution and buyer-vendor coordination. Despite the The last contribution is to describe a set of negotiation tactics

importance of the results obtained, the coordination of multiple for generating counterproposals, by making concessions.

supply chain functions is still an open problem. Intentional agents equipped with the negotiation mechanism are

We sketch simplified solutions to the integration and coordina- currently being implemented in Prolog. Our work follows an ex-

tion problems in this article. More specifically, we address these perimental line. The form of the mechanism, and the assumptions

problems by organizing the supply chain as a collection of inten- it makes, has been guided by our experiences in developing agents

tional agents that are able to coordinate their activities through for the domain of supply chain management. In earlier work, we

negotiation.

described intentional agents and presented part of the formal negotiation mechanism (see [23]). In this article, we define the

2.1 System architecture

concept of conflict of interests and continue the description of the negotiation mechanism. We also introduce the type of application

The supply chain of a manufacturing enterprise is modeled as a domains we are interested in, by describing a simplified multi-

multi-agent system [7]. The system is composed of a collection of agent supply chain system.

intentional agents, each responsible for performing one or more The remainder of this article is organized as follows. Section 2

supply chain functions. The architecture of a simplified system is describes a simplified multi-agent supply chain system. Section 3

shown in Fig. 1. We are currently working on the following agents: presents the components of the mental state and the planning

logistics agent, scheduler, resource management agent, dispatcher, mechanism of intentional agents. Section 4 presents the concept of

a number of suppliers, and a number of customers. A brief de- conflict of interests and describes axioms for conflict detection.

scription of each agent follows.

Section 5 describes the main components of the negotiation The logistics agent manages the movement of raw materials mechanism. Finally, related work and concluding remarks are

from the suppliers, the manufacturing of intermediate goods and presented in sections 6 and 7 respectively.

final products by the enterprise, and the distribution of the prod- ucts to the customers. He receives customer orders, deviations in