Eugénio C. Oliveira

Multi-agent systems: which research for which applications

For sometime now agent-based and multi-agent systems (MASs) have attracted the interest of researchers far beyond traditional computer science and artificial intelligence (AI). In this article we try to identify focal points of interest for researchers working in the area of distributed AI (DAI) and MAS as well as application-oriented researchers coming from related disciplines, e.g. electrical and mechanical engineering. We do this by presenting key research topics in DAI and MAS research and by identifying application domains in which the DAI and MAS technologies are most suitable. The research topics we discuss are separated into agent architectures and organisations, negotiation among agents, and self-adaptation of MAS using learning techniques. Regarding the application domains for these techniques we distinguish the application domains according to whether the agents control a physical or virtual body (Gestalt) or not. This separation of the application domains is not strict; it represents two ends of a continuum. On the one end of this continuum we have autonomous robot systems which act in a physical environment (sometimes referred to as hardware agents), and on the other end, we have abstract environments, such as in workflow systems, which rarely display the geometrical and physical aspects of the environment we are used to living in.

Situation Based Strategic Positioning for Coordinating a Team of Homogeneous Agents

In this paper we are proposing an approach for coordinating a team of homogeneous agents based on a flexible common Team Strategy as well as on the concepts of Situation Based Strategic Positioning and Dynamic Positioning and Role Exchange. We also introduce an Agent Architecture including a specific high-level decision module capable of implementing this strategy. Our proposal is based on the formalization of what is a team strategy for competing with an opponent team having opposite goals. A team strategy is composed of a set of agent types and a set of tactics, which are also composed of several formations. Formations are used for different situations and assign each agent a default spatial positioning and an agent type (defining its behaviour at several levels). Agents reactivity is also introduced for appropriate response to the dynamics of the current situation. However, in our approach this is done in a way that preserves team coherence instead of permitting uncoordinated agent behaviour. We have applied, with success, this coordination approach to the RoboSoccer simulated domain. The FC Portugal team, developed using this approach won the RoboCup2000 (simulation league) European and World championships scoring a total of 180 goals and conceding none.

An Electronic Market Architecture for the Formation of Virtual Enterprises

Economic organisations are facing new challenges due to the proliferation of Electronic Markets where competition and responsiveness are issues that will determine organisation’s economic survival. A Virtual Enterprise is a temporary network of individual enterprises, which, due to its higher flexibility and agility is capable of effectively responding to those challenging requirements. This paper proposes an Electronic Market system’s architecture together with a multi-criteria negotiation protocol for Virtual Enterprise formation.

Virtual enterprise normative framework within electronic institutions

Virtual Enterprises are a major trend within the B2B scenario. Technological support towards enabling this cooperation model includes the multi-agent systems paradigm. In this paper we identify requirements of Virtual Enterprise contracts, developing a normative framework for contract validation and enforcement. Furthermore, we enclose this conception within the structure of an Electronic Institution, which governs and supports the interaction of agents in business scenarios, providing specific services such as brokering, reputation, negotiation mediation, and contract related services. We focus on electronic contracting as a means of establishing cooperation agreements, and we describe the institutions role on the e-contracting life-cycle.

Ontology-based Services to help solving the heterogeneity problem in e-commerce negotiations

In a dynamic environment of e-commerce negotiations where transactions involve interaction among different enterprises, using different representations and terminologies, a common understanding is crucial. This paper combines the use of ontologies and agent technologies to help in solving the heterogeneity problem in e-commerce negotiations. The result is an implementation of the Ontology-based Services, which apply a methodology that assesses lexical and semantic similarity among concepts represented in different ontologies. A solution integrating the Jade platform and OWL format is presented as well as an Ontology Interaction Protocol, which is combined with the FIPA Contract Net Protocol.

More like these: growing entity classes from seeds

We present a corpus-based approach to the class expansion task. For a given set of seed entities we use co-occurrence statistics taken from a text collection to define a membership function that is used to rank candidate entities for inclusion in the set. We describe an evaluation framework that uses data from Wikipedia. The performance of our class extension method improves as the size of the text collection increases.

Emotional advantage for adaptability and autonomy

During the last two decades, researchers have collected a decisive amount of experimental evidence about the fundamental role of Emotion on cognitive processing. Emotional phenomena have been correlated with effective decision-making processes, memory, learning and other high-level cognitive capabilities and skills (e.g. risk assessment). In this paper we will describe an ongoing work that aims to design new Agent Architectures influenced by what has been learned in psychology and neurosciences about Emotion-cognition interaction. We will present an Agent architecture that includes several emotional-like mechanisms, namely: emotional evaluation functions, Emotion-biased processing, emotional tagging and mood congruent memory. These mechanisms are intended to increase the performance and adaptability of Agents operating in real-time environments. We will also introduce Pyrosim, a MAS platform we have developed to serve as an appropriate test-bed for Emotional-based Architectures, which simulates a forest fire in a complex 3D environment.

Electronic institutions for B2B: dynamic normative environments

The regulation of the activity of multiple autonomous entities represented in a multi-agent system, in environments with no central design (and thus with no cooperative assumption), is gaining much attention in the research community. Approaches to this concern include the use of norms in so-called normative multi-agent systems and the development of electronic institution frameworks. In this paper we describe our approach towards the development of an electronic institution providing an enforceable normative environment. Within this environment, institutional services are provided that assist agents in forming cooperative structures whose commitments are made explicit through contracts. Our normative framework borrows some concepts from contract law theory. Contracts are formalized using norms which are used by the institution while monitoring agents’ activities, thus making our normative environment dynamic. We regard the electronic institution as a means to facilitate both the creation and the enforcement of contracts between agents. A model of “institutional reality” is presented that allows for monitoring the fulfillment of norms. The paper also distinguishes our approach from other developments of the electronic institution concept. We address the application of our proposal in the B2B field, namely regarding the formation of Virtual Organizations.

Towards an Architecture for Emotional BDI Agents

In this paper we present the emotional-BDI architecture, an extension to the BDI architecture supporting artificial emotions and including internal representations for agents capabilities and resources. The architecture we present here is conceptual, defining which components should exist so that emotional-BDI agents can use effective capabilities as well as effective resources in order to better cope with highly dynamic environments

A Language for Specifying Complete Timetabling Problems

The timetabling problem consists in fixing a sequence of meetings between teachers and students in a given period of time, satisfying a set of different constraints. There are a number of different versions of the timetabling problem. These include school timetabling (where students are grouped in classes with similar degree plans), university timetabling (where students are considered individually) and examination timetabling (i.e. scheduling of university exams, avoiding student double booking). Several other problems are also associated with the more general timetabling problem, including room allocation, meeting scheduling, staff allocation and invigilator assignment. Many data formats have been developed for representing different timetabling problems. The variety of data formats currently in use, and the diversity of existing timetabling problems, makes the comparison of research results and exchange of data concerning real problems extremely difficult. In this paper we identify eight timetabling sub-problems and, based on that identification, we present a new language (UniLang) for representing timetabling problems. UniLang intends to be a standard suitable as input language for any timetabling system. It enables a clear and natural representation of data, constraints, quality measures and solutions for different timetabling (as well as related) problems, such as school timetabling, university timetabling and examination scheduling.