María-Victoria Belmonte

Ontologies and agents for a bus fleet management system

This paper reports on the design and implementation of a multi-agent decision support system for the bus fleet management domain. In particular, we show a complete description of the proposed multi-agent architecture and focus mainly on knowledge and software engineering features. The system has been developed in collaboration with the Malaga urban bus company (EMT) and it is based on a faithful reproduction of the real operating conditions of three existing lines of this company.

Coalition formation in p2p file sharing systems

P2P file sharing systems are distributed systems consisting of interconnected nodes able to organize themselves in networks, with the purpose of sharing content. Recent empirical studies have shown that they suffer from freeloaders, that is, peers that consume many more resources or content than they contribute. In this paper we propose a coalition formation based incentive mechanism for P2P file sharing systems, that improves the system performance for the coalition participant peers. In addition, it discourages free-loader like behavior. The mechanism presents a formal approach to the problem based on game theory that takes into account the rational and self-interested behavior of the peers.

Agent coordination for bus fleet management

This paper presents an abstract multiagent architecture useful for Decision Support Systems (DSS), and shows how this architecture can be instantiated to a particular real-world domain, Bus Fleet Management (BFM). After discussing the benefits of adopting a multiagent approach for DSS, the paper introduces the real world case study and analyzes it. Next, an abstract MAS architecture for DSS in general, and specialized then for BFM case study is presented. The architecture includes a set of different agents which are in charge of different social roles, and what is needed for their coordination, the Coordination Facilitator and the coordination protocols. The paper is concentrated in this point showing a concrete example in the BFM domain.

A robust deception-free coalition formation model

We study two properties of coalition formation algorithms, very important for their application in real-life scenarios: robustness and tolerance to some agent misbehaviors. The study is performed for a previously proposed coalition formation model-based upon game theory for a class of task-oriented problems that guarantees an optimum task allocation and a stable (fair) profit division. The results show acceptable behavior and performance.

Layered shape grammars

Abstract In this article we propose a computer-aided conceptual design system to assist modelling at the early stages of design. More precisely, we address the problem of providing the designer with design alternatives that can be used as starting points of the design process. To guide the generation of such alternatives according to a given set of design requirements, the designer can express both visual knowledge in the form of basic geometric transformation rules, and also logic constraints that guide the modelling process. Our approach is based on the formalism of shape grammars, and supplements the basic algorithms with procedures that integrate logic design constraints and goals. Additionally, we introduce a layered scheme for shape grammars that can greatly reduce the computational cost of shape generation. Shape grammars, constraints, goals and layers can be handled through a graphic environment. We illustrate the functionalities of ShaDe through two use cases taken from the architectural design and video games domains, and also evaluate the performance of the system.

COALITIONS AMONG INTELLIGENT AGENTS: A TRACTABLE CASE

Coalition formation is an important mechanism for cooperation in multiagent systems. In this paper we address the problem of coalition formation among self‐interested agents in superadditive task‐oriented domains. We assume that each agent has some “structure,” i.e., that it can be described by the values taken by a set of m nonnegative attributes that represent the resources w each agent is endowed with. By defining the coalitional value as a function V of w, we prove a sufficient condition for the existence of a stable payment configuration—in the sense of the core—in terms of certain properties of V. We apply these ideas to a simple case that can be described by a linear program and show that it is possible to compute for it—in polynomial time—an optimal task allocation and a stable payment configuration.

An Intelligent Tutor for a Web-Based Chess Course

Web-based intelligent tutoring systems try to fill the gap between human teachers and printed textbooks as distance learning aids. Actually, intelligent tutoring systems research is concerned with the development of computer tools that show adaptive capabilities in the domain of tutoring, where the students progress is autonomously monitored and guided according to some tutoring strategy. This paper provides details on the analysis, design and implementation of such a system. STIA (Sistema Tutor en Internet de Ajedrez) is a fully implemented Web-based tool developed to provide adaptive guidance and help while learning chess basics. In STIA the task of the tutor is to guide the student efficiently through the course material, according to the tutoring strategy defined by the course authors. This is achieved in two ways. First, it imposes limits on the portion of course material the students can access. This prevents them from getting lost in a flood of information. Second, the tutor evaluates each students knowledge through a set of problems, and according to result recommends reviewing theory, solving more problems or advancing through the course.

Learning Bayesian Networks for Student Modeling

In the last decade, there has been a growing interest in using Bayesian Networks (BN) in the student modelling problem. In order to develop a Bayesian Student Model (BSM), it is necessary to define the structure (nodes and links) and the parameters. Usually the structure can be elicited with the help of human experts (teachers), but the difficulty of the problem of parameter specification is widely recognized in this and other domains. In the work presented here we have performed a set of experiments to compare the performance of two Bayesian Student Models, whose parameters have been specified by experts and learnt from data respectively. Results show that both models are able to provide reasonable estimations for knowledge variables in the student model.

Designing Multiagent Decision Support Systems for Traffic Management

Modern Decision Support Systems (DSS) not only store large amounts of decision-relevant data, but also aim at assisting decision-makers in exploring the meaning of that data, so as to take decisions based on understanding. To this end, a distributed approach to the construction of DSS has become popular: decision-support agents are responsible for parts of the decision-making process in a (semi-)autonomous (individually) rational fashion. However, despite the advances in the field of agent-oriented software engineering, a principled approach to the design of multiagent systems for decision support is still to come.

File Sharing Service over a Generic P2P Simulator

This work describes a generic peer to peer (P2P) simulator for service oriented networks. The tool has been designed to test different algorithms, the version presented here includes the implementation of a collaborative file sharing service, designed to simulate different user behaviours with the goal of analyzing the impact of malicious users on this kind of service. The file sharing service proposal includes a coalition formation algorithm and a reputation mechanism to ensure service equity, based on game theory.