Josep Lluis Arcos

AMELI: An Agent-Based Middleware for Electronic Institutions

The design and development of open multi-agent systems (MAS) is a key aspect in agent research. We advocate that they can be realised as electronic institutions. In this paper we focus on the execution of electronic institutions by introducing AMELI, an infrastructure that mediates agentsý interactions while enforcing institutional rules. An innovative feature of AMELI is that it is of general purpose (it can interpret any institution specification), and therefore it can be regarded as domain-independent. The combination of ISLANDER [5] and AMELI provides full support for the design and development of electronic institutions.

On the Formal Specifications of Electronic Institutions

In this article we argue that open agent organisations can be effectively designed and implemented as institutionalized electronic organisations (electronic institutions) composed of a vast amount of heterogeneous (human and software) agents playing different roles and interacting by means of speech acts. Here we take the view that the design and development of electronic institutions must be guided by a principled methodology. Along this direction, we advocate for the presence of an underlying formal method that underpins the use of structured design techniques and formal analysis, facilitating development, composition and reuse. For this purpose we propose a specification formalism for electronic institutions that founds their design, analysis and development.

Content-based Transformations

We describe a computer program which is able to estimate the tempo and the times of musical beats in expressively performed music. The input data may be either digital audio or a symbolic representation of music such as MIDI. The data is processed off-line to detect the salient rhythmic events and the timing of these events is analysed to generate hypotheses of the tempo at various metrical levels. Based on these tempo hypotheses, a multiple hypothesis search finds the sequence of beat times which has the best fit to the rhythmic events. We show that estimating the perceptual salience of rhythmic events significantly improves the results. No prior knowledge of the tempo, meter or musical style is assumed; all required information is derived from the data. Results are presented for a range of different musical styles, including classical, jazz, and popular works with a variety of tempi and meters. The system calculates the tempo correctly in most cases, the most common error being a doubling or halving of the tempo. The calculation of beat times is also robust. When errors are made concerning the phase of the beat, the system recovers quickly to resume correct beat tracking, despite the fact that there is no high level musical knowledge encoded in the system.

Engineering open environments with electronic institutions

Nowadays, with the expansion of Internet, there is a need of methodologies and software tools to ease the development of applications where distributed homogeneous entities can participate. Multiagent systems, and electronic institutions in particular, can play a main role in the development of this type of systems. Electronic institutions define the rules of the game in agent societies, by fixing what agents are permitted and forbidden to do and under what circumstances. The goal of this paper is to present EIDE, an integrated development environment for supporting the engineering of multiagent systems as electronic institutions.

Description and composition of bio-inspired design patterns: a complete overview

In the last decade, bio-inspired self-organising mechanisms have been applied to different domains, achieving results beyond traditional approaches. However, researchers usually use these mechanisms in an ad-hoc manner. In this way, their interpretation, definition, boundary (i.e. when one mechanism stops, and when another starts), and implementation typically vary in the existing literature, thus preventing these mechanisms from being applied clearly and systematically to solve recurrent problems. To ease engineering of artificial bio-inspired systems, this paper describes a catalogue of bio-inspired mechanisms in terms of modular and reusable design patterns organised into different layers. This catalogue uniformly frames and classifies a variety of different patterns. Additionally, this paper places the design patterns inside existing self-organising methodologies and hints for selecting and using a design pattern.

SaxEx: a case-based reasoning system for generating expressive musical performances

Abstract The problem of generating expressive musical performances in the context of tenor saxophone interpretations was studied. Several recordings of a tenor sax playing different Jazz ballads with different degrees of expressiveness including an inexpressive interpretation of each ballad were made. These recordings were analyzed, using Sms spectral modeling techniques, to extract information related to several expressive parameters. This set of parameters and the scores constitute the set of cases (examples) of a case‐based system. From this set of cases, the system infers a set of possible expressive transformations for a given new phrase applying similarity criteria, based on background musical knowledge, between this new phrase and the set of cases. Finally, SaxEx applies the inferred expressive transformations to the new phrase using the synthesis capabilities of Sms.

A case-based approach for coordinated action selection in robot soccer

Designing coordinated robot behaviors in uncertain, dynamic, real-time, adversarial environments, such as in robot soccer, is very challenging. In this work we present a case-based reasoning approach for cooperative action selection, which relies on the storage, retrieval, and adaptation of example cases. We focus on cases of coordinated attacking passes between robots in the presence of the defending opponent robots. We present the case representation explicitly distinguishing between controllable and uncontrollable indexing features, corresponding to the positions of the team members and opponent robots, respectively. We use the symmetric properties of the domain to automatically augment the case library. We introduce a retrieval technique that weights the similarity of a situation in terms of the continuous ball positional features, the uncontrollable features, and the cost of moving the robots from the current situation to match the case controllable features. The case adaptation includes a best match between the positions of the robots in the past case and in the new situation. The robots are assigned an adapted position to which they move to maximize the match to the retrieved case. Case retrieval and reuse are achieved within the distributed team of robots through communication and sharing of own internal states and actions. We evaluate our approach, both in simulation and with real robots, in laboratory scenarios with two attacking robots versus two defending robots as well as versus a defender and a goalie. We show that we achieve the desired coordinated passing behavior, and also outperform a reactive action selection approach.

Cooperative Case-Based Reasoning

We are investigating possible modes of cooperation among homogeneous agents with learning capabilities. In this paper we will be focused on agents that learn and solve problems using Case-based Reasoning (CBR), and we will present two modes of cooperation among them: Distributed Case-based Reasoning (DistCBR) and Collective Case-based Reasoning (ColCBR). We illustrate these modes with an application where different CBR agents able to recommend chromatography techniques for protein purification cooperate. The approach taken is to extend Noos, the representation language being used by the CBR agents. Noos is knowledge modeling framework designed to integrate learning methods and based on the task/method decomposition principle. The extension we present, Plural Noos, allows communication and cooperation among agents implemented in Noos by means of three basic constructs: alien references, foreign method evaluation, and mobile methods.

KNOWLEDGE AND EXPERIENCE REUSE THROUGH COMMUNICATION AMONG COMPETENT (PEER) AGENTS

This article addresses an extension of the knowledge modeling approaches, namely to multi-agent systems where communication and coordination are necessary. We propose the notion of competent agent and define the basic capabilities of these agents for the extension to be effective. An agent is competent when it is capable of reasoning about its own competence and that of the other agents with which it cooperates in a given domain. In our framework, an agent has competence models of itself and of its acquaintances from which it can decide, for a specific problem to be solved, the type of cooperative activity it can request and from which agent. In this paper we focus on societies of peer agents, i.e. agents that are able to solve the same type of task but that may have different degrees of competence for specific problem ranges.

An Interactive Case-Based Reasoning Approach for Generating Expressive Music

In this paper we present an extension of an existing system, called SaxEx, capable of generating expressive musical performances based on Case-Based Reasoning (CBR) techniques. The previous version of SaxEx used pre-fixed criteria within the different CBR steps and, therefore, there was no room for user interaction. This paper discusses the necessity of user interaction during the CBR process and how this decision enhances the capabilities and the usability of the system. The set of evaluation experiments conducted show the advantages of SaxExs new interactive functionality, particularly for future educational applications of the system.