Exploiting simple corporate memory in iterative coalition games

Amongst the challenging problems that must be addressed in order to create increasingly automated electronic commerce systems are those which involve forming coalitions of agents to exploit a particular market opportunity. Furthermore economic systems are normally continuous dynamic systems generating many instances of the same or similar problems (the regular calls for tender, regular emergence of new markets etc.).The work described in this paper explores how simple forms of memory can be exploited by agents over time to guide decision making in iterative sequences of coalition formation problems enabling them to build up social knowledge in order to improve their own utility and the ability of the population to produce increasingly well suited coalitions for a simple call-for-tender economy.Postprint (published version

Towards a contract-based interoperation model

Web Services-based solutions for interoperating processes are considered to be one of the most promising technologies for achieving truly interoperable functioning in open environments. In the last three years, the specification in particular of agreements between resource / service providers and consumers, as well as protocols for their negotiation have been proposed as a possible solution for managing the resulting computing systems. In this report, the state of the art in the area of contract-based web service applications is closely studied, identifying current limitations and possibilities. On the basis of this analysis, a general model for contract specification, negotiation, agreement, execution and management is introduced. Such a model has broad applicability both in electronic business integration and distributed knowledge management systems for decision support. Initial work presented here was completed in September 2005 and is published here as background for the European Commission funded project IST CONTRACT http://www.ist-contract.org/.Postprint (published version

The impact of network topology on trade in bartering networks: Devising and assessing network information propagation mechanisms

Resource allocation in distributed systems is an exciting area of research. Inherent properties in this environment, such as strategic users acting selfishly and the structure of the environment within which exchanges occur, are relevant challenges to study. This paper proposes a market–based resource allocation in a distributed environment. Our model has as it is objective the exploration of the effects of network structure in the allocation of performance together with mechanisms to improve the performance of the market. The proposed model, as well as mechanisms to maximize the allocation of objects/goods have been implemented and studied experimentally. The results obtained shows that topology affects the performance of the market. Using information propagation mechanisms clearly contributes to its improvement.Postprint (published version

Studying viable free markets in peer-to-peer file exchange applications without altruistic agents

File sharing networks are among the most popular applications of Peer-to-Peer (P2P) technology to date and have been widely studied in terms of the performance, behavior, topology and other properties. A persistent theme throughout this research has been the evidence that many P2P file sharing systems rely on the presence of altruistic users, who provide files, network capacity or some other goods without obvious personal gain to work and are potentially damaged by the presence of too many free-riders (users who consume resources but do not provide to others in return). In this paper we will explore the use of simple market mechanisms for P2P file sharing which function without the need of altruistic users considering the conditions under which such markets may be viable.Postprint (published version

Modelo unificado para la integración entre ontologías y mapas conceptuales

El desarrollo y utilización de las ontologías, se está viendo cada vez más en ascenso, demostrando con ello su gran utilidad en los contextos en los que se necesite formalizar y compartir un conocimiento. Cada vez más se está requiriendo la creación de un ambiente que facilite la colaboración en el trabajo con las ontologías y hoy no están creadas las condiciones para esto. El proceso de elaboración de ontologías, las herramientas disponibles para su obtención y mantenimiento y los lenguajes de especificación que se están utilizando, tienen un alto grado de complejidad para su interpretación y amplia utilización por parte de personas no son expertas en el tema. Esto sugiere la utilización de herramientas más simple, que vinculada con las ontologías pueda ser comprendida y mejor aprovechadas por el hombre y que a su vez mantenga las capacidades para su interpretación computacionalmente. Los mapas conceptuales son una herramienta muy intuitiva para la representación del conocimiento que posee el hombre. Las facilidades que brinda en su elaboración, flexibilidad y estructura, lo han convertido en una herramienta muy útil para la gestión del conocimiento y la colaboración. La flexibilidad de los mapas conceptuales, lo convierte en una herramienta muy poco formal, a diferencia de las ontologías, sin embargo, se considera que esto no impide pensar que se puedan integrar con las ontologías y ser utilizados como un lenguaje de representación gráfico conceptual de estas. En esta investigación se propone la definición de un modelo que permite la integración entre las ontologías y los mapas conceptuales. El Modelo Unificado, como se le ha llamado, es resultado de la unificación de algunas características resultantes de análisis realizados a diferentes formas de representación del conocimiento de la Inteligencia Artificial y los mapas conceptuales. La características identificadas e integradas generó un conjunto de criterios que fundamentan la integración propuesta en ontologías y mapas conceptuales. Se proponen un conjunto de métodos que permiten la transformación del conocimiento representado en un mapa conceptual a OWL y viceversa, como implementación de este modelo. Son propuestas algunas especificaciones sintácticas y el uso de EuroWordnet en los procesos de transformación y se describen algunos ejemplos para un mayor entendimiento del modelo propuesto.Postprint (published version

An analysis of paperclip arbitrage

While bartering is arguably the world's oldest form of trade there are still many instances where it surprises us. One such case is the remarkable story of Kyle MacDonald who, by means of a sequence of bartering exchanges between July 2005 and July 2006, managed to trade a small red paperclip for a full sized house in the town of Kipling Saskatchewan. Although there are many factors to consider in this achievement, his feat raises basic questions about the nature of the trades made and to what extent they are repeatable by others. Furthermore, it raises issues as to whether such events could occur in Agent–based Electronic Environments – and under what conditions. In this paper we provide an intuitive model for the type of trading environment experienced Kyle and study its consequences. In particular the work is focused on understanding whether such trading phenomena require altruistic agents to be present in the environment and under what conditions agents can reach their individual goals. Results cover both the case of a singlePostprint (published version

Applying Internet random early detection strategies to scheduling in grid environments

Resource Allocation in Grid environments to date is generally carried out under the assumption that there is one primary scheduling system scheduling jobs. However, as environments tend towards larger open “utility” Grids it becomes increasingly likely that deployments will involve multiple independent schedulers allocating jobs over the same resources. In this paper we show that, if using current standard scheduling approaches, such multi­scheduler environments may well be prone to serious oscillation problems in resource allocation similar to those commonly found in IP network traffic. Further we demonstrate how common techniques from IP networks – in particularly approaches based on Random Early Detection (RED) buffer management and its subsequent extensions / variations – may provide an effective way to damp or eliminate such oscillations. The paper describes the analogy between multi­scheduler Grid resource allocation and IP network routing and explores the impact of oscillation and RED methods by simulation.Postprint (published version

Illegal agents? creating wholly independent autonomous entities in online worlds

The last 2-3 years have seen an explosion in new types of on-line worlds accessible both to human users and, increasingly, automated electronic systems - from new e-Business services to advanced Web applications and huge Internet based multi-player gaming worlds. The aim of this paper is to demonstrate that it may now already be possible (although potentially illegal) to exploit these online environments in order to construct wholly independent autonomous electronic entities able to act for themselves in the real world: sustaining themselves financially, to all intents purposes appearing externally as a legal person indistinguishable from a human being and surviving for periods of up to several years without external assistance.Postprint (published version

Modelling coalition formation over time for iterative coalition games

Postprint (published version