The organisation of sociality: a manifesto for a new science of multi-agent systems

In this paper, we pose and motivate a challenge, namely the need for a new science of multi-agent systems. We propose that this new science should be grounded, theoretically on a richer conception of sociality, and methodologically on the extensive use of computational modelling for real-world applications and social simulations. Here, the steps we set forth towards meeting that challenge are mainly theoretical. In this respect, we provide a new model of multi-agent systems that reflects a fully explicated conception of cognition, both at the individual and the collective level. Finally, the mechanisms and principles underpinning the model will be examined with particular emphasis on the contributions provided by contemporary organisation theory

Algorithms for finding coalitions exploiting a new reciprocity condition

We introduce a reciprocity criterion for coalition formation among goal-directed agents, which we call the indecomposable do-ut-des property. It refines an older reciprocity property, called the do-ut-des or give-to-get property by considering the fact that agents prefer to form coalitions whose components cannot be formed independently. A formal description of this property is provided as well as an analysis of algorithms and their complexity. We provide an algorithm to decide whether a coalition has the desired property, and we show that the problem to verify whether a single coalition satisfies the property is tractable. Moreover, we provide an algorithm to search all the sub-coalitions of a given coalition satisfying the new property. Even if this problem is not computationally tractable, we show that in several cases, also the complexity of this problem may decrease considerably

XML documents schema design

The eXtensible Markup Language (XML) is fast emerging as the dominant standard for storing, describing and interchanging data among various systems and databases on the intemet. It offers schema such as Document Type Definition (DTD) or XML Schema Definition (XSD) for defining the syntax and structure of XML documents. To enable efficient usage of XML documents in any application in large scale electronic environment, it is necessary to avoid data redundancies and update anomalies. Redundancy and anomalies in XML documents can lead not only to higher data storage cost but also to increased costs for data transfer and data manipulation.To overcome this problem, this thesis proposes to establish a formal framework of XML document schema design. To achieve this aim, we propose a method to improve and simplify XML schema design by incorporating a conceptual model of the DTD with a theory of database normalization. A conceptual diagram, Graph-Document Type Definition (G-DTD) is proposed to describe the structure of XML documents at the schema level. For G- DTD itself, we define a structure which incorporates attributes, simple elements, complex elements, and relationship types among them. Furthermore, semantic constraints are also precisely defined in order to capture semantic meanings among the defined XML objects.In addition, to provide a guideline to a well-designed schema for XML documents, we propose a set of normal forms for G-DTD on the basis of rules proposed by Arenas and Libkin and Lv. et al. The corresponding normalization rules to transform from a G- DTD into a normal form schema are also discussed. A case study is given to illustrate the applicability of the concept. As a result, we found that the new normal forms are more concise and practical, in particular as they allow the user to find an 'optimal' structure of XML elements/attributes at the schema level. To prove that our approach is applicable for the database designer, we develop a prototype of XML document schema design using a Z formal specification language. Finally, using the same case study, this formal specification is tested to check for correctness and consistency of the specification. Thus, this gives a confidence that our prototype can be implemented successfully to generate an automatic XML schema design

Contributions to an anthropological approach to the cultural adaptation of migrant agents

This thesis proposes the use of Cultural Anthropology as a source of inspiration for solutions to the problem of adaptation of autonomous, intelligent, computational agents that migrate to societies of agents with distinctive features from the ones of the society where those agents were originally conceived. This has implications for interoperation of disparate Multi-Agent Systems. In particular, the cognitive approach to anthropology is argued to be a suitable theoretical foun-dation for this topic. Fieldwork practice in social anthropology is also indicated as an useful source of ideas. A pragmatic theory of intensionality is incorporated in this anthropological approach, resulting in a mechanism that allows agents to ascribe intensional ontologies of terms to societies that use unfamiliar means of communication; also, taxonomical relations among the terms in such ontologies can be retrieved, by means of a process inspired by the counterpart activity of ethnographers. This is presented using the Z notation for formal specification of systems, and illustrated on a set of terms from the game of cricket. Subsequently, a simulation of a game of cricket is described where one of the players is unfamiliar with the game, and therefore needs to learn the game by observing the other players. A reasonable behaviour for such a player is obtained, and the simulation offers grounds for further anthropologically-based studies. Further, a study of theories of moral sentiments is presented, and the Iterated Prisoner's Dilemma is used in simulations based on those ideas. The results of the simulations show clearly the positive impact, on groups of agents, of altruistic behaviour; this can only be coherently obtained in autonomous agents by modelling emotions, which are relevant for this project as anthropologists recognise them as an essential cross-cultural link. Finally, the consequences of this project to conceptions of Distributed Artificial Intelligence are discussed

SMA aplicado a la gestión de tráfico de voz en redes LAN

El objetivo principal de este proyecto es el desarrollo de una metodología para el diseño de redes de datos que soporten de una forma efectiva, aplicaciones en tiempo real como es el caso de la VoIP. Así mismo se plantea la implementación de un sistema multiagente para la gestión del tráfico en la red, mejorando el desempeño de ésta, permitiendo la priorización efectiva del tráfico. Este proyecto utiliza los conceptos básicos para diseño de redes LAN como son la segmentación de tráfico, los dominios de broadcast y de colisiones para proponer un diseño físico y lógico de la red. Se analizan las características de una red de datos existente como la capacidad de procesamiento y conmutación de los equipos activos de red, la función de distribución de probabilidad de tráfico, el sistema operativo, la velocidad de transmisión y los servicios utilizados por las estaciones de trabajo. Se realiza la simulación de la red de datos utilizando software especializado como el OP-NET, proceso que permite obtener información de la capacidad y la utilización de la red, variables requeridas por los algoritmos como SLoPS y TOPP, para determinar el ancho de banda disponible para el tráfico de VoIP. La inserción del tráfico de VoIp tambien es simulado para determinar si es necesario un replanteamiento de la estructura de la red. Se utiliza la metodología MAS CommonKads [25] para el diseño y la implantación del SMA, sistema encargado de mantener una calidad del servicio adecuada en los momentos de tráfico pico de la red / Abstract: The main objective of this project is the development of a methodology in order to design data networks that can support in a effective way real time applications such as VoIP. Also it is proposed the implementation of a Multi Agent System for the management of the network traffic, enhancing the performance of the network, and allowing the effective scheduling of the traffic. This project uses basic concepts for the design of LAN networks such as traffic segmentation, broadcast and collision domains to propose a physical and logical design of the network. The characteristics of an existing network are analyzed, including the process and switching capacities of active network equipment, the traffic probability function, the operating system, the transmission rate and the services utilized by the workstations. The simulation of the data network is done using specialized software such as OPNET. This process allows to get information about the capacity and the utilization of the network, which are important variables required by the algorithms such as SLoPS and TOPP in order to calculate the available bandwidth for the VoIP traffic. The VoIP traffic insertion is also simulated to calculate if it is necessary to change the network structure. The methodology MAS CommonKads [25] is used in order to design and implement the MAS, which is the system that has to maintain an adequate QoS at the peak traffic hours of the network.Maestrí

A Formal View of Social Dependence Networks

In response to the problems that have arisen regarding the terminology and concepts of agent-oriented systems, previous work has described a formal framework for understanding agency and autonomy. In particular, this work made the claim that the framework could serve as a vehicle for the precise presentation and evaluation of models and theories of multi-agent systems. We support this claim by outlining the framework and refining it through adding further levels of detail to formalise the concepts of external descriptions and social dependence networks. Social Dependence Networks are a valuable source of information about the relationships within a multi-agentworld. They allow agents to reason about the resources and capabilities of others in order that they mayenter into a negotiation to persuade these others to assist them in completing their tasks. By formalising social dependence networks within the framework we are able to identify deficiencies in the original cha..