TOWARD A PLATFORM FOR MULTI-LAYERED MULTI-AGENT SITUATED SYSTEM (MMASS)-BASED SIMULATIONS: FOCUSING ON FIELD DIFFUSION

The paper introduces some issues and related solutions adopted in order to realize the MMASS platform. This is a framework to specify and execute simulation applications based on the multilayered multi-agent situated system model (MMASS). MMASS is a model for multi-agent systems (MAS) situated in an environment whose structure is explicitly defined. The behavior and interaction models of MMASS agents are strongly related to the spatial structure of their environment. The MMASS model is the result of a long-term research that has its roots and motivations on application domains and problems that require spatial features to be considered. Our experiences with these problems have concerned the design of domain models and their implementations, according to the MAS approach for simulation purposes. This activity has revealed that currently available tools do not support the management of spatial features of agent environment and interaction mechanisms defined by the MMASS model and thus they are not suitable for our purposes. The paper focuses on the MMASS platform that aims to support the specification and development of applications (mainly, simulations) based on MMASS. Design issues and related solutions that have been adopted in order to manage those aspects that characterize the MMASS model will be shown. After a description of the conceptual model that underlies the MMASS platform and its general architecture, we will overview how the platform supports the specification of agent structured environment, behavior and interaction, and how it supports the execution of agent actions and interactions. Then we will describe issues and adopted solutions (both algorithmic and implementative ones) to manage at-a-distance interaction among MMASS agents

Multi-agent Systems as Discrete Dynamical Systems: Influences and Reactions as a Modelling Principle

Finding adequate descriptions of multi-agent systems is a central issue for modelling collective dynamics. We propose a mathematical description of multi-agent systems as discrete dynamical systems. The ground of our proposition is the influence-reaction method of Ferber and Müller. The key idea is that agents should never act directly on other components of the system (agents or environment) but release influences which are then combined to update the state of the system. We propose a method which decomposes the definitions of multi-agent system into six parts. We illustrate our method on the multi-Turmite model, also known as the multiple Langton's ants model. We exhibit two formulations of this model, which we study with three different simulation schemes. We show that for the same formulation, and the same initial conditions, the use of different simulation schemes may lead to qualitatively different evolutions of the system. As a positive spin-off of this study, we exhibit new phenomena of the multi-Turmite model such as deadlocks or gliders

Cognitive assistance in intelligent environments

Tese de doutoramento em Engenharia BiomédicaCurrently society responds badly to some social issues. One of the problems lies on the society concept itself. The common pyramid describing the social strata does not reflect the new social reality, given that the elderly strata largely exceed the teenage strata. This fact also implies a change in terms of social and medical needs. Thus, a great number of medical services should be adapted to respond to the needs of the elderly people. In fact, any common family cannot take care of an elderly person and, in many cases they cannot also afford the required medical care. Having less time, and often, less money, a family cannot have their older relatives in their homes. In addition, the necessary support required to overcome the elderly limitations, makes it even more difficult. One solution could be that elderly people go to nursing homes or care centers. However, due to the overgrowth of the elderly community, geriatric units are not enough to take care of all those people. As a solution, technology can provide wellbeing and assistance in the elderly everyday life through personalized services at low cost. This thesis presents a cognitive assistant platform, named iGenda. A cognitive assistant provides numerous user oriented services, and it ubiquitously and transparently interacts directly with the user. Therefore, this research work has as motto: impacting the user’s life without causing an impact. It means that the platform aim is to influence the user’s life, by providing a greater quality of life, without being too complex to use. The answers to our society’s social and technological challenges are provided by the development of a platform that is intuitive to the user, cheap and able to be integrated in an Ambient Assisted Living ecosystem. Thus, this thesis presents a multi-agent, platform-independent architecture capable of intelligent scheduling. Being the cognitive assistant implemented in four case studies, namely: a sensor platform, a digital clinical guideline system, an orientation system based on augmented reality, and a fall detection application. These case studies validate the social and technological challenges, therefore the iGenda too. This is due to the complete integration with other systems, without major changes of the architecture and archetype.Atualmente, a sociedade debate-se com um problema para o qual não há uma solução simples. O problema reside na própria sociedade, mais especificamente no seu conceito. A pirâmide populacional clássica não retrata a sociedade como é atualmente, sendo que o número de idosos ultrapassa o número de jovens. Ora, este facto acarreta uma mudança nas necessidades sociais e cuidados médicos. Deste modo, um grande número de serviços médicos têm que ser reajustados para as necessidades das pessoas mais idosas. Com menos tempo e frequentemente sem dinheiro, a família não é capaz de ter um idoso na sua casa. Tendo em conta as limitações das pessoas idosas em termos de saúde, a incapacidade de assistir uma pessoa idosa é ainda maior. Uma possível solução é colocar os idosos em casas de repouso ou centros geriátricos. Contudo, devido ao crescimento da comunidade idosa, não existem unidades geriátricas suficientes para todas as pessoas. A tecnologia pode providenciar assistência e bem-estar na vida cotidiana de uma pessoa idosa, através de serviços personalizados de baixo custo, servindo como uma possível resposta aos problemas apresentados. Nesta tese apresenta-se o iGenda, como uma plataforma de desenvolvimento de assistentes cognitivos. Um assistente cognitivo que assegura vários serviços orientados ao utilizador, interagindo com o utilizador de forma ubíqua e transparente. Este trabalho de investigação tem como lema: mudar a vida do utilizador sem o mudar. Isto significa que a plataforma tem como objetivo mudar a vida do utilizador, ao proporcionar uma maior qualidade de vida, sem que o utilizador tenha dificuldade a adaptar-se ou a utilizar a plataforma. As respostas para os desafios sociais e tecnológicos apresentados pela nossa sociedade são fornecidas pelo desenvolvimento de uma plataforma intuitiva, barata e capaz de ser integrada num ecossistema de Ambient Assisted Living. Deste modo, o processo de agendamento inteligente é assegurado por uma arquitetura multiagente e independente de plataformas, apresentada nesta tese. Sendo que o assistente cognitivo é implementado em quatro casos de estudo: uma plataforma de sensores, um sistema digital de guias clínicos, um sistema de orientação baseado em realidade aumentada e um sistema de deteção de quedas. Estes casos de estudo validam os desafios sociais e tecnológicos, portanto validando também o iGenda. Isto verifica-se com a integração completa com outros sistemas, sem muitas alterações à arquitetura ou ao arquétip

Approches environnement-centrées pour la simulation de systèmes multi-agents: Pour un déplacement de la complexité des agents vers l'environnement

This habilitation thesis synthesizes research works which are mainly related to the field of Multi-Agent Based Simulation (MABS). MABS is a general framework for modeling and experimenting with systems in which the dynamics emerges from local interactions among individuals (autonomous agents). Examples of use range from the study of natural systems (e.g. ant colonies, crowds or traffic jams) to the engineering of artificial ones (e.g., collective robotics, distributed artificial intelligence-based softwares). To this end, MABS modeling represents the behavior of individuals, their environment and interactions, so that global dynamics can be computed and studied from the bottom up. In this context, we have been investigating research on the theory and practice of MABS from two different perspectives : (1) the design of generic abstractions dedicated to the modeling of multi-agent dynamics (e.g., the IRM4S model) and (2) the engineering of MABS (MaDKit and TurtleKit platforms). Besides, we have been experimenting with MABS in different application domains such as image processing, video games, and collective robotics. Contrary to approaches that put the emphasis on the agent behaviors, all these works have been done by considering the environment of the agents as a first order abstraction. In this thesis, we first reflect upon the research we have conducted according to this perspective. Next, we show how we actually use this perspective to propose an original approach for using General-Purpose processing on Graphics Processing Units (GPGPU) within MABS, and then present the research perspectives related to our positioning.Les travaux de recherche synthétisés dans ce mémoire s’inscrivent principalement dans le domaine de la modélisation et de la simulation de systèmes multi-agents (SMA). La simulation multi-agents met en œuvre des modèles où les individus, leur environnement et leurs interactions sont directement représentés. Dans ces modèles, chaque individu –agent autonome– possède son propre comportement et produit ses actions en fonction d’une perception locale de son environnement. Ainsi, la simulation multi-agents est utilisée pour étudier des systèmes naturels comme les colonies de fourmis, les dynamiques de foules ou le trafic urbain, mais aussi pour concevoir des systèmes artificiels, par exemple dans le cadre de la robotique collective ou le développement de logiciels basés sur de l’intelligence artificielle distribuée. Dans ce cadre, nos recherches ont porté sur des problématiques liées à la modélisation de simulations multi-agents, avec la proposition de modèles formels et conceptuels (e.g. le modèle IRM4S) et d’outils logiciels génériques (plates-formes MaDKit et TurtleKit), et sur leur utilisation dans divers domaines tels que le jeu vidéo, le traitement numérique de l’image ou la robotique collective. Contrairement aux approches centrées sur la conception des comportements individuels, dans ces travaux l’environnement des agents est considéré comme une abstraction de premier ordre. Dans ce mémoire, nous dressons tout d’abord un bilan de nos recherches en argumentant l’intérêt d’une telle démarche pour les modèles multi-agents. Nous montrons ensuite comment celle-ci nous a récemment permis de proposer une approche originale dans le cadre de l’utilisation du calcul haute performance sur carte graphique (GPGPU) pour la simulation de SMA, avant de présenter les perspectives de recherche associées à notre positionnement

Model for simultaneous actions in situated multi-agent systems

A model for explaining the simultaneous actions in a multi-agent system (MAS) is discussed. The simultaneous actions are executed by different software agents at the same time, in MAS. The model is independent of the applied agent architecture. It functionally describes the simultaneous actions situated in multi-agent systems which are established through synchronization.status: publishe