Automated observation of multi-agent based simulations: a statistical analysis approach

International audienceMulti-agent based simulations (MABS) have been successfully used to model complex systems in different areas. Nevertheless a pitfall of MABS is that their complexity increases with the number of agents and the number of different types of behavior considered in the model. For average and large systems, it is impossible to validate the trajectories of single agents in a simulation. The classical validation approaches, where only global indicators are evaluated, are too simplistic to give enough confidence in the simulation. It is then necessary to introduce intermediate levels of validation. In this paper we propose the use of data clustering and automated characterization of clusters in order to build, describe and follow the evolution of groups of agents in simulations. These tools provides the modeler with an intermediate point of view on the evolution of the model. Those tools are flexible enough to allow the modeler to define the groups level of abstraction (i.e. the distance between the groups level and the agents level) and the underlying hypotheses of groups formation. We give an online application on a simple NetLogo library model (Bank Reserves) and an offline log application on a more complex Economic Market Simulation

Validation of agent-based land use model by Markovian model : application to forest-agriculture transitions in Madagascar

The determination of transition rules that farmers adopt to manage crop-fallow after forest clearing, is essential for deciding a sustainable strategy for forest conservation. The effect of the type of farms with respect to these transition rules in forest border may mitigate incentive measures planned by forest conservation policy. Agent-base modeling (ABM) of land use is a relevant approach to manage the dynamics of heterogeneous mosaic landscapes such as the border of the Malagasy Eastern rainforest. Transition rules between six land uses (forest, fallow, crop, grass, plantation and paddy ?eld) are formalized at a plot level. A historical database containing transitions between the ?rst four land use states was used to calibrate transition models for the ecological and farmer land use dynamics. Three land-use models have been built: (1) a Markov chain (stochastic), (2) a timed automaton (deterministic), (3) and an agent-based model, which introduces the farmers. The land use ABM allows to test scenarios of deforestation with both varying initial population and farm spatial organization, size or strategy. The land use ABM is ?rst calibrated via a timed automaton, ?tting time delay parameters, the duration of each land use state (fallow, crop, grass), and the number of cropping cycles since the ?rst forest clearing. It is then validated with the help of a Markovian model, comparing two transition matrices with ?2 metrics. The two transition matrices were respectively created with historical data of plot land use, and with simulated data produced by the land use ABM. We ?nish with a general discussion on the validation of such a complex system with a simple mathematical model. (Résumé d'auteur

Specifying in B the Influence/Reaction Model to Study Situated MAS: Application to vehicles platooning

International audienceThis paper addresses the formal specification and verification of situated Multi-Agent Systems (MAS) that can be formulated within the Influence/Reaction model as proposed in 1996 by Ferber \& Muller. In this model, our objective is to prove the correctness of reactive MAS with respect to a certain formal specification or property, using formal methods. This is an important step to bring MAS to high quality standards as required for critical applications encountered in domains such as transport systems. A generic B representation of systems instantiating the Influence/Reaction model is proposed, using patterns of specification. We illustrate our approach with a MAS to control unmanned land vehicles to form a platoon. The papers ends with considerations about further improvements of the framework, involving simulation and study of the properties of the system

Survey on Data-Centric based Routing Protocols for Wireless Sensor Networks

The great concern for energy that grew with the technological advances in the field of networks and especially in sensor network has triggered various approaches and protocols that relate to sensor networks. In this context, the routing protocols were of great interest. The aim of the present paper is to discuss routing protocols for sensor networks. This paper will focus mainly on the discussion of the data-centric approach (COUGAR, rumor, SPIN, flooding and Gossiping), while shedding light on the other approaches occasionally. The functions of the nodes will be discussed as well. The methodology selected for this paper is based on a close description and discussion of the protocol. As a conclusion, open research questions and limitations are proposed to the reader at the end of this paper

A Methodology to Engineer and Validate Dynamic Multi-level Multi-agent Based Simulations

This article proposes a methodology to model and simulate complex systems, based on IRM4MLS, a generic agent-based meta-model able to deal with multi-level systems. This methodology permits the engineering of dynamic multi-level agent-based models, to represent complex systems over several scales and domains of interest. Its goal is to simulate a phenomenon using dynamically the lightest representation to save computer resources without loss of information. This methodology is based on two mechanisms: (1) the activation or deactivation of agents representing different domain parts of the same phenomenon and (2) the aggregation or disaggregation of agents representing the same phenomenon at different scales.Comment: Presented at 3th International Workshop on Multi-Agent Based Simulation, Valencia, Spain, 5th June 201

Etude comparative de l'analyse des mouvements lors d'une interaction tactile : adultes versus ainés

International audienceThis paper reports a comparative study on the analysis of the users’ movements and their consequences in users’ performances (time, error rates) during interaction of 15 older adults and 15 adults with touchscreen. The analysis of the movement of the users’ wrist during the execution of interaction gestures allow to understand the differences in performances between older and younger users.Cet article présente une étude comparative de l'analyse des mouvements de l'utilisateur et leurs conséquences sur la performance (temps, taux d'erreurs) durant l'interaction avec des écrans tactiles sur une population de 15 participants âgés versus 15 adultes. L'analyse du mouvement du poignet durant l'exécution des gestes d'interaction permet de comprendre les différences de performances entre utilisateurs âgés et plus jeunes

A coalgebraic perspective on logical interpretations

In Computer Science stepwise refinement of algebraic specifications is a well-known formal methodology for rigorous program development. This paper illustrates how techniques from Algebraic Logic, in particular that of interpretation, understood as a multifunction that preserves and reflects logical consequence, capture a number of relevant transformations in the context of software design, reuse, and adaptation, difficult to deal with in classical approaches. Examples include data encapsulation and the decomposition of operations into atomic transactions. But if interpretations open such a new research avenue in program refinement, (conceptual) tools are needed to reason about them. In this line, the paper’s main contribution is a study of the correspondence between logical interpretations and morphisms of a particular kind of coalgebras. This opens way to the use of coalgebraic constructions, such as simulation and bisimulation, in the study of interpretations between (abstract) logics.Fundação para a Ciência e a Tecnologia (FCT

Refinement via interpretation

Traditional notions of refinement of algebraic specifications, based on signature morphisms, are often too rigid to capture a number of relevant transformations in the context of software design, reuse and adaptation. This paper proposes an alternative notion of specification refinement, building on recent work on logic interpretation. The concept is discussed, its theory partially developed, its use illustrated through a number of examples.This research was supported by FCT (the Portuguese Foundation for Science and Technology) under contracts PTDC/EIA/73252/2006, at Minho University, as well as PTDC/MAT/68723/2006 and the Unidade de Investigacao Matematica e Aplicaoes of University of Aveiro