Sara Manzoni

Heterogeneous Agents Situated in Heterogeneous Spaces

This paper introduces the Multi-layered Multi-Agent Situated System model (MMASS), a model for Multi-Agent Systems (MAS) situated in an environment. The main feature of the MMASS model is to give an explicit definition of the spatial structure of the environment in which the system of situated agents are acting and interacting. Moreover, the presented model allows the representation of the heterogeneity that characterizes both agent types and interactions, and the spatial structures of the environment in which they are situated. The MMASS model allows the representaton of both open and closed systems: examples of its application (one for each class of systems) will be shown.

Towards a methodology for situated cellular agent based crowd simulations

This paper introduces a research activity aimed at the definition of a methodology to provide a solid conceptual framework for the development of simulation systems focused on crowd dynamics and based on the Situated Cellular Agent (SCA) model. After a brief introduction of the SCA Model, the general methodological approach is described. The main steps provide the definition of the spatial abstraction of the environment, the definition of its active elements, and the specification of types of mobile agents, the related behaviours with particular attention to their movement by means of the notion of utility. A case study is also briefly described in order to show how the methodology was applied in the modelling of crowd behaviour in an underground station.

Towards an agent-based proxemic model for pedestrian and group dynamics: motivations and first experiments

The simulation of pedestrian dynamics is a consolidated area of application for agent-based models: successful case studies can be found in the literature and off-the-shelf simulators are commonly employed by end-users, decision makers and consultancy companies. These models, however, generally neglect or treat in a simplistic way aspects like (i) the impact of cultural heterogeneity among individuals and (ii) the effects of the presence of groups and particular relationships among pedestrians. This work is aimed, on one hand, at introducing some fundamental anthropological considerations on which most pedestrian models are based, and in particular Edward T. Halls work on proxemics. On the other hand, the paper describes an agent-based model encapsulating in the pedestrians behavioural model effects representing both proxemics and a simplified account of influences related to the presence of groups in the crowd. The model is tested in a simple scenario to evaluate the implications of some modeling choices and the presence of groups in the simulated scenario. Results are discussed and compared to experimental observations and to data available in the literature.Models for the simulation of pedestrian dynamics and crowds of pedestrians have already been successfully applied to several scenarios and case studies, off-the-shelf simulators can be found on the market and they are commonly employed by end-user and consultancy companies. However, these models are the result of a first generation of research efforts considering individuals, their interactions with the environment and among themselves, but generally neglecting aspects like (a) the impact of cultural heterogeneity among individuals and (b) the effects of the presence of groups and particular relationships among pedestrians. This work is aimed, on one hand, at clarifying some fundamental anthropological considerations on which most pedestrian models are based, and in particular Edward T. Hall’s work on proxemics. On the other hand, the paper will briefly describe the first steps towards the definition of an agentbased model encapsulating in the pedestrian’s behavioural model effects capturing both proxemics and influences due to potential presence of groups in the crowd.

A support system to COTS-based software development for business services

The work described in this paper deals with the problem of selecting, configuring, integrating and deploying COTS components to deliver tailored software systems. Since formal and precise description of components is not usually available, a reasonable approach is to augment the available documentation with the informal knowledge derived by practices and experience of experts. The development of a knowledge-based system is a way to organize this empirical knowledge and deliver a tool that can support software designers in the tough goal of COTS-based development.

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 multi-layered 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.

L*MASS: A Language for Situated Multi-agent Systems

The main aim of this paper is to present a language for the description of systems of reactive agents situated in an environment. This language for Multi-Agent Situated Systems (MASS) has been inspired by a previously introduced Reaction-Diffusion Machine (RDM). It will be shown that it can describe heterogeneous systems of reactive agents, that is agents with different capabilities through an action model based on reaction-diffusion metaphor. Moreover we show how the model has been applied to the location of suitable sites for extra-urban shopping centres.

Enhancing Cellular Spaces by Multilayered Multi Agent Situated Systems

This paper presents the formal description of the Multilayered Multi-Agent Situated System (MMASS) which can be seen as a generalization of cellular spaces since it relaxes some constraints on uniformity, locality and closure. MMASS allows the description, representation and simulation of complex systems that explicitly require to consider spatial features. Different forms of interaction are possible within a MMASS: synchronous reaction between spatially adjacent agents and asynchronous and at-a-distance interaction through a field emission-propagation-perception mechanism.

A Support System Based on CBR for the Design of Rubber Compounds in Motor Racing

This work presents P-Race, a knowledge-based system developed for the Motorsports Department of Pirelli Tyres. The system supports the formulation of rubber compounds of tyre tread, in order to take part (and win) in motor racing. Multiple knowledge representations have been adopted and integrated into a single Case-Based Reasoning (CBR) computational framework in order to capture the different competence involved in the decision making process. Moreover, a dedicated representation formalism called Abstract Compounds Machine (ACM) has been introduced in order to represent, compute, and integrate in the CBR architecture the core knowledge regarding rubber compounds. The result is a general case-based architecture where the adaptation step is demanded to a component based on the ACM model.

CBR Adaptation for Chemical Formulation

Solution adaptation of previously solved cases to fit new situations is one of the basic tasks of the Case-Based Reasoning (CBR) approach for problem solving. The central issue of the paper is to present a formal computational model for the chemical formulation as innovative adaptation of previously developed products for new scenario and/or constraints in product design process. This general model (called Abstract Compound Machine - ACM) allows knowledge about chemical formulation to be explicitly represented, computed, integrated and performed in a CBR architecture. The specific domain that is presented as an example for the implementation of the ACM model regards the creation of rubber compounds. Its generality allows it to be adopted in cases of chemical formulation where basic ingredients are expressed in discrete quantities.

Crowd Modeling and Simulation

The paper introduces a Multi Agent Systems (MAS) approach to crowd modelling and simulation, based on the Situated Cellular Agents (SCA) model. This is a special class of Multilayered Multi Agent Situated System (MMASS), exploiting basic elements of Cellular Automata. In particular SCA model provides an explicit spatial representation and the definition of adjacency geometries, but also a concept of autonomous agent, provided with an internal architecture, an individual state and behaviour. The latter provides different means of space-mediated interaction among agents: synchronous, between adjacent agents, and asynchronous among at-a-distance entities. Heterogeneous entities may be modelled through the specification of different agent types, defining different behaviours and perceptive capabilities. After a brief description of the model, its application to simple crowd behaviours will be given, and an application providing the integration of a bidimensional simulator based on this model and a 3D modelling application (3D Studio) will also be described. The adoption of this kind of system allows the specification and simulation of an architectural design with reference to the behaviour of entities that will act in it. The system is also able to easily produce a realistic visualization of the simulation, in order to facilitate the evaluation of the design and the communication with involved decision-makers. In fact, while experts often require only abstract and analytical results deriving from a quantitative analysis of simulation results, other people involved in the decision-making process related to the design may be helped by qualitative aspects better represented by other forms of graphical visualization.