A comparison of different ventilation strategies for dwellings in terms of airflow rates and airflow paths

The context of ventilation in Belgian dwellings has changed since the publication of the Belgian standard NBN D 50-001:1991. Due to the higher energy performance of these dwellings, ventilation plays nowadays a more essential role in maintaining a good indoor air quality. Therefore, new rules for improved ventilation strategies are needed to accomplish high energy-efficient ventilation while providing a good indoor air quality. A first step is to compare different ventilation strategies, including strategies that don’t comply with the current standard, in terms of airflow rates and airflow paths. This comparison also includes the influence of demand controlled ventilation. This paper covers a simulation study using multi-zone airflow and contaminant transport calculation software (CONTAM) which compares the performances of the different ventilation strategies in terms of indoor air quality and average airflow rates. The evaluation of the indoor air quality is based on the exposure of the occupants to CO2 and VOC and on the relative humidity in the rooms. The different ventilation strategies can achieve a comparable indoor air quality, including the strategies not conform to the Belgian standard. However, some strategies require up to twice the airflow rate than others

Modelling a Centralized Academic Labour Market: Efficiency and Fairness

International audienceA formalization of the centralized French Academic Labour Market in terms of Multi-Agent System is presented. Extensive simulations are used to investigate typical and possible regimes of the system, supporting a sensitivity analysis of the main parameters of the model, such as the applicative pressure and the preference bias towards local candidates. Based on the calibration of the parameters of the abstract model after the information disclosed from o±cial sources, some positive and normative results are presented. Three prototypical settings are distinguished: the equilibrium setting corresponds to the perfect market case, where each candidate interacts with each University; the Humanities and Sciences setting; and the Law and Management setting. The differences between the last two settings concern both the applicative pressure (number of candidate per academic position) and the scope of each candidate (interacting with few or many Universities). Counter-intuitive findings, related in particular to the role of the preference biases, are presented and discussed

Description automatique de dynamiques de groupes dans des simulations à base d'agents

ISBN 978-2-36493-037-7National audienceMulti agent based simulations (MABS) have been successfully exploited 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 behaviours 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 on the simulation's model. 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. The description of clusters is used to generate profiles of agents that are reintroduced in simulations in order to study the stability of the descriptions and structures of clusters over several simulations and decide their capability to describe the modelled phenomena. These tools provides the modeller with an intermediate point of view on the evolution of the model. They are flexible enough to be applied both offline and online, and we illustrate it with both a NetLogo and a CSV-simulation log example

SimAnalyzer: automated description of groups dynamics in agent-based simulations

International audienceMulti agent based simulations (MABS) have been successfully exploited 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 behaviours 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 on the simulation's model. 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. The description of clusters is used to generate profiles of agents that are reintroduced in simulations in order to study the stability of the descriptions and structures of clusters over several simulations and decide their capability to describe the modelled phenomena. These tools provides the modeller with an intermediate point of view on the evolution of the model. They are flexible enough to be applied both offline and online, and we illustrate it with both a NetLogo and a CSV-simulation log example

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

Which Buyer-Supplier Strategies on Uncertain Markets? A Multi-Agents Simulation

International audienceThe relationship the firm has with its clients and suppliers largely determines the amount of value it is able to capture in the chain. Yet little is known about the impact of market uncertainty on the choice of the best buyer-supplier strategy in terms of value appropriation. The paper proposes to investigate which among different types of strategies bring more value to the buyer when market uncertainty increases. It relies on a very innovative method of multi-agents simulation based on an in-depth ethnographic observation phase of a real market in France. It shows that pure loyalty is not necessarily the best strategy when market uncertainty increases and that the buyer may face a dilemma between maximizing the margin rate and ensuring regularity of supply

Negotiation protocols and dynamic social networks

International audienceMulti-agent system make it possible to investigate systems with complex interaction protocols and limited information sharing. Our objective in this paper is to emphasize the impact of exchange protocols in social networks. The presented MAS considers a loan-granting scenario where each agent can borrow/lend money to its neighbors and/or consume it. We define six interaction protocols, ranging from fixed equilibrium rate loans to double-free auctions, and we study their impact on the network structure and the global welfare of the economy. Further, the agent fitness is investigated in relation with its connectivity (number of neighbors) and eccentricity (longest path to the other agents)