Modulation of exploratory behavior for adaptation to the context

For autonomous agents (children, animals or robots), exploratory learning is essential as it allows them to take advantage of their past experiences in order to improve their reactions in any situation similar to a situation already experimented. We have already exposed in Blanchard and Canamero (2005) how a robot can learn which situations it should memorize and try to reach, but we expose here architectures allowing the robot to take initiatives and explore new situations by itself. However, exploring is a risky behavior and we propose to moderate this behavior using novelty and context based on observations of animals behaviors. After having implemented and tested these architectures, we present a very interesting emergent behavior which is low-level imitation modulated by context

The baryon mass function for galaxy clusters

Context: The evolution of the cluster abundance with redshift is known to be a powerful cosmological constraint when applied to X-ray clusters. Recently, the evolution of the baryon mass function has been proposed as a new variant that is free of the uncertainties present in the temperature-mass relation. A flat model with Omega_matter ~ 0.3 was shown to be preferred in the case of a standard cold dark matter scenario. Aims: We compared the high redshift predictions of the baryon mass in clusters with data for a more general class of spectra with a varying shape factor Gamma without any restriction to the standard cold dark matter scenario in models normalized to reproduce the local baryon mass function. Methods: Using various halo mass functions existing in the literature we evaluated the corresponding baryon mass functions for the case of the non-standard power spectra mentioned previously. Results: We found that models with Omega_matter ~ 1 and Gamma ~ 0.12 reproduce high redshift cluster data just as well as the concordance model does. Conclusions: Finally, we conclude that the baryon mass function evolution alone does not efficiently discriminate between the more general family of flat cosmological models with non-standard power spectra.Comment: Typos corrected. Replaced to match published version. 5 pages, 2 figures, aa.cl