8,602 research outputs found
Bounded Rational Decision-Making in Changing Environments
A perfectly rational decision-maker chooses the best action with the highest
utility gain from a set of possible actions. The optimality principles that
describe such decision processes do not take into account the computational
costs of finding the optimal action. Bounded rational decision-making addresses
this problem by specifically trading off information-processing costs and
expected utility. Interestingly, a similar trade-off between energy and entropy
arises when describing changes in thermodynamic systems. This similarity has
been recently used to describe bounded rational agents. Crucially, this
framework assumes that the environment does not change while the decision-maker
is computing the optimal policy. When this requirement is not fulfilled, the
decision-maker will suffer inefficiencies in utility, that arise because the
current policy is optimal for an environment in the past. Here we borrow
concepts from non-equilibrium thermodynamics to quantify these inefficiencies
and illustrate with simulations its relationship with computational resources.Comment: 9 pages, 2 figures, NIPS 2013 Workshop on Planning with Information
Constraint
Age determination of the HR8799 planetary system using asteroseismology
Discovery of the first planetary system by direct imaging around HR8799 has
made the age determination of the host star a very important task. This
determination is the key to derive accurate masses of the planets and to study
the dynamical stability of the system. The age of this star has been estimated
using different procedures. In this work we show that some of these procedures
have problems and large uncertainties, and the real age of this star is still
unknown, needing more observational constraints. Therefore, we have developed a
comprehensive modeling of HR8799, and taking advantage of its gamma
Doradus-type pulsations, we have estimated the age of the star using
asteroseismology. The accuracy in the age determination depends on the rotation
velocity of the star, and therefore an accurate value of the inclination angle
is required to solve the problem. Nevertheless, we find that the age estimate
for this star previously published in the literature ([30,160] Myr) is
unlikely, and a more accurate value might be closer to the Gyr. This
determination has deep implications on the value of the mass of the objects
orbiting HR8799. An age around 1 Gyr implies that these objects are
brown dwarfs.Comment: 5 pages, 3 figures, accepted in MNRAS Letter
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