102
Abstracts
the basis of the mathematics of computability theory, does help to sever the situationally determined link between individual rationality and predictability. Such a result resurrects, analytically, the enlightened individualism of Smithian economics and relegates the role of predictability to group and social phenomena. This is fully compatible with the rich results of probability theory (even when computationally constrained). It is also a result and a methodology that libertarians should welcome.
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Learning in Recurrent Neural Networks.
and Institute for Neural Computation, USA.
Halbert White, Department of Economics University of California, San Diego, CA,
This presentation focuses on a class of artificial neural networks known as recurrent neural networks. These networks possess a rich internal dynamic structure and have been used to study linguistic structure, recognize speech, control robot movement, and forecast time series. Like humans, such networks learn from experience by a process of trial and error. The learning methods in current use perform fairly well, but theory describing the convergence of recurrent network learning algorithms has previously been missing. In this talk I present some recent results that provide the missing theory, demonstrating that appropriate learning rules for recurrent neural networks converge to network weights with certain optimality properties. Interestingly, the theory underlying these convergence results has applications to the study of economic agents learning about a system under their partial or com-
Abstracts
103
plete control, to the related engineering problem of a nonlinear dynamic controller learning to adaptively control an unknown plant, and also to statistical estimation of time-series models containing dynamic latent variables, such as ARMA and bilinear models.