Search Results for author: Nihat Ay

Found 16 papers, 4 papers with code

On the Fisher-Rao Gradient of the Evidence Lower Bound

no code implementations20 Jul 2023 Nihat Ay, Jesse van Oostrum

This article studies the Fisher-Rao gradient, also referred to as the natural gradient, of the evidence lower bound, the ELBO, which plays a crucial role within the theory of the Variational Autonecoder, the Helmholtz Machine and the Free Energy Principle.

Inversion of Bayesian Networks

no code implementations20 Dec 2022 Jesse van Oostrum, Peter van Hintum, Nihat Ay

Variational autoencoders and Helmholtz machines use a recognition network (encoder) to approximate the posterior distribution of a generative model (decoder).

Invariance Properties of the Natural Gradient in Overparametrised Systems

no code implementations30 Jun 2022 Jesse van Oostrum, Johannes Müller, Nihat Ay

The natural gradient field is a vector field that lives on a model equipped with a distinguished Riemannian metric, e. g. the Fisher-Rao metric, and represents the direction of steepest ascent of an objective function on the model with respect to this metric.

How Morphological Computation shapes Integrated Information in Embodied Agents

1 code implementation2 Aug 2021 Carlotta Langer, Nihat Ay

In this article, we combine different methods in order to examine the information flows among and within the body, the brain and the environment of an agent.

Natural Reweighted Wake-Sleep

1 code implementation NeurIPS Workshop DL-IG 2020 Csongor Várady, Riccardo Volpi, Luigi Malagò, Nihat Ay

These models are commonly trained using a two-step optimization algorithm called Wake-Sleep (WS) and more recently by improved versions, such as Reweighted Wake-Sleep (RWS) and Bidirectional Helmholtz Machines (BiHM).

On the Locality of the Natural Gradient for Deep Learning

no code implementations21 May 2020 Nihat Ay

We develop the theory for studying the relation between the two versions of the natural gradient and outline a method for the simplification of the natural gradient with respect to the second geometry based on the first one.

Comparing Information-Theoretic Measures of Complexity in Boltzmann Machines

no code implementations29 Jun 2017 Maxinder S. Kanwal, Joshua A. Grochow, Nihat Ay

In the past three decades, many theoretical measures of complexity have been proposed to help understand complex systems.

Evaluating Morphological Computation in Muscle and DC-motor Driven Models of Human Hopping

2 code implementations1 Dec 2015 Keyan Ghazi-Zahedi, Daniel F. B. Haeufle, Guido Montufar, Syn Schmitt, Nihat Ay

An important aspect of morphological computation is that it cannot be assigned to an embodied system per se, but that it is, as we show, behavior- and state-dependent.

Geometry and Determinism of Optimal Stationary Control in Partially Observable Markov Decision Processes

no code implementations24 Mar 2015 Guido Montufar, Keyan Ghazi-Zahedi, Nihat Ay

For partially observable Markov decision processes (POMDPs), optimal memoryless policies are generally stochastic.

The Information Theory of Individuality

1 code implementation8 Dec 2014 David Krakauer, Nils Bertschinger, Eckehard Olbrich, Nihat Ay, Jessica C. Flack

We consider biological individuality in terms of information theoretic and graphical principles.

Expressive Power and Approximation Errors of Restricted Boltzmann Machines

no code implementations NeurIPS 2011 Guido Montufar, Johannes Rauh, Nihat Ay

We present explicit classes of probability distributions that can be learned by Restricted Boltzmann Machines (RBMs) depending on the number of units that they contain, and which are representative for the expressive power of the model.

Geometry and Expressive Power of Conditional Restricted Boltzmann Machines

no code implementations14 Feb 2014 Guido Montufar, Nihat Ay, Keyan Ghazi-Zahedi

Conditional restricted Boltzmann machines are undirected stochastic neural networks with a layer of input and output units connected bipartitely to a layer of hidden units.

Linear combination of one-step predictive information with an external reward in an episodic policy gradient setting: a critical analysis

no code implementations26 Sep 2013 Keyan Zahedi, Georg Martius, Nihat Ay

Previous experiments have shown that the predictive information (PI) is a good candidate to support autonomous, open-ended learning of complex behaviours, because a maximisation of the PI corresponds to an exploration of morphology- and environment-dependent behavioural regularities.

Information driven self-organization of complex robotic behaviors

no code implementations30 Jan 2013 Georg Martius, Ralf Der, Nihat Ay

We study nonlinear and nonstationary systems and introduce the time-local predicting information (TiPI) which allows us to derive exact results together with explicit update rules for the parameters of the controller in the dynamical systems framework.

Quantifying Morphological Computation

no code implementations29 Jan 2013 Keyan Zahedi, Nihat Ay

We believe that the field would benefit from a formalisation of this concept as we would like to ask how much the morphology and the environment contribute to an embodied agent's behaviour, or how an embodied agent can maximise the exploitation of its morphology within its environment.

Cannot find the paper you are looking for? You can Submit a new open access paper.