Search Results for author: Bryan Lim

Found 28 papers, 9 papers with code

Beyond Expected Return: Accounting for Policy Reproducibility when Evaluating Reinforcement Learning Algorithms

no code implementations12 Dec 2023 Manon Flageat, Bryan Lim, Antoine Cully

We highlight that existing procedures that only use the expected return are limited on two fronts: first an infinite number of return distributions with a wide range of performance-reproducibility trade-offs can have the same expected return, limiting its effectiveness when used for comparing policies; second, the expected return metric does not leave any room for practitioners to choose the best trade-off value for considered applications.

Bayesian Optimisation Reinforcement Learning (RL)

Mix-ME: Quality-Diversity for Multi-Agent Learning

no code implementations3 Nov 2023 Garðar Ingvarsson, Mikayel Samvelyan, Bryan Lim, Manon Flageat, Antoine Cully, Tim Rocktäschel

In many real-world systems, such as adaptive robotics, achieving a single, optimised solution may be insufficient.

Continuous Control

Quality-Diversity Optimisation on a Physical Robot Through Dynamics-Aware and Reset-Free Learning

no code implementations24 Apr 2023 Simón C. Smith, Bryan Lim, Hannah Janmohamed, Antoine Cully

This method uses a dynamics model, learned from interactions between the robot and the environment, to predict the robot's behaviour and improve sample efficiency.

Don't Bet on Luck Alone: Enhancing Behavioral Reproducibility of Quality-Diversity Solutions in Uncertain Domains

no code implementations7 Apr 2023 Luca Grillotti, Manon Flageat, Bryan Lim, Antoine Cully

Quality-Diversity (QD) algorithms are designed to generate collections of high-performing solutions while maximizing their diversity in a given descriptor space.

Enhancing MAP-Elites with Multiple Parallel Evolution Strategies

no code implementations10 Mar 2023 Manon Flageat, Bryan Lim, Antoine Cully

With the development of fast and massively parallel evaluations in many domains, Quality-Diversity (QD) algorithms, that already proved promising in a large range of applications, have seen their potential multiplied.

Efficient Exploration using Model-Based Quality-Diversity with Gradients

no code implementations22 Nov 2022 Bryan Lim, Manon Flageat, Antoine Cully

Methods such as Quality-Diversity deals with this by encouraging novel solutions and producing a diversity of behaviours.

Efficient Exploration

Online Damage Recovery for Physical Robots with Hierarchical Quality-Diversity

no code implementations18 Oct 2022 Maxime Allard, Simón C. Smith, Konstantinos Chatzilygeroudis, Bryan Lim, Antoine Cully

Quality-Diversity (QD) algorithms have been successfully used to make robots adapt to damages in seconds by leveraging a diverse set of learned skills.

Efficient Learning of Locomotion Skills through the Discovery of Diverse Environmental Trajectory Generator Priors

no code implementations10 Oct 2022 Shikha Surana, Bryan Lim, Antoine Cully

Data-driven learning based methods have recently been particularly successful at learning robust locomotion controllers for a variety of unstructured terrains.

Neuroevolution is a Competitive Alternative to Reinforcement Learning for Skill Discovery

1 code implementation6 Oct 2022 Felix Chalumeau, Raphael Boige, Bryan Lim, Valentin Macé, Maxime Allard, Arthur Flajolet, Antoine Cully, Thomas Pierrot

Recent work has shown that training a mixture of policies, as opposed to a single one, that are driven to explore different regions of the state-action space can address this shortcoming by generating a diverse set of behaviors, referred to as skills, that can be collectively used to great effect in adaptation tasks or for hierarchical planning.

reinforcement-learning Reinforcement Learning (RL)

Learning to Walk Autonomously via Reset-Free Quality-Diversity

no code implementations7 Apr 2022 Bryan Lim, Alexander Reichenbach, Antoine Cully

Quality-Diversity (QD) algorithms can discover large and complex behavioural repertoires consisting of both diverse and high-performing skills.

Accelerated Quality-Diversity through Massive Parallelism

2 code implementations2 Feb 2022 Bryan Lim, Maxime Allard, Luca Grillotti, Antoine Cully

With recent advances in simulators that run on accelerators, thousands of evaluations can now be performed in parallel on single GPU/TPU.

Dynamics-Aware Quality-Diversity for Efficient Learning of Skill Repertoires

no code implementations16 Sep 2021 Bryan Lim, Luca Grillotti, Lorenzo Bernasconi, Antoine Cully

In this paper, we propose Dynamics-Aware Quality-Diversity (DA-QD), a framework to improve the sample efficiency of QD algorithms through the use of dynamics models.

Zero-Shot Learning

Enhancing Cross-Sectional Currency Strategies by Context-Aware Learning to Rank with Self-Attention

1 code implementation20 May 2021 Daniel Poh, Bryan Lim, Stefan Zohren, Stephen Roberts

The performance of a cross-sectional currency strategy depends crucially on accurately ranking instruments prior to portfolio construction.

Information Retrieval Learning-To-Rank +2

Deep Learning for Market by Order Data

no code implementations17 Feb 2021 Zihao Zhang, Bryan Lim, Stefan Zohren

Market by order (MBO) data - a detailed feed of individual trade instructions for a given stock on an exchange - is arguably one of the most granular sources of microstructure information.

Building Cross-Sectional Systematic Strategies By Learning to Rank

no code implementations13 Dec 2020 Daniel Poh, Bryan Lim, Stefan Zohren, Stephen Roberts

The success of a cross-sectional systematic strategy depends critically on accurately ranking assets prior to portfolio construction.

Information Retrieval Learning-To-Rank +1

Time Series Forecasting With Deep Learning: A Survey

no code implementations28 Apr 2020 Bryan Lim, Stefan Zohren

Numerous deep learning architectures have been developed to accommodate the diversity of time series datasets across different domains.

Time Series Time Series Forecasting

Detecting Changes in Asset Co-Movement Using the Autoencoder Reconstruction Ratio

no code implementations23 Jan 2020 Bryan Lim, Stefan Zohren, Stephen Roberts

Detecting changes in asset co-movements is of much importance to financial practitioners, with numerous risk management benefits arising from the timely detection of breakdowns in historical correlations.

Denoising Dimensionality Reduction +1

Temporal Fusion Transformers for Interpretable Multi-horizon Time Series Forecasting

34 code implementations19 Dec 2019 Bryan Lim, Sercan O. Arik, Nicolas Loeff, Tomas Pfister

Multi-horizon forecasting problems often contain a complex mix of inputs -- including static (i. e. time-invariant) covariates, known future inputs, and other exogenous time series that are only observed historically -- without any prior information on how they interact with the target.

Interpretable Machine Learning Time Series +1

Population-based Global Optimisation Methods for Learning Long-term Dependencies with RNNs

no code implementations23 May 2019 Bryan Lim, Stefan Zohren, Stephen Roberts

Despite recent innovations in network architectures and loss functions, training RNNs to learn long-term dependencies remains difficult due to challenges with gradient-based optimisation methods.

reinforcement-learning Reinforcement Learning (RL) +2

Enhancing Time Series Momentum Strategies Using Deep Neural Networks

1 code implementation9 Apr 2019 Bryan Lim, Stefan Zohren, Stephen Roberts

While time series momentum is a well-studied phenomenon in finance, common strategies require the explicit definition of both a trend estimator and a position sizing rule.

Position Time Series +1

Recurrent Neural Filters: Learning Independent Bayesian Filtering Steps for Time Series Prediction

1 code implementation23 Jan 2019 Bryan Lim, Stefan Zohren, Stephen Roberts

Testing this on three real-world time series datasets, we demonstrate that the decoupled representations learnt not only improve the accuracy of one-step-ahead forecasts while providing realistic uncertainty estimates, but also facilitate multistep prediction through the separation of encoder stages.

Time Series Time Series Prediction

Forecasting Treatment Responses Over Time Using Recurrent Marginal Structural Networks

1 code implementation NeurIPS 2018 Bryan Lim

Electronic health records provide a rich source of data for machine learning methods to learn dynamic treatment responses over time.

Epidemiology

Forecasting Disease Trajectories in Alzheimer's Disease Using Deep Learning

no code implementations6 Jul 2018 Bryan Lim, Mihaela van der Schaar

Joint models for longitudinal and time-to-event data are commonly used in longitudinal studies to forecast disease trajectories over time.

Disease-Atlas: Navigating Disease Trajectories with Deep Learning

no code implementations27 Mar 2018 Bryan Lim, Mihaela van der Schaar

Joint models for longitudinal and time-to-event data are commonly used in longitudinal studies to forecast disease trajectories over time.

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