Search Results for author: Alex J. Chan

Found 12 papers, 6 papers with code

Dense Reward for Free in Reinforcement Learning from Human Feedback

1 code implementation1 Feb 2024 Alex J. Chan, Hao Sun, Samuel Holt, Mihaela van der Schaar

Reinforcement Learning from Human Feedback (RLHF) has been credited as the key advance that has allowed Large Language Models (LLMs) to effectively follow instructions and produce useful assistance.

reinforcement-learning

When is Off-Policy Evaluation Useful? A Data-Centric Perspective

no code implementations23 Nov 2023 Hao Sun, Alex J. Chan, Nabeel Seedat, Alihan Hüyük, Mihaela van der Schaar

On the one hand, it brings opportunities for safe policy improvement under high-stakes scenarios like clinical guidelines.

Off-policy evaluation

Optimising Human-AI Collaboration by Learning Convincing Explanations

no code implementations13 Nov 2023 Alex J. Chan, Alihan Huyuk, Mihaela van der Schaar

Machine learning models are being increasingly deployed to take, or assist in taking, complicated and high-impact decisions, from quasi-autonomous vehicles to clinical decision support systems.

Autonomous Vehicles Decision Making +1

How to Catch an AI Liar: Lie Detection in Black-Box LLMs by Asking Unrelated Questions

1 code implementation26 Sep 2023 Lorenzo Pacchiardi, Alex J. Chan, Sören Mindermann, Ilan Moscovitz, Alexa Y. Pan, Yarin Gal, Owain Evans, Jan Brauner

Large language models (LLMs) can "lie", which we define as outputting false statements despite "knowing" the truth in a demonstrable sense.

Misinformation

Practical Approaches for Fair Learning with Multitype and Multivariate Sensitive Attributes

no code implementations11 Nov 2022 Tennison Liu, Alex J. Chan, Boris van Breugel, Mihaela van der Schaar

It is important to guarantee that machine learning algorithms deployed in the real world do not result in unfairness or unintended social consequences.

Fairness

Synthetic Model Combination: An Instance-wise Approach to Unsupervised Ensemble Learning

2 code implementations11 Oct 2022 Alex J. Chan, Mihaela van der Schaar

Consider making a prediction over new test data without any opportunity to learn from a training set of labelled data - instead given access to a set of expert models and their predictions alongside some limited information about the dataset used to train them.

Ensemble Learning Model Selection +1

POETREE: Interpretable Policy Learning with Adaptive Decision Trees

no code implementations ICLR 2022 Alizée Pace, Alex J. Chan, Mihaela van der Schaar

Building models of human decision-making from observed behaviour is critical to better understand, diagnose and support real-world policies such as clinical care.

Decision Making

Inverse Online Learning: Understanding Non-Stationary and Reactionary Policies

2 code implementations ICLR 2022 Alex J. Chan, Alicia Curth, Mihaela van der Schaar

Human decision making is well known to be imperfect and the ability to analyse such processes individually is crucial when attempting to aid or improve a decision-maker's ability to perform a task, e. g. to alert them to potential biases or oversights on their part.

Decision Making

The Medkit-Learn(ing) Environment: Medical Decision Modelling through Simulation

1 code implementation8 Jun 2021 Alex J. Chan, Ioana Bica, Alihan Huyuk, Daniel Jarrett, Mihaela van der Schaar

Understanding decision-making in clinical environments is of paramount importance if we are to bring the strengths of machine learning to ultimately improve patient outcomes.

Benchmarking Decision Making

Scalable Bayesian Inverse Reinforcement Learning

2 code implementations12 Feb 2021 Alex J. Chan, Mihaela van der Schaar

Bayesian inference over the reward presents an ideal solution to the ill-posed nature of the inverse reinforcement learning problem.

Bayesian Inference Imitation Learning +2

Unlabelled Data Improves Bayesian Uncertainty Calibration under Covariate Shift

no code implementations ICML 2020 Alex J. Chan, Ahmed M. Alaa, Zhaozhi Qian, Mihaela van der Schaar

In this paper, we develop an approximate Bayesian inference scheme based on posterior regularisation, wherein unlabelled target data are used as "pseudo-labels" of model confidence that are used to regularise the model's loss on labelled source data.

Bayesian Inference Decision Making +1

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