Search Results for author: Susan Murphy

Found 20 papers, 3 papers with code

reBandit: Random Effects based Online RL algorithm for Reducing Cannabis Use

no code implementations27 Feb 2024 Susobhan Ghosh, Yongyi Guo, Pei-Yao Hung, Lara Coughlin, Erin Bonar, Inbal Nahum-Shani, Maureen Walton, Susan Murphy

The escalating prevalence of cannabis use, and associated cannabis-use disorder (CUD), poses a significant public health challenge globally.

Reinforcement Learning (RL)

Online Uniform Risk Times Sampling: First Approximation Algorithms, Learning Augmentation with Full Confidence Interval Integration

no code implementations3 Feb 2024 Xueqing Liu, Kyra Gan, Esmaeil Keyvanshokooh, Susan Murphy

We propose two online approximation algorithms for this problem, one with and one without learning augmentation, and provide rigorous theoretical performance guarantees for them using competitive ratio analysis.

Reinforcement Learning Interventions on Boundedly Rational Human Agents in Frictionful Tasks

no code implementations26 Jan 2024 Eura Nofshin, Siddharth Swaroop, Weiwei Pan, Susan Murphy, Finale Doshi-Velez

Many important behavior changes are frictionful; they require individuals to expend effort over a long period with little immediate gratification.

Attribute

Dyadic Reinforcement Learning

2 code implementations15 Aug 2023 Shuangning Li, Lluis Salvat Niell, Sung Won Choi, Inbal Nahum-Shani, Guy Shani, Susan Murphy

This presents opportunities in mobile health to design interventions that target the dyadic relationship -- the relationship between a target person and their care partner -- with the aim of enhancing social support.

reinforcement-learning

Online learning in bandits with predicted context

no code implementations26 Jul 2023 Yongyi Guo, Ziping Xu, Susan Murphy

When the context error is non-vanishing, classical bandit algorithms fail to achieve sublinear regret.

Decision Making

Effect-Invariant Mechanisms for Policy Generalization

no code implementations19 Jun 2023 Sorawit Saengkyongam, Niklas Pfister, Predrag Klasnja, Susan Murphy, Jonas Peters

A major challenge in policy learning is how to adapt efficiently to unseen environments or tasks.

Contextual Bandits with Budgeted Information Reveal

no code implementations29 May 2023 Kyra Gan, Esmaeil Keyvanshokooh, Xueqing Liu, Susan Murphy

Contextual bandit algorithms are commonly used in digital health to recommend personalized treatments.

Multi-Armed Bandits

Did we personalize? Assessing personalization by an online reinforcement learning algorithm using resampling

1 code implementation11 Apr 2023 Susobhan Ghosh, Raphael Kim, Prasidh Chhabria, Raaz Dwivedi, Predrag Klasnja, Peng Liao, Kelly Zhang, Susan Murphy

We use a working definition of personalization and introduce a resampling-based methodology for investigating whether the personalization exhibited by the RL algorithm is an artifact of the RL algorithm stochasticity.

Decision Making Reinforcement Learning (RL)

Modeling Mobile Health Users as Reinforcement Learning Agents

no code implementations1 Dec 2022 Eura Shin, Siddharth Swaroop, Weiwei Pan, Susan Murphy, Finale Doshi-Velez

Mobile health (mHealth) technologies empower patients to adopt/maintain healthy behaviors in their daily lives, by providing interventions (e. g. push notifications) tailored to the user's needs.

Decision Making reinforcement-learning +1

Doubly robust nearest neighbors in factor models

no code implementations25 Nov 2022 Raaz Dwivedi, Katherine Tian, Sabina Tomkins, Predrag Klasnja, Susan Murphy, Devavrat Shah

We consider a matrix completion problem with missing data, where the $(i, t)$-th entry, when observed, is given by its mean $f(u_i, v_t)$ plus mean-zero noise for an unknown function $f$ and latent factors $u_i$ and $v_t$.

counterfactual Counterfactual Inference +1

Counterfactual inference for sequential experiments

no code implementations14 Feb 2022 Raaz Dwivedi, Katherine Tian, Sabina Tomkins, Predrag Klasnja, Susan Murphy, Devavrat Shah

Our goal is to provide inference guarantees for the counterfactual mean at the smallest possible scale -- mean outcome under different treatments for each unit and each time -- with minimal assumptions on the adaptive treatment policy.

counterfactual Counterfactual Inference +3

Online structural kernel selection for mobile health

no code implementations21 Jul 2021 Eura Shin, Pedja Klasnja, Susan Murphy, Finale Doshi-Velez

Motivated by the need for efficient and personalized learning in mobile health, we investigate the problem of online kernel selection for Gaussian Process regression in the multi-task setting.

regression

Fast Physical Activity Suggestions: Efficient Hyperparameter Learning in Mobile Health

no code implementations21 Dec 2020 Marianne Menictas, Sabina Tomkins, Susan Murphy

We propose an algorithm for providing physical activity suggestions in mHealth settings.

IntelligentPooling: Practical Thompson Sampling for mHealth

no code implementations31 Jul 2020 Sabina Tomkins, Peng Liao, Predrag Klasnja, Susan Murphy

In this work we are concerned with the following challenges: 1) individuals who are in the same context can exhibit differential response to treatments 2) only a limited amount of data is available for learning on any one individual, and 3) non-stationary responses to treatment.

reinforcement-learning Reinforcement Learning (RL) +1

Batch Policy Learning in Average Reward Markov Decision Processes

no code implementations23 Jul 2020 Peng Liao, Zhengling Qi, Runzhe Wan, Predrag Klasnja, Susan Murphy

The performance of the method is illustrated by simulation studies and an analysis of a mobile health study promoting physical activity.

Power Constrained Bandits

1 code implementation13 Apr 2020 Jiayu Yao, Emma Brunskill, Weiwei Pan, Susan Murphy, Finale Doshi-Velez

However, when bandits are deployed in the context of a scientific study -- e. g. a clinical trial to test if a mobile health intervention is effective -- the aim is not only to personalize for an individual, but also to determine, with sufficient statistical power, whether or not the system's intervention is effective.

Decision Making Multi-Armed Bandits

Rapidly Personalizing Mobile Health Treatment Policies with Limited Data

no code implementations23 Feb 2020 Sabina Tomkins, Peng Liao, Predrag Klasnja, Serena Yeung, Susan Murphy

In mobile health (mHealth), reinforcement learning algorithms that adapt to one's context without learning personalized policies might fail to distinguish between the needs of individuals.

Reinforcement Learning (RL)

Off-Policy Estimation of Long-Term Average Outcomes with Applications to Mobile Health

no code implementations30 Dec 2019 Peng Liao, Predrag Klasnja, Susan Murphy

The mHealth intervention policies, often called just-in-time adaptive interventions, are decision rules that map an individual's current state (e. g., individual's past behaviors as well as current observations of time, location, social activity, stress and urges to smoke) to a particular treatment at each of many time points.

Personalized HeartSteps: A Reinforcement Learning Algorithm for Optimizing Physical Activity

no code implementations8 Sep 2019 Peng Liao, Kristjan Greenewald, Predrag Klasnja, Susan Murphy

In this paper, we develop a Reinforcement Learning (RL) algorithm that continuously learns and improves the treatment policy embedded in the JITAI as the data is being collected from the user.

reinforcement-learning Reinforcement Learning (RL)

Personalizing Intervention Probabilities By Pooling

no code implementations2 Dec 2018 Sabina Tomkins, Predrag Klasnja, Susan Murphy

In many mobile health interventions, treatments should only be delivered in a particular context, for example when a user is currently stressed, walking or sedentary.

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