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Rewards play an essential role in reinforcement learning. In contrast to rule-based game environments with well-defined reward functions, complex real-world robotic applications, such as contact-rich manipulation, lack explicit and…

Machine Learning · Computer Science 2022-05-30 Yuning Wu , Jieliang Luo , Hui Li

Improving sample efficiency is central to Reinforcement Learning (RL), especially in environments where the rewards are sparse. Some recent approaches have proposed to specify reward functions as manually designed or learned reward…

Machine Learning · Computer Science 2024-01-26 Shuai Han , Mehdi Dastani , Shihan Wang

Reinforcement learning is an appropriate and successful method to robustly perform low-level robot control under noisy conditions. Symbolic action planning is useful to resolve causal dependencies and to break a causally complex problem…

Machine Learning · Computer Science 2019-12-10 Manfred Eppe , Phuong D. H. Nguyen , Stefan Wermter

Problems which require both long-horizon planning and continuous control capabilities pose significant challenges to existing reinforcement learning agents. In this paper we introduce a novel hierarchical reinforcement learning agent which…

Machine Learning · Computer Science 2023-07-25 Jan Achterhold , Markus Krimmel , Joerg Stueckler

We study the problem of generating keyphrases that summarize the key points for a given document. While sequence-to-sequence (seq2seq) models have achieved remarkable performance on this task (Meng et al., 2017), model training often relies…

Computation and Language · Computer Science 2019-09-09 Hai Ye , Lu Wang

Reinforcement learning, which acquires a policy maximizing long-term rewards, has been actively studied. Unfortunately, this learning type is too slow and difficult to use in practical situations because the state-action space becomes huge…

Machine Learning · Computer Science 2024-10-28 Takato Okudo , Seiji Yamada

Hierarchical reinforcement learning has been a compelling approach for achieving goal directed behavior over long sequences of actions. However, it has been challenging to implement in realistic or open-ended environments. A main challenge…

Machine Learning · Computer Science 2023-09-22 Arun Ahuja , Kavya Kopparapu , Rob Fergus , Ishita Dasgupta

Decision-making in complex, continuous multi-task environments is often hindered by the difficulty of obtaining accurate models for planning and the inefficiency of learning purely from trial and error. While precise environment dynamics…

Machine Learning · Computer Science 2025-03-20 Jeff Jewett , Sandhya Saisubramanian

Unsupervised reinforcement learning aims to acquire skills without prior goal representations, where an agent automatically explores an open-ended environment to represent goals and learn the goal-conditioned policy. However, this procedure…

Machine Learning · Computer Science 2021-10-27 Jinxin Liu , Hao Shen , Donglin Wang , Yachen Kang , Qiangxing Tian

Reinforcement learning optimizes policies for expected cumulative reward. Need the supervision be so narrow? Reward is delayed and sparse for many tasks, making it a difficult and impoverished signal for end-to-end optimization. To augment…

Machine Learning · Computer Science 2017-03-10 Evan Shelhamer , Parsa Mahmoudieh , Max Argus , Trevor Darrell

Agentic large language models often rely on skills, reusable natural language procedures that guide planning, action, and tool use. In practice, skills are typically improved through prompt engineering or by aligning the task LLM itself,…

Open-endedness stands to benefit from the ability to generate an infinite variety of diverse, challenging environments. One particularly interesting type of challenge is meta-learning ("learning-to-learn"), a hallmark of intelligent…

Machine Learning · Computer Science 2023-12-12 Thomas Miconi

Unsupervised Reinforcement Learning (RL) aims to discover diverse behaviors that can accelerate the learning of downstream tasks. Previous methods typically focus on entropy-based exploration or empowerment-driven skill learning. However,…

Machine Learning · Computer Science 2025-06-18 Ting Xiao , Jiakun Zheng , Rushuai Yang , Kang Xu , Qiaosheng Zhang , Peng Liu , Chenjia Bai

In many real-world scenarios, reward signal for agents are exceedingly sparse, making it challenging to learn an effective reward function for reward shaping. To address this issue, the proposed approach in this paper performs reward…

Machine Learning · Computer Science 2026-05-18 Wenyun Li , Wenjie Huang , Chen Sun

A major obstacle in reinforcement learning-based sentence generation is the large action space whose size is equal to the vocabulary size of the target-side language. To improve the efficiency of reinforcement learning, we present a novel…

Computation and Language · Computer Science 2019-04-08 Kazuma Hashimoto , Yoshimasa Tsuruoka

Applying reinforcement learning (RL) to sparse reward domains is notoriously challenging due to insufficient guiding signals. Common RL techniques for addressing such domains include (1) learning from demonstrations and (2) curriculum…

Machine Learning · Computer Science 2023-03-29 Vaibhav Bajaj , Guni Sharon , Peter Stone

Being able to reason in an environment with a large number of discrete actions is essential to bringing reinforcement learning to a larger class of problems. Recommender systems, industrial plants and language models are only some of the…

Imitation learning is an effective alternative approach to learn a policy when the reward function is sparse. In this paper, we consider a challenging setting where an agent and an expert use different actions from each other. We assume…

Machine Learning · Computer Science 2019-08-27 Konrad Zolna , Negar Rostamzadeh , Yoshua Bengio , Sungjin Ahn , Pedro O. Pinheiro

We propose Scheduled Auxiliary Control (SAC-X), a new learning paradigm in the context of Reinforcement Learning (RL). SAC-X enables learning of complex behaviors - from scratch - in the presence of multiple sparse reward signals. To this…

We consider the problem of reinforcement learning under safety requirements, in which an agent is trained to complete a given task, typically formalized as the maximization of a reward signal over time, while concurrently avoiding…

Machine Learning · Computer Science 2018-09-25 Tu-Hoa Pham , Giovanni De Magistris , Don Joven Agravante , Subhajit Chaudhury , Asim Munawar , Ryuki Tachibana