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Max-Mean N-step Temporal-Difference Learning Using Multi-Step Return

멀티-스텝 누적 보상을 활용한 Max-Mean N-Step 시간차 학습

  • 황규영 (한국기술교육대학교 컴퓨터공학과 미래융합공학전공) ;
  • 김주봉 (한국기술교육대학교 컴퓨터공학과 미래융합공학전공) ;
  • 허주성 (한국기술교육대학교 컴퓨터공학과 미래융합공학전공) ;
  • 한연희 (한국기술교육대학교 컴퓨터공학과)
  • Received : 2020.12.10
  • Accepted : 2021.02.20
  • Published : 2021.05.31

Abstract

n-step TD learning is a combination of Monte Carlo method and one-step TD learning. If appropriate n is selected, n-step TD learning is known as an algorithm that performs better than Monte Carlo method and 1-step TD learning, but it is difficult to select the best values of n. In order to solve the difficulty of selecting the values of n in n-step TD learning, in this paper, using the characteristic that overestimation of Q can improve the performance of initial learning and that all n-step returns have similar values for Q ≈ Q*, we propose a new learning target, which is composed of the maximum and the mean of all k-step returns for 1 ≤ k ≤ n. Finally, in OpenAI Gym's Atari game environment, we compare the proposed algorithm with n-step TD learning and proved that the proposed algorithm is superior to n-step TD learning algorithm.

n-스텝 시간차 학습은 몬테카를로 방법과 1-스텝 시간차 학습을 결합한 것으로, 적절한 n을 선택할 경우 몬테카를로 방법과 1-스텝 시간차 학습보다 성능이 좋은 알고리즘으로 알려져 있지만 최적의 n을 선택하는 것에 어려움이 있다. n-스텝 시간차 학습에서 n값 선택의 어려움을 해소하기 위해, 본 논문에서는 Q의 과대평가가 초기 학습의 성능을 높일 수 있다는 특징과 Q ≈ Q* 경우, 모든 n-스텝 누적 보상이 비슷한 값을 가진다는 성질을 이용하여 1 ≤ k ≤ n에 대한 모든 k-스텝 누적 보상의 최댓값과 평균으로 구성된 새로운 학습 타겟인 Ω-return을 제안한다. 마지막으로 OpenAI Gym의 Atari 게임 환경에서 n-스텝 시간차 학습과의 성능 비교 평가를 진행하여 본 논문에서 제안하는 알고리즘이 n-스텝 시간차 학습 알고리즘보다 성능이 우수하다는 것을 입증한다.

Keywords

Acknowledgement

이 논문은 정부(교육부)의 재원으로 한국연구재단의 지원을 받아 수행된 기초연구사업임(No. 2018R1A6A1A03025526 및 No. NRF-2020R1I1A3065610).

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