A reinforcement learning framework for answering complex questions

  • Authors:
  • Yllias Chali;Sadid A. Hasan;Kaisar Imam

  • Affiliations:
  • University of Lethbridge, Lethbridge, AB, Canada;University of Lethbridge, Lethbridge, AB, Canada;University of Lethbridge, Lethbridge, AB, Canada

  • Venue:
  • Proceedings of the 16th international conference on Intelligent user interfaces
  • Year:
  • 2011

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Abstract

Scoring sentences in documents given abstract summaries created by humans is important in extractive multi-document summarization. In this paper, we use extractive multi-document summarization techniques to perform complex question answering and formulate it as a reinforcement learning problem. We use a reward function that measures the relatedness of the candidate (machine generated) summary sentences with abstract summaries. In the training stage, the learner iteratively selects original document sentences to be included in the candidate summary, analyzes the reward function and updates the related feature weights accordingly. The final weights found in this phase are used to generate summaries as answers to complex questions given unseen test data. We use a modified linear, gradient-descent version of Watkins' Q(») algorithm with µ-greedy policy to determine the best possible action i.e. selecting the most important sentences. We compare the performance of this system with a Support Vector Machine (SVM) based system. Evaluation results show that the reinforcement method advances the SVM system improving the ROUGE scores by