4 research outputs found
Nonstrict hierarchical reinforcement learning for interactive systems and robots
Conversational systems and robots that use reinforcement learning for policy optimization in large domains often face the problem of limited scalability. This problem has been addressed either by using function approximation techniques that estimate the approximate true value function of a policy or by using a hierarchical decomposition of a learning task into subtasks. We present a novel approach for dialogue policy optimization that combines the benefits of both hierarchical control and function approximation and that allows flexible transitions between dialogue subtasks to give human users more control over the dialogue. To this end, each reinforcement learning agent in the hierarchy is extended with a subtask transition function and a dynamic state space to allow flexible switching between subdialogues. In addition, the subtask policies are represented with linear function approximation in order to generalize the decision making to situations unseen in training. Our proposed approach is evaluated in an interactive conversational robot that learns to play quiz games. Experimental results, using simulation and real users, provide evidence that our proposed approach can lead to more flexible (natural) interactions than strict hierarchical control and that it is preferred by human users
Machine Generated Text: A Comprehensive Survey of Threat Models and Detection Methods
Machine generated text is increasingly difficult to distinguish from human
authored text. Powerful open-source models are freely available, and
user-friendly tools that democratize access to generative models are
proliferating. ChatGPT, which was released shortly after the first preprint of
this survey, epitomizes these trends. The great potential of state-of-the-art
natural language generation (NLG) systems is tempered by the multitude of
avenues for abuse. Detection of machine generated text is a key countermeasure
for reducing abuse of NLG models, with significant technical challenges and
numerous open problems. We provide a survey that includes both 1) an extensive
analysis of threat models posed by contemporary NLG systems, and 2) the most
complete review of machine generated text detection methods to date. This
survey places machine generated text within its cybersecurity and social
context, and provides strong guidance for future work addressing the most
critical threat models, and ensuring detection systems themselves demonstrate
trustworthiness through fairness, robustness, and accountability.Comment: Manuscript submitted to ACM Special Session on Trustworthy AI.
2022/11/19 - Updated reference