Ravenna Thielstrom


2020

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Generating Explanations of Action Failures in a Cognitive Robotic Architecture
Ravenna Thielstrom | Antonio Roque | Meia Chita-Tegmark | Matthias Scheutz
2nd Workshop on Interactive Natural Language Technology for Explainable Artificial Intelligence

We describe an approach to generating explanations about why robot actions fail, focusing on the considerations of robots that are run by cognitive robotic architectures. We define a set of Failure Types and Explanation Templates, motivating them by the needs and constraints of cognitive architectures that use action scripts and interpretable belief states, and describe content realization and surface realization in this context. We then describe an evaluation that can be extended to further study the effects of varying the explanation templates.

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It’s About Time: Turn-Entry Timing For Situated Human-Robot Dialogue
Felix Gervits | Ravenna Thielstrom | Antonio Roque | Matthias Scheutz
Proceedings of the 21th Annual Meeting of the Special Interest Group on Discourse and Dialogue

Turn-entry timing is an important requirement for conversation, and one that spoken dialogue systems largely fail at. In this paper, we introduce a computational framework based on work from Psycholinguistics, which is aimed at achieving proper turn-taking timing for situated agents. The approach involves incremental processing and lexical prediction of the turn in progress, which allows a situated dialogue system to start its turn and initiate actions earlier than would otherwise be possible. We evaluate the framework by integrating it within a cognitive robotic architecture and testing performance on a corpus of task-oriented human-robot directives. We demonstrate that: 1) the system is superior to a non-incremental system in terms of faster responses, reduced gap between turns, and the ability to perform actions early, 2) the system can time its turn to come in immediately at a transition point or earlier to produce several types of overlap, and 3) the system is robust to various forms of disfluency in the input. Overall, this domain-independent framework can be integrated into various dialogue systems to improve responsiveness, and is a step toward more natural, human-like turn-taking behavior.

2019

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Engaging in Dialogue about an Agent’s Norms and Behaviors
Daniel Kasenberg | Antonio Roque | Ravenna Thielstrom | Matthias Scheutz
Proceedings of the 1st Workshop on Interactive Natural Language Technology for Explainable Artificial Intelligence (NL4XAI 2019)

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Generating justifications for norm-related agent decisions
Daniel Kasenberg | Antonio Roque | Ravenna Thielstrom | Meia Chita-Tegmark | Matthias Scheutz
Proceedings of the 12th International Conference on Natural Language Generation

We present an approach to generating natural language justifications of decisions derived from norm-based reasoning. Assuming an agent which maximally satisfies a set of rules specified in an object-oriented temporal logic, the user can ask factual questions (about the agent’s rules, actions, and the extent to which the agent violated the rules) as well as “why” questions that require the agent comparing actual behavior to counterfactual trajectories with respect to these rules. To produce natural-sounding explanations, we focus on the subproblem of producing natural language clauses from statements in a fragment of temporal logic, and then describe how to embed these clauses into explanatory sentences. We use a human judgment evaluation on a testbed task to compare our approach to variants in terms of intelligibility, mental model and perceived trust.