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Continually improving grounded natural language understanding through human-robot dialog
As robots become ubiquitous in homes and workplaces such as hospitals and factories, they must be able to communicate with humans. Several kinds of knowledge are required to understand and respond to a human's natural language commands and questions. If a person requests an assistant robot to take me to Alice's office, the robot must know that Alice is a person who owns some unique office, and that take me means it should navigate there. Similarly, if a person requests bring me the heavy, green mug, the robot must have accurate mental models of the physical concepts heavy, green, and mug. To avoid forcing humans to use key phrases or words robots already know, this thesis focuses on helping robots understanding new language constructs through interactions with humans and with the world around them. To understand a command in natural language, a robot must first convert that command to an internal representation that it can reason with. Semantic parsing is a method for performing this conversion, and the target representation is often semantic forms represented as predicate logic with lambda calculus. Traditional semantic parsing relies on hand-crafted resources from a human expert: an ontology of concepts, a lexicon connecting language to those concepts, and training examples of language with abstract meanings. One thrust of this thesis is to perform semantic parsing with sparse initial data. We use the conversations between a robot and human users to induce pairs of natural language utterances with the target semantic forms a robot discovers through its questions, reducing the annotation effort of creating training examples for parsing. We use this data to build more dialog-capable robots in new domains with much less expert human effort (Thomason et al., 2015; Padmakumar et al., 2017). Meanings of many language concepts are bound to the physical world. Understanding object properties and categories, such as heavy, green, and mug requires interacting with and perceiving the physical world. Embodied robots can use manipulation capabilities, such as pushing, picking up, and dropping objects to gather sensory data about them. This data can be used to understand non-visual concepts like heavy and empty (e.g. get the empty carton of milk from the fridge), and assist with concepts that have both visual and non-visual expression (e.g. tall things look big and also exert force sooner than short things when pressed down on). A second thrust of this thesis focuses on strategies for learning these concepts using multi-modal sensory information. We use human-in-the-loop learning to get labels between concept words and actual objects in the environment (Thomason et al., 2016, 2017). We also explore ways to tease out polysemy and synonymy in concept words (Thomason and Mooney, 2017) such as light, which can refer to a weight or a color, the latter sense being synonymous with pale. Additionally, pushing, picking up, and dropping objects to gather sensory information is prohibitively time-consuming, so we investigate strategies for using linguistic information and human input to expedite exploration when learning a new concept (Thomason et al., 2018). Finally, we build an integrated agent with both parsing and perception capabilities that learns from conversations with users to improve both components over time. We demonstrate that parser learning from conversations (Thomason et al., 2015) can be combined with multi-modal perception (Thomason et al., 2016) using predicate-object labels gathered through opportunistic active learning (Thomason et al., 2017) during those conversations to improve performance for understanding natural language commands from humans. Human users also qualitatively rate this integrated learning agent as more usable after it has improved from conversation-based learning.Computer Science
Improving Grounded Natural Language Understanding through Human-Robot Dialog
Natural language understanding for robotics can require substantial domain-
and platform-specific engineering. For example, for mobile robots to
pick-and-place objects in an environment to satisfy human commands, we can
specify the language humans use to issue such commands, and connect concept
words like red can to physical object properties. One way to alleviate this
engineering for a new domain is to enable robots in human environments to adapt
dynamically---continually learning new language constructions and perceptual
concepts. In this work, we present an end-to-end pipeline for translating
natural language commands to discrete robot actions, and use clarification
dialogs to jointly improve language parsing and concept grounding. We train and
evaluate this agent in a virtual setting on Amazon Mechanical Turk, and we
transfer the learned agent to a physical robot platform to demonstrate it in
the real world
Agent AI: Surveying the Horizons of Multimodal Interaction
Multi-modal AI systems will likely become a ubiquitous presence in our
everyday lives. A promising approach to making these systems more interactive
is to embody them as agents within physical and virtual environments. At
present, systems leverage existing foundation models as the basic building
blocks for the creation of embodied agents. Embedding agents within such
environments facilitates the ability of models to process and interpret visual
and contextual data, which is critical for the creation of more sophisticated
and context-aware AI systems. For example, a system that can perceive user
actions, human behavior, environmental objects, audio expressions, and the
collective sentiment of a scene can be used to inform and direct agent
responses within the given environment. To accelerate research on agent-based
multimodal intelligence, we define "Agent AI" as a class of interactive systems
that can perceive visual stimuli, language inputs, and other
environmentally-grounded data, and can produce meaningful embodied actions. In
particular, we explore systems that aim to improve agents based on
next-embodied action prediction by incorporating external knowledge,
multi-sensory inputs, and human feedback. We argue that by developing agentic
AI systems in grounded environments, one can also mitigate the hallucinations
of large foundation models and their tendency to generate environmentally
incorrect outputs. The emerging field of Agent AI subsumes the broader embodied
and agentic aspects of multimodal interactions. Beyond agents acting and
interacting in the physical world, we envision a future where people can easily
create any virtual reality or simulated scene and interact with agents embodied
within the virtual environment
Guiding Pretraining in Reinforcement Learning with Large Language Models
Reinforcement learning algorithms typically struggle in the absence of a
dense, well-shaped reward function. Intrinsically motivated exploration methods
address this limitation by rewarding agents for visiting novel states or
transitions, but these methods offer limited benefits in large environments
where most discovered novelty is irrelevant for downstream tasks. We describe a
method that uses background knowledge from text corpora to shape exploration.
This method, called ELLM (Exploring with LLMs) rewards an agent for achieving
goals suggested by a language model prompted with a description of the agent's
current state. By leveraging large-scale language model pretraining, ELLM
guides agents toward human-meaningful and plausibly useful behaviors without
requiring a human in the loop. We evaluate ELLM in the Crafter game environment
and the Housekeep robotic simulator, showing that ELLM-trained agents have
better coverage of common-sense behaviors during pretraining and usually match
or improve performance on a range of downstream tasks
Firearms and Tigers are Dangerous, Kitchen Knives and Zebras are Not: Testing whether Word Embeddings Can Tell
This paper presents an approach for investigating the nature of semantic
information captured by word embeddings. We propose a method that extends an
existing human-elicited semantic property dataset with gold negative examples
using crowd judgments. Our experimental approach tests the ability of
supervised classifiers to identify semantic features in word embedding vectors
and com- pares this to a feature-identification method based on full vector
cosine similarity. The idea behind this method is that properties identified by
classifiers, but not through full vector comparison are captured by embeddings.
Properties that cannot be identified by either method are not. Our results
provide an initial indication that semantic properties relevant for the way
entities interact (e.g. dangerous) are captured, while perceptual information
(e.g. colors) is not represented. We conclude that, though preliminary, these
results show that our method is suitable for identifying which properties are
captured by embeddings.Comment: Accepted to the EMNLP workshop "Analyzing and interpreting neural
networks for NLP
BWIBots: A platform for bridging the gap between AI and human–robot interaction research
Recent progress in both AI and robotics have enabled the development of general purpose robot platforms that are capable of executing a wide variety of complex, temporally extended service tasks in open environments. This article introduces a novel, custom-designed multi-robot platform for research on AI, robotics, and especially human–robot interaction for service robots. Called BWIBots, the robots were designed as a part of the Building-Wide Intelligence (BWI) project at the University of Texas at Austin. The article begins with a description of, and justification for, the hardware and software design decisions underlying the BWIBots, with the aim of informing the design of such platforms in the future. It then proceeds to present an overview of various research contributions that have enabled the BWIBots to better (a) execute action sequences to complete user requests, (b) efficiently ask questions to resolve user requests, (c) understand human commands given in natural language, and (d) understand human intention from afar. The article concludes with a look forward towards future research opportunities and applications enabled by the BWIBot platform
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