Verb Physics: Relative Physical Knowledge of Actions and Objects

Learning commonsense knowledge from natural language text is nontrivial due to reporting bias: people rarely state the obvious, e.g., "My house is bigger than me." However, while rarely stated explicitly, this trivial everyday knowledge does influence the way people talk about the world, which provides indirect clues to reason about the world. For example, a statement like, "Tyler entered his house" implies that his house is bigger than Tyler. In this paper, we present an approach to infer relative physical knowledge of actions and objects along five dimensions (e.g., size, weight, and strength) from unstructured natural language text. We frame knowledge acquisition as joint inference over two closely related problems: learning (1) relative physical knowledge of object pairs and (2) physical implications of actions when applied to those object pairs. Empirical results demonstrate that it is possible to extract knowledge of actions and objects from language and that joint inference over different types of knowledge improves performance.Comment: 11 pages, published in Proceedings of ACL 201

Learning non-monotonic Logic Programs to Reason about Actions and Change

[Resumen] El objetivo de esta tesis es el diseño de métodos de aprendizaje automático capaces de encontrar un modelo de un sistema dinámico que determina cómo las propiedades del sistema con afectadas por la ejecución de acciones, Esto permite obtener de manera automática el conocimiento específico del dominio necesario para las tareas de planficación o diagnóstico así como predecir el comportamiento futuro del sistema. La aproximación seguida difiere de las aproximaciones previas en dos aspectos. Primero, el uso de formalismos no monótonos para el razonamiento sobre acciones y el cambio con respecto a los clásicos operadores tipo STRIPS o aquellos basados en formalismos especializados en tareas muy concretas, y por otro lado el uso de métodos de aprendizaje de programas lógicos (Inductive Logic Programming). La combinación de estos dos campos permite obtener un marco declarativo para el aprendizaje, donde la especificación de las acciones y sus efectos es muy intuitiva y natural y que permite aprender teorías más expresivas que en anteriores aproximaciones

Mapping Instructions and Visual Observations to Actions with Reinforcement Learning

We propose to directly map raw visual observations and text input to actions for instruction execution. While existing approaches assume access to structured environment representations or use a pipeline of separately trained models, we learn a single model to jointly reason about linguistic and visual input. We use reinforcement learning in a contextual bandit setting to train a neural network agent. To guide the agent's exploration, we use reward shaping with different forms of supervision. Our approach does not require intermediate representations, planning procedures, or training different models. We evaluate in a simulated environment, and show significant improvements over supervised learning and common reinforcement learning variants.Comment: In Proceedings of the Conference on Empirical Methods in Natural Language Processing (EMNLP), 201

The effect of multiple knowledge sources on learning and teaching

Current paradigms for machine-based learning and teaching tend to perform their task in isolation from a rich context of existing knowledge. In contrast, the research project presented here takes the view that bringing multiple sources of knowledge to bear is of central importance to learning in complex domains. As a consequence teaching must both take advantage of and beware of interactions between new and existing knowledge. The central process which connects learning to its context is reasoning by analogy, a primary concern of this research. In teaching, the connection is provided by the explicit use of a learning model to reason about the choice of teaching actions. In this learning paradigm, new concepts are incrementally refined and integrated into a body of expertise, rather than being evaluated against a static notion of correctness. The domain chosen for this experimentation is that of learning to solve "algebra story problems." A model of acquiring problem solving skills in this domain is described, including: representational structures for background knowledge, a problem solving architecture, learning mechanisms, and the role of analogies in applying existing problem solving abilities to novel problems. Examples of learning are given for representative instances of algebra story problems. After relating our views to the psychological literature, we outline the design of a teaching system. Finally, we insist on the interdependence of learning and teaching and on the synergistic effects of conducting both research efforts in parallel

The Associative Chance

In Locke’s Essay, he introduces the Associations of Ideas, as the linking of ideas so that, if one is brought to mind so is the other. Locke’s definition describes these associations as either emerging voluntarily or involuntarily (by chance). I argue, however, that all associations are in part involuntary. This diminishes the role of voluntary actions in Locke’s description, though they still can lead to the opportunities that allow for associations to be created. Nevertheless, this adjustment to Locke’s framework implies a weakness of reason in a few ways. Firstly, Locke intended for associations to be what allowed for unlike ideas to become combined, sometimes in contradiction. If these contradictions require randomness to come about, then reason is more imperiled than even Locke postulates, due to the randomness. Secondly, the process of learning is unintuitive because of this concession. Learning is the voluntary creation of associations, and associations require randomness to be formed. Ergo, there is a role of chance in learning. This is not to say that voluntary actions cannot be a part of learning, but chance is a necessary factor. The creation of Associations of Ideas, in all contexts, requires chance as a factor