115,684 research outputs found
Insights into Analogy Completion from the Biomedical Domain
Analogy completion has been a popular task in recent years for evaluating the
semantic properties of word embeddings, but the standard methodology makes a
number of assumptions about analogies that do not always hold, either in recent
benchmark datasets or when expanding into other domains. Through an analysis of
analogies in the biomedical domain, we identify three assumptions: that of a
Single Answer for any given analogy, that the pairs involved describe the Same
Relationship, and that each pair is Informative with respect to the other. We
propose modifying the standard methodology to relax these assumptions by
allowing for multiple correct answers, reporting MAP and MRR in addition to
accuracy, and using multiple example pairs. We further present BMASS, a novel
dataset for evaluating linguistic regularities in biomedical embeddings, and
demonstrate that the relationships described in the dataset pose significant
semantic challenges to current word embedding methods.Comment: Accepted to BioNLP 2017. (10 pages
The Coat Problem. Counterfactuals, Truth-makers, and Temporal specification
Standard semantic treatments of counterfactuals appeal to a relation of similarity between possible worlds. Similarity, however, is a vague notion. Lewis suggests reducing the vagueness of similarity by adopting a principle known as 'late departure' (LD): the more the past two worlds share, the more they are similar. LD has several virtues. However, as Bennett points out, a standard semantics based on LD suffers from the so-called coat problem. In a nutshell, we are led to assign counterintuitive truth-values to counterfactuals whose antecedent time is left underspecified. In the present paper, we argue that the coat problem may be solved by defining a time-sensitive notion of similarity. To illustrate, we assume a Priorean, tensed language, interpreted on branching-time frames in the usual, 'Ockhamist' way, and we enrich it with a counterfactual connective. Within this framework, we define a time-sensitive relation of similarity, based on Yablo's work on truth-makers and partial truth. In the resulting semantics, which has independent interest, the coat problem does not arise
Typicality, graded membership, and vagueness
This paper addresses theoretical problems arising from the vagueness of language terms, and intuitions of the vagueness of the concepts to which they refer. It is argued that the central intuitions of prototype theory are sufficient to account for both typicality phenomena and psychological intuitions about degrees of membership in vaguely defined classes. The first section explains the importance of the relation between degrees of membership and typicality (or goodness of example) in conceptual categorization. The second and third section address arguments advanced by Osherson and Smith (1997), and Kamp and Partee (1995), that the two notions of degree of membership and typicality must relate to fundamentally different aspects of conceptual representations. A version of prototype theory—the Threshold Model—is proposed to counter these arguments and three possible solutions to the problems of logical selfcontradiction and tautology for vague categorizations are outlined. In the final section graded membership is related to the social construction of conceptual boundaries maintained through language use
Incorporating Structured Commonsense Knowledge in Story Completion
The ability to select an appropriate story ending is the first step towards
perfect narrative comprehension. Story ending prediction requires not only the
explicit clues within the context, but also the implicit knowledge (such as
commonsense) to construct a reasonable and consistent story. However, most
previous approaches do not explicitly use background commonsense knowledge. We
present a neural story ending selection model that integrates three types of
information: narrative sequence, sentiment evolution and commonsense knowledge.
Experiments show that our model outperforms state-of-the-art approaches on a
public dataset, ROCStory Cloze Task , and the performance gain from adding the
additional commonsense knowledge is significant
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
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