6 research outputs found
Open-Vocabulary Semantic Parsing with both Distributional Statistics and Formal Knowledge
Traditional semantic parsers map language onto compositional, executable
queries in a fixed schema. This mapping allows them to effectively leverage the
information contained in large, formal knowledge bases (KBs, e.g., Freebase) to
answer questions, but it is also fundamentally limiting---these semantic
parsers can only assign meaning to language that falls within the KB's
manually-produced schema. Recently proposed methods for open vocabulary
semantic parsing overcome this limitation by learning execution models for
arbitrary language, essentially using a text corpus as a kind of knowledge
base. However, all prior approaches to open vocabulary semantic parsing replace
a formal KB with textual information, making no use of the KB in their models.
We show how to combine the disparate representations used by these two
approaches, presenting for the first time a semantic parser that (1) produces
compositional, executable representations of language, (2) can successfully
leverage the information contained in both a formal KB and a large corpus, and
(3) is not limited to the schema of the underlying KB. We demonstrate
significantly improved performance over state-of-the-art baselines on an
open-domain natural language question answering task.Comment: Re-written abstract and intro, other minor changes throughout. This
version published at AAAI 201
Multi-Grained Named Entity Recognition
This paper presents a novel framework, MGNER, for Multi-Grained Named Entity
Recognition where multiple entities or entity mentions in a sentence could be
non-overlapping or totally nested. Different from traditional approaches
regarding NER as a sequential labeling task and annotate entities
consecutively, MGNER detects and recognizes entities on multiple granularities:
it is able to recognize named entities without explicitly assuming
non-overlapping or totally nested structures. MGNER consists of a Detector that
examines all possible word segments and a Classifier that categorizes entities.
In addition, contextual information and a self-attention mechanism are utilized
throughout the framework to improve the NER performance. Experimental results
show that MGNER outperforms current state-of-the-art baselines up to 4.4% in
terms of the F1 score among nested/non-overlapping NER tasks.Comment: In ACL 2019 as a long pape