10,381 research outputs found
Knowledge Base Population using Semantic Label Propagation
A crucial aspect of a knowledge base population system that extracts new
facts from text corpora, is the generation of training data for its relation
extractors. In this paper, we present a method that maximizes the effectiveness
of newly trained relation extractors at a minimal annotation cost. Manual
labeling can be significantly reduced by Distant Supervision, which is a method
to construct training data automatically by aligning a large text corpus with
an existing knowledge base of known facts. For example, all sentences
mentioning both 'Barack Obama' and 'US' may serve as positive training
instances for the relation born_in(subject,object). However, distant
supervision typically results in a highly noisy training set: many training
sentences do not really express the intended relation. We propose to combine
distant supervision with minimal manual supervision in a technique called
feature labeling, to eliminate noise from the large and noisy initial training
set, resulting in a significant increase of precision. We further improve on
this approach by introducing the Semantic Label Propagation method, which uses
the similarity between low-dimensional representations of candidate training
instances, to extend the training set in order to increase recall while
maintaining high precision. Our proposed strategy for generating training data
is studied and evaluated on an established test collection designed for
knowledge base population tasks. The experimental results show that the
Semantic Label Propagation strategy leads to substantial performance gains when
compared to existing approaches, while requiring an almost negligible manual
annotation effort.Comment: Submitted to Knowledge Based Systems, special issue on Knowledge
Bases for Natural Language Processin
Finding Person Relations in Image Data of the Internet Archive
The multimedia content in the World Wide Web is rapidly growing and contains
valuable information for many applications in different domains. For this
reason, the Internet Archive initiative has been gathering billions of
time-versioned web pages since the mid-nineties. However, the huge amount of
data is rarely labeled with appropriate metadata and automatic approaches are
required to enable semantic search. Normally, the textual content of the
Internet Archive is used to extract entities and their possible relations
across domains such as politics and entertainment, whereas image and video
content is usually neglected. In this paper, we introduce a system for person
recognition in image content of web news stored in the Internet Archive. Thus,
the system complements entity recognition in text and allows researchers and
analysts to track media coverage and relations of persons more precisely. Based
on a deep learning face recognition approach, we suggest a system that
automatically detects persons of interest and gathers sample material, which is
subsequently used to identify them in the image data of the Internet Archive.
We evaluate the performance of the face recognition system on an appropriate
standard benchmark dataset and demonstrate the feasibility of the approach with
two use cases
BlogForever D2.6: Data Extraction Methodology
This report outlines an inquiry into the area of web data extraction, conducted within the context of blog preservation. The report reviews theoretical advances and practical developments for implementing data extraction. The inquiry is extended through an experiment that demonstrates the effectiveness and feasibility of implementing some of the suggested approaches. More specifically, the report discusses an approach based on unsupervised machine learning that employs the RSS feeds and HTML representations of blogs. It outlines the possibilities of extracting semantics available in blogs and demonstrates the benefits of exploiting available standards such as microformats and microdata. The report proceeds to propose a methodology for extracting and processing blog data to further inform the design and development of the BlogForever platform
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