39,080 research outputs found
Towards Learning Instantiated Logical Rules from Knowledge Graphs
Efficiently inducing high-level interpretable regularities from knowledge
graphs (KGs) is an essential yet challenging task that benefits many downstream
applications. In this work, we present GPFL, a probabilistic rule learner
optimized to mine instantiated first-order logic rules from KGs. Instantiated
rules contain constants extracted from KGs. Compared to abstract rules that
contain no constants, instantiated rules are capable of explaining and
expressing concepts in more details. GPFL utilizes a novel two-stage rule
generation mechanism that first generalizes extracted paths into templates that
are acyclic abstract rules until a certain degree of template saturation is
achieved, then specializes the generated templates into instantiated rules.
Unlike existing works that ground every mined instantiated rule for evaluation,
GPFL shares groundings between structurally similar rules for collective
evaluation. Moreover, we reveal the presence of overfitting rules, their impact
on the predictive performance, and the effectiveness of a simple validation
method filtering out overfitting rules. Through extensive experiments on public
benchmark datasets, we show that GPFL 1.) significantly reduces the runtime on
evaluating instantiated rules; 2.) discovers much more quality instantiated
rules than existing works; 3.) improves the predictive performance of learned
rules by removing overfitting rules via validation; 4.) is competitive on
knowledge graph completion task compared to state-of-the-art baselines
Path Ranking with Attention to Type Hierarchies
The objective of the knowledge base completion problem is to infer missing
information from existing facts in a knowledge base. Prior work has
demonstrated the effectiveness of path-ranking based methods, which solve the
problem by discovering observable patterns in knowledge graphs, consisting of
nodes representing entities and edges representing relations. However, these
patterns either lack accuracy because they rely solely on relations or cannot
easily generalize due to the direct use of specific entity information. We
introduce Attentive Path Ranking, a novel path pattern representation that
leverages type hierarchies of entities to both avoid ambiguity and maintain
generalization. Then, we present an end-to-end trained attention-based RNN
model to discover the new path patterns from data. Experiments conducted on
benchmark knowledge base completion datasets WN18RR and FB15k-237 demonstrate
that the proposed model outperforms existing methods on the fact prediction
task by statistically significant margins of 26% and 10%, respectively.
Furthermore, quantitative and qualitative analyses show that the path patterns
balance between generalization and discrimination.Comment: Thirty-Fourth AAAI Conference on Artificial Intelligence (AAAI-20
Finding Streams in Knowledge Graphs to Support Fact Checking
The volume and velocity of information that gets generated online limits
current journalistic practices to fact-check claims at the same rate.
Computational approaches for fact checking may be the key to help mitigate the
risks of massive misinformation spread. Such approaches can be designed to not
only be scalable and effective at assessing veracity of dubious claims, but
also to boost a human fact checker's productivity by surfacing relevant facts
and patterns to aid their analysis. To this end, we present a novel,
unsupervised network-flow based approach to determine the truthfulness of a
statement of fact expressed in the form of a (subject, predicate, object)
triple. We view a knowledge graph of background information about real-world
entities as a flow network, and knowledge as a fluid, abstract commodity. We
show that computational fact checking of such a triple then amounts to finding
a "knowledge stream" that emanates from the subject node and flows toward the
object node through paths connecting them. Evaluation on a range of real-world
and hand-crafted datasets of facts related to entertainment, business, sports,
geography and more reveals that this network-flow model can be very effective
in discerning true statements from false ones, outperforming existing
algorithms on many test cases. Moreover, the model is expressive in its ability
to automatically discover several useful path patterns and surface relevant
facts that may help a human fact checker corroborate or refute a claim.Comment: Extended version of the paper in proceedings of ICDM 201
Predicting ConceptNet Path Quality Using Crowdsourced Assessments of Naturalness
In many applications, it is important to characterize the way in which two
concepts are semantically related. Knowledge graphs such as ConceptNet provide
a rich source of information for such characterizations by encoding relations
between concepts as edges in a graph. When two concepts are not directly
connected by an edge, their relationship can still be described in terms of the
paths that connect them. Unfortunately, many of these paths are uninformative
and noisy, which means that the success of applications that use such path
features crucially relies on their ability to select high-quality paths. In
existing applications, this path selection process is based on relatively
simple heuristics. In this paper we instead propose to learn to predict path
quality from crowdsourced human assessments. Since we are interested in a
generic task-independent notion of quality, we simply ask human participants to
rank paths according to their subjective assessment of the paths' naturalness,
without attempting to define naturalness or steering the participants towards
particular indicators of quality. We show that a neural network model trained
on these assessments is able to predict human judgments on unseen paths with
near optimal performance. Most notably, we find that the resulting path
selection method is substantially better than the current heuristic approaches
at identifying meaningful paths.Comment: In Proceedings of the Web Conference (WWW) 201
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