77,721 research outputs found
Leveraging Multi-level Dependency of Relational Sequences for Social Spammer Detection
Much recent research has shed light on the development of the
relation-dependent but content-independent framework for social spammer
detection. This is largely because the relation among users is difficult to be
altered when spammers attempt to conceal their malicious intents. Our study
investigates the spammer detection problem in the context of multi-relation
social networks, and makes an attempt to fully exploit the sequences of
heterogeneous relations for enhancing the detection accuracy. Specifically, we
present the Multi-level Dependency Model (MDM). The MDM is able to exploit
user's long-term dependency hidden in their relational sequences along with
short-term dependency. Moreover, MDM fully considers short-term relational
sequences from the perspectives of individual-level and union-level, due to the
fact that the type of short-term sequences is multi-folds. Experimental results
on a real-world multi-relational social network demonstrate the effectiveness
of our proposed MDM on multi-relational social spammer detection
Probabilistic Relational Model Benchmark Generation
The validation of any database mining methodology goes through an evaluation
process where benchmarks availability is essential. In this paper, we aim to
randomly generate relational database benchmarks that allow to check
probabilistic dependencies among the attributes. We are particularly interested
in Probabilistic Relational Models (PRMs), which extend Bayesian Networks (BNs)
to a relational data mining context and enable effective and robust reasoning
over relational data. Even though a panoply of works have focused, separately ,
on the generation of random Bayesian networks and relational databases, no work
has been identified for PRMs on that track. This paper provides an algorithmic
approach for generating random PRMs from scratch to fill this gap. The proposed
method allows to generate PRMs as well as synthetic relational data from a
randomly generated relational schema and a random set of probabilistic
dependencies. This can be of interest not only for machine learning researchers
to evaluate their proposals in a common framework, but also for databases
designers to evaluate the effectiveness of the components of a database
management system
Reasoning about Independence in Probabilistic Models of Relational Data
We extend the theory of d-separation to cases in which data instances are not
independent and identically distributed. We show that applying the rules of
d-separation directly to the structure of probabilistic models of relational
data inaccurately infers conditional independence. We introduce relational
d-separation, a theory for deriving conditional independence facts from
relational models. We provide a new representation, the abstract ground graph,
that enables a sound, complete, and computationally efficient method for
answering d-separation queries about relational models, and we present
empirical results that demonstrate effectiveness.Comment: 61 pages, substantial revisions to formalisms, theory, and related
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