82 research outputs found
A Study on Replay Attack and Anti-Spoofing for Automatic Speaker Verification
For practical automatic speaker verification (ASV) systems, replay attack
poses a true risk. By replaying a pre-recorded speech signal of the genuine
speaker, ASV systems tend to be easily fooled. An effective replay detection
method is therefore highly desirable. In this study, we investigate a major
difficulty in replay detection: the over-fitting problem caused by variability
factors in speech signal. An F-ratio probing tool is proposed and three
variability factors are investigated using this tool: speaker identity, speech
content and playback & recording device. The analysis shows that device is the
most influential factor that contributes the highest over-fitting risk. A
frequency warping approach is studied to alleviate the over-fitting problem, as
verified on the ASV-spoof 2017 database
Exploring Communities in Large Profiled Graphs
Given a graph and a vertex , the community search (CS) problem
aims to efficiently find a subgraph of whose vertices are closely related
to . Communities are prevalent in social and biological networks, and can be
used in product advertisement and social event recommendation. In this paper,
we study profiled community search (PCS), where CS is performed on a profiled
graph. This is a graph in which each vertex has labels arranged in a
hierarchical manner. Extensive experiments show that PCS can identify
communities with themes that are common to their vertices, and is more
effective than existing CS approaches. As a naive solution for PCS is highly
expensive, we have also developed a tree index, which facilitate efficient and
online solutions for PCS
Wiki-induced Cognitive Elaboration in Project Teams: An Empirical Study
Researchers have exerted increasing efforts to understand how wikis can be used to improve team performance. Previous studies have mainly focused on the effect of the quantity of wiki use on performance in wiki-based communities; however, only inconclusive results have been obtained. Our study focuses on the quality of wiki use in a team context. We develop a construct of wiki-induced cognitive elaboration, and explore its nomological network in the team context. Integrating the literatures on wiki and distributed cognition, we propose that wiki-induced cognitive elaboration influences team performance through knowledge integration among team members. We also identify its team-based antecedents, including task involvement, critical norm, task reflexivity, time pressure and process accountability, by drawing on the motivated information processing literature. The research model is empirically tested using multiple-source survey data collected from 46 wiki-based student project teams. The theoretical and practical implications of our findings are also discussed
Deep factorization for speech signal
Various informative factors mixed in speech signals, leading to great
difficulty when decoding any of the factors. An intuitive idea is to factorize
each speech frame into individual informative factors, though it turns out to
be highly difficult. Recently, we found that speaker traits, which were assumed
to be long-term distributional properties, are actually short-time patterns,
and can be learned by a carefully designed deep neural network (DNN). This
discovery motivated a cascade deep factorization (CDF) framework that will be
presented in this paper. The proposed framework infers speech factors in a
sequential way, where factors previously inferred are used as conditional
variables when inferring other factors. We will show that this approach can
effectively factorize speech signals, and using these factors, the original
speech spectrum can be recovered with a high accuracy. This factorization and
reconstruction approach provides potential values for many speech processing
tasks, e.g., speaker recognition and emotion recognition, as will be
demonstrated in the paper.Comment: Accepted by ICASSP 2018. arXiv admin note: substantial text overlap
with arXiv:1706.0177
EPISTEMIC MOTIVATION AND KNOWLEDGE CONTRIBUTION BEHAVIORS IN WIKI TEAMS: A CROSS-LEVEL MODERATION MODEL
Prior research on how to facilitate individuals’ participation in wiki knowledge contribution generally pays little attention to the differentiation of knowledge contributions and the embeddedness of individual team members in team context. This paper examines how an individual’s epistemic motivation and team task reflexivity interact to jointly influence adding, deleting and revising behaviors in distinct ways. Empirical data of 166 university students in 51 teams support our hypotheses. Individuals’ adding, deleting and revising behaviors on wikis are influenced differently by the interactive effect of individual epistemic motivation and team task reflexivity. First, the positive relationship between epistemic motivation and adding behaviors is stronger when the team’s task reflexivity is high. Second, the epistemic motivation stimulates deleting behaviors only when team task reflexivity is high. Third, epistemic motivation is significantly associated with more revising behaviors no matter the level of task reflexivity is high or low
Deep Structural Knowledge Exploitation and Synergy for Estimating Node Importance Value on Heterogeneous Information Networks
Node importance estimation problem has been studied conventionally with
homogeneous network topology analysis. To deal with network heterogeneity, a
few recent methods employ graph neural models to automatically learn diverse
sources of information. However, the major concern revolves around that their
full adaptive learning process may lead to insufficient information
exploration, thereby formulating the problem as the isolated node value
prediction with underperformance and less interpretability. In this work, we
propose a novel learning framework: SKES. Different from previous automatic
learning designs, SKES exploits heterogeneous structural knowledge to enrich
the informativeness of node representations. Based on a sufficiently
uninformative reference, SKES estimates the importance value for any input
node, by quantifying its disparity against the reference. This establishes an
interpretable node importance computation paradigm. Furthermore, SKES dives
deep into the understanding that "nodes with similar characteristics are prone
to have similar importance values" whilst guaranteeing that such
informativeness disparity between any different nodes is orderly reflected by
the embedding distance of their associated latent features. Extensive
experiments on three widely-evaluated benchmarks demonstrate the performance
superiority of SKES over several recent competing methods.Comment: Accepted by AAAI 202
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