1,302 research outputs found
Connectivity-Aware Semi-Decentralized Federated Learning over Time-Varying D2D Networks
Semi-decentralized federated learning blends the conventional device
to-server (D2S) interaction structure of federated model training with
localized device-to-device (D2D) communications. We study this architecture
over practical edge networks with multiple D2D clusters modeled as time-varying
and directed communication graphs. Our investigation results in an algorithm
that controls the fundamental trade-off between (a) the rate of convergence of
the model training process towards the global optimizer, and (b) the number of
D2S transmissions required for global aggregation. Specifically, in our
semi-decentralized methodology, D2D consensus updates are injected into the
federated averaging framework based on column-stochastic weight matrices that
encapsulate the connectivity within the clusters. To arrive at our algorithm,
we show how the expected optimality gap in the current global model depends on
the greatest two singular values of the weighted adjacency matrices (and hence
on the densities) of the D2D clusters. We then derive tight bounds on these
singular values in terms of the node degrees of the D2D clusters, and we use
the resulting expressions to design a threshold on the number of clients
required to participate in any given global aggregation round so as to ensure a
desired convergence rate. Simulations performed on real-world datasets reveal
that our connectivity-aware algorithm reduces the total communication cost
required to reach a target accuracy significantly compared with baselines
depending on the connectivity structure and the learning task.Comment: 10 pages, 5 figures. This paper has been accepted to ACM-MobiHoc 202
Knowledge-Rich Approach to Automatic Grammatical Information Acquisition: Enriching Chinese Sketch Engine with a Lexical Grammar
PACLIC 20 / Wuhan, China / 1-3 November, 200
Knowledge-Rich Approach to Automatic Grammatical Information Acquisition: Enriching Chinese Sketch Engine with a Lexical Grammar
PACLIC 20 / Wuhan, China / 1-3 November, 200
Mitigating Biases in Student Performance Prediction via Attention-Based Personalized Federated Learning
Traditional learning-based approaches to student modeling generalize poorly
to underrepresented student groups due to biases in data availability. In this
paper, we propose a methodology for predicting student performance from their
online learning activities that optimizes inference accuracy over different
demographic groups such as race and gender. Building upon recent foundations in
federated learning, in our approach, personalized models for individual student
subgroups are derived from a global model aggregated across all student models
via meta-gradient updates that account for subgroup heterogeneity. To learn
better representations of student activity, we augment our approach with a
self-supervised behavioral pretraining methodology that leverages multiple
modalities of student behavior (e.g., visits to lecture videos and
participation on forums), and include a neural network attention mechanism in
the model aggregation stage. Through experiments on three real-world datasets
from online courses, we demonstrate that our approach obtains substantial
improvements over existing student modeling baselines in predicting student
learning outcomes for all subgroups. Visual analysis of the resulting student
embeddings confirm that our personalization methodology indeed identifies
different activity patterns within different subgroups, consistent with its
stronger inference ability compared with the baselines.Comment: 10 pages, CIKM 202
Decreased brain-expressed X-linked 4 (BEX4) expression promotes growth of oral squamous cell carcinoma
© 2016 Gao et al.Background: Brain-expressed X-linked (BEX) 4 is a member of BEX family. The functional role of BEX4 in oral squamous cell carcinoma (OSCC) remains unknown. Methods: Expression level of BEX family members (BEX1-5) in OSCC tissues and the paired normal epithelial were examined. Functions of epigenetic changes (DNA methylation and histone modifications) on BEX4 suppression in OSCC were examined by zebularine and trichostatin A (TSA) treatment on OSCC cell lines. Lentivector containing full-length BEX4 was used to generate OSCC cell lines with stable BEX4 expression. Effects of BEX4 expression on OSCC proliferation were monitored with xCELLigence RTCA real-time cell analyzer. BEX4-overexpressing CAL27 was implanted into nude mice to evaluate the effects on tumor growth in vivo. The signaling pathways regulated by BEX4 in OSCC was explored using human whole-transcript expression microarray. Results: Among the 5 BEX family members, BEX1 and BEX4 showed significant down-regulation in OSCC (P < 0.001). BEX3, in comparison, was overexpressed in the primary tumor. BEX4 expression in OSCC cell lines was re-activated after zebularine and TSA treatment. High BEX4 expression could suppress proliferation of OSCC in vitro. Subcutaneous tumor volume of BEX4-overexpressing CAL27 was remarkably reduced in nude mice. Microarray experiment showed that S100A family members (S100A7, S100A7A, S100A8, S100A9 & S100A12) might be the downstream targets of BEX4 in OSCC. Conclusions: BEX4 functions as tumor suppressor by inhibiting proliferation and growth of oral cancer. Decreased BEX4 contributes to the increased proliferative propensity of OSCC.published_or_final_versio
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