177 research outputs found
Impact of Online Learning on International Students’ English Language Concerns
With the onset of COVID-19, U.S. universities have been forced to move many, even all, courses online. At the University of Richmond, many of our international students faced visa restrictions due to COVID and were required to stay in their countries. As a result, the majority of our international students must attend their classes remotely. International students may find language to be a challenge during online learning. The purpose of our study is to learn more about how, if at all, online classes have an impact on international students’ English language concerns
EMO: Episodic Memory Optimization for Few-Shot Meta-Learning
Few-shot meta-learning presents a challenge for gradient descent optimization
due to the limited number of training samples per task. To address this issue,
we propose an episodic memory optimization for meta-learning, we call
\emph{EMO}, which is inspired by the human ability to recall past learning
experiences from the brain's memory. EMO retains the gradient history of past
experienced tasks in external memory, enabling few-shot learning in a
memory-augmented way. By learning to retain and recall the learning process of
past training tasks, EMO nudges parameter updates in the right direction, even
when the gradients provided by a limited number of examples are uninformative.
We prove theoretically that our algorithm converges for smooth, strongly convex
objectives. EMO is generic, flexible, and model-agnostic, making it a simple
plug-and-play optimizer that can be seamlessly embedded into existing
optimization-based few-shot meta-learning approaches. Empirical results show
that EMO scales well with most few-shot classification benchmarks and improves
the performance of optimization-based meta-learning methods, resulting in
accelerated convergence.Comment: Accepted by CoLLAs 202
Fast Butterfly-Core Community Search For Large Labeled Graphs
Community Search (CS) aims to identify densely interconnected subgraphs
corresponding to query vertices within a graph. However, existing heterogeneous
graph-based community search methods need help identifying cross-group
communities and suffer from efficiency issues, making them unsuitable for large
graphs. This paper presents a fast community search model based on the
Butterfly-Core Community (BCC) structure for heterogeneous graphs. The Random
Walk with Restart (RWR) algorithm and butterfly degree comprehensively evaluate
the importance of vertices within communities, allowing leader vertices to be
rapidly updated to maintain cross-group cohesion. Moreover, we devised a more
efficient method for updating vertex distances, which minimizes vertex visits
and enhances operational efficiency. Extensive experiments on several
real-world temporal graphs demonstrate the effectiveness and efficiency of this
solution.Comment: 8 pages, 8 figure
Adversarial Attacks and Defenses for Semantic Communication in Vehicular Metaverses
For vehicular metaverses, one of the ultimate user-centric goals is to
optimize the immersive experience and Quality of Service (QoS) for users on
board. Semantic Communication (SemCom) has been introduced as a revolutionary
paradigm that significantly eases communication resource pressure for vehicular
metaverse applications to achieve this goal. SemCom enables high-quality and
ultra-efficient vehicular communication, even with explosively increasing data
traffic among vehicles. In this article, we propose a hierarchical
SemCom-enabled vehicular metaverses framework consisting of the global
metaverse, local metaverses, SemCom module, and resource pool. The global and
local metaverses are brand-new concepts from the metaverse's distribution
standpoint. Considering the QoS of users, this article explores the potential
security vulnerabilities of the proposed framework. To that purpose, this study
highlights a specific security risk to the framework's SemCom module and offers
a viable defense solution, so encouraging community researchers to focus more
on vehicular metaverse security. Finally, we provide an overview of the open
issues of secure SemCom in the vehicular metaverses, notably pointing out
potential future research directions
Reconfigurable Intelligent Surface Aided TeraHertz Communications Under Misalignment and Hardware Impairments
TeraHertz (THz) communications are envisioned to help satisfy the ever high
data rates demand with massive bandwidth in the future wireless communication
systems. However, severe path attenuation, transceiver antenna misalignment,
and hardware imperfection greatly alleviate the performance of THz
communications. To solve this challenge, we utilize the recently proposed
reconfigurable intelligent surface (RIS) technology and provide a comprehensive
analytical framework of RIS-aided THz communications. More specifically, we
first prove that the small-scale amplitude fading of THz signals can be exactly
modeled by the fluctuating two-ray distribution based on recent measurements.
Exact statistical characterizations of end-to-end signal-to-noise plus
distortion ratio (SNDR) and signal-to-noise ratio (SNR) are derived. Moreover,
we propose a novel method of optimizing the phase-shifts at the RIS elements
under discrete phase constraints. Finally, we derive analytical expressions for
the outage probability and ergodic capacity, respectively. The tight upper
bounds of ergodic capacity for both ideal and non-ideal radio frequency chains
are obtained. We provided Monte-Carlo simulations to validate the accuracy of
our results. It is interesting to find that the impact of path loss is more
pronounced compared to others, and increasing the number of elements at the RIS
can significantly improve the THz communication system performance
- …