721 research outputs found
Knowledge Graph-Augmented Language Models for Knowledge-Grounded Dialogue Generation
Language models have achieved impressive performances on dialogue generation
tasks. However, when generating responses for a conversation that requires
factual knowledge, they are far from perfect, due to an absence of mechanisms
to retrieve, encode, and reflect the knowledge in the generated responses. Some
knowledge-grounded dialogue generation methods tackle this problem by
leveraging facts from Knowledge Graphs (KGs); however, they do not guarantee
that the model utilizes a relevant piece of knowledge from the KG. To overcome
this limitation, we propose SUbgraph Retrieval-augmented GEneration (SURGE), a
framework for generating context-relevant and knowledge-grounded dialogues with
the KG. Specifically, our SURGE framework first retrieves the relevant subgraph
from the KG, and then enforces consistency across facts by perturbing their
word embeddings conditioned by the retrieved subgraph. Then, we utilize
contrastive learning to ensure that the generated texts have high similarity to
the retrieved subgraphs. We validate our SURGE framework on OpendialKG and
KOMODIS datasets, showing that it generates high-quality dialogues that
faithfully reflect the knowledge from KG.Comment: Preprint. Under revie
Opportunistic Feedback Assisted Scheduling and Resource Allocation in OFDMA Systems
Abstract-This paper proposes an efficient channel information feedback method to minimize feedback overhead without performance loss for orthogonal frequency division multiple access (OFDMA) frequency division duplexing (FDD) systems in time-varying channel. The proposed best M users' best L subbands feedback method can significantly reduce the feedback overhead. The proposed scheme utilizes the property of the proposed fair (PF) scheduler that most of the subbands are assigned to the users with high average SNR by time selectivity of channel and some high SNR subbands are assigned to the users by frequency selectivity. For adaptive implementation, the threshold assisted feedback method is proposed. In the numerical results, it is showed that the feedback overhead of the proposed scheme is about 12% of the full CSI feedback method with little throughput loss when the number of users is 50
Nearly Massless Electrons in the Silicon Interface with a Metal Film
We demonstrate the realization of nearly massless electrons in the most
widely used device material, silicon, at the interface with a metal film. Using
angle-resolved photoemission, we found that the surface band of a monolayer
lead film drives a hole band of the Si inversion layer formed at the interface
with the film to have nearly linear dispersion with an effective mass about 20
times lighter than bulk Si and comparable to graphene. The reduction of mass
can be accounted for by repulsive interaction between neighboring bands of the
metal film and Si substrate. Our result suggests a promising way to take
advantage of massless carriers in silicon-based thin-film devices, which can
also be applied for various other semiconductor devices.Comment: 4 pages, 4 figures, accepted for publication in Physical Review
Letter
Journey of Mesenchymal Stem Cells for Homing: Strategies to Enhance Efficacy and Safety of Stem Cell Therapy
Human mesenchymal stem cells (MSCs) communicate with other cells in the human body and appear to “home” to areas of injury in response to signals of cellular damage, known as homing signals. This review of the state of current research on homing of MSCs suggests that favorable cellular conditions and the in vivo environment facilitate and are required for the migration of MSCs to the site of insult or injury in vivo. We review the current understanding of MSC migration and discuss strategies for enhancing both the environmental and cellular conditions that give rise to effective homing of MSCs. This may allow MSCs to quickly find and migrate to injured tissues, where they may best exert clinical benefits resulting from improved homing and the presence of increased numbers of MSCs
In-situ fabrication of cobalt-doped SrFe2As2 thin films by using pulsed laser deposition with excimer laser
The remarkably high superconducting transition temperature and upper critical
field of iron(Fe)-based layered superconductors, despite ferromagnetic material
base, open the prospect for superconducting electronics. However, success in
superconducting electronics has been limited because of difficulties in
fabricating high-quality thin films. We report the growth of high-quality
c-axis-oriented cobalt(Co)-doped SrFe2As2 thin films with bulk
superconductivity by using an in-situ pulsed laser deposition technique with a
248-nm-wavelength KrF excimer laser and an arsenic(As)-rich phase target. The
temperature and field dependences of the magnetization showing strong
diamagnetism and transport critical current density with superior Jc-H
performance are reported. These results provide necessary information for
practical applications of Fe-based superconductors.Comment: 8 pages, 3figures. to be published at Appl. Phys. Let
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