174 research outputs found
Topological Structure Learning for Weakly-Supervised Out-of-Distribution Detection
Out-of-distribution (OOD) detection is the key to deploying models safely in
the open world. For OOD detection, collecting sufficient in-distribution (ID)
labeled data is usually more time-consuming and costly than unlabeled data.
When ID labeled data is limited, the previous OOD detection methods are no
longer superior due to their high dependence on the amount of ID labeled data.
Based on limited ID labeled data and sufficient unlabeled data, we define a new
setting called Weakly-Supervised Out-of-Distribution Detection (WSOOD). To
solve the new problem, we propose an effective method called Topological
Structure Learning (TSL). Firstly, TSL uses a contrastive learning method to
build the initial topological structure space for ID and OOD data. Secondly,
TSL mines effective topological connections in the initial topological space.
Finally, based on limited ID labeled data and mined topological connections,
TSL reconstructs the topological structure in a new topological space to
increase the separability of ID and OOD instances. Extensive studies on several
representative datasets show that TSL remarkably outperforms the
state-of-the-art, verifying the validity and robustness of our method in the
new setting of WSOOD
Localization and Discrete Beamforming with a Large Reconfigurable Intelligent Surface
In millimeter-wave (mmWave) cellular systems, reconfigurable intelligent
surfaces (RISs) are foreseeably deployed with a large number of reflecting
elements to achieve high beamforming gains. The large-sized RIS will make radio
links fall in the near-field localization regime with spatial non-stationarity
issues. Moreover, the discrete phase restriction on the RIS reflection
coefficient incurs exponential complexity for discrete beamforming. It remains
an open problem to find the optimal RIS reflection coefficient design in
polynomial time. To address these issues, we propose a scalable
partitioned-far-field protocol that considers both the near-filed
non-stationarity and discrete beamforming. The protocol approximates near-field
signal propagation using a partitioned-far-field representation to inherit the
sparsity from the sophisticated far-field and facilitate the near-field
localization scheme. To improve the theoretical localization performance, we
propose a fast passive beamforming (FPB) algorithm that optimally solves the
discrete RIS beamforming problem, reducing the search complexity from
exponential order to linear order. Furthermore, by exploiting the partitioned
structure of RIS, we introduce a two-stage coarse-to-fine localization
algorithm that leverages both the time delay and angle information. Numerical
results demonstrate that centimeter-level localization precision is achieved
under medium and high signal-to-noise ratios (SNR), revealing that RISs can
provide support for low-cost and high-precision localization in future cellular
systems.Comment: 13 page
HCVP: Leveraging Hierarchical Contrastive Visual Prompt for Domain Generalization
Domain Generalization (DG) endeavors to create machine learning models that
excel in unseen scenarios by learning invariant features. In DG, the prevalent
practice of constraining models to a fixed structure or uniform
parameterization to encapsulate invariant features can inadvertently blend
specific aspects. Such an approach struggles with nuanced differentiation of
inter-domain variations and may exhibit bias towards certain domains, hindering
the precise learning of domain-invariant features. Recognizing this, we
introduce a novel method designed to supplement the model with domain-level and
task-specific characteristics. This approach aims to guide the model in more
effectively separating invariant features from specific characteristics,
thereby boosting the generalization. Building on the emerging trend of visual
prompts in the DG paradigm, our work introduces the novel \textbf{H}ierarchical
\textbf{C}ontrastive \textbf{V}isual \textbf{P}rompt (HCVP) methodology. This
represents a significant advancement in the field, setting itself apart with a
unique generative approach to prompts, alongside an explicit model structure
and specialized loss functions. Differing from traditional visual prompts that
are often shared across entire datasets, HCVP utilizes a hierarchical prompt
generation network enhanced by prompt contrastive learning. These generative
prompts are instance-dependent, catering to the unique characteristics inherent
to different domains and tasks. Additionally, we devise a prompt modulation
network that serves as a bridge, effectively incorporating the generated visual
prompts into the vision transformer backbone. Experiments conducted on five DG
datasets demonstrate the effectiveness of HCVP, outperforming both established
DG algorithms and adaptation protocols
Constructing quantum dots@flake g-C3N4 isotype heterojunctions for enhanced visible-light-driven NADH regeneration and enzymatic hydrogenation
The authors thank the financial support from National Natural Science Funds of China (21406163, 91534126, 21621004), Tianjin Research Program of Application Foundation and Advanced Technology (15JCQNJC10000), Open Funding Project of the National Key Laboratory of Biochemical Engineering (2015KF-03), and the Program of Introducing Talents of Discipline to Universities (B06006). X.W. also acknowledges financial support from The Carnegie Trust for the Universities of Scotland (70265) and The Royal Society (RG150001 and IE150611).Peer reviewedPostprin
PuCRZ1, an C2H2 transcription factor from Polyporus umbellatus, positively regulates mycelium response to osmotic stress
Polyporus umbellatus is an edible and medicinal mushroom with the capacity to produce sclerotia. However, the mechanism of P. umbellatus sclerotia formation is unclear. CRZ1 is a C2H2 family transcription factor involved in the Ca2+-calcineurin signaling pathway, which has the function of regulating sclerotia formation, maintaining ion homeostasis, and responding to stress. In this study, we identified 28 C2H2 transcription factors in P. umbellatus genome, 13 of which are differentially expressed between mycelium and sclerotia, including PuCRZ1. Combining DNA affinity purification and sequencing (DAP-seq) and quantitative real-time PCR (qRT-PCR), three genes (PuG10, PuG11, PuG12) were identified as putative PuCRZ1 target genes containing a putative binding motif (GTGGCG) within their promoter. Yeast single hybridization (Y1H) and EMSA further confirmed that PuCRZ1 can bind to the promoter region of PuG10, PuG11, and PuG12. PuCRZ1 gene could reduce the sensitivity of NaCl in yeast cells. Furthermore, overexpression of the PuCRZ1 target gene, especially the FVLY domain containing gene PuG11, could improve the mycelia growth rate and mannitol tolerance in P. umbellatus. These results demonstrate that PuCRZ1 in the Ca2+-calcineurin signaling pathway plays an important role in mycelia growth, as well as osmotic stress tolerance
How Well Does GPT-4V(ision) Adapt to Distribution Shifts? A Preliminary Investigation
In machine learning, generalization against distribution shifts -- where
deployment conditions diverge from the training scenarios -- is crucial,
particularly in fields like climate modeling, biomedicine, and autonomous
driving. The emergence of foundation models, distinguished by their extensive
pretraining and task versatility, has led to an increased interest in their
adaptability to distribution shifts. GPT-4V(ision) acts as the most advanced
publicly accessible multimodal foundation model, with extensive applications
across various domains, including anomaly detection, video understanding, image
generation, and medical diagnosis. However, its robustness against data
distributions remains largely underexplored. Addressing this gap, this study
rigorously evaluates GPT-4V's adaptability and generalization capabilities in
dynamic environments, benchmarking against prominent models like CLIP, LLaVA,
and Gemini. We delve into GPT-4V's zero-shot generalization across 13 diverse
datasets spanning natural, medical, and molecular domains. We further
investigate its adaptability to controlled data perturbations and examine the
efficacy of in-context learning as a tool to enhance its adaptation. Our
findings delineate GPT-4V's capability boundaries in distribution shifts,
shedding light on its strengths and limitations across various scenarios.
Importantly, this investigation contributes to our understanding of how AI
foundation models generalize to distribution shifts, offering pivotal insights
into their adaptability and robustness. The code is publicly available at
https://github.com/jameszhou-gl/gpt-4v-distribution-shift.Comment: added the investigation of Gemini. 66 pages, 41 figure
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