12 research outputs found
Cross Contrastive Feature Perturbation for Domain Generalization
Domain generalization (DG) aims to learn a robust model from source domains
that generalize well on unseen target domains. Recent studies focus on
generating novel domain samples or features to diversify distributions
complementary to source domains. Yet, these approaches can hardly deal with the
restriction that the samples synthesized from various domains can cause
semantic distortion. In this paper, we propose an online one-stage Cross
Contrasting Feature Perturbation (CCFP) framework to simulate domain shift by
generating perturbed features in the latent space while regularizing the model
prediction against domain shift. Different from the previous fixed synthesizing
strategy, we design modules with learnable feature perturbations and semantic
consistency constraints. In contrast to prior work, our method does not use any
generative-based models or domain labels. We conduct extensive experiments on a
standard DomainBed benchmark with a strict evaluation protocol for a fair
comparison. Comprehensive experiments show that our method outperforms the
previous state-of-the-art, and quantitative analyses illustrate that our
approach can alleviate the domain shift problem in out-of-distribution (OOD)
scenarios
Aggregation of Disentanglement: Reconsidering Domain Variations in Domain Generalization
Domain Generalization (DG) is a fundamental challenge for machine learning
models, which aims to improve model generalization on various domains. Previous
methods focus on generating domain invariant features from various source
domains. However, we argue that the domain variantions also contain useful
information, ie, classification-aware information, for downstream tasks, which
has been largely ignored. Different from learning domain invariant features
from source domains, we decouple the input images into Domain Expert Features
and noise. The proposed domain expert features lie in a learned latent space
where the images in each domain can be classified independently, enabling the
implicit use of classification-aware domain variations. Based on the analysis,
we proposed a novel paradigm called Domain Disentanglement Network (DDN) to
disentangle the domain expert features from the source domain images and
aggregate the source domain expert features for representing the target test
domain. We also propound a new contrastive learning method to guide the domain
expert features to form a more balanced and separable feature space.
Experiments on the widely-used benchmarks of PACS, VLCS, OfficeHome, DomainNet,
and TerraIncognita demonstrate the competitive performance of our method
compared to the recently proposed alternatives
Correlation between Chlamydia Pneumoniae IgG Positive in Lung Cancer Patients and Cytokines Related to Radiation-induced Pulmonary Lesion
Background and objective There exsits intimate relationship between infection with chlamydia pneumoniae (Cpn) and lung cancer incidence. But few studies have been reported about radiation-induced pulmonary lesion in lung cancer patients infected with Cpn. The aim of this study is to explore the correlation between cytokines related to radiation-induced pulmonary lesion and Cpn IgG positive in lung cancer patients. Methods A total of 69 patients with lung cancer received chest radiotherapy. Blood samples were collected and frozen before radiotherapy (pre-RT), middle radiotherapy (mid-RT) and after radiotherapy (post-RT). Cpn IgG and levels of IL-1β, SP-A, TGF-β, and TNF-α were measured by enzymelinked immunosorbent assay (ELISA). Results In the total of 69 patients, 21 patients were Cpn IgG positive, 48 patients negative. The positive rate was 30.43%. In mid-RT concentration of IL-1β in Cpn IgG positive and negative group were (35.82±10.09) ng/L and (30.01±6.46) ng/L, with statistically significant difference (P < 0.05). Pre-RT and post-RT concentrations of IL-1β in Cpn IgG positive and negative group had no statistically significant difference. Mid-RT concentrations of SP-A in Cpn IgG positive group and negative group were (641.78±106.81) ng/L and (100.86±61.4) ng/L respectively, with statistically significant difference (P < 0.05). Post-RT concentration of SP-A in Cpn IgG positive and negative group were (657.47±115.19) ng/L and (93.23±47.15) ng/L respectively, with statistically significant difference (P < 0.05). Concentrations of TNF-α in Cpn IgG positive and negative group had no statistically significant difference. Concentrations of TGF-β in Cpn IgG positive group were (710.67±358.16) pg/mL in pre-RT, (1,002.06±542.16) pg/mL in mid-RT, (2,125.16±1,522.29) pg/mL in post-RT; those in negative group were (867.77±412.48) pg/mL, (914.05±425.70) pg/mL, (1,073.36±896.01) pg/mL. Concentration of TGF-β in post-RT between Cpn IgG positive and negative group had statistically significant difference (P < 0.05). Conclusion Cpn IgG positive in lung cancer patients influenced levels of IL-1β, SP-A, TGF-β during chest radiotherapy. This might aggravate radiation-induced pulmonary lesion
Rethinking Alignment and Uniformity in Unsupervised Image Semantic Segmentation
Unsupervised image semantic segmentation(UISS) aims to match low-level visual
features with semantic-level representations without outer supervision. In this
paper, we address the critical properties from the view of feature alignments
and feature uniformity for UISS models. We also make a comparison between UISS
and image-wise representation learning. Based on the analysis, we argue that
the existing MI-based methods in UISS suffer from representation collapse. By
this, we proposed a robust network called Semantic Attention Network(SAN), in
which a new module Semantic Attention(SEAT) is proposed to generate pixel-wise
and semantic features dynamically. Experimental results on multiple semantic
segmentation benchmarks show that our unsupervised segmentation framework
specializes in catching semantic representations, which outperforms all the
unpretrained and even several pretrained methods.Comment: AAAI2
DNAGPT: A Generalized Pre-trained Tool for Versatile DNA Sequence Analysis Tasks
Pre-trained large language models demonstrate potential in extracting
information from DNA sequences, yet adapting to a variety of tasks and data
modalities remains a challenge. To address this, we propose DNAGPT, a
generalized DNA pre-training model trained on over 200 billion base pairs from
all mammals. By enhancing the classic GPT model with a binary classification
task (DNA sequence order), a numerical regression task (guanine-cytosine
content prediction), and a comprehensive token language, DNAGPT can handle
versatile DNA analysis tasks while processing both sequence and numerical data.
Our evaluation of genomic signal and region recognition, mRNA abundance
regression, and artificial genomes generation tasks demonstrates DNAGPT's
superior performance compared to existing models designed for specific
downstream tasks, benefiting from pre-training using the newly designed model
structure
GPT-4V(ision) as A Social Media Analysis Engine
Recent research has offered insights into the extraordinary capabilities of
Large Multimodal Models (LMMs) in various general vision and language tasks.
There is growing interest in how LMMs perform in more specialized domains.
Social media content, inherently multimodal, blends text, images, videos, and
sometimes audio. Understanding social multimedia content remains a challenging
problem for contemporary machine learning frameworks. In this paper, we explore
GPT-4V(ision)'s capabilities for social multimedia analysis. We select five
representative tasks, including sentiment analysis, hate speech detection, fake
news identification, demographic inference, and political ideology detection,
to evaluate GPT-4V. Our investigation begins with a preliminary quantitative
analysis for each task using existing benchmark datasets, followed by a careful
review of the results and a selection of qualitative samples that illustrate
GPT-4V's potential in understanding multimodal social media content. GPT-4V
demonstrates remarkable efficacy in these tasks, showcasing strengths such as
joint understanding of image-text pairs, contextual and cultural awareness, and
extensive commonsense knowledge. Despite the overall impressive capacity of
GPT-4V in the social media domain, there remain notable challenges. GPT-4V
struggles with tasks involving multilingual social multimedia comprehension and
has difficulties in generalizing to the latest trends in social media.
Additionally, it exhibits a tendency to generate erroneous information in the
context of evolving celebrity and politician knowledge, reflecting the known
hallucination problem. The insights gleaned from our findings underscore a
promising future for LMMs in enhancing our comprehension of social media
content and its users through the analysis of multimodal information
Black-box Source-free Domain Adaptation via Two-stage Knowledge Distillation
Source-free domain adaptation aims to adapt deep neural networks using only
pre-trained source models and target data. However, accessing the source model
still has a potential concern about leaking the source data, which reveals the
patient's privacy. In this paper, we study the challenging but practical
problem: black-box source-free domain adaptation where only the outputs of the
source model and target data are available. We propose a simple but effective
two-stage knowledge distillation method. In Stage
\uppercase\expandafter{\romannumeral1}, we train the target model from scratch
with soft pseudo-labels generated by the source model in a knowledge
distillation manner. In Stage \uppercase\expandafter{\romannumeral2}, we
initialize another model as the new student model to avoid the error
accumulation caused by noisy pseudo-labels. We feed the images with weak
augmentation to the teacher model to guide the learning of the student model.
Our method is simple and flexible, and achieves surprising results on three
cross-domain segmentation tasks.Comment: 10 pages,3 figure
Rethinking Alignment and Uniformity in Unsupervised Image Semantic Segmentation
Unsupervised image segmentation aims to match low-level visual features with semantic-level representations without outer supervision. In this paper, we address the critical properties from the view of feature alignments and feature uniformity for UISS models. We also make a comparison between UISS and image-wise representation learning. Based on the analysis, we argue that the existing MI-based methods in UISS suffer from representation collapse. By this, we proposed a robust network called Semantic Attention Network(SAN), in which a new module Semantic Attention(SEAT) is proposed to generate pixel-wise and semantic features dynamically. Experimental results on multiple semantic segmentation benchmarks show that our unsupervised segmentation framework specializes in catching semantic representations, which outperforms all the unpretrained and even several pretrained methods
Towards Generalizable Medical Image Segmentation with Pixel-wise Uncertainty Estimation
Deep neural networks (DNNs) achieve promising performance in visual
recognition under the independent and identically distributed (IID) hypothesis.
In contrast, the IID hypothesis is not universally guaranteed in numerous
real-world applications, especially in medical image analysis. Medical image
segmentation is typically formulated as a pixel-wise classification task in
which each pixel is classified into a category. However, this formulation
ignores the hard-to-classified pixels, e.g., some pixels near the boundary
area, as they usually confuse DNNs. In this paper, we first explore that
hard-to-classified pixels are associated with high uncertainty. Based on this,
we propose a novel framework that utilizes uncertainty estimation to highlight
hard-to-classified pixels for DNNs, thereby improving its generalization. We
evaluate our method on two popular benchmarks: prostate and fundus datasets.
The results of the experiment demonstrate that our method outperforms
state-of-the-art methods.Comment: 11 pages, 3 figure
Mechanical Properties, Radiation Resistance Performances, and Mechanism Insights of Nitrile Butadiene Rubber Irradiated with High-Dose Gamma Rays
The radiation effect of materials is very important and directly related to the safety and reliability of nuclear reactors. Polymer materials, one of the indispensable materials in nuclear power equipment, must withstand the ordeal of high-energy ionizing rays. In this work, through screening different γ-ray dose irradiation conditions, we systematically and comprehensively study the changes in the structure and properties of nitrile butadiene rubber (NBR) before and after γ-ray static irradiation at a high dose rate, and master the rule and mechanism of the γ-ray static irradiation effect of these polymer materials. The mapping relationship between the macroscopic properties, microstructure, and irradiation dose of NBR is accurately characterized. With an increase in total irradiation dose, the C=C double bond reaction occurs, and the C≡N bond, C=C, and C=O participate in the hyper crosslinking reaction. The glass transition temperature (Tg) increases with the cumulative irradiation amount. With the increased total irradiation amount, the degree of rubber cross-linking increases, causing an increased crystallinity and decomposition temperature. A growing amount of gamma irradiation causes the mechanical properties of the rubber to degrade simultaneously, increasing the shore hardness while decreasing the tensile strength and ultimate elongation at break. When the cumulative amount reaches 1 MGy, the ultimate elongation at break decreases significantly. A cumulative dose of radiation resistance of 4 MGy can be achieved by the samples. This work can provide theoretical and experimental support for the long-term stability of nitrile butadiene rubber and its derivatives in nuclear radiation fields and space radiation conditions