231 research outputs found
Coping with Change: Learning Invariant and Minimum Sufficient Representations for Fine-Grained Visual Categorization
Fine-grained visual categorization (FGVC) is a challenging task due to
similar visual appearances between various species. Previous studies always
implicitly assume that the training and test data have the same underlying
distributions, and that features extracted by modern backbone architectures
remain discriminative and generalize well to unseen test data. However, we
empirically justify that these conditions are not always true on benchmark
datasets. To this end, we combine the merits of invariant risk minimization
(IRM) and information bottleneck (IB) principle to learn invariant and minimum
sufficient (IMS) representations for FGVC, such that the overall model can
always discover the most succinct and consistent fine-grained features. We
apply the matrix-based R{\'e}nyi's -order entropy to simplify and
stabilize the training of IB; we also design a ``soft" environment partition
scheme to make IRM applicable to FGVC task. To the best of our knowledge, we
are the first to address the problem of FGVC from a generalization perspective
and develop a new information-theoretic solution accordingly. Extensive
experiments demonstrate the consistent performance gain offered by our IMS.Comment: Manuscript accepted by CVIU, code is available at Githu
The Distributional Characteristics of Heavy Metal in Jiangsu Province Shoal Sea
After the analysis of surface samples and core samples collected in Xinyanggang tidal land, the contents of Pb, Cu, Zn, and Cr were obtained and analyzed in this paper. The heavy metal accumulation rule and pollution status were studied by Index of geo-accumulation, latent ecological risk index method, and elements accumulation index method. The research suggests that (1) the contents of heavy metal Pb, Cu, Zn, and Cr in Xinyanggang tidal land have the same change trend, and such trend remains unchanged after the data were normalized, while the fluctuation range becomes smaller. (2) After analyzing the heavy metal content in the surface samples, it was revealed that the contents of heavy metals are getting lower from high tidal zone to low tidal zone, but the ranges of the change were different. Cu, Ni, and Zn emerge obvious decline from supratidal zone to subtidal zone, while the changes of Cr and Pb are not obvious. (3) Pb and Cr contents in Xinyanggang tidal land present accumulative character, as Pb in Xinyanggang is 3 times as much as the local background value, whose EF reaches 3.774. (4) RI value in Xinyanggang is 23.552, which indicates that though Xinyanggang tidal land has some heavy metal pollution and accumulation, there are no ecosystem risks, and the whole Xinyanggang core area environment quality is relatively good
Quadratic Quantum Measurements
We develop a theory of quadratic quantum measurements by a mesoscopic
detector. It is shown that quadratic measurements should have non-trivial
quantum information properties, providing, for instance, a simple way of
entangling two non-interacting qubits. We also calculate output spectrum of a
quantum detector with both linear and quadratic response continuously
monitoring coherent oscillations in two qubits.Comment: 5 pages, 2 figure
The inhibition of high ammonia to in vitro rumen fermentation is pH dependent
Ammonia is an important rumen internal environment indicator. In livestock production, feeding a large amount of non-protein nitrogen to ruminants will create high ammonia stress to the animals, which increases the risk of ammonia toxicity. However, the effects of ammonia toxicity on rumen microbiota and fermentation are still unknown. In this study, an in vitro rumen fermentation technique was used to investigate the effects of different concentrations of ammonia on rumen microbiota and fermentation. To achieve the four final total ammonia nitrogen (TAN) concentrations of 0, 8, 32, and 128 mmol/L, ammonium chloride (NH4Cl) was added at 0, 42.8, 171.2, and 686.8 mg/100 mL, and urea was added at 0, 24, 96, and 384 mg/100 mL. Urea hydrolysis increased, while NH4Cl dissociation slightly reduced the pH. At similar concentrations of TAN, the increased pH of the rumen culture by urea addition resulted in a much higher free ammonia nitrogen (FAN) concentration compared to NH4Cl addition. Pearson correlation analysis revealed a strong negative correlation between FAN and microbial populations (total bacteria, protozoa, fungi, and methanogens) and in vitro rumen fermentation profiles (gas production, dry matter digestibility, total volatile fatty acid, acetate, propionate, etc.), and a much weaker correlation between TAN and the above indicators. Additionally, bacterial community structure changed differently in response to TAN concentrations. High TAN increased Gram-positive Firmicutes and Actinobacteria but reduced Gram-negative Fibrobacteres and Spirochaetes. The current study demonstrated that the inhibition of in vitro rumen fermentation by high ammonia was pH-dependent and was associated with variations of rumen microbial populations and communities
Learning with Free Object Segments for Long-Tailed Instance Segmentation
One fundamental challenge in building an instance segmentation model for a
large number of classes in complex scenes is the lack of training examples,
especially for rare objects. In this paper, we explore the possibility to
increase the training examples without laborious data collection and
annotation. We find that an abundance of instance segments can potentially be
obtained freely from object-centric images, according to two insights: (i) an
object-centric image usually contains one salient object in a simple
background; (ii) objects from the same class often share similar appearances or
similar contrasts to the background. Motivated by these insights, we propose a
simple and scalable framework FreeSeg for extracting and leveraging these
"free" object foreground segments to facilitate model training in long-tailed
instance segmentation. Concretely, we investigate the similarity among
object-centric images of the same class to propose candidate segments of
foreground instances, followed by a novel ranking of segment quality. The
resulting high-quality object segments can then be used to augment the existing
long-tailed datasets, e.g., by copying and pasting the segments onto the
original training images. Extensive experiments show that FreeSeg yields
substantial improvements on top of strong baselines and achieves
state-of-the-art accuracy for segmenting rare object categories
ERNIE-mmLayout: Multi-grained MultiModal Transformer for Document Understanding
Recent efforts of multimodal Transformers have improved Visually Rich
Document Understanding (VrDU) tasks via incorporating visual and textual
information. However, existing approaches mainly focus on fine-grained elements
such as words and document image patches, making it hard for them to learn from
coarse-grained elements, including natural lexical units like phrases and
salient visual regions like prominent image regions. In this paper, we attach
more importance to coarse-grained elements containing high-density information
and consistent semantics, which are valuable for document understanding. At
first, a document graph is proposed to model complex relationships among
multi-grained multimodal elements, in which salient visual regions are detected
by a cluster-based method. Then, a multi-grained multimodal Transformer called
mmLayout is proposed to incorporate coarse-grained information into existing
pre-trained fine-grained multimodal Transformers based on the graph. In
mmLayout, coarse-grained information is aggregated from fine-grained, and then,
after further processing, is fused back into fine-grained for final prediction.
Furthermore, common sense enhancement is introduced to exploit the semantic
information of natural lexical units. Experimental results on four tasks,
including information extraction and document question answering, show that our
method can improve the performance of multimodal Transformers based on
fine-grained elements and achieve better performance with fewer parameters.
Qualitative analyses show that our method can capture consistent semantics in
coarse-grained elements.Comment: Accepted by ACM Multimedia 202
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