287 research outputs found
Chords of longest circuits of graphs
This thesis is on a long standing open conjecture proposed by one of the most prominent mathematicians, Dr. C. Thomassen: Every longest circuit of 3-connected graph has a chord. In 1987, C. Q. Zhang proved that every longest circuit of a 3-connected planar graph G has a chord if G is cubic or if the minimum degree is at least 4. In 1997, Carsten Thomassen proved that every longest circuit of 3-connected cubic graph has a chord.;In this dissertation, we prove the following three independent partial results: (1) Every longest circuit of a 3-connected graph embedded in a projective plane with minimum degree at least has a chord (Theorem 2.3.1). (2) Every longest circuit of a 3-connected cubic graph has at least two chords. Furthermore if the graph is also a planar, then every longest circuit has at least three chords (Theorem 3.2.6, 3.2.7). (3) Every longest circuit of a 4-connected graph embedded in a torus or Klein bottle has a chord.;We get these three independent results with three totally different approaches: Connectivity (Tutte circuit), second Hamilton circuit, and charge and discharge methods
The Directional Transport of Self-Propelled Ellipsoidal Particles Confined in 2D Channel
Transport phenomenon of self-propelled ellipsoidal particles confined in a
smooth corrugated channel with a two-dimensional asymmetric potential and
Gaussian colored noise is investigated. Effects of the channel, potential and
coloured noise are discussed. The moving direction changes from along x axis to
opposite x axis with increasing load f. Proper size of pore is good at the
directional transport, but too large or too small pore size will inhibit the
transport speed. Large x axis noise intensity will inhibit the directional
transport phenomena. Proper y axis noise intensity will help to the directional
transport. Transport reverse phenomenon appears with increasing self-propelled
speed v0. Perfect sphere particle is more easier for directional transport than
needlelike ellipsoid particle
PMAA: A Progressive Multi-scale Attention Autoencoder Model for High-Performance Cloud Removal from Multi-temporal Satellite Imagery
Satellite imagery analysis plays a vital role in remote sensing, but the
information loss caused by cloud cover seriously hinders its application. This
study presents a high-performance cloud removal architecture called Progressive
Multi-scale Attention Autoencoder (PMAA), which simultaneously leverages global
and local information. It mainly consists of a cloud detection backbone and a
cloud removal module. The cloud detection backbone uses cloud masks to
reinforce cloudy areas to prompt the cloud removal module. The cloud removal
module mainly comprises a novel Multi-scale Attention Module (MAM) and a Local
Interaction Module (LIM). PMAA establishes the long-range dependency of
multi-scale features using MAM and modulates the reconstruction of the
fine-grained details using LIM, allowing for the simultaneous representation of
fine- and coarse-grained features at the same level. With the help of diverse
and multi-scale feature representation, PMAA outperforms the previous
state-of-the-art model CTGAN consistently on the Sen2_MTC_Old and Sen2_MTC_New
datasets. Furthermore, PMAA has a considerable efficiency advantage, with only
0.5% and 14.6% of the parameters and computational complexity of CTGAN,
respectively. These extensive results highlight the potential of PMAA as a
lightweight cloud removal network suitable for deployment on edge devices. We
will release the code and trained models to facilitate the study in this
direction.Comment: 8 pages, 5 figure
ARFA: An Asymmetric Receptive Field Autoencoder Model for Spatiotemporal Prediction
Spatiotemporal prediction aims to generate future sequences by paradigms
learned from historical contexts. It holds significant importance in numerous
domains, including traffic flow prediction and weather forecasting. However,
existing methods face challenges in handling spatiotemporal correlations, as
they commonly adopt encoder and decoder architectures with identical receptive
fields, which adversely affects prediction accuracy. This paper proposes an
Asymmetric Receptive Field Autoencoder (ARFA) model to address this issue.
Specifically, we design corresponding sizes of receptive field modules tailored
to the distinct functionalities of the encoder and decoder. In the encoder, we
introduce a large kernel module for global spatiotemporal feature extraction.
In the decoder, we develop a small kernel module for local spatiotemporal
information reconstruction. To address the scarcity of meteorological
prediction data, we constructed the RainBench, a large-scale radar echo dataset
specific to the unique precipitation characteristics of inland regions in China
for precipitation prediction. Experimental results demonstrate that ARFA
achieves consistent state-of-the-art performance on two mainstream
spatiotemporal prediction datasets and our RainBench dataset, affirming the
effectiveness of our approach. This work not only explores a novel method from
the perspective of receptive fields but also provides data support for
precipitation prediction, thereby advancing future research in spatiotemporal
prediction.Comment: 0 pages, 5 figure
PlantDet: A benchmark for Plant Detection in the Three-Rivers-Source Region
The Three-River-Source region is a highly significant natural reserve in
China that harbors a plethora of untamed botanical resources. To meet the
practical requirements of botanical research and intelligent plant management,
we construct a large-scale dataset for Plant detection in the
Three-River-Source region (PTRS). This dataset comprises 6965 high-resolution
images of 2160*3840 pixels, captured by diverse sensors and platforms, and
featuring objects of varying shapes and sizes. Subsequently, a team of
botanical image interpretation experts annotated these images with 21 commonly
occurring object categories. The fully annotated PTRS images contain 122, 300
instances of plant leaves, each labeled by a horizontal rectangle. The PTRS
presents us with challenges such as dense occlusion, varying leaf resolutions,
and high feature similarity among plants, prompting us to develop a novel
object detection network named PlantDet. This network employs a window-based
efficient self-attention module (ST block) to generate robust feature
representation at multiple scales, improving the detection efficiency for small
and densely-occluded objects. Our experimental results validate the efficacy of
our proposed plant detection benchmark, with a precision of 88.1%, a mean
average precision (mAP) of 77.6%, and a higher recall compared to the baseline.
Additionally, our method effectively overcomes the issue of missing small
objects. We intend to share our data and code with interested parties to
advance further research in this field.Comment: 10 pages, 5 figure
Cynaropicrin inhibits lung cancer proliferation by targeting EGFR/AKT signaling pathway
Purpose: To investigate the anti-proliferative effect of cynaropicrin on lung cancer cell lines, and the underlying molecular mechanism.
Methods: The effect of cynaropicrin treatment on the viabilities of H1975 and H460 cells was measured using Cell Counting Kit-8. Apoptosis was analysed by annexin-V/FITC staining, while protein expressions were assayed by western blotting.
Results: Treatment of H1975 and H460 cells with cynaropicrin at doses of 0.25 – 2.0 μM led to a marked reduction in their viability (p < 0.05). In cynaropicrin-treated H1975 and H460 cells, there was significant increase in apoptosis, when compared to control cells. Caspase-3 and caspase-9 levels were also significantly increased in H1975 and H460 cells on treatment with cynaropicrin at doses of 0.25 and 2.0 μM while treatment with cynaropicrin at doses of 0.25 - 2.0 μM significantly down-regulated the mRNA expression of CCND1 in the two cell lines (p < 0.05). Cynaropicrin markedly inhibited mRNA and protein expressions of EGFR, and also downregulated AKT in H1975 and H460 cells (p < 0.05). However, cynaropicrin significantly increased the expressions of miR-202 and miR-370.
Conclusion: Cynaropicrin exerts anti-proliferative and proapoptotic effects on H1975 and H460 lung cancer cells via deactivation of EGFR/AKT signaling pathway. Moreover, it upregulated the expressions of miR-202 and miR-370 in these cells. Thus, cynaropicrin has potentials for the treatment of lung cancer
High-Fidelity Lake Extraction via Two-Stage Prompt Enhancement: Establishing a Novel Baseline and Benchmark
The extraction of lakes from remote sensing images is a complex challenge due
to the varied lake shapes and data noise. Current methods rely on multispectral
image datasets, making it challenging to learn lake features accurately from
pixel arrangements. This, in turn, affects model learning and the creation of
accurate segmentation masks. This paper introduces a unified prompt-based
dataset construction approach that provides approximate lake locations using
point, box, and mask prompts. We also propose a two-stage prompt enhancement
framework, LEPrompter, which involves prompt-based and prompt-free stages
during training. The prompt-based stage employs a prompt encoder to extract
prior information, integrating prompt tokens and image embeddings through self-
and cross-attention in the prompt decoder. Prompts are deactivated once the
model is trained to ensure independence during inference, enabling automated
lake extraction. Evaluations on Surface Water and Qinghai-Tibet Plateau Lake
datasets show consistent performance improvements compared to the previous
state-of-the-art method. LEPrompter achieves mIoU scores of 91.48% and 97.43%
on the respective datasets without introducing additional parameters or GFLOPs.
Supplementary materials provide the source code, pre-trained models, and
detailed user studies.Comment: 8 pages, 7 figure
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