146 research outputs found
Orientation-Aware Leg Movement Learning for Action-Driven Human Motion Prediction
The task of action-driven human motion prediction aims to forecast future
human motion from the observed sequence while respecting the given action
label. It requires modeling not only the stochasticity within human motion but
the smooth yet realistic transition between multiple action labels. However,
the fact that most of the datasets do not contain such transition data
complicates this task. Existing work tackles this issue by learning a
smoothness prior to simply promote smooth transitions, yet doing so can result
in unnatural transitions especially when the history and predicted motions
differ significantly in orientations. In this paper, we argue that valid human
motion transitions should incorporate realistic leg movements to handle
orientation changes, and cast it as an action-conditioned in-betweening (ACB)
learning task to encourage transition naturalness. Because modeling all
possible transitions is virtually unreasonable, our ACB is only performed on
very few selected action classes with active gait motions, such as Walk or Run.
Specifically, we follow a two-stage forecasting strategy by first employing the
motion diffusion model to generate the target motion with a specified future
action, and then producing the in-betweening to smoothly connect the
observation and prediction to eventually address motion prediction. Our method
is completely free from the labeled motion transition data during training. To
show the robustness of our approach, we generalize our trained in-betweening
learning model on one dataset to two unseen large-scale motion datasets to
produce natural transitions. Extensive methods on three benchmark datasets
demonstrate that our method yields the state-of-the-art performance in terms of
visual quality, prediction accuracy, and action faithfulness
Learning to Predict Diverse Human Motions from a Single Image via Mixture Density Networks
Human motion prediction, which plays a key role in computer vision, generally
requires a past motion sequence as input. However, in real applications, a
complete and correct past motion sequence can be too expensive to achieve. In
this paper, we propose a novel approach to predicting future human motions from
a much weaker condition, i.e., a single image, with mixture density networks
(MDN) modeling. Contrary to most existing deep human motion prediction
approaches, the multimodal nature of MDN enables the generation of diverse
future motion hypotheses, which well compensates for the strong stochastic
ambiguity aggregated by the single input and human motion uncertainty. In
designing the loss function, we further introduce the energy-based formulation
to flexibly impose prior losses over the learnable parameters of MDN to
maintain motion coherence as well as improve the prediction accuracy by
customizing the energy functions. Our trained model directly takes an image as
input and generates multiple plausible motions that satisfy the given
condition. Extensive experiments on two standard benchmark datasets demonstrate
the effectiveness of our method in terms of prediction diversity and accuracy
Multilevel Saliency-Guided Self-Supervised Learning for Image Anomaly Detection
Anomaly detection (AD) is a fundamental task in computer vision. It aims to
identify incorrect image data patterns which deviate from the normal ones.
Conventional methods generally address AD by preparing augmented negative
samples to enforce self-supervised learning. However, these techniques
typically do not consider semantics during augmentation, leading to the
generation of unrealistic or invalid negative samples. Consequently, the
feature extraction network can be hindered from embedding critical features. In
this study, inspired by visual attention learning approaches, we propose
CutSwap, which leverages saliency guidance to incorporate semantic cues for
augmentation. Specifically, we first employ LayerCAM to extract multilevel
image features as saliency maps and then perform clustering to obtain multiple
centroids. To fully exploit saliency guidance, on each map, we select a pixel
pair from the cluster with the highest centroid saliency to form a patch pair.
Such a patch pair includes highly similar context information with dense
semantic correlations. The resulting negative sample is created by swapping the
locations of the patch pair. Compared to prior augmentation methods, CutSwap
generates more subtle yet realistic negative samples to facilitate quality
feature learning. Extensive experimental and ablative evaluations demonstrate
that our method achieves state-of-the-art AD performance on two mainstream AD
benchmark datasets
Combinatory optimization of chromosomal integrated mevalonate pathway for β-carotene production in Escherichia coli
Additional file 1: Table S1. Primers used in this work. Table S2. Modulating genes of mvaS-mvaA-mavD1 operon for improving β-carotene production. Table S3. Modulating genes of Hmg1-erg12 operon for improving β-carotene production. Table S4. Sequences of representative artificial regulatory parts. Table S5. Plasmids used in this work. Table S6. Escherichia coli strains used in this work. Table S7. Calculated strength of mvaS and Hmg1 RBS, RBS sequence and relative β-carotene yield of strains from Re-modulation libraries. Figure S1. Two-step recombination method for inserting Hmg1-erg12 operon in E. coli chromosome. Figure S2. Two-step recombination method for modulating gene expression in E. coli chromosome by different artificial regulatory parts
A Multi-In and Multi-Out Dendritic Neuron Model and its Optimization
Artificial neural networks (ANNs), inspired by the interconnection of real
neurons, have achieved unprecedented success in various fields such as computer
vision and natural language processing. Recently, a novel mathematical ANN
model, known as the dendritic neuron model (DNM), has been proposed to address
nonlinear problems by more accurately reflecting the structure of real neurons.
However, the single-output design limits its capability to handle multi-output
tasks, significantly lowering its applications. In this paper, we propose a
novel multi-in and multi-out dendritic neuron model (MODN) to tackle
multi-output tasks. Our core idea is to introduce a filtering matrix to the
soma layer to adaptively select the desired dendrites to regress each output.
Because such a matrix is designed to be learnable, MODN can explore the
relationship between each dendrite and output to provide a better solution to
downstream tasks. We also model a telodendron layer into MODN to simulate
better the real neuron behavior. Importantly, MODN is a more general and
unified framework that can be naturally specialized as the DNM by customizing
the filtering matrix. To explore the optimization of MODN, we investigate both
heuristic and gradient-based optimizers and introduce a 2-step training method
for MODN. Extensive experimental results performed on 11 datasets on both
binary and multi-class classification tasks demonstrate the effectiveness of
MODN, with respect to accuracy, convergence, and generality
ActiveSelfHAR: Incorporating Self Training into Active Learning to Improve Cross-Subject Human Activity Recognition
Deep learning-based human activity recognition (HAR) methods have shown great
promise in the applications of smart healthcare systems and wireless body
sensor network (BSN). Despite their demonstrated performance in laboratory
settings, the real-world implementation of such methods is still hindered by
the cross-subject issue when adapting to new users. To solve this issue, we
propose ActiveSelfHAR, a framework that combines active learning's benefit of
sparsely acquiring data with actual labels and self- training's benefit of
effectively utilizing unlabeled data to enable the deep model to adapt to the
target domain, i.e., the new users. In this framework, the model trained in the
last iteration or the source domain is first utilized to generate pseudo labels
of the target-domain samples and construct a self-training set based on the
confidence score. Second, we propose to use the spatio-temporal relationships
among the samples in the non-self-training set to augment the core set selected
by active learning. Finally, we combine the self-training set and the augmented
core set to fine-tune the model. We demonstrate our method by comparing it with
state-of-the-art methods on two IMU-based datasets and an EMG-based dataset.
Our method presents similar HAR accuracies with the upper bound, i.e. fully
supervised fine-tuning with less than 1\% labeled data of the target dataset
and significantly improves data efficiency and time cost. Our work highlights
the potential of implementing user-independent HAR methods into smart
healthcare systems and BSN
S-diclofenac Protects against Doxorubicin-Induced Cardiomyopathy in Mice via Ameliorating Cardiac Gap Junction Remodeling
Hydrogen sulfide (H2S), as a novel gaseous mediator, plays important roles in mammalian cardiovascular tissues. In the present study, we investigated the cardioprotective effect of S-diclofenac (2-[(2,6-dichlorophenyl)amino] benzeneacetic acid 4-(3H-1,2,dithiol-3-thione-5-yl)phenyl ester), a novel H2S-releasing derivative of diclofenac, in a murine model of doxorubicin-induced cardiomyopathy. After a single dose injection of doxorubicin (15 mg/kg, i.p.), male C57BL/6J mice were given daily treatment of S-diclofenac (25 and 50 µmol/kg, i.p.), diclofenac (25 and 50 µmol/kg, i.p.), NaHS (50 µmol/kg, i.p.), or same volume of vehicle. The cardioprotective effect of S-diclofenac was observed after 14 days. It showed that S-diclofenac, but not diclofenac, dose-dependently inhibited the doxorubicin-induced downregulation of cardiac gap junction proteins (connexin 43 and connexin 45) and thus reversed the remodeling of gap junctions in hearts. It also dose-dependently suppressed doxorubicin-induced activation of JNK in hearts. Furthermore, S-diclofenac produced a dose-dependent anti-inflammatory and anti-oxidative effect in this model. As a result, S-diclofenac significantly attenuated doxorubicin-related cardiac injury and cardiac dysfunction, and improved the survival rate of mice with doxorubicin-induced cardiomyopathy. These effects of S-diclofenac were mimicked in large part by NaHS. Therefore, we propose that H2S released from S-diclofenac in vivo contributes to the protective effect in doxorubicin-induced cardiomyopathy. These data also provide evidence for a critical role of H2S in the pathogenesis of doxorubicin-induced cardiomyopathy
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