50 research outputs found
CAT: Closed-loop Adversarial Training for Safe End-to-End Driving
Driving safety is a top priority for autonomous vehicles. Orthogonal to prior
work handling accident-prone traffic events by algorithm designs at the policy
level, we investigate a Closed-loop Adversarial Training (CAT) framework for
safe end-to-end driving in this paper through the lens of environment
augmentation. CAT aims to continuously improve the safety of driving agents by
training the agent on safety-critical scenarios that are dynamically generated
over time. A novel resampling technique is developed to turn log-replay
real-world driving scenarios into safety-critical ones via probabilistic
factorization, where the adversarial traffic generation is modeled as the
multiplication of standard motion prediction sub-problems. Consequently, CAT
can launch more efficient physical attacks compared to existing safety-critical
scenario generation methods and yields a significantly less computational cost
in the iterative learning pipeline. We incorporate CAT into the MetaDrive
simulator and validate our approach on hundreds of driving scenarios imported
from real-world driving datasets. Experimental results demonstrate that CAT can
effectively generate adversarial scenarios countering the agent being trained.
After training, the agent can achieve superior driving safety in both
log-replay and safety-critical traffic scenarios on the held-out test set. Code
and data are available at https://metadriverse.github.io/cat.Comment: 7th Conference on Robot Learning (CoRL 2023
Why Is Maternal Control Harmful? The Relation between Maternal Control, Insecure Attachment and Antisocial Personality Disorder Features in Chinese College Students:A Sequential Mediation Model
Background: Previous work has indicated that a negative parenting style is associated with antisocial personality disorder features in Chinese college students, yet few studies have explored the unique role of negative mothering in children’s antisocial personality disorder. Methods: The current study mainly examined the sequential mediation effect of parental antipathy and neglect (PAN) and mother negative loving (a form of insecure attachment) in the association between mother control and adulthood antisocial personality disorder features (ASPD features) in the framework of attachment theory and cognitive–behavioral theory. A community sample of 1547 Chinese college students filled in the Parental Bonding Instrument, the Childhood Experience of Care and Abuse Questionnaire, the Adult Attachment Questionnaire and the Personality Diagnostic Questionnaire-4+. Results: A sequential mediation model analysis showed that maternal control significantly predicted PAN, mother negative loving, as well as ASPD features. Conclusions: Mother control and mother negative loving appear to advance on the development and exacerbation of ASPD features in college students
RenderIH: A Large-scale Synthetic Dataset for 3D Interacting Hand Pose Estimation
The current interacting hand (IH) datasets are relatively simplistic in terms
of background and texture, with hand joints being annotated by a machine
annotator, which may result in inaccuracies, and the diversity of pose
distribution is limited. However, the variability of background, pose
distribution, and texture can greatly influence the generalization ability.
Therefore, we present a large-scale synthetic dataset RenderIH for interacting
hands with accurate and diverse pose annotations. The dataset contains 1M
photo-realistic images with varied backgrounds, perspectives, and hand
textures. To generate natural and diverse interacting poses, we propose a new
pose optimization algorithm. Additionally, for better pose estimation accuracy,
we introduce a transformer-based pose estimation network, TransHand, to
leverage the correlation between interacting hands and verify the effectiveness
of RenderIH in improving results. Our dataset is model-agnostic and can improve
more accuracy of any hand pose estimation method in comparison to other real or
synthetic datasets. Experiments have shown that pretraining on our synthetic
data can significantly decrease the error from 6.76mm to 5.79mm, and our
Transhand surpasses contemporary methods. Our dataset and code are available at
https://github.com/adwardlee/RenderIH.Comment: Accepted by ICCV 202
Constrained Update Projection Approach to Safe Policy Optimization
Safe reinforcement learning (RL) studies problems where an intelligent agent
has to not only maximize reward but also avoid exploring unsafe areas. In this
study, we propose CUP, a novel policy optimization method based on Constrained
Update Projection framework that enjoys rigorous safety guarantee. Central to
our CUP development is the newly proposed surrogate functions along with the
performance bound. Compared to previous safe RL methods, CUP enjoys the
benefits of 1) CUP generalizes the surrogate functions to generalized advantage
estimator (GAE), leading to strong empirical performance. 2) CUP unifies
performance bounds, providing a better understanding and interpretability for
some existing algorithms; 3) CUP provides a non-convex implementation via only
first-order optimizers, which does not require any strong approximation on the
convexity of the objectives. To validate our CUP method, we compared CUP
against a comprehensive list of safe RL baselines on a wide range of tasks.
Experiments show the effectiveness of CUP both in terms of reward and safety
constraint satisfaction. We have opened the source code of CUP at this link
https://github.com/zmsn-2077/ CUP-safe-rl.Comment: Accepted by NeurIPS2022. arXiv admin note: substantial text overlap
with arXiv:2202.0756
Learning Better with Less: Effective Augmentation for Sample-Efficient Visual Reinforcement Learning
Data augmentation (DA) is a crucial technique for enhancing the sample
efficiency of visual reinforcement learning (RL) algorithms. Notably, employing
simple observation transformations alone can yield outstanding performance
without extra auxiliary representation tasks or pre-trained encoders. However,
it remains unclear which attributes of DA account for its effectiveness in
achieving sample-efficient visual RL. To investigate this issue and further
explore the potential of DA, this work conducts comprehensive experiments to
assess the impact of DA's attributes on its efficacy and provides the following
insights and improvements: (1) For individual DA operations, we reveal that
both ample spatial diversity and slight hardness are indispensable. Building on
this finding, we introduce Random PadResize (Rand PR), a new DA operation that
offers abundant spatial diversity with minimal hardness. (2) For multi-type DA
fusion schemes, the increased DA hardness and unstable data distribution result
in the current fusion schemes being unable to achieve higher sample efficiency
than their corresponding individual operations. Taking the non-stationary
nature of RL into account, we propose a RL-tailored multi-type DA fusion scheme
called Cycling Augmentation (CycAug), which performs periodic cycles of
different DA operations to increase type diversity while maintaining data
distribution consistency. Extensive evaluations on the DeepMind Control suite
and CARLA driving simulator demonstrate that our methods achieve superior
sample efficiency compared with the prior state-of-the-art methods.Comment: NeurIPS 2023 poste
Green interfacial synthesis of two-dimensional poly(2,5-dimethoxyaniline) nanosheets as a promising electrode for high performance electrochemical capacitors
National Natural Science Foundation of China [51202004]; Natural Science Foundation of Anhui Province [KJ2013A051]; CAS Key Laboratory of Materials for Energy Conversion [2014001]2D poly(2,5-dimethoxyaniline) nanosheets were first designed and tailored as intriguing pseudo-capacitive electrode for advanced supercapacitors via green interfacial synthetic strategy, and yielded large specific capacitance (SC) and remarkable SC retention at high rates in 1 M HCl electrolyte
Study on ultrasound-guided thyroid fine needle puncture assisted by rapid on-side evaluation
Objective·To explore the clinical effect of ultrasound-guided fine needle aspiration cytology assisted by rapid on-side evaluation (ROSE).Methods·The data of patients with thyroid nodules diagnosed in Gongli Hospital of Shanghai Pudong New Area from January 2019 to December 2022 were retrospectively analyzed (n=874). According to cytological detection methods, they were divided into ROSE+thinprep cytologic test (TCT) group (n=469) and cell smear (CS)+TCT group (n=405). In the ROSE+TCT group, the tissue and cell samples of ROSE were detected by Diff-Quik staining and continue puncturing until the specimen was satisfied. In the CS+TCT group, the tissue and cell samples were detected by hematoxylin-eosin staining (H-E staining) + Pap staining. Cytologic diagnosis was made according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) cytologic classification criteria, and the cell dissatisfaction rates and clinical outcomes of the 2 methods were compared.Results·The dissatisfaction rates of the ROSE+TCT group and CS+TCT group were 2.4% and 14.1%, respectively, with statistical significance (P=0.000). The smear cells of the ROSE+TCT group were concentrated, and the structure was clear and easy to observe. The samples with a cytologic diagnosis of grade Ⅲ and above were prepared as cell wax blocks to improve the efficiency of subsequent diagnosis. The cells of the CS+TCT group could not produce wax blocks due to the small numbers of cells. The puncture times of the ROSE+TCT group were significantly different from that of the CS+TCT group (P=0.011).Conclusion·The ultrasound-guided thyroid fine needle aspiration assisted by rapid on-site assessment method can assess the effective number of cells in the specimen on the spot, give feedback to the puncturing doctors on the spot, meet the diagnostic accuracy requirements of pathologists by collecting a sufficient number of cells, reduce the number of punctures and treatment time, and play a good auxiliary role in the diagnosis and follow-up examination of clinicians
Polymer-assisted synthesis of a 3D hierarchical porous network-like spinel NiCo2O4 framework towards high-performance electrochemical capacitors
National Natural Science Foundation of China [51202004, 21173120]; Nature Science Foundation of Anhui Province [KJ2013A051]; Specialized Research Fund for the Doctoral Program of Higher Education of China [20060287026]; Nature Science Foundation of Jiangsu Province [BK2011030]; Foundation of Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education [201201]We have developed a facile yet scalable polymer-assisted chemical solution route to prepare a three-dimensional (3D) hierarchical porous network-like NiCo2O4 framework for advanced electrochemical capacitors (ECs). The unique interconnected hierarchical porous framework is constructed by nanosized spinel NiCo2O4 building blocks of 20-30 nm size, thus, a 3D continuous electron transport expressway, convenient electrolyte penetration-diffusion and large electrode-electrolyte interface are obtained simultaneously. The combination of these appealing structural features in the striking network-like NiCo2O4 framework results in a drastically enhanced kinetic behavior, large specific capacitance (SC) and a remarkable cycling stability at high rates. The unique network-like NiCo2O4 electrode features a SC of 587 F g(-1) at 2 A g(-1), and can deliver up to 518 F g(-1) at a large current density of 16 A g(-1). Also, a SC deterioration of similar to 6% of the maximum SC is evident after continuous 3500 charge-discharge cycles at varying current densities, ranging from 2 to 16 A g(-1). Furthermore, the synthetic strategy presented here can be easily extended to fabricate other binary complex metal oxides and/or ternary metal oxides with a controlled composition and porous structure, which may be promising candidates for high-performance ECs, and even advanced Li-ion batteries
Template-engaged synthesis of uniform mesoporous hollow NiCo2O4 sub-microspheres towards high-performance electrochemical capacitors
National Natural Science Foundation of China [51202004]; Nature Science Foundation of Anhui Province [KJ2013A051]An efficient template-engaged synthetic strategy, where silica spheres were applied as hard templates, was developed to synthesize hierarchical mesoporous hollow NiCo2O4 sub-microspheres assembled entirely from ultrathin nanosheets with a thickness of a few nanometers. The as-prepared mesoporous hollow NiCo2O4 sub-microspheres are very uniform in size, mesoporous in textual property, and structurally robust benefiting from the in situ template removal. The morphologies of the hollow submicrospherical architecture can be tuned easily by varying the concentrations of Ni2+, Co2+, and the precipitant. When evaluated as an appealing electroactive material for electrochemical capacitors (ECs), the as-fabricated hierarchical hollow NiCo2O4 sub-microspheres delivered a specific capacitance (SC) of 678 F g(-1) at a current density of 1 A g(-1), and even kept it as high as 540 F g(-1) at 10 A g(-1). Additionally, a desirable cycling stability of 13% SC degradation over 3500 continuous cycles at a current density of 10 A g(-1) is observed, suggesting their promising application in advanced ECs
Facile synthesis of Co2P2O7 nanorods as a promising pseudocapacitive material towards high-performance electrochemical capacitors
National Natural Science Foundation of China [51202004]; Natural Science Foundation of Anhui Province [KJ2013A051]In the present work, we developed an efficient one-step template-free strategy to fabricate intriguing one-dimensional (1D) Co2P2O7 nanorods (NRs) at room temperature, and utilized the unique monoclinic Co2P2O7 NRs as an excellent electrode material for high-performance pseudocapacitors using 3 M KOH as an electrolyte. Strikingly, the as-synthesized 1D Co2P2O7 NR electrode delivered a specific capacitance (SC) of 483 F g(-1) at 1 A g(-1), and even at 402 F g(-1) a high current loading of 10 A g(-1). And the SC retention of similar to 90% over continuous 3000 charge-discharge cycles at a current density of 6 A g(-1) confirmed its stable long-term cycling ability at high current density. More significantly, the underlying electrochemical energy-storage mechanism of the Co2P2O7 NR electrode in alkaline KOH aqueous solution was tentatively proposed. And the appealing strategy was proposed for future exploration and development of other low-cost pseudocapacitive materials for next-generation ECs