94 research outputs found
Learning Harmonic Molecular Representations on Riemannian Manifold
Molecular representation learning plays a crucial role in AI-assisted drug
discovery research. Encoding 3D molecular structures through Euclidean neural
networks has become the prevailing method in the geometric deep learning
community. However, the equivariance constraints and message passing in
Euclidean space may limit the network expressive power. In this work, we
propose a Harmonic Molecular Representation learning (HMR) framework, which
represents a molecule using the Laplace-Beltrami eigenfunctions of its
molecular surface. HMR offers a multi-resolution representation of molecular
geometric and chemical features on 2D Riemannian manifold. We also introduce a
harmonic message passing method to realize efficient spectral message passing
over the surface manifold for better molecular encoding. Our proposed method
shows comparable predictive power to current models in small molecule property
prediction, and outperforms the state-of-the-art deep learning models for
ligand-binding protein pocket classification and the rigid protein docking
challenge, demonstrating its versatility in molecular representation learning.Comment: 25 pages including Appendi
Parsing is All You Need for Accurate Gait Recognition in the Wild
Binary silhouettes and keypoint-based skeletons have dominated human gait
recognition studies for decades since they are easy to extract from video
frames. Despite their success in gait recognition for in-the-lab environments,
they usually fail in real-world scenarios due to their low information entropy
for gait representations. To achieve accurate gait recognition in the wild,
this paper presents a novel gait representation, named Gait Parsing Sequence
(GPS). GPSs are sequences of fine-grained human segmentation, i.e., human
parsing, extracted from video frames, so they have much higher information
entropy to encode the shapes and dynamics of fine-grained human parts during
walking. Moreover, to effectively explore the capability of the GPS
representation, we propose a novel human parsing-based gait recognition
framework, named ParsingGait. ParsingGait contains a Convolutional Neural
Network (CNN)-based backbone and two light-weighted heads. The first head
extracts global semantic features from GPSs, while the other one learns mutual
information of part-level features through Graph Convolutional Networks to
model the detailed dynamics of human walking. Furthermore, due to the lack of
suitable datasets, we build the first parsing-based dataset for gait
recognition in the wild, named Gait3D-Parsing, by extending the large-scale and
challenging Gait3D dataset. Based on Gait3D-Parsing, we comprehensively
evaluate our method and existing gait recognition methods. The experimental
results show a significant improvement in accuracy brought by the GPS
representation and the superiority of ParsingGait. The code and dataset are
available at https://gait3d.github.io/gait3d-parsing-hp .Comment: 16 pages, 14 figures, ACM MM 2023 accepted, project page:
https://gait3d.github.io/gait3d-parsing-h
Why Deep Surgical Models Fail?: Revisiting Surgical Action Triplet Recognition through the Lens of Robustness
Surgical action triplet recognition provides a better understanding of the
surgical scene. This task is of high relevance as it provides to the surgeon
with context-aware support and safety. The current go-to strategy for improving
performance is the development of new network mechanisms. However, the
performance of current state-of-the-art techniques is substantially lower than
other surgical tasks. Why is this happening? This is the question that we
address in this work. We present the first study to understand the failure of
existing deep learning models through the lens of robustness and explainabilty.
Firstly, we study current existing models under weak and strong
perturbations via adversarial optimisation scheme. We then provide the
failure modes via feature based explanations. Our study revels that the key for
improving performance and increasing reliability is in the core and spurious
attributes. Our work opens the door to more trustworthiness and reliability
deep learning models in surgical science
Measuring Perceptual Color Differences of Smartphone Photographs
Measuring perceptual color differences (CDs) is of great importance in modern
smartphone photography. Despite the long history, most CD measures have been
constrained by psychophysical data of homogeneous color patches or a limited
number of simplistic natural photographic images. It is thus questionable
whether existing CD measures generalize in the age of smartphone photography
characterized by greater content complexities and learning-based image signal
processors. In this paper, we put together so far the largest image dataset for
perceptual CD assessment, in which the photographic images are 1) captured by
six flagship smartphones, 2) altered by Photoshop, 3) post-processed by
built-in filters of the smartphones, and 4) reproduced with incorrect color
profiles. We then conduct a large-scale psychophysical experiment to gather
perceptual CDs of 30,000 image pairs in a carefully controlled laboratory
environment. Based on the newly established dataset, we make one of the first
attempts to construct an end-to-end learnable CD formula based on a lightweight
neural network, as a generalization of several previous metrics. Extensive
experiments demonstrate that the optimized formula outperforms 33 existing CD
measures by a large margin, offers reasonable local CD maps without the use of
dense supervision, generalizes well to homogeneous color patch data, and
empirically behaves as a proper metric in the mathematical sense. Our dataset
and code are publicly available at https://github.com/hellooks/CDNet.Comment: 10 figures, 8 tables, 14 page
Traceable Identity-Based Group Signature
Group signature is a useful cryptographic primitive, which makes every group member sign
messages on behalf of a group they belong to. Namely group signature allows that group
member anonymously signs any message without revealing his/her specific identity. However,
group signature may make the signers abuse their signing rights if there are no measures
of keeping them from abusing signing rights in the group signature schemes. So, group
manager must be able to trace (or reveal) the identity of the signer by the signature when
the result of the signature needs to be arbitrated, and some revoked group members must
fully lose their capability of signing a message on behalf of the group they belong to. A
practical model meeting the requirement is verifier-local revocation, which supports the
revocation of group member. In this model, the verifiers receive the group member
revocation messages from the trusted authority when the relevant signatures need to be
verified. With the rapid development of identity-based cryptography, several
identity-based group signature (IBGS) schemes have been proposed. Compared with group
signature based on public key cryptography, IBGS can simplify key management and be used
for more applications. Although some identity-based group signature schemes have been
proposed, few identity-based group signature schemes are constructed in the standard model
and focus on the traceability of signature. In this paper, we present a fully traceable
(and verifier-local revocation) identity-based group signature (TIBGS) scheme, which has a
security reduction to the computational Diffie–Hellman (CDH) assumption. Also, we give a
formal security model for traceable identity-based group signature and prove that the
proposed scheme has the properties of traceability and anonymity
Realization of high-dynamic-range broadband magnetic-field sensing with ensemble nitrogen-vacancy centers in diamond
We present a new magnetometry method integrating an ensemble of
nitrogen-vacancy (NV) centers in a single-crystal diamond with an extended
dynamic range for monitoring the fast changing magnetic-field. The NV-center
spin resonance frequency is tracked using a closed-loop frequency locked
technique with fast frequency hopping to achieve a 10 kHz measurement
bandwidth, thus, allowing for the detection of fast changing magnetic signals
up to 0.723 T/s.This technique exhibits an extended dynamic range subjected to
the working bandwidth of the microwave source. This extended dynamic range can
reach up to 4.3 mT, which is 86 times broader than the intrinsic dynamic range.
The essential components for NV spin control and signal processing such as
signal generation, microwave frequency control, data processing and readout are
integrated in a board-level system. With this platform, we demonstrate
broadband magnetometry with an optimized sensitivity of 4.2 nT-Hz-1/2. This
magnetometry method has the potential to be implemented in a multichannel
frequency locked vector magnetometer suitable for a wide range of practical
applications such as magnetocardiography and high-precision current sensors.Comment: 18 pages, 9 figure
MammoDG: Generalisable Deep Learning Breaks the Limits of Cross-Domain Multi-Center Breast Cancer Screening
Breast cancer is a major cause of cancer death among women, emphasising the
importance of early detection for improved treatment outcomes and quality of
life. Mammography, the primary diagnostic imaging test, poses challenges due to
the high variability and patterns in mammograms. Double reading of mammograms
is recommended in many screening programs to improve diagnostic accuracy but
increases radiologists' workload. Researchers explore Machine Learning models
to support expert decision-making. Stand-alone models have shown comparable or
superior performance to radiologists, but some studies note decreased
sensitivity with multiple datasets, indicating the need for high generalisation
and robustness models. This work devises MammoDG, a novel deep-learning
framework for generalisable and reliable analysis of cross-domain multi-center
mammography data. MammoDG leverages multi-view mammograms and a novel
contrastive mechanism to enhance generalisation capabilities. Extensive
validation demonstrates MammoDG's superiority, highlighting the critical
importance of domain generalisation for trustworthy mammography analysis in
imaging protocol variations
Bypass transition in a boundary layer flow induced by plasma actuators
Bypass transition in ow over a at plate triggered by a pair of Dielectric-barrier-discharge (DBD) plasma actuators mounted on the plate surface and aligned in the streamwise direction is investigated. A 4-species plasma-uid model is used to model the electrohydrodynamic (EHD) force generated by the plasma actuation. A pair of counter-rotating streamwise vortices is created downstream of the actuators, leading to the formation of a high-speed streak in the centre and two low-speed streaks on each side. As the length of actuators increases, more momentum is added to the boundary layer and eventually a turbulent wedge is generated at an almost fixed location. With large spanwise distance between the actuators (wide layout), direct numerical simulations (DNS) indicate that the low-speed streaks on both sides lose secondary stability via an inclined varicose-like mode simultaneously, leaving a symmetric perturbation pattern with respect to the centre of the actuators. Further downstream, the perturbations are tilted by the mean shear of the high- and low-speed streaks and consequently a `W' shape pattern is observed. When the pair of plasma actuators is placed closer (narrow layout) in the spanwise direction, the mean shear in the centre becomes stronger and secondary instability first occurs on the high-speed streak with an asymmetric pattern. Inclined varicose-like and sinuous-like instabilities coexist in the following breakdown of the negative streaks on the side and the perturbations remain asymmetric with respect to the centre. Here the tilting of disturbances is dominated by the mean shear in the centre and the perturbations display a `V' shape. Linear analysis techniques including biglobal stability and transient growth are performed to further examine the uid physics and the aforementioned phenomena at narrow and wide layouts, such as the secondary instabilities, `V' and `W' shapes, the symmetric and asymmetric breakdown, are all observed
- …