123 research outputs found
WM-NET: Robust Deep 3D Watermarking with Limited Data
The goal of 3D mesh watermarking is to embed the message in 3D meshes that
can withstand various attacks imperceptibly and reconstruct the message
accurately from watermarked meshes. Traditional methods are less robust against
attacks. Recent DNN-based methods either introduce excessive distortions or
fail to embed the watermark without the help of texture information. However,
embedding the watermark in textures is insecure because replacing the texture
image can completely remove the watermark. In this paper, we propose a robust
deep 3D mesh watermarking WM-NET, which leverages attention-based convolutions
in watermarking tasks to embed binary messages in vertex distributions without
texture assistance. Furthermore, our WM-NET exploits the property that
simplified meshes inherit similar relations from the original ones, where the
relation is the offset vector directed from one vertex to its neighbor. By
doing so, our method can be trained on simplified meshes(limited data) but
remains effective on large-sized meshes (size adaptable) and unseen categories
of meshes (geometry adaptable). Extensive experiments demonstrate our method
brings 50% fewer distortions and 10% higher bit accuracy compared to previous
work. Our watermark WM-NET is robust against various mesh attacks, e.g. Gauss,
rotation, translation, scaling, and cropping
Interaction of Phonons and Dirac Fermions on the Surface of Bi2Se3: A Strong Kohn Anomaly
We report the first measurements of phonon dispersion curves on the (001)
surface of the strong three-dimensional topological insulator Bi2Se3. The
surface phonon measurements were carried out with the aid of coherent helium
beam surface scattering techniques. The results reveal a prominent signature of
the exotic metallic Dirac fermion quasi-particles, including a strong Kohn
anomaly. The signature is manifest in a low energy isotropic convex dispersive
surface phonon branch with a frequency maximum of 1.8 THz, and having a
V-shaped minimum at approximately 2kF that defines the Kohn anomaly.
Theoretical analysis attributes this dispersive profile to the renormalization
of the surface phonon excitations by the surface Dirac fermions. The
contribution of the Dirac fermions to this renormalization is derived in terms
of a Coulomb-type perturbation model
p
We are concerned with the exponential stability problem of a class of nonlinear hybrid stochastic heat equations (known as stochastic heat equations with Markovian switching) in an infinite state space. The fixed point theory is utilized to discuss the existence, uniqueness, and pth moment exponential stability of the mild solution. Moreover, we also acquire the Lyapunov exponents by combining the fixed point theory and the Gronwall inequality. At last, two examples are provided to verify the effectiveness of our obtained results
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