418 research outputs found
Self-Supervised Transformer with Domain Adaptive Reconstruction for General Face Forgery Video Detection
Face forgery videos have caused severe social public concern, and various
detectors have been proposed recently. However, most of them are trained in a
supervised manner with limited generalization when detecting videos from
different forgery methods or real source videos. To tackle this issue, we
explore to take full advantage of the difference between real and forgery
videos by only exploring the common representation of real face videos. In this
paper, a Self-supervised Transformer cooperating with Contrastive and
Reconstruction learning (CoReST) is proposed, which is first pre-trained only
on real face videos in a self-supervised manner, and then fine-tuned a linear
head on specific face forgery video datasets. Two specific auxiliary tasks
incorporated contrastive and reconstruction learning are designed to enhance
the representation learning. Furthermore, a Domain Adaptive Reconstruction
(DAR) module is introduced to bridge the gap between different forgery domains
by reconstructing on unlabeled target videos when fine-tuning. Extensive
experiments on public datasets demonstrate that our proposed method performs
even better than the state-of-the-art supervised competitors with impressive
generalization
Information-Theoretic Limits of Integrated Sensing and Communication with Correlated Sensing and Channel States for Vehicular Networks
In connected vehicular networks, it is vital to have vehicular nodes that are
capable of sensing about surrounding environments and exchanging messages with
each other for automating and coordinating purpose. Towards this end,
integrated sensing and communication (ISAC), combining both sensing and
communication systems to jointly utilize their resources and to pursue mutual
benefits, emerges as a new cost-effective solution. In ISAC, the hardware and
spectrum co-sharing leads to a fundamental tradeoff between sensing and
communication performance, which is not well understood except for very simple
cases with the same sensing and channel states, and perfect channel state
information at the receiver (CSIR). In this paper, a general point-to-point
ISAC model is proposed to account for the scenarios that the sensing state is
different from but correlated with the channel state, and the CSIR is not
necessarily perfect. For the model considered, the optimal tradeoff is
characterized by a capacity-distortion function that quantifies the best
communication rate for a given sensing distortion constraint requirement. An
iterative algorithm is proposed to compute such tradeoff, and a few non-trivial
examples are constructed to demonstrate the benefits of ISAC as compared to the
separation-based approach
Flow around an oscillating circular disk at low to moderate Reynolds numbers
Direct numerical simulations of the flow induced by a circular disk oscillating sinusoidally along its axis are performed. The aspect ratio of the disk is 10. The Reynolds number , based on the maximum speed and the diameter of the disk, is in the range of . The Keulegan-Carpenter number is in the range of . Five flow regimes are observed in the considered-space: (I) axisymmetric flow (AS), (II) planar symmetric flow in the low-region (PSL), (III) azimuthally rotating flow in the low-region (ARL), (IV) planar symmetric flow in the high-region (PSH) and (V) azimuthally rotating flow in the high-region (ARH). The critical boundaries between different flow regimes are identified based on the evolutions of the magnitude and direction of transverse force acting on the disk. For the non-axisymmetric flow regimes, the flow is one-sided with respect to the axis of the disk and is associated with a non-zero mean value of the transverse force acting on the disk
Release Profile of Nitrogen during Thermal Treatment of Waste Wooden Packaging Materials
In this paper, the fast pyrolysis experiment of particle board was carried out on a fixed bed reactor and a Py-GC/MS equipment. The effects of temperature and gas phase residence time on the product yields and its components distribution were investigated. The effect of components of particle board on product yields and its components distribution was also investigated. The results showed that the temperature has a great influence on the yields of fast pyrolysis products, and the yield of pyrolysis oil reached the highest at 550°C. The urea-formaldehyde resin would prevent the pyrolysis of particle board. Compared with the bio-oil from fast pyrolysis of wood, the major components of the bio-oil from fast pyrolysis of particle board did not change much
The dual actions, equivariant autoequivalences and stable tilting objects
For a finite abelian group action on a linear category, we study the dual
action given by the character group acting on the category of equivariant
objects. We prove that the groups of equivariant autoequivalences on these two
categories are isomorphic. In the triangulated situation, this isomorphism
implies that the classifications of stable tilting objects for these two
categories are in a natural bijection. We apply these results to stable tilting
complexes on weighted projective lines of tubular type.Comment: comments welcom
- …