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This paper presents our Facial Action Units (AUs) detection submission to the fifth Affective Behavior Analysis in-the-wild Competition (ABAW). Our approach consists of three main modules: (i) a pre-trained facial representation encoder which produce a strong facial representation from each input face image in the input sequence; (ii) an AU-specific feature generator that specifically learns a set of AU features from each facial representation; and (iii) a spatio-temporal graph learning module that constructs a spatio-temporal graph representation. This graph representation describes AUs contained in all frames and predicts the occurrence of each AU based on both the modeled spatial information within the corresponding face and the learned temporal dynamics among frames. The experimental results show that our approach outperformed the baseline and the spatio-temporal graph representation learning allows our model to generate the best results among all ablated systems. Our model ranks at the 4th place in the AU recognition track at the 5th ABAW Competition. Our code is publicly available at https://github.com/wzh125/ABAW-5.

Incommensurate structures arise from stacking single layers of low-dimensional materials on top of one another with misalignment such as an in-plane twist in orientation. While these structures are of significant physical interest, they pose many theoretical challenges due to the loss of periodicity. In this paper, we characterize the density of states of Schr\"{o}dinger operators in the weak sense for the incommensurate system and develop novel numerical methods to approximate them. In particular, we (i) justify the thermodynamic limit of the density of states in the real space formulation; and (ii) propose efficient numerical schemes to evaluate the density of states based on planewave approximations and reciprocal space sampling. We present both rigorous analysis and numerical simulations to support the reliability and efficiency of our numerical algorithms., Comment: 29 pages

Future air-ground integrated vehicular network (AGVN) is a vital part of the expected ubiquitous communication system. The resources in AGVN are geographically separated and are often heterogeneous. Therefore, distributed management and cooperative management are key issues in a multi-tier based topology of AGVN. Recently, artificial intelligence (AI) shows advantages in facilitating the management of AGVN; however, adequate, real-time, and secure information for driving AI is still a big concern. In this article, we propose a conceptual enhanced AGVN by introducing a so-called surveillance plane to promote the management in the control plane. Thus, components such as virtual network functions (VNFs) and service function chaining (SFC) can get profits. Concepts and trials of utilizing the surveillance plane and side information are presented from three different aspects, namely networking, security, and application. We also summarize research directions in designing a more flexible management scheme by coupling the service, surveillance, and control planes of the enhanced AGVN. © 2002-2012 IEEE.

This dissertation presents theoretical investigations of two novel functional materials, TlBr and MoS2. TlBr is interesting due to its potential application as a high-quality room temperature radiation detector. The stability and electronic structures of three phases of TlBr are studied using Density Functional Theorem (DFT) calculations employing a hybrid functional. The calculated band gaps from DFT with the hybrid functional are in excellent agreement with experimental measurements. The influence of some interstitial and substitutional dopants on TlBr properties is further studied. DFT predicts that interstitial and substitutional C, N, and O dopants in TlBr can display large, localized magnetic moments. A simple model that employs Pauli exclusion principle and group theory is introduced to explain the magnitude of the moments. Van der Waals (VDW) bonded, layered transition metal dichalcogenides (TMDCs) are promising 2D materials and have drawn much research attention recently. A theory for the epitaxial growth on the transition metal dichalcogenides is developed and analyzed. A prototypical example of Au epitaxially grown on MoS2 is studied. It is demonstrated that if one accounts for interfacial energies and strains, the presence of misfit dislocations, and the compliance of the MoS2 substrate, the experimentally observed growth orientation (Au {111} orientation) will be energetically favored. Meanwhile, with only the top substrate layer being compliant (strained), this epitaxy method can serve as a means to exfoliate and transfer large single layers sheets of MoS2. The exfoliation of monolayer based on this epitaxy idea has been realized experimentally. This epitaxy model could prove technologically useful in 2D electronic devices and in epitaxial thin film growth applications.

This dissertation presents theoretical investigations of two novel functional materials, TlBr and MoS2. TlBr is interesting due to its potential application as a high-quality room temperature radiation detector. The stability and electronic structures of three phases of TlBr are studied using Density Functional Theorem (DFT) calculations employing a hybrid functional. The calculated band gaps from DFT with the hybrid functional are in excellent agreement with experimental measurements. The influence of some interstitial and substitutional dopants on TlBr properties is further studied. DFT predicts that interstitial and substitutional C, N, and O dopants in TlBr can display large, localized magnetic moments. A simple model that employs Pauli exclusion principle and group theory is introduced to explain the magnitude of the moments. Van der Waals (VDW) bonded, layered transition metal dichalcogenides (TMDCs) are promising 2D materials and have drawn much research attention recently. A theory for the epitaxial growth on the transition metal dichalcogenides is developed and analyzed. A prototypical example of Au epitaxially grown on MoS2 is studied. It is demonstrated that if one accounts for interfacial energies and strains, the presence of misfit dislocations, and the compliance of the MoS2 substrate, the experimentally observed growth orientation (Au {111} orientation) will be energetically favored. Meanwhile, with only the top substrate layer being compliant (strained), this epitaxy method can serve as a means to exfoliate and transfer large single layers sheets of MoS2. The exfoliation of monolayer based on this epitaxy idea has been realized experimentally. This epitaxy model could prove technologically useful in 2D electronic devices and in epitaxial thin film growth applications.