Inducing Effect on the Percolation Transition in Complex Networks

Percolation theory concerns the emergence of connected clusters that percolate through a networked system. Previous studies ignored the effect that a node outside the percolating cluster may actively induce its inside neighbours to exit the percolating cluster. Here we study this inducing effect on the classical site percolation and K-core percolation, showing that the inducing effect always causes a discontinuous percolation transition. We precisely predict the percolation threshold and core size for uncorrelated random networks with arbitrary degree distributions. For low-dimensional lattices the percolation threshold fluctuates considerably over realizations, yet we can still predict the core size once the percolation occurs. The core sizes of real-world networks can also be well predicted using degree distribution as the only input. Our work therefore provides a theoretical framework for quantitatively understanding discontinuous breakdown phenomena in various complex systems.Comment: Main text and appendices. Title has been change

Heterogeneous 360 Degree Videos in Metaverse: Differentiated Reinforcement Learning Approaches

Advanced video technologies are driving the development of the futuristic Metaverse, which aims to connect users from anywhere and anytime. As such, the use cases for users will be much more diverse, leading to a mix of 360-degree videos with two types: non-VR and VR 360-degree videos. This paper presents a novel Quality of Service model for heterogeneous 360-degree videos with different requirements for frame rates and cybersickness. We propose a frame-slotted structure and conduct frame-wise optimization using self-designed differentiated deep reinforcement learning algorithms. Specifically, we design two structures, Separate Input Differentiated Output (SIDO) and Merged Input Differentiated Output (MIDO), for this heterogeneous scenario. We also conduct comprehensive experiments to demonstrate their effectiveness.Comment: This paper appears in IEEE Global Communications Conference (GLOBECOM) 202

The origin of p-type conduction in (P, N) co-doped ZnO

P mono-doped and (P, N) co-doped ZnO are investigated by the first-principles calculations. It is found that substitutive P defect forms a deep acceptor level at O site (PO) and it behaves as a donor at Zn site (PZn), while interstitial P (Pi) is amphoteric. Under equilibrium conditions, these defects contribute little to the p-type conductivity of ZnO samples since the formation energy of PZn is much lower than that of Pi or PO when EF is below mid-gap (a prerequisite p-type condition). Zinc vacancies (VZn) and PZn-2VZn complex are demonstrated to be shallow acceptors with ionization energies around 100 meV, but they are easily compensated by PZn defect. Fortunately, PZn-4NO complexes may have lower formation energy than that of PZn under Zn rich condition by proper choices of P and N sources. In addition, the neutral PZn-3NO passive defects may form an impurity band right above the valence band maximum of ZnO as in earlier reported (Ga,N) or (Zr,N) doped ZnO. This significantly reduces the acceptor level of PZn-4NO complexes, and helps improving the p-type conductivity in ZnO.Comment: 25 pages, 7 figure