Beijing University of Posts and Telecommunications

About: Beijing University of Posts and Telecommunications is a education organization based out in Beijing, Beijing, China. It is known for research contribution in the topics: MIMO & Quality of service. The organization has 39576 authors who have published 41525 publications receiving 403759 citations. The organization is also known as: BUPT.

Quantum-secret-sharing scheme based on local distinguishability of orthogonal multiqudit entangled states

Abstract: In this study, we propose the concept of judgment space to investigate the quantum-secret-sharing scheme based on local distinguishability (called LOCC-QSS). Because of the proposing of this conception, the property of orthogonal mutiqudit entangled states under restricted local operation and classical communication (LOCC) can be described more clearly. According to these properties, we reveal that, in the previous ($k,n$)-threshold LOCC-QSS scheme, there are two required conditions for the selected quantum states to resist the unambiguous attack: (i) their $k$-level judgment spaces are orthogonal, and (ii) their ($k\ensuremath{-}1$)-level judgment spaces are equal. Practically, if $kln$ (this is almost always true in the LOCC-QSS scheme), it is very difficult to satisfy the two conditions simultaneously. In the current study, we further establish a simple encoding method, which can concurrently ease the selection of quantum states and ensure the scheme's security, i.e., even if the ($k\ensuremath{-}1$)-level judgment spaces of the selected quantum states are not equal, these states can still be used for defeating the unambiguous attack. With this encoding method, we propose a more secure ($k,n$)-threshold LOCC-QSS scheme, and give two specific examples for illustration.

Particle Swarm Optimization for Energy-Aware Virtual Machine Placement Optimization in Virtualized Data Centers

Abstract: A critical research issue is to lower the energy consumption of a virtualized data center by means of virtual machine placement optimization while satisfying the resource requirements of the cloud services. In this paper, we focus on different existing schemes and on the energy-aware virtual machine placement optimization problem of a heterogeneous virtualized data center. We attempt to explore a better alternative approach to minimizing the energy consumption, and we observe that particle swarm optimization (PSO) has considerable potential. However, the PSO must be improved to solve an optimization problem. The improvement includes redefining the parameters and operators of the PSO, adopting an energy-aware local fitness first strategy and designing a novel coding scheme. Using the improved PSO, an optimal virtual machine replacement scheme with the lowest energy consumption can be found. Experimental results indicate that our approach significantly outperforms other approaches, and can lessen 13%-23% energy consumption in the context of this paper.

Enhanced dielectric properties and energy storage density of PVDF nanocomposites by co-loading of BaTiO 3 and CoFe 2 O 4 nanoparticles

Abstract: Dielectric polymer-based nanocomposites with high dielectric constant and energy density have attracted extensive attention in modern electronic and electrical applications. Core-satellite BaTiO3-CoFe2O4 (BT-CF) structures with a BT core of ~ 100 nm and CF satellites (~ 28 nm) on the surface of the BT particle were prepared. The dielectric properties and energy storage density of PVDF nanocomposites were enhanced by BT-CF heterostructures at a small loading of CF nanoparticles. Compared to the general adopted BT/PVDF composites, the dielectric constant can be effectively improved with no additional loss by introducing a small amount of CF nanoparticles to the BT/PVDF composite. Moreover, the energy density and efficiency of the BT/PVDF nanocomposites were also improved by the small loading of CF. The discharged energy density of the BT-CF/PVDF nanocomposites with 7 wt.% CF nanoparticles showed that the maximal energy density value is 5.60 J/cm3 at the electric field of 263 kV/mm. The results showed that the small amount of CF nanoparticles has beneficial effects on enhancing the dielectric constant and energy storage of the BT/PVDF nanocomposites.