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Zhaoli Zheng,Fahui Zhu,Di Zhang,Yonghui Xie 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.3
A generalized and efficient method is proposed in this paper for parametric response analysis of large-scale asymmetric rotor. If the bearings are anisotropic in asymmetric rotor, the motion of the rotor-bearing system will be governed by ordinary differential equations with periodically time-variant coefficients in both fixed and rotating frame. Response analysis of such parametric system can be attempted by assuming solution based on Hill’s method. If the number of degree of freedoms (DOFs) of the original model is N and the number of terms considered in the truncated assumed solution is m, for response analysis one has to solve a set of equations with (2m+1)N unknowns. Calculating this kind of equations requires a lot of computational costs, and the application of 3D finite element model will lead to greater computational costs. To avoid this costly approach, the fixed-interface component mode synthesis (CMS) is employed to form a reduced-order model (ROM). Although conventional CMS is adequate enough to make response analysis of largescale structures, an optimized scheme still needs to be developed for the response analysis of large-scale asymmetric rotor to achieve high efficiency and accuracy. The optimized scheme concerning a single substructure and multiple substructures are established respectively. Finally, the developed approach is validated through a simple model and a large-scale realistic two-pole generator rotor. And factors that influence the parametric response are investigated.
Traffic and QoS-Aware Base Station Sleeping Scheme in Heterogeneous Cellular Networks
Lin Xiao,Fahui Wu,Dingcheng Yang,Yutao Zhu,Jietong Liu 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.9
With the rapid development of cellular networks, wireless communication industry has brought huge energy consumption and becomes the major consumer of environmental degradation inevitably. Thus, it is undoubtedly that realizing the sustainable development of green wireless communication has become the primary goal of global information and communications technology industry. Particularly, in cellular networks, sleep mode applied to base station (BS) is an efficient way. According to the cell traffic intensity, BS switching off/on strategy can reduce power consumption of BS effectively with a pre-condition that the quality of service (QoS) of users must be ensured. In the heterogeneous cellular networks, we proposed a BS sleeping scheme based on the traffic load varying in each cell, which is able to optimize both energy efficiency and power consumption by a multi-objective optimization problem. Then a sub-optimal solution is obtained according to a heuristic algorithm. The simulation results verified that the proposed scheme can improve the network performance.