VM Consolidation Plan for Improving the Energy Efficiency of Cloud

Achieving energy-efficiency with minimal Service Level Agreement (SLA) violation constraint is a major challenge in cloud datacenters owing to financial and environmental concerns. The static consolidation of Virtual Machines (VMs) is not much significant in recent time and has become outdated because of the unpredicted workload of cloud users. In this paper, a dynamic consolidation plan is proposed to optimize the energy consumption of the cloud datacenter. The proposed plan encompasses algorithms for VM selection and VM placement. The VM selection algorithm estimates power consumption of each VM to select the required VMs for migration from the overloaded Physical Machine (PM). The proposed VM allocation algorithm estimates the net increase in Imbalance Utilization Value (IUV) and power consumption of a PM, in advance before allocating the VM. The analysis of simulation results suggests that the proposed dynamic consolidation plan outperforms other state of arts.

Variation in Micro-Pores During Dynamic Consolidation and Compression of Soft Marine Soil

In this study, to explore the microstructure deformation mechanism of marine soft marine soil under cyclic loading, we analyzed the dynamic properties of soft marine soil under cyclic loading via dynamic consolidation compression testing. Then, using Image-Pro Plus (IPP) 6.0 image analysis software, and according to the dynamic consolidation compression test results and the images from a scanning electron microscope (SEM), we determined the weakening effect of soft soils under different consolidation confining pressures, different cyclic stress ratios, and different over-consolidation ratios. After dynamic consolidation and compression, the pore structure of undisturbed soft marine soil tends to compact, the degree of soil particle fragmentation intensifies, small pores increase, large pores decrease, the pores become more regular, and the distribution of pores is directional. Subsequently, for undisturbed soft marine soil, the higher the consolidated confining pressure, cyclic dynamic stress ratio, and over-consolidation ratio, the greater the damage to the pore structure, and the more obvious the structural weakening effect exhibited under cyclic loading.

On the effects of pore water pressure buildup and dissipation on the seismic performance of a propped r.c. diaphragm wall in sand

The study concerns the analysis of a retaining structure composed by a couple of r.c. diaphragm walls propped at the crest in loose and medium-dense, variably saturated sand under seismic conditions. Fully coupled dynamic equilibrium conditions and pore water flow in the porous soil have been taken into account, in order to assess the effects that the development and subsequent dissipation of excess pore water pressures can have on the performance of such structures under seismic conditions. To this end, a series of simulations in which the saturated soil permeability is varied of about two orders of magnitude has been carried out, in order to consider different evolution rates for the dynamic consolidation process. The von Wolffersdorff hypoplastic model and the van Genuchten water retention equation have been used to describe the mechanical and hydraulic behavior of the sand. The results obtained in a large series of finite element simulations show a significant dependence of the seismic performance of the structure evaluated in terms of permanent rotations and structural loads, in view of the modern performance-based design criteria on the excess pore pressures buildup during the seismic shaking and on its dissipation with time. For the particular seismic input considered, neither fully drained nor fully undrained conditions can be considered applicable in most of the cases considered. In such conditions, the quantitative assessment of wall and soil displacements, pore water pressures and effective stress distributions within the soil requires necessarily the solution of a fully coupled, nonlinear dynamic consolidation problem.