Minimization of VM Placement Change in Energy-Aware Resource Provisioning for Cloud Data Center

Numerous part of the energy-aware resource provision research for cloud data center just considers how to maximize the resource utilization, i.e. minimize the required servers, without considering the overhead of a virtual machine (abbreviated as a VM) placement change. In this work, we propose a new method to minimize the energy consumption and VM placement change at the same time, moreover we also design a network-flow-theory based approximate algorithm to solve it. The simulation results show that, compared to existing work, the proposed method can slightly decrease the energy consumption but greatly decrease the number of VM placement change

Can Stability in Out-of-Home Care Be Improved? An Analysis of Unplanned and Planned Placement Changes in Foster Care

This article presents the findings of a study of unplanned and planned placement changes in foster care programs designed for restoration or time-limited assessment for long-term care. In this study, the causes of placement changes in the program are analysed to assess whether stability could be improved. The study was undertaken by examining computer records of placement changes over a 6-year period, in five Temporary Family Care (TFC) programs. Once these changes were identified, social workers were asked to describe the circumstances of the placement change for each named child. These were then categorised into two groups: unplanned and planned placement changes. Unplanned changes are those that were not anticipated at initial entry to care, nor during scheduled case reviews. The frequency of unplanned changes was 2% of all placements; within this group of unplanned changes no child had more than two unplanned moves and only 0.6% of children had two unplanned changes. Planned placement changes were those changes considered as part of routine case decision-making according to the requirements of the ‘Looking After Children’ (LAC) system. These changes occurred in 4.5% of all planned placements. Some children experienced both planned and unplanned changes. The changes were then categorised according to the reasons for change. Some placement changes appeared unavoidable. This finding leads to questions about whether instability can ever be entirely eliminated. The TFC programs appear to have a lower rate of breakdown than that reported in the literature; however, variations in study design make comparisons difficult.