Minimizing the monetary penalty and energy cost of server migration service

Current IaaS (Infrastructure as a Service) cloud service may not satisfy communication QoS (Quality of Service) requirements of delay-sensitive network applications, if there is a significant physical distance between a server of the network application (NetApp server) at a data center and its network application clients (NetApp clients). In order to improve communication QoS of NetApp clients, we propose Server Migration Service (SMS) in this paper. SMS allowsNetApp servers to migrate among different locations in the network (1) to optimally locate themselves in relation to NetApp clients and mitigate the QoS degradation caused by location-related factors (i.e., propagation delays on network links) and (2) to optimally distribute traffic load over routers and processing load over (physical) computers and decrease the energy consumption. We develop a mixed-integer programming model that determines when and to which locations NetApp servers migrate to minimize the total operating cost of SMS, i.e., the sum of the monetary penalty incurred due to QoS violation and energy cost incurred due to energy consumption, while preventing NetApp servers from excessively migrating and adversely impacting QoS of the non-SMS service that share the resource of the substrate network with SMS. Simulation results show that the model developed in this paper achieves up to 42% lower total operating cost of SMS compared to the model that only minimizes the monetary penalty of SMS without considering the energy cost of SMS

Platinum nanosheets synthesized via topotactic reduction of single-layer platinum oxide nanosheets for electrocatalysis

2D metals are promising electrocatalysts due to their potentially large surface area. Here we report double-layer Pt nanosheets derived from exfoliated PtOx nanosheets with higher electrochemically active surface area, oxygen reduction reaction activity, and stability compared to Pt nanoparticles