Abstract—This paper presents data centers from a cyberphysical system (CPS) perspective. Current methods for controlling information technology (IT) and cooling technology (CT) in data centers are classified according to the degree to which they take into account both cyber and physical considerations. To evaluate the potential impact of coordinated CPS strategies at the data-center level, we introduce a control-oriented model that represents the data center as two coupled networks: a computational network representing the cyber dynamics and a thermal network representing the physical dynamics. These networks are coupled through the influence of the IT on both networks: servers affect both the quality of service (QoS) delivered by the computational network and the generation of heat in the thermal network. Using this model, three control strategies are evaluated with respect to their energy efficiency and computational performance: a baseline strategy that ignores CPS considerations, an uncoordinated strategy that manages the IT and CT independently, and a coordinated strategy that manages the IT and CT together to achieve optimal performance with respect to both QoS and energy efficiency. Simulation results show that the benefits to be realized from coordinating the control of IT and CT depend on the distribution and heterogeneity of the computational and cooling resources throughout the data center. A new cyber-physical index (CPI) is introduced as a measure of this combined distribution of cyber and physical effects in a given data center. We illustrate how the CPI indicates the potential impact of using coordinated CPS control strategies.

introduce novel statistical simulation approaches to include the effect of surface roughness in coupled mechanical, electronic and thermal processes in N/MEMS and semiconductor devices in the 10 nm- 1 µm range. A model is presented to estimate roughness rms ∆ and autocorrelation L from experimental surfaces and edges, and subsequently generate statistical series of rough geometrical devices from these observable parameters. Using such series of rough electrodes under Holm’s theory, we present a novel simulation framework which predicts a contact resistance of 80 mΩ in MEMS gold-gold micro-contacts, for applied pressures above 0.3 mN on 1 µm × 1 µm surfaces. The non-contacting state of such devices is simulated through statistical Monte Carlo iterations on percolative networks to derive a time to electro-thermal failure through electrical discharges in the gas insulating metal electrodes. The observable parameters L and ∆ are further integrated in semi-classical solutions to the electronic and thermal Boltzman transport equation (BTE), and we show roughness limited heat and electronic transport