Max-Weight Revisited: Sequences of Non-Convex Optimisations Solving Convex Optimisations

We investigate the connections between max-weight approaches and dual subgradient methods for convex optimisation. We find that strong connections exist and we establish a clean, unifying theoretical framework that includes both max-weight and dual subgradient approaches as special cases. Our analysis uses only elementary methods, and is not asymptotic in nature. It also allows us to establish an explicit and direct connection between discrete queue occupancies and Lagrange multipliers.Comment: convex optimisation, max-weight scheduling, backpressure, subgradient method

Proportional Fair MU-MIMO in 802.11 WLANs

We consider the proportional fair rate allocation in an 802.11 WLAN that supports multi-user MIMO (MU-MIMO) transmission by one or more stations. We characterise, for the first time, the proportional fair allocation of MU-MIMO spatial streams and station transmission opportunities. While a number of features carry over from the case without MU-MIMO, in general neither flows nor stations need to be allocated equal airtime when MU-MIMO is available

Full Exploitation of Limited Memory in Quantum Entanglement Switching

We study the problem of operating a quantum switch with memory constraints. In particular, the switch has to allocate quantum memories to clients to generate link-level entanglements (LLEs), and then use these to serve end-to-end entanglements requests. The paper's main contributions are (i) to characterize the switch's capacity region, and (ii) to propose a memory allocation policy (MEW) that is throughput optimal. The worst-case time complexity of MEW is exponential on the system parameters. However, when the requests are bipartite and the LLE attempts are always successful, we propose a variant of MEW (MEW2) that has polynomial time complexity. We evaluate the proposed policies numerically and illustrate their performance depending on the requests arrivals characteristics and the time available to obtain a memory allocation

Is Leader Developing Behavior related to Employees' Health Complaints? A Multilevel Investigation

The goals of this study were to ascertain whether a specific leadership behavior (developing subordinates) is related to employees' health complaints and determine some of the underlying mechanisms involved. The hypothesized relationships were investigated in a sample composed of 538 employees working in 170 work-units of a public regional health service. Multilevel structural equation modeling was used to estimate the hypothesized relationships at the individual and work-unit levels. Results obtained at the individual level showed, as expected, that leader developing behavior was negatively related to employees' health complaints through two mediators: organizational commitment and emotional exhaustion. At the work-unit level, leader developing behavior was not related to employees' health complaints. Our findings uncover some of the mechanisms linking leader developing behavior and employees' health complaints at the individual level, show that the observed relationships cannot be generalized across levels, and have implications for the Job Demands-Resources theory