This paper evaluates four mechanisms for providing service differentiation in IEEE 802.11 wireless LANs, the Point Coordinator Function (PCF) of IEEE 802.11, the Enhanced Distributed Coordinator Function (EDCF) of the proposed IEEE 802.11e extension to IEEE 802.11, Distributed Fair Scheduling (DFS), and Blackburst using the ns-2 simulator. The metrics used in the evaluation are throughput, medi...

We present an approach to wireless fair scheduling in a distributed architecture. Our scheme is based on a simple extension of wireline fair scheduling by compensation for lost capacity after the losses occur. In addition, the scheduler provides limited compensation for unused capacity. This provides an incentive for users of the location-dependent wireless channel to optimize their channel usa...

A fair scheduling algorithm accounting for the weight and execution time of tasks is critical in the Grid environment. The MTWCT (Minimize Total Weighted Completion Time) has been proved to minimize the total weighted completion time of a set of independent tasks in a processor, but it results in another problem that the response time of some tasks is far longer. To decrease the incidence of th...

Three of the great sources of meaning in life are the good, the true, and the beautiful, and I aim to make headway on the grand Enlightenment project of ascertaining what, if anything, they have in common. Concretely, if we take a (stereotypical) Mother Teresa, Mandela, Darwin, Einstein, Dostoyevsky, and Picasso, what might they share that makes it apt to deem their lives to have truly mattered...

We address the problem of fair scheduling of packets in Internet routers with input-queued (IQ) switches and unity speedup. Scheduling in IQ switches is formulated as tracking the behaviour of an outputqueued (OQ) switch that provides optimal performance. We present the notion of “lag” as a performance metric that measures the difference between a packet’s departure time in an IQ switch over th...

in a non cylindrical domain. This model, without the resistance represented for f(u), is a linearization of Kirchhoff’s equation for small vibrations of a stretched elastic string when the ends are variables, see Medeiros, Limaco, Menezes (2002). We employ a variant, due to Zuazua (1990b), of the Hilbert Uniqueness Method (HUM), idealized by Lions (1988a, b).

Weak fairness guarantees that continuously enabled actions are executed infinitely often. Strong fairness, on the other hand, guarantees that actions that are enabled infinitely often (but not necessarily continuously) are executed infinitely often. In this paper, we present a distributed algorithm for scheduling actions for execution. Assuming weak fairness for the execution of this algorithm,...

Despite the longstanding recognition of the importance of product assortment planning (PAP), existing literature has failed to provide satisfactory solutions to a great deal of problems that reside in this area of research. The issue of optimal assortment planning in the retail sector becomes even more important in periods of economic crisis, as retailers must adapt their product portfolios to ...