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The growing cost of tuning and managing computer systems is leading to out-sourcing of commercial services to hosting centers. These centers provision thousands of dense servers within a relatively small real-estate in order to host the applications/services of different customers who may have been assured by a service-level agreement (SLA). Power(More)
We consider a fluid model of a system that handles multiple classes of traffic. The delay and cell-loss requirements of the different classes of traffic are generally widely different and are achieved by assigning different buffers for different classes, and serving them in a strict priority order. We use results from the effective bandwidth of the output(More)
Scheduling in large-scale parallel systems has been and continues to be an important and challenging research problem. Several key factors, including the increasing use of off-the-shelf clusters of workstations to build such parallel systems, have resulted in the emergence of a new class of scheduling strategies, broadly referred to as dynamic coscheduling.(More)
W e derive an analytical expression for the cumulative distribution function of travel time for a vehicle traversing a freeway link of arbitrary length. The vehicle's speed is assumed to be modulated by a random environment that can be modeled as a stochastic process. We first present a partial differential equation (PDE) describing the travel time(More)
In this paper, we consider time-varying multi-server queues with abandonment and retrials. For their performance analysis, fluid and diffusion limits utilizing strong approximations have been widely used in the literature. Although those limits are asymptotically exact, they may not accurately approximate performance of multi-server queues even if the(More)
—We consider a system where inelastic demand for electric power is met from three sources: the grid, in-house renewables such as wind turbines or solar panels, and an in-house energy storage device. In our setting, power demand, renewable power supply, and cost for grid power are all time-varying and stochastic. Further, there are limits and efficiency(More)
We consider the scenario where users access Next Generation Networks via Network Access Providers (NAP). We assume that users belong to N different classes and the bandwidth received by each class is determined by a user share differentiation (USD) scheme. According to USD, each class is guaranteed a minimum bandwidth and all users accepted into the NAP are(More)
One of the key concerns for practitioners and academicians is that there are almost no platforms based on analytical models for testing the impact of various architectural and design modifications for intelligent Network Interface Cards (NICs). Simulations are typically time-consuming, especially for experimenting different scenarios and what-if analysis.(More)
The noncentrosomal cortical microtubules (CMTs) of plant cells self-organize into a parallel three-dimensional (3D) array that is oriented transverse to the cell elongation axis in wild-type plants and is oblique in some of the mutants that show twisted growth. To study the mechanisms of CMT array organization, we developed a 3D computer simulation model(More)
Synthesizing I/O requests that can accurately capture workload behavior is extremely valuable for the design, implementation and optimization of disk subsystems. This paper presents a synthetic workload generator for TPC-H, an important decision-support commercial workload, by completely characterizing the arrival and access patterns of its queries. We(More)