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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)
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)
In this paper, we consider a queue whose service speed changes according to an external environment that is governed by a Markov process. It is possible that the server changes its service speed many times while serving a customer. We derive first and second moments of the service time of customers in system using first step analysis to obtain an insight on(More)
—We consider wireless networks in which multiple paths are available between each source and destination. We allow each source to split traffic among all of its available paths, and ask the question: how do we attain the lowest possible number of transmissions to support a given traffic matrix? Traffic bound in opposite directions over two wireless hops can(More)
It has been well established that wireless network coding can significantly improve the efficiency of multihop wireless networks. However, in a stochastic environment, some of the packets might not have coding pairs, which limits the number of available coding opportunities. In this context, an important decision is whether to delay packet transmission in(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)
To predict the delay between a source and a destination as well as to identify anomalies in a network, it is useful to continuously monitor the network by sending probes between all sources and destinations. It is of prime importance to reduce the number of probes drastically and yet be able to reasonably predict delays and identify anomalies. In this paper(More)
Scalability issues for routing in mobile ad hoc networks (MANETs) have been typically addressed using hybrid routing schemes operating in a hierarchical network architecture. Several clustering schemes have been proposed to dynamically identify and maintain hierarchy in MANETs. To achieve significant performance gains, it is important that the underlying(More)