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Real production applications ranging from enterprise applications to large e-commerce sites share a crucial but seldom-noted characteristic: The relative frequencies of transaction types in their workloads are <i>nonstationary</i>, i.e., the transaction mix changes over time. Accurately predicting application-level performance in business-critical(More)
— This work considers the problem of hosting multiple third-party Internet services in a cost-effective manner so as to maximize a provider's business objective. For this purpose, we present a dynamic capacity management framework based on an optimization model, which links a cost model based on SLA contracts with an analytical queuing-based performance(More)
This report documents two mathematical models for extracting the price-demand relationship, commonly known as t he demand function or demand curve, for consumer products using on-line auction bid data. The first model assumes that all bidding sequences are equally likely; the second model assumes that the bidders arrive in Poisson streams and utilizes the(More)
Messenger RNA coding for BNP precursor has been detected and mapped in histological sections of rat brain by in situ hybridization using specific rat BNP DNA probes labelled with 32P. The results showed that areas of highest concentration of BNP gene expression were located in the hypothalamus and in the verge area of the thalamus. Successively decreased(More)
Growing evidence suggests that oxidative stress is involved in the neuronal degeneration and can promote the aggregation of alpha-synuclein. However, the role of alpha-synuclein under physiological and pathological conditions remains poorly understood. In the present study, we examined the possible interaction between the alpha-synuclein and oxidative(More)
As Internet services become ubiquitous, the selection and management of diverse server platforms now affects the bottom line of almost every firm in every industry. Ideally, such cross-platform management would yield high performance at low cost, but in practice, the performance consequences of such decisions are often hard to predict. In this paper, we(More)
Restoring data operations after a disaster is a daunting task: how should recovery be performed to minimize data loss and application downtime? Administrators are under considerable pressure to recover quickly, so they lack time to make good scheduling decisions. They schedule recovery based on rules of thumb, or on pre-determined orders that might not be(More)
service level agreement, web performance tuning, software performance modeling, response time, queueing, optimization We present a nonlinear integer optimization model for determining the number of machines at each tier in a multi-tier server network. We utilize a result from an open queueing network model on the average response time; the optimization(More)
— Configuring virtual machine parameters in a virtualized server environment is a challenging task for IT operators. For instance, while current management products can dynamically size virtual machines in order to maintain resource utilization targets, default target values are rarely ideal for individual workloads and operators find it difficult to decide(More)