Whitt Ward

Ward Whitt

Information about the author Ward Whitt will soon be added to the site.
Found 104 papers in total
Fluid models for multiserver queues with abandonments
Fluid models for multiserver queues with abandonments
2006
Deterministic fluid models are developed to provide simple first-order performance...
Sensitivity of performance in the Erlang-A queueing model to changes in the model parameters
Sensitivity of performance in the Erlang-A queueing model to changes in the model parameters
2006
This paper studies the M/M/s+M queue, i.e., the M/M/s queue with customer...
Efficiency-driven heavy-traffic approximations for many-server queues with abandonments
Efficiency-driven heavy-traffic approximations for many-server queues with abandonments
2004
To provide useful practical insight into the performance of service-oriented...
A diffusion approximation for the G/GI/n/m queue
A diffusion approximation for the G/GI/n/m queue
2004
We develop a diffusion approximation for the queue-length stochastic process in the...
Engineering solution of a basic call-center model
Engineering solution of a basic call-center model
2005
An algorithm is developed to rapidly compute approximations for all the standard...
Heavy-traffic limits for the G/H2*/n/m queue
Heavy-traffic limits for the G/H2*/n/m queue
2005
We establish heavy-traffic stochastic-process limits for queue-length, waiting-time...
Two fluid approximations for multi-server queues with abandonments
Two fluid approximations for multi-server queues with abandonments
2005
Insight is provided into a previously developed M/M/s/r+M(n) approximation for...
Decomposition approximations for time-dependent Markovian queueing networks
Decomposition approximations for time-dependent Markovian queueing networks
1999
Motivated by the development of complex telephone call center networks, we present a...
Dynamic staffing in a telephone call center aiming to immediately answer calls
Dynamic staffing in a telephone call center aiming to immediately answer calls
1999
This paper proposes practical modeling and analysis methods to facilitate dynamic...
How multiserver queues scale with growing congestion-dependent demand
How multiserver queues scale with growing congestion-dependent demand
2003
We investigate how performance scales in the standard M/M/n queue in the presence of...
The reflection map with discontinuities
The reflection map with discontinuities
2001
We study the multidimensional reflection map on the spaces D([0, T], ℝ...
An overview of Brownian and non-Brownian FCLTs for the single-server queue
An overview of Brownian and non-Brownian FCLTs for the single-server queue
2000
We review functional central limit theorems (FCLTs) for the queue-content process in a...
The impact of a heavy-tailed service-time distribution upon the M/GI/s waiting-time distribution
The impact of a heavy-tailed service-time distribution upon the M/GI/s waiting-time distribution
2000
By exploiting an infinite-server-model lower bound, we show that the tails of the...
Explicit M/G/1 waiting-time distributions for a class of long-tail service-time distributions
Explicit M/G/1 waiting-time distributions for a class of long-tail service-time distributions
1999
O.J. Boxma and J.W. Cohen recently obtained an explicit expression for the M/G/1...
Linear stochastic fluid networks
Linear stochastic fluid networks
1999
We introduce open stochastic fluid networks that can be regarded as continuous...
An overview of Brownian and non-Brownian FCLTs for the single-server queue
An overview of Brownian and non-Brownian FCLTs for the single-server queue
2000
We review functional central limit theorems (FCLTs) for the queue-content process in a...
The impact of a heavy-tailed service-time distribution upon the M/G/s waiting-time distribution
The impact of a heavy-tailed service-time distribution upon the M/G/s waiting-time distribution
2000
By exploiting an infinite-server-model lower bound, we show that the tails of the...
Computing Laplace transforms for numerical inversion via continued fractions
Computing Laplace transforms for numerical inversion via continued fractions
1999
It is often possible to effectively calculate probability density functions (pdfs) and...
Variance reduction in simulations of loss models
Variance reduction in simulations of loss models
1999
We propose a new estimator of steady-state blocking probabilities for simulations of...
Partitioning customers into service groups
Partitioning customers into service groups
1999
We explore the issues of when and how to partition arriving customers into service...
Exponential approximations for tail probabilities in queues. 2. Sojourn time and workload
Exponential approximations for tail probabilities in queues. 2. Sojourn time and workload
1996
We continue to focus on simple exponential approximations for steady-state tail...
Stationary-process approximations for the nonstationary Erlang loss model
Stationary-process approximations for the nonstationary Erlang loss model
1996
In this paper we consider the M(t)/G/s/0 model, which has s servers in parallel, no...
Numerical solution of piecewise-stationary Mt/G(t)/1 queues
Numerical solution of piecewise-stationary Mt/G(t)/1 queues
1997
We develop an algorithm for computing the (exact) cumulative distribution function of...
Using different response-time requirements to smooth time-varying demand for service
Using different response-time requirements to smooth time-varying demand for service
1999
Many service systems have demand that varies significantly by time of day, making it...
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