1,293 research outputs found
Staffing under Taylor's Law: A Unifying Framework for Bridging Square-root and Linear Safety Rules
Staffing rules serve as an essential management tool in service industries to
attain target service levels. Traditionally, the square-root safety rule, based
on the Poisson arrival assumption, has been commonly used. However, empirical
findings suggest that arrival processes often exhibit an ``over-dispersion''
phenomenon, in which the variance of the arrival exceeds the mean. In this
paper, we develop a new doubly stochastic Poisson process model to capture a
significant dispersion scaling law, known as Taylor's law, showing that the
variance is a power function of the mean. We further examine how
over-dispersion affects staffing, providing a closed-form staffing formula to
ensure a desired service level. Interestingly, the additional staffing level
beyond the nominal load is a power function of the nominal load, with the power
exponent lying between (the square-root safety rule) and (the linear
safety rule), depending on the degree of over-dispersion. Simulation studies
and a large-scale call center case study indicate that our staffing rule
outperforms classical alternatives.Comment: 55 page
Learning to Simulate: Generative Metamodeling via Quantile Regression
Stochastic simulation models, while effective in capturing the dynamics of
complex systems, are often too slow to run for real-time decision-making.
Metamodeling techniques are widely used to learn the relationship between a
summary statistic of the outputs (e.g., the mean or quantile) and the inputs of
the simulator, so that it can be used in real time. However, this methodology
requires the knowledge of an appropriate summary statistic in advance, making
it inflexible for many practical situations. In this paper, we propose a new
metamodeling concept, called generative metamodeling, which aims to construct a
"fast simulator of the simulator". This technique can generate random outputs
substantially faster than the original simulation model, while retaining an
approximately equal conditional distribution given the same inputs. Once
constructed, a generative metamodel can instantaneously generate a large amount
of random outputs as soon as the inputs are specified, thereby facilitating the
immediate computation of any summary statistic for real-time decision-making.
Furthermore, we propose a new algorithm -- quantile-regression-based generative
metamodeling (QRGMM) -- and study its convergence and rate of convergence.
Extensive numerical experiments are conducted to investigate the empirical
performance of QRGMM, compare it with other state-of-the-art generative
algorithms, and demonstrate its usefulness in practical real-time
decision-making.Comment: Main body: 36 pages, 7 figures; supplemental material: 12 page
Virtual Group Learning Effectiveness via eLearning Mediums
Online learning provides the potential for more differentiated, integrated, and open learning environments to solve team project assignments. We argue that although it is feasible to increase information richness via adopting multimedia technologies, the effectiveness to promote interpersonal skills, critical thinking, and cognitive learning processes via virtual group discussion is uncertain. To substantiate the argument, we invited 156 subjects, divided into 46 groups, to resolve decision- and intellective-tasks in text-messaging and audio-conferencing e-learning environments. A pedagogical interpretation of how we can use these two e-learning systems to improve effectiveness for group-based tasks was posited
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FEE-BASED ONLINE SERVICES: EXPLORING CONSUMERS\u27 WILLINGNESS TO PAY
Many online service businesses are beginning to charge fees for services that they used to provide for free. It is unclear whether consumers are ready to embrace this practice. This study explores consumer attitudes toward fee-based online services. The results of the study indicate that consumers\u27 willingness to pay for online services is likely to be influenced by their perceived value of convenience these services provide, and by the extent to which they utilize these services. While consumers appear more willing to pay for services that are qualitatively better than free services, there is also indication that the belief remains strong among many that online services that were free in the past should remain free
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