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It is a bright day for you, as your new coatings formulation has been approved by a major prospect that you and your firm have been chasing for two years. [...]

An approach to matching the first three moments is presented for distributions with positive support and coefficient of variation greater than one Necessary and sufficient bounds are derived for the phase-type distribution defined by appending a Coxian stage to an Erlang distribution. This result is an extension of Altiok's use of a Coxian-2 distribution for 3-moment matching

An efficient algorithm for determining the optimal arrival schedule for customers in a stochastic service system is developed. All customers arrive exactly when scheduled, and service times are modeled as iid Erlang random variables. Costs are incurred at a fixed rate per unit of time each customer waits for service, and an additional cost is incurred for every unit of time the server operates beyond a scheduled closing time. The objective is to minimize total operating cost. This type of problem arises in many operational contexts including transportation, manufacturing, and appointment-based services. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 549–559, 1999

This article presents an approximate analytical method for evaluating an aircraft sortie generation process. The process is modeled as a closed network of multiserver queues and fork-join nodes that allow concurrent service activities. The model uses a variation of mean value analysis (MVA) to capture the effect of mean service times, resource levels, and network topology on performance measures including resource utilizations and the overall sortie generation rate. The quality of the analytical approximation is demonstrated through comparison with simulation results. © 1997 John Wiley & Sons, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America. Naval Research Logistics 44: 153–164, 1997

Studies were conducted to assess the effects of inducers of hepatic mixed function oxidases on DNA repair responses to 13 different genotoxic agents in hepatocytes from adult male mice. Phenobarbital pretreatment increased DNA repair elicited by diethylnitrosamine but had no effect on responses to the other compounds. Pretreatment with p,p'-dichlorodiphenyltrichloroethane, 3-methylcholanthrene or ß-naphthoflavone induced the DNA repair responses to a variety of activation-dependent carcinogens. DNA repair responses to the direct-acting alkylating agents methyl methanesulfonate and N-methyl-N'-nitro-N-nitrosoguanidine were not increased by any of the pretreatments, which indicated that the pretreatment-related enhancement of responses to the other compounds was due to induction of their metabolic activation. Taken together, the findings suggest that Aroclor, or other pretreatments, may increase the sensitivity of the hepatocyte DNA repair assay for detecting the genotoxicity of certain compounds; however, the potential benefit may be limited due to specific features of the assay. In contrast, Aroclor pretreatment did not produce any enhancement of in vivo DNA repair elicited by dimethylnitrosamine, diethylnitrosamine, o-aminoazotoluene, 2-acetylaminofluorene, 3-methylcholanthrene or aflatoxin B1, and thus does not appear to be useful for improving the sensitivity of the in vivo/in vitro assay.

The article reports on the developments in the activities of the Polk City Area Chamber in Iowa, including the staging of the Four Seasons Festival on July 20-21, 2012 and a 5-kilometer (km) run/walk event.

We synergistically apply queueing theory, integer programming, and stochastic simulation to determine an optimal staffing policy for a repair call handling center. A stationary Markovian queueing model is employed to determine minimal staffing levels for a sequence of time intervals with varying call volumes and mean handling times. These staffing requirements populate an integer program model for determining the mix of call agent shifts that will achieve service quality standards at minimum cost. Since the analytical modeling requires simplifying assumptions, expected performance of the optimal staffing policy is evaluated using stochastic simulation. Computational efficiency of the simulation is improved dramatically by employing the queueing model to generate an analytic control variate.