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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Truncation rules in simulation analysis : effect of batch size, time scale and input distribution on the application of Schriber's rule

Baxter, Lori K. 04 June 1990 (has links)
The objective of many simulations is to study the steady-state behavior of a nonterminating system. The initial conditions of the system are often atypical because of the complexity of the system. Simulators often start the simulation with the system empty and idle, and truncate, or delete, some quantity of the initial observations to reduce the initialization bias. This paper studies the application of Schriber's truncation rule to a queueing model, and the effects of parameter selection. Schriber's rule requires the simulator to select the parameters of batch size, number of batches, and a measure of precision. In addition, Schriber's rule assumes the output is a time series of discrete observations. Previous studies of Schriber's rule have not considered the effect of variation in the time scale (time between observations). The performance measures for comparison are the mean squared error and the half-length of the confidence interval. The results indicate that the time scale and batch size are significant parameters, and that the number of batches has little effect on the output. A change in the distribution of service time did not alter the results. In addition, it was determined that multiple replicates should be used in establishing the truncation point instead of a single run, and the simulator should carefully consider the choice of time scale for the output series and the batch size. / Graduation date: 1991
2

Steady-state analysis in simulation : an application of Schriber's truncation rule to complex queueing systems

Saleh, Budiman 12 December 1991 (has links)
The objective of many steady-state simulations is to study the behavior of a nonterminating system with a peak load of infinite duration. Due to the complexity of the system, the initial conditions of the system are often atypical that often requires the simulators to start the system with the empty and idle conditions. Consequently, deletion of some initial observations is required to reduce the initialization bias induced by atypical initial conditions. This paper studies the application of Schriber's truncation rule to the complex queueing systems (specifically, the two-machine and three-machine tandem queueing system) and the effects of parameter selection (i.e. parameters batch size and time between observations) on performance measures. Based on the previous studies of Schriber's rule on the one-machine system, parameters batch count and tolerance are held constant. Mean-squared error and half length are used as measures of accuracy and interval precision in comparing the results. The results of both systems show that time between observations and batch size are significant parameters, and the recommendations for the two-machine system can be generalized for the three-machine system. Increasing the number of machines in the system from two to three requires a careful reduction in the value of time between observations. Besides, multiple replications should be used to minimize the extreme results in determining the steady-state mean number of entities and the truncation point. / Graduation date: 1992

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