Improving operational effectiveness at vehicle inspection centres

Samah, AA

Abstract

In this research, operational problems at vehicle inspection centres (VIC) are explored
and investigated. Simulation is used in this new application area to improve operational
effectiveness at the VIC. In particular, simulation is used to gain insights, model the
interactions of operational activities and experiment with specific operational policies.
Critical input random variables corresponding to service times and arrival patterns are
modelled based upon empirical data collected at the VIC. Modelling the arrival process
involves a thorough analysis of separate patterns of arrival for scheduled and non-
scheduled vehicles at a typical VIC. Developing the most appropriate of several ideas,
we generate methods for simulating typical streams of arrivals at the VIC. For non-
scheduled arrivals, we adopt distinct beta distributions for morning and afternoon
activities. For scheduled arrivals, this research demonstrates that customer punctuality
varies according to planned appointment times, which leads to an adaptive model for
customer punctuality that takes account of these appointment times. Specifically, we
construct generalised beta distributions with parameters that evolve over time.
In this research, we integrate the design of experiments within our simulation model. In
particular, we propose a fractional factorial design matrix to replace traditional ways of
planning simulation experiments. Further work involves incorporating blocking into our
design matrix, which reduces the experimental size and provides a useful backup
support feature for our VIC simulation. The proposed design matrix is then used in the
output analysis along with other statistical methods, to determine factors that contribute
significantly to specific performance measures. In this study, general linear models that
link the control factors and the performance measures are developed.
A major contribution of this research is its impact on simulation modelling, which helps
us to characterize more realistic arrival patterns for customers compared with previous
research techniques. Additionally, aspects of our research that include experimental
design enrich the literature on simulation and modelling particularly in the application
of simulation to service shop problems.

Citation

Samah, A. Improving operational effectiveness at vehicle inspection centres. (Thesis). Salford : University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 3, 2012
• Award Date: Jan 1, 2010