Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Appropriate inspection and control are significant components of production systems. Many products are manufactured in multistage production lines. At each stage the process can produce defective units. In order to produce finished products with desired quality in an economical way, considerations must be given to the explicit costs of inspection, repair, processing and disposal associated with particular levels of control and inspection. In this dissertation models and solution techniques are developed for simultaneous selection of sampling inspection plans and manufacturing operations control levels within multistage production systems. Per unit expected minimum cost of output quality, which satisfies specified consumer's and producer's risks, is used as the optimization criterion. The solution techniques allow for solving models with non-linear cost functions. Three different models are developed for three different situations. A model for situations where the defective items are not repairable is considered first. This is followed by a model for situations where the defective items are repairable and the number of defects and the types of defects are significant factors in computing repair costs. In the third model the effect of inspection errors is considered. The solution techniques are based on the forward recursion of dynamic programming and a numerical search method. Computer programs for solving all three models are presented.